Imaging Diagnosis and Biomarkers

Chapter 3

Abstract

1. Background

43

Cumulative Mild Head Injury

The effect of cumulative mild head injury (CMHI) in contact sports such as rugby union and football (soccer) is seen at all levels as more concussive injuries are reported each year globally and in South Africa. This is problematic as repeated concussions may lead to cognitive deficits in attention and poorer overall cognitive profiles both in the short and long term. The aim of this chapter is to present a brief review of research on CMHI in football and rugby and other sports (briefly) both international and South African underpinned by an overview of the anatomy and neuroanatomy of the brain to illustrate the mechanisms involved in head injuries.

Concussions, described as a traumatically induced disturbance of brain function involving complex pathophysiological processes, are a major concern in a number of contact and collision sports. Multiple concussions can be referred to as cumulative mild head injury (CMHI), and are problematic particularly if athletes have competed from a very young age. There is a concern about the sequelae of repeated

Rugby union and football are examples of designated contact sports where this occurs as a result of collision injuries and in football because of repeated heading of the ball [2]. Rugby union (hereafter referred to as rugby) players (both backs and forwards) are involved in tackling where head to head, head to body or head to

Various kinds of head injury occur ranging from severe to mild. Traumatic Brain Injury (TBI) refers to a catastrophic event in which a closed or open head-injury results in serious neural damage which causes permanent cognitive damage [4]. Lack of oxygen to the brain (anoxia) and Cerebrovascular Accidents (CVAs), com-

This chapter focuses on CMHI in the contact sports soccer (hereafter referred to as football) and rugby union (rugby). A description of CMHI will be undertaken however, in order to contextualise this properly TBI and MHI (sometimes called Mild Traumatic Brain Injury—MTBI) will be described. After this a brief review of research, referring to international studies generally and South African studies in particular will be undertaken with specific reference to those involving the author(s).

(CMHI) in Contact Sports

Kathryn Nel and Saraswathie Govender

Risk factors for all types of MHI are also given.

Keywords: rugby (union), football (soccer), concussion

concussions which has gained prominence in sports psychology [1].

ground impact occurs also resulting in concussive injury [3].

monly called 'strokes,' also fall under TBIs.

#### Chapter 3

## Cumulative Mild Head Injury (CMHI) in Contact Sports

Kathryn Nel and Saraswathie Govender

#### Abstract

The effect of cumulative mild head injury (CMHI) in contact sports such as rugby union and football (soccer) is seen at all levels as more concussive injuries are reported each year globally and in South Africa. This is problematic as repeated concussions may lead to cognitive deficits in attention and poorer overall cognitive profiles both in the short and long term. The aim of this chapter is to present a brief review of research on CMHI in football and rugby and other sports (briefly) both international and South African underpinned by an overview of the anatomy and neuroanatomy of the brain to illustrate the mechanisms involved in head injuries. Risk factors for all types of MHI are also given.

Keywords: rugby (union), football (soccer), concussion

#### 1. Background

Concussions, described as a traumatically induced disturbance of brain function involving complex pathophysiological processes, are a major concern in a number of contact and collision sports. Multiple concussions can be referred to as cumulative mild head injury (CMHI), and are problematic particularly if athletes have competed from a very young age. There is a concern about the sequelae of repeated concussions which has gained prominence in sports psychology [1].

Rugby union and football are examples of designated contact sports where this occurs as a result of collision injuries and in football because of repeated heading of the ball [2]. Rugby union (hereafter referred to as rugby) players (both backs and forwards) are involved in tackling where head to head, head to body or head to ground impact occurs also resulting in concussive injury [3].

Various kinds of head injury occur ranging from severe to mild. Traumatic Brain Injury (TBI) refers to a catastrophic event in which a closed or open head-injury results in serious neural damage which causes permanent cognitive damage [4]. Lack of oxygen to the brain (anoxia) and Cerebrovascular Accidents (CVAs), commonly called 'strokes,' also fall under TBIs.

This chapter focuses on CMHI in the contact sports soccer (hereafter referred to as football) and rugby union (rugby). A description of CMHI will be undertaken however, in order to contextualise this properly TBI and MHI (sometimes called Mild Traumatic Brain Injury—MTBI) will be described. After this a brief review of research, referring to international studies generally and South African studies in particular will be undertaken with specific reference to those involving the author(s). Nonetheless, international studies on rugby, football and other contact sports are included. It must be noted that this is a complex topic which, cannot be covered comprehensively in a chapter, thus it is a contextual overview of the subject.

#### 1.1 Head injury

Traumatic Brain Injury (TBI) is a catastrophic brain injury. The vast majority of TBIs are closed meaning that the brain is not exposed (the skull is not opened). Closed head injuries (CHIs) are usually called blunt head trauma injuries. This means that the skull can have a fracture but the injury is still closed. Penetrating head injuries (PHIs) are referred to as open head injuries. PHI can include injuries from any source in which the skull and dura are penetrated. The term TBI also encompasses other aetiologies for instance, CVAs (cerebrovascular accidents or strokes) and lack of oxygen to the brain (anoxia) which can be catastrophic [4].

#### 1.2 Frontal lobes of the brain

The frontal lobes of the brain are very vulnerable to damage because of their position (at the front of the head = forehead). Damage to these lobes can be caused by illness (for instance, viral meningitis) or any kind of head injury from a blow to the head caused by a fall, being hit with an object or repeated blows to the head (for instance, in a sport such as boxing). A blow to another part of the head can also cause damage to the frontal lobes of the brain. This happens because the brain is not attached to the inside of the skull and moves around when a head injury is incurred. When the skull hits the back of the head the brain moves and hits the bony protuberances in the skull. This causes bruising (or bleeding) in the brain from slight to catastrophic, depending on the force of the blow to the skull [4, 5]. Figure 1 is used to illustrate where the frontal lobes of the brain lie illustrating their larger size, which makes them vulnerable to damage from multiple contexts for instance, MVAs (Motor Vehicle Accidents), to illness (Meningitis) and/or sporting injuries (Concussion and CMHIs).

#### 1.3 Open head injury

An open head injury occurs when the skull is penetrated by force which results in a perforated skull [5]. Damage that is incurred is usually in the pathway of the foreign object which often results in the exposure of the intra-dural contents of the brain [6]. Damage may occur because of tangential injuries when something strikes the skull and bone fragments are driven into the brain. These objects may pass through the brain or become embedded in it for instance, bullets causing either/or entrance and exit wounds [5]. There is specific neurological symptomology associated with different types of wounds in this regard [7]. For instance, severe scalp wounds resulting in loss-of-blood may cause low blood pressure (hypotension) and gunshot wounds can cause severe bruises in the brain (contusions) particularly where the enter and leave the skull (countercoup sites). The brain swells and fill with blood and intracranial haematomas can occur [4–6] (Figure 2).

occurs in MVAs when a fast moving vehicle stops suddenly which can cause anything from mild to massive brain trauma. However, repeated blows to the head in sport can cause mild brain injury (CMHI) which can be chronic rather than acute

Mild head injury (MHI) and its effects are controversial particularly with regard to definition and classification. For instance, the classification of mild to moderate head injuries is problematic in the research field [11]. MHI refers to an injury in which loss of consciousness (LOC) and/or Post Traumatic Amnesia (PTA) is quite brief and where there is no pathology (or noticeable injury) to the skull [12]. Criterion used to define MHI is underpinned by states of consciousness defined by the Glasgow Coma Scale (GCS) [13]. Problematically, when these are used to define CMHI or MHIs they are unreliable. A classification of MHI in terms of a LOC lasting 30 minutes or less, which is not linked to more neurological

A broader definition of MHI includes different grades of injury and: (a) any period of LOC for less than 30 minutes, with GCS of 13–15 following the LOC; (b) any loss of memory for events immediately before or after the accident with

and, as a result, the injury effects may not be noticed [9, 10] (Figure 3).

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

1.5 Mild head injury (MHI)

Figure 1. Lobes of the brain.

45

symptomology, is often used [14].

#### 1.4 Closed head injury

There are various causes of closed-head injury however, the most common cause is when the skull is injured and the brain suffers acceleration or deceleration and/or both [8]. This can happen in sport for instance, when the skull is hit by something moving quickly such as ball or bat of some kind. This type of accident commonly

Figure 1. Lobes of the brain.

Nonetheless, international studies on rugby, football and other contact sports are included. It must be noted that this is a complex topic which, cannot be covered comprehensively in a chapter, thus it is a contextual overview of the subject.

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

Traumatic Brain Injury (TBI) is a catastrophic brain injury. The vast majority of TBIs are closed meaning that the brain is not exposed (the skull is not opened). Closed head injuries (CHIs) are usually called blunt head trauma injuries. This means that the skull can have a fracture but the injury is still closed. Penetrating head injuries (PHIs) are referred to as open head injuries. PHI can include injuries from any source in which the skull and dura are penetrated. The term TBI also encompasses other aetiologies for instance, CVAs (cerebrovascular accidents or strokes) and lack of oxygen to the brain (anoxia) which can be catastrophic [4].

The frontal lobes of the brain are very vulnerable to damage because of their position (at the front of the head = forehead). Damage to these lobes can be caused by illness (for instance, viral meningitis) or any kind of head injury from a blow to the head caused by a fall, being hit with an object or repeated blows to the head (for instance, in a sport such as boxing). A blow to another part of the head can also cause damage to the frontal lobes of the brain. This happens because the brain is not attached to the inside of the skull and moves around when a head injury is incurred. When the skull hits the back of the head the brain moves and hits the bony protuberances in the skull. This causes bruising (or bleeding) in the brain from slight to catastrophic, depending on the force of the blow to the skull [4, 5]. Figure 1 is used to illustrate where the frontal lobes of the brain lie illustrating their larger size, which makes them vulnerable to damage from multiple contexts for instance, MVAs (Motor Vehicle Accidents), to illness (Meningitis) and/or sporting injuries

An open head injury occurs when the skull is penetrated by force which results in a perforated skull [5]. Damage that is incurred is usually in the pathway of the foreign object which often results in the exposure of the intra-dural contents of the brain [6]. Damage may occur because of tangential injuries when something strikes the skull and bone fragments are driven into the brain. These objects may pass through the brain or become embedded in it for instance, bullets causing either/or entrance and exit wounds [5]. There is specific neurological symptomology associated with different types of wounds in this regard [7]. For instance, severe scalp wounds resulting in loss-of-blood may cause low blood pressure (hypotension) and gunshot wounds can cause severe bruises in the brain (contusions) particularly where the enter and leave the skull (countercoup sites). The brain swells and fill

There are various causes of closed-head injury however, the most common cause is when the skull is injured and the brain suffers acceleration or deceleration and/or both [8]. This can happen in sport for instance, when the skull is hit by something moving quickly such as ball or bat of some kind. This type of accident commonly

with blood and intracranial haematomas can occur [4–6] (Figure 2).

1.1 Head injury

1.2 Frontal lobes of the brain

(Concussion and CMHIs).

1.3 Open head injury

1.4 Closed head injury

44

occurs in MVAs when a fast moving vehicle stops suddenly which can cause anything from mild to massive brain trauma. However, repeated blows to the head in sport can cause mild brain injury (CMHI) which can be chronic rather than acute and, as a result, the injury effects may not be noticed [9, 10] (Figure 3).

#### 1.5 Mild head injury (MHI)

Mild head injury (MHI) and its effects are controversial particularly with regard to definition and classification. For instance, the classification of mild to moderate head injuries is problematic in the research field [11]. MHI refers to an injury in which loss of consciousness (LOC) and/or Post Traumatic Amnesia (PTA) is quite brief and where there is no pathology (or noticeable injury) to the skull [12]. Criterion used to define MHI is underpinned by states of consciousness defined by the Glasgow Coma Scale (GCS) [13]. Problematically, when these are used to define CMHI or MHIs they are unreliable. A classification of MHI in terms of a LOC lasting 30 minutes or less, which is not linked to more neurological symptomology, is often used [14].

A broader definition of MHI includes different grades of injury and: (a) any period of LOC for less than 30 minutes, with GCS of 13–15 following the LOC; (b) any loss of memory for events immediately before or after the accident with

#### Figure 2. Schematic diagram of an open head injury.

PTA of less than 24 hours; (c) any alteration in mental state at the time of the accident (for instance, double vision, loss of balance, taste or smell) that may or may not be transient [11].

difficult resulted in guidelines for cerebral concussion [21]. Grade 1 (mild) = transient confusion; no loss of consciousness with symptoms resolving in 15 minutes or less: Grade 2 (moderate) = transient confusion, no loss of consciousness and symptoms lasting longer than 15 minutes and lastly, Grade 3 (severe): any loss of con-

The authors in this chapter often use terms like concussion, mild head injury (MHI), mild traumatic brain injury (MBTI) and cumulative mild head injury (CMHI) interchangeably as in the sporting arena to all intent and purpose they often refer to the same thing depending on the sporting code and/or country the

At the first International Conference of Concussion it was stated that concussion was a complex pathophysiological caused by biochemical forces impacting on the brain [23]. The definition included the following concussion: (1) may be caused by a blow to the head face, neck, or elsewhere with force that is transferred to the brain; (2) characteristically causes the speedy onset of brief impairment of neurological functions that resolve spontaneously; (3) results in neuropathological changes however, acute clinical symptomology reflects functional disturbances as opposed to structural injury; (4) is a set of clinical syndromes that sometimes (but not always) involves a LOC. Symptomology is resolved following a specific sequence and (5) it is characteristically associated with fundamentally normal structural neuroimaging. A later addition to this was that in some cases post-concussive symptoms can be protracted and persistent [19]. It is used to refer to a closed, MHI such as those incurred by athletes who play contact sports. It falls within the ambit

sciousness (brief or prolonged) [22].

Schematic representation of a closed head injury.

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

injury.

47

Figure 3.

#### 1.6 Cumulative mild head injury (CMHI)

There is increasing evidence that CMHI can cause more neuropsychological impairment as a result of neural attrition, which can cause athletes problems later in life [15]. Cumulative damage to hippocampal cells can cause cognitive damage [16]. Moreover, CMHI which occurs over months or years is likely to cause neurological and cognitive deficits [17]. The effects of MHI and concussions in the sporting arena are likely cumulative which has significant implications for athletes who play contact sports where concussion and CMHI occur frequently [18, 19]. Research suggests that permanent cognitive deficits are increasing as a result of CMHI [20].

#### 1.7 Concussive injuries (Concussion)

Concussion is any head injury which causes headaches and/or changed levels of consciousness. Fundamentally, an immediate change in neurological functioning because of a blow or injury to the head which results in diffuse axonal injuries (DAI) in the brain structures [20]. This suggests that even short-lived impairment to neural function, after a head injury resulting in a LOC or alteration of consciousness, disturbance of vision and/or equilibrium, is referred to as a concussion. Concerns about the various concussion categories making medical and other research

Cumulative Mild Head Injury (CMHI) in Contact Sports DOI: http://dx.doi.org/10.5772/intechopen.80668

Figure 3. Schematic representation of a closed head injury.

difficult resulted in guidelines for cerebral concussion [21]. Grade 1 (mild) = transient confusion; no loss of consciousness with symptoms resolving in 15 minutes or less: Grade 2 (moderate) = transient confusion, no loss of consciousness and symptoms lasting longer than 15 minutes and lastly, Grade 3 (severe): any loss of consciousness (brief or prolonged) [22].

The authors in this chapter often use terms like concussion, mild head injury (MHI), mild traumatic brain injury (MBTI) and cumulative mild head injury (CMHI) interchangeably as in the sporting arena to all intent and purpose they often refer to the same thing depending on the sporting code and/or country the injury.

At the first International Conference of Concussion it was stated that concussion was a complex pathophysiological caused by biochemical forces impacting on the brain [23]. The definition included the following concussion: (1) may be caused by a blow to the head face, neck, or elsewhere with force that is transferred to the brain; (2) characteristically causes the speedy onset of brief impairment of neurological functions that resolve spontaneously; (3) results in neuropathological changes however, acute clinical symptomology reflects functional disturbances as opposed to structural injury; (4) is a set of clinical syndromes that sometimes (but not always) involves a LOC. Symptomology is resolved following a specific sequence and (5) it is characteristically associated with fundamentally normal structural neuroimaging. A later addition to this was that in some cases post-concussive symptoms can be protracted and persistent [19]. It is used to refer to a closed, MHI such as those incurred by athletes who play contact sports. It falls within the ambit

PTA of less than 24 hours; (c) any alteration in mental state at the time of the accident (for instance, double vision, loss of balance, taste or smell) that may or

There is increasing evidence that CMHI can cause more neuropsychological impairment as a result of neural attrition, which can cause athletes problems later in life [15]. Cumulative damage to hippocampal cells can cause cognitive damage [16]. Moreover, CMHI which occurs over months or years is likely to cause neurological and cognitive deficits [17]. The effects of MHI and concussions in the sporting arena are likely cumulative which has significant implications for athletes who play contact sports where concussion and CMHI occur frequently [18, 19]. Research suggests that permanent cognitive deficits are increasing as a result of CMHI [20].

Concussion is any head injury which causes headaches and/or changed levels of consciousness. Fundamentally, an immediate change in neurological functioning because of a blow or injury to the head which results in diffuse axonal injuries (DAI) in the brain structures [20]. This suggests that even short-lived impairment to neural function, after a head injury resulting in a LOC or alteration of consciousness, disturbance of vision and/or equilibrium, is referred to as a concussion. Concerns about the various concussion categories making medical and other research

may not be transient [11].

Schematic diagram of an open head injury.

Figure 2.

46

1.6 Cumulative mild head injury (CMHI)

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

1.7 Concussive injuries (Concussion)

of MHI and CMHI and can be difficult to detect as symptoms can last from a few seconds to minutes [5]. In this chapter this type of head injury denotes any impact to the head which often go un-reported (Figure 4).

1.9 The mechanics of mild head injury (MHI)

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

or days after the first injury [27].

the frontal and temporal lobes [5].

1.11 Secondary brain injury

can lead to death [30].

49

1.10 Primary brain injury

Mild head injury (MHI) involves primary and secondary brain injury. Primary injury occurs on impact and secondary injury occurs after the impact. Secondary brain injury can stem from complications arising out of a primary brain injury. The time-span in which secondary damage can be from seconds, minutes to hours and/

The contact force is the major origin of brain damage in so-called still injuries where an immobile victim receives a blow to the head. The knock to the head results in movement of the head and neck on impact and causes angular acceleration, a combination of translational and rotational acceleration [5]. Cerebral bruises or contusions are made up of focal damage to the brain tissue which can result in a tear or laceration as a result of head trauma. The coup is an injury that results from a direct blow to the head and appears below the site of impact. A countercoup is when the brain sustains contusion(s) in an area opposite the blow which occurs mostly in

The major theories which explain countercoup injuries are: (1) vibration or Echo theory which states that the traumatic impact sets up vibrations which are reflected in damage to the opposite pole of the brain; (2) Transmitted Force Theory which suggests that traumatic impact results in a transmission of applied force through brain tissue which causes the contralateral structures of the brain to be pushed against the inside of the skull; (3) Brain Displacement Theory which posits that countercoup injuries are a result of avulsion of the cerebral cortex from the overlying meninges; (4) Pressure Gradient Theory suggests that when there is a sudden fall in intracranial pressure, opposite to the point of impact, blood vessels rupture; and (5) Rotational Theory posits that after a blow to the skull the brain is set in a centrifugal motion in line with the direction of the original force or impact. The brain is then thrust against the bony protuberances on the interior of the skull [4].

Secondary brain injury occurs at different lengths of time after head trauma. It is

important to recognise that Mild Traumatic Brain Injury (MTBI) is a dynamic process as the symptomology and pathology evolves hourly and sometimes days after an injury occurs [28]. In fact, much of the brain damage which eventually ensues is as a result of the secondary injury [1]. Hypoxia or low oxygen to the brain and/or insufficient blood supply (ischemia) are the mechanisms through which it suffers an insult [29]. Haematoma, oedema (swelling) in the white matter of the brain next to focal mass lesions, intracranial haemorrhage, diffuse brain swelling, ischaemic brain damage, raised intracranial pressure, brain shift and herniation are other conditions which cause secondary brain injury [28]. Furthermore, although far less common, the risk of Second Impact Syndrome (SIS), a very serious and even fatal brain injury may occur even after a relatively mild impact, which can be significant in young rugby players. SIS occurs when an athlete suffers a concussion and before the first injury has recovered suffers another injury to the head. In SIS it is possible for rapid deterioration and even death. This happens because the brain has not recovered from the first injury and the second injury results in rapid swelling and pressure within the skull. This intracranial pressure, if uncontrolled,

#### 1.8 Occurrence of mild head injury (MHI)

Reliable statistics about the occurrence (prevalence) of MHIs that are closed are quite difficult to ascertain. This is as a result of different names for instance, mild, minor, moderate, and minimal being applied to this type of head injury.

The incidence of MHI is difficult to determine because the majority of country health surveys only look at patients who have been hospitalised. This means that patients who have suffered a MHI or CMHI are not included in survey data. The International Classification of Diseases (ICD 10, 2010) has specific terms of reference for instance, for maxillofacial injuries and scalp lacerations but do not specify CMHI or MHI. Individuals admitted to hospitals who have multiple injuries are usually classified in terms of their most severe injuries (thus an MHI goes unreported [24]).

In South Africa there are few statistics on MHI however, an average of 316 per 100,000 incidents of brain injuries per year was reported in the early nineties [25]. It is estimated for instance, that up to 89,000 brain injuries (mostly TBIs) are seen per year in the country [26]. Moreover, rugby has the highest incidence of concussion amongst contact sport with up to 50% of athletes suffering from a concussion in their playing careers [11].

Figure 4. Schematic representation of how a concussion occurs.

#### 1.9 The mechanics of mild head injury (MHI)

Mild head injury (MHI) involves primary and secondary brain injury. Primary injury occurs on impact and secondary injury occurs after the impact. Secondary brain injury can stem from complications arising out of a primary brain injury. The time-span in which secondary damage can be from seconds, minutes to hours and/ or days after the first injury [27].

#### 1.10 Primary brain injury

of MHI and CMHI and can be difficult to detect as symptoms can last from a few seconds to minutes [5]. In this chapter this type of head injury denotes any impact

Reliable statistics about the occurrence (prevalence) of MHIs that are closed are quite difficult to ascertain. This is as a result of different names for instance, mild,

The incidence of MHI is difficult to determine because the majority of country health surveys only look at patients who have been hospitalised. This means that patients who have suffered a MHI or CMHI are not included in survey data. The International Classification of Diseases (ICD 10, 2010) has specific terms of reference for instance, for maxillofacial injuries and scalp lacerations but do not specify CMHI or MHI. Individuals admitted to hospitals who have multiple injuries are usually classified in terms of their most severe injuries (thus an MHI goes

In South Africa there are few statistics on MHI however, an average of 316 per 100,000 incidents of brain injuries per year was reported in the early nineties [25]. It is estimated for instance, that up to 89,000 brain injuries (mostly TBIs) are seen per year in the country [26]. Moreover, rugby has the highest incidence of concussion amongst contact sport with up to 50% of athletes suffering from a concussion

minor, moderate, and minimal being applied to this type of head injury.

to the head which often go un-reported (Figure 4).

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

1.8 Occurrence of mild head injury (MHI)

unreported [24]).

Figure 4.

48

Schematic representation of how a concussion occurs.

in their playing careers [11].

The contact force is the major origin of brain damage in so-called still injuries where an immobile victim receives a blow to the head. The knock to the head results in movement of the head and neck on impact and causes angular acceleration, a combination of translational and rotational acceleration [5]. Cerebral bruises or contusions are made up of focal damage to the brain tissue which can result in a tear or laceration as a result of head trauma. The coup is an injury that results from a direct blow to the head and appears below the site of impact. A countercoup is when the brain sustains contusion(s) in an area opposite the blow which occurs mostly in the frontal and temporal lobes [5].

The major theories which explain countercoup injuries are: (1) vibration or Echo theory which states that the traumatic impact sets up vibrations which are reflected in damage to the opposite pole of the brain; (2) Transmitted Force Theory which suggests that traumatic impact results in a transmission of applied force through brain tissue which causes the contralateral structures of the brain to be pushed against the inside of the skull; (3) Brain Displacement Theory which posits that countercoup injuries are a result of avulsion of the cerebral cortex from the overlying meninges; (4) Pressure Gradient Theory suggests that when there is a sudden fall in intracranial pressure, opposite to the point of impact, blood vessels rupture; and (5) Rotational Theory posits that after a blow to the skull the brain is set in a centrifugal motion in line with the direction of the original force or impact. The brain is then thrust against the bony protuberances on the interior of the skull [4].

#### 1.11 Secondary brain injury

Secondary brain injury occurs at different lengths of time after head trauma. It is important to recognise that Mild Traumatic Brain Injury (MTBI) is a dynamic process as the symptomology and pathology evolves hourly and sometimes days after an injury occurs [28]. In fact, much of the brain damage which eventually ensues is as a result of the secondary injury [1]. Hypoxia or low oxygen to the brain and/or insufficient blood supply (ischemia) are the mechanisms through which it suffers an insult [29]. Haematoma, oedema (swelling) in the white matter of the brain next to focal mass lesions, intracranial haemorrhage, diffuse brain swelling, ischaemic brain damage, raised intracranial pressure, brain shift and herniation are other conditions which cause secondary brain injury [28]. Furthermore, although far less common, the risk of Second Impact Syndrome (SIS), a very serious and even fatal brain injury may occur even after a relatively mild impact, which can be significant in young rugby players. SIS occurs when an athlete suffers a concussion and before the first injury has recovered suffers another injury to the head. In SIS it is possible for rapid deterioration and even death. This happens because the brain has not recovered from the first injury and the second injury results in rapid swelling and pressure within the skull. This intracranial pressure, if uncontrolled, can lead to death [30].

#### 1.12 The pathophysiology of mild head injury (MHI) and CMHI

#### 1.12.1 Diffuse Axonal Injury (DAI)

Diffuse Axonal Injury (DAI) is caused through acceleration-deceleration trauma when the brain twists or rotates inside the skull (rotational acceleration). Focally diffuse axonal strain and tensile stress results in one of the most compromising types of injury in brain trauma [31]. Fundamentally, after a serious head injury it is probably the major cause of unconsciousness and persistent vegetative states. It was first described in the late 1950s after post-mortems conducted on individuals who had died as a result of severe head trauma [32]. This kind of injury has a serious impact on the executive functioning of the brain and alters for instance, the speed of information processing, working memory and attention span [4]. It is postulated that DAI is involved in persistent post-concussive symptomology and attentional deficits following MTBI [33] (Figure 5).

In the sporting arena there are various physical and neurological symptoms experienced by athletes for instance, headaches and dizziness, impaired concentration and memory plus poor problem solving ability. This type of symptomology may be based on personality characteristics in athletes or be related to malingering

The two most commonly cited systems for defining and diagnosing PCS are the 10th edition of the International Classification of Disease [35] and the Diagnostic and Statistical Manual of Mental Disorders—DSM-5 [36]. In this chapter we present the ICD-10 (2010) diagnostic criteria as it is more universally applied and many individuals do not meet the DSM-5 criteria pertaining to cognitive deficits and clinically significant criteria (which can also be problematic in terms of finding incidence and prevalence of PCS): (a) history of head trauma with loss of consciousness precedes symptoms onset by maximum of 4 weeks and (b) symptoms in

and/or the possibility of financial gain [5].

DOI: http://dx.doi.org/10.5772/intechopen.80668

Cumulative Mild Head Injury (CMHI) in Contact Sports

three or more of the following categories:

• Insomnia;

• Reduced alcohol tolerance;

important [4] (Table 2).

Table 1. Concussion grading.

51

1.13.1 Post-concussive syndrome (PCS) diagnostic criteria

• Headache, dizziness, malaise, fatigue, noise tolerance;

hypochondriacal concerns and adoption of sick role.

• Subjective concentration, memory, or intellectual difficulties without neuropsychological evidence of marked improvement impairment;

• Preoccupation with above symptoms and fear of brain damage with

1.13.2 Recovery and symptomology related to post-concussive syndrome (PCS)

The grading of concussions is also important in this regard see Table 1 [22].

Diagnosis of PCS is based on the subjective symptomology reported by individuals as is recovery (based on symptom resolution) [5]. Adults' cognitive deficits and symptoms in terms of PCS are commonly found in the acute stage and resolve within 3–12 months [37]. The duration of amnesia related to any LOC is also very

• Irritability, depression, anxiety, emotional lability;

#### 1.13 Post-concussive syndrome (PCS)

Minor impacts to the head cause a pattern of self-reported symptomology referred to as post-concussive syndrome (PCS). These symptoms can persist long after the original injury, and can be both acute and/or chronic. They are categorised into three main symptom areas: cognitive, physical and psychological [34]. Although symptoms generally resolve within a period of a week to 3 months there can be chronic symptomology which occurs from months to years after the initial trauma [5]. These reactions to MHI are facilitated by various issues and are based on an interaction between organic and psychological factors basically, they begin at an organic level and sometimes persist and are experienced at a psychological level. Somatic symptomology includes dizziness, tiredness and headaches whereas psychological symptomology is related to: poor concentration and memory; irritability, emotional lability and depression and anxiety [4].

Figure 5. Schematic representation of a diffuse axonal injury.

In the sporting arena there are various physical and neurological symptoms experienced by athletes for instance, headaches and dizziness, impaired concentration and memory plus poor problem solving ability. This type of symptomology may be based on personality characteristics in athletes or be related to malingering and/or the possibility of financial gain [5].

#### 1.13.1 Post-concussive syndrome (PCS) diagnostic criteria

The two most commonly cited systems for defining and diagnosing PCS are the 10th edition of the International Classification of Disease [35] and the Diagnostic and Statistical Manual of Mental Disorders—DSM-5 [36]. In this chapter we present the ICD-10 (2010) diagnostic criteria as it is more universally applied and many individuals do not meet the DSM-5 criteria pertaining to cognitive deficits and clinically significant criteria (which can also be problematic in terms of finding incidence and prevalence of PCS): (a) history of head trauma with loss of consciousness precedes symptoms onset by maximum of 4 weeks and (b) symptoms in three or more of the following categories:


1.12 The pathophysiology of mild head injury (MHI) and CMHI

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

Diffuse Axonal Injury (DAI) is caused through acceleration-deceleration trauma when the brain twists or rotates inside the skull (rotational acceleration). Focally diffuse axonal strain and tensile stress results in one of the most compromising types of injury in brain trauma [31]. Fundamentally, after a serious head injury it is probably the major cause of unconsciousness and persistent vegetative states. It was first described in the late 1950s after post-mortems conducted on individuals who had died as a result of severe head trauma [32]. This kind of injury has a serious impact on the executive functioning of the brain and alters for instance, the speed of information processing, working memory and attention span [4]. It is postulated that DAI is involved in persistent post-concussive symptomology and attentional

Minor impacts to the head cause a pattern of self-reported symptomology referred to as post-concussive syndrome (PCS). These symptoms can persist long after the original injury, and can be both acute and/or chronic. They are categorised

into three main symptom areas: cognitive, physical and psychological [34]. Although symptoms generally resolve within a period of a week to 3 months there can be chronic symptomology which occurs from months to years after the initial trauma [5]. These reactions to MHI are facilitated by various issues and are based on an interaction between organic and psychological factors basically, they begin at an organic level and sometimes persist and are experienced at a psychological level. Somatic symptomology includes dizziness, tiredness and headaches whereas psychological symptomology is related to: poor concentration and memory; irritability,

1.12.1 Diffuse Axonal Injury (DAI)

deficits following MTBI [33] (Figure 5).

1.13 Post-concussive syndrome (PCS)

emotional lability and depression and anxiety [4].

Figure 5.

50

Schematic representation of a diffuse axonal injury.


The grading of concussions is also important in this regard see Table 1 [22].

#### 1.13.2 Recovery and symptomology related to post-concussive syndrome (PCS)

Diagnosis of PCS is based on the subjective symptomology reported by individuals as is recovery (based on symptom resolution) [5]. Adults' cognitive deficits and symptoms in terms of PCS are commonly found in the acute stage and resolve within 3–12 months [37]. The duration of amnesia related to any LOC is also very important [4] (Table 2).


Table 1. Concussion grading.


#### Table 2.

Post traumatic amnesia.

MHI symptomology are often non-specific and may be the same as those reported after for instance, orthopaedic injuries. The most frequently reported symptoms are headaches, blurred vision, dizziness, subjective memory problems and sleep disturbance [35] (Table 3).

Return to play protocols for professional athletes in football and rugby are the norm and well-defined (see Tables 4 and 5) but this is not the case in the amateur spheres of the game where injuries may be more severe because of the poorer skill levels of the athletes [38].

#### 1.14 Neuropsychological sequelae of mild head injuries (MHIs)

Individuals who sustain MTBI often report symptomology comparative with PCS. It has been reported that 10–20% of MTBI patients report PCS that go beyond a recovery period of 6–12 months [39]. Severe tiredness (up to 50% of individuals who report PCS) is often reported which impacts on an individual's cognitive ability and can cause day-to-day problems in living relating to work, exercise and sports participation as well as social interactions. Psychological symptomology for instance, depression is also associated with MHIs as well as anxiety and irritability [40]. Children who experience MHI are more likely to experience impulse control problems and, as a result, have poorer planning ability. They are at a higher risk of difficulty with high-level cognitive functions [41]. As many children and adolescents play rugby and football this is a problematic finding.

#### 1.14.1 Changes to the neurochemical make-up of the brain after a head injury

Neurochemical change as a result of head injury is facilitated by damaged brain cells and occurs within an hour and up to 10 days post-injury [18]. This creates a metabolic dysfunction which means there is an imbalance between the demand of


the brain for energy (to heal itself) and for it to work at its usual capacity. This may be one of the reasons for SIS. The protein S-100 has been found at higher than normal levels for around a year after MHIs which impairs neurological functioning

Damage to the hypothalamus and/or the pituitary gland can cause hormonal problems as these glands regulate hormones in the body [4]. Changes in sexual function, depression, headaches and tiredness may occur. As these are also linked to concussive injury, hormonal damage can be overlooked. In one study after severe

in the brain [42].

Graduated return to play protocol.

Table 5.

53

Table 4.

1.14.2 Imbalances in hormones after a head injury

Management of concussion and return to play protocols.

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

#### Cumulative Mild Head Injury (CMHI) in Contact Sports DOI: http://dx.doi.org/10.5772/intechopen.80668


#### Table 4.

MHI symptomology are often non-specific and may be the same as those reported after for instance, orthopaedic injuries. The most frequently reported symptoms are headaches, blurred vision, dizziness, subjective memory problems

1.14 Neuropsychological sequelae of mild head injuries (MHIs)

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

cents play rugby and football this is a problematic finding.

1.14.1 Changes to the neurochemical make-up of the brain after a head injury

Neurochemical change as a result of head injury is facilitated by damaged brain cells and occurs within an hour and up to 10 days post-injury [18]. This creates a metabolic dysfunction which means there is an imbalance between the demand of

Return to play protocols for professional athletes in football and rugby are the norm and well-defined (see Tables 4 and 5) but this is not the case in the amateur spheres of the game where injuries may be more severe because of the poorer skill

Individuals who sustain MTBI often report symptomology comparative with PCS. It has been reported that 10–20% of MTBI patients report PCS that go beyond a recovery period of 6–12 months [39]. Severe tiredness (up to 50% of individuals who report PCS) is often reported which impacts on an individual's cognitive ability and can cause day-to-day problems in living relating to work, exercise and sports participation as well as social interactions. Psychological symptomology for instance, depression is also associated with MHIs as well as anxiety and irritability [40]. Children who experience MHI are more likely to experience impulse control problems and, as a result, have poorer planning ability. They are at a higher risk of difficulty with high-level cognitive functions [41]. As many children and adoles-

and sleep disturbance [35] (Table 3).

levels of the athletes [38].

Table 2.

Table 3.

52

ICD10 post concussive criteria.

Post traumatic amnesia.

Management of concussion and return to play protocols.


#### Table 5. Graduated return to play protocol.

the brain for energy (to heal itself) and for it to work at its usual capacity. This may be one of the reasons for SIS. The protein S-100 has been found at higher than normal levels for around a year after MHIs which impairs neurological functioning in the brain [42].

#### 1.14.2 Imbalances in hormones after a head injury

Damage to the hypothalamus and/or the pituitary gland can cause hormonal problems as these glands regulate hormones in the body [4]. Changes in sexual function, depression, headaches and tiredness may occur. As these are also linked to concussive injury, hormonal damage can be overlooked. In one study after severe

TBIs abnormal hormone levels were found in 60% of patients [43]. This could occur in some cases of MHI and CMHI (Figure 6).

not recover timeously, costing their franchises much money. As a result baseline neuropsychological testing was used by several major American Football franchises.

This suggests that the assessment of cognitive functions is critical in terms of amateur and professional sport particularly in contact sports, and should include baseline cognitive and postural stability testing for athletes in high-risk contact

Different types of attention can be assessed using various neuropsychological tests for instance, arousal and alertness can be evaluated using an electroencephalography spectral analysis because the hippocampal theta rhythm is linked to heightened attention [5]. Selective attention can be assessed by using different neuropsychological measures such as hemi-spatial inattention using Line Bisection, Letter cancellation, and the drawing of symmetrical figures. Focused attention can be assessed using the Stroop Color and Word Test. Fundamentally, focused attention is usually evaluated in the visual and auditory areas by utilising dichotic listening tasks. In this type of test an individual listens to various kinds of auditory stimuli and is asked to make specific choices. Other tests of focused attention are the Letter Cancellation Task, the Trail Making Tests and Reaction Time with Distraction tests. Divided attention deficits are usually seen by lower speeds in performance tasks and assessed using for instance, the Paced Auditory Serial Addition Test where the degree of deficit compares positively with the severity of injury. Individuals suffering mild concussion have been found to be up to three times slower than control group individuals with no concussive injury. Athletes who experienced severe concussion were found to be up to five times slower than control group members with no concussive injury. Sustained attention deficits can be seen as time-on-task deficits. In other words, an individual takes longer than the norm to complete a task. Other neuropsychological tests for sustained attention are for instance, the Letter cancellation test, Vigilance

Computerised cognitive tests (CCTS) are available that evaluate changes in cognition [46]. For instance, the Post-Concussion Assessment and Cognitive Test (ImPACT). These can be more accurate than pen-paper tests but qualitative data from interviewing patients must also be used to give a complete report on any head

Reaction time (RT) is the period in milliseconds from when a test stimulus is

presented to the time the individual reacts. In simple RT testing (using a computerised programme) there is only one stimulus and one response which measures psychomotor skills [46]. In choice RT testing the testee gives a response when presented with a stimulus on the computer screen [4]. Computerised assessment is more accurate than older pen-paper tests and, because of high overall use of smart phones and computers, all populations are able to complete these tests [45]. The two critical measurements taken during this type of assessment are reaction time (RT) and movement time (MT). RT, according to some pundits, reflects decision time which is defined as the length of time for stimulus evaluation and response programming. Conversely, movement time (MT), is the measure of the time it takes to complete a response. RT is reflective of cognitive processes while

The National Hockey League (NHL) in the United States of America (USA) authorised this type of testing for comparable reasons. Baseline neuropsychological testing has, since then, become the norm in some countries in collegiate and professional sport and has allowed post injury evaluation of subtle cognitive functions linked to CMHIS. In turn, this data has supported intervention (and treatment)

protocols for various professional sporting codes [4].

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

tests and Perceptual Speed tests [4, 5].

1.17 Reaction time related to head injuries

injured athlete.

55

sports [44, 45].

#### 1.15 Neuropsychological recovery following mild and cumulative mild head injuries (CMHI)

Some pundits suggest that acute sequelae resolution of any MHI neuropsychological deficits takes from 4 to 5 weeks post the initial head trauma but that there still might be problems with psychosocial capabilities. These can be mild cognitive insufficiencies related to slower information processing and slower visuomotor speed. Deficits pertaining to tiredness, dizziness and headaches often reduce after a period of 2 months post-injury but some patients still report PCS 3 months postinjury. These symptoms are often mild and may go unnoticed at medical follow-ups [34]. Return to play protocols are thus very important [38].

#### 1.16 Neuropsychological assessment of deficits related to CMHI

In the mid-1980s medical and allied health professionals started neuropsychological testing [22] because head injuries in professional sports (especially contact sports) were noted as potentially keeping the athlete of the field of play (and sport requires its sporting heroes in order to make money). A number of high profile professional athletes who played American Football incurred head injuries and did

Figure 6. The pituitary gland.

#### Cumulative Mild Head Injury (CMHI) in Contact Sports DOI: http://dx.doi.org/10.5772/intechopen.80668

TBIs abnormal hormone levels were found in 60% of patients [43]. This could occur

Some pundits suggest that acute sequelae resolution of any MHI neuropsychological deficits takes from 4 to 5 weeks post the initial head trauma but that there still might be problems with psychosocial capabilities. These can be mild cognitive insufficiencies related to slower information processing and slower visuomotor speed. Deficits pertaining to tiredness, dizziness and headaches often reduce after a period of 2 months post-injury but some patients still report PCS 3 months postinjury. These symptoms are often mild and may go unnoticed at medical follow-ups

In the mid-1980s medical and allied health professionals started neuropsychological testing [22] because head injuries in professional sports (especially contact sports) were noted as potentially keeping the athlete of the field of play (and sport requires its sporting heroes in order to make money). A number of high profile professional athletes who played American Football incurred head injuries and did

1.15 Neuropsychological recovery following mild and cumulative mild head

in some cases of MHI and CMHI (Figure 6).

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

[34]. Return to play protocols are thus very important [38].

1.16 Neuropsychological assessment of deficits related to CMHI

injuries (CMHI)

Figure 6. The pituitary gland.

54

not recover timeously, costing their franchises much money. As a result baseline neuropsychological testing was used by several major American Football franchises. The National Hockey League (NHL) in the United States of America (USA) authorised this type of testing for comparable reasons. Baseline neuropsychological testing has, since then, become the norm in some countries in collegiate and professional sport and has allowed post injury evaluation of subtle cognitive functions linked to CMHIS. In turn, this data has supported intervention (and treatment) protocols for various professional sporting codes [4].

This suggests that the assessment of cognitive functions is critical in terms of amateur and professional sport particularly in contact sports, and should include baseline cognitive and postural stability testing for athletes in high-risk contact sports [44, 45].

Different types of attention can be assessed using various neuropsychological tests for instance, arousal and alertness can be evaluated using an electroencephalography spectral analysis because the hippocampal theta rhythm is linked to heightened attention [5]. Selective attention can be assessed by using different neuropsychological measures such as hemi-spatial inattention using Line Bisection, Letter cancellation, and the drawing of symmetrical figures. Focused attention can be assessed using the Stroop Color and Word Test. Fundamentally, focused attention is usually evaluated in the visual and auditory areas by utilising dichotic listening tasks. In this type of test an individual listens to various kinds of auditory stimuli and is asked to make specific choices. Other tests of focused attention are the Letter Cancellation Task, the Trail Making Tests and Reaction Time with Distraction tests. Divided attention deficits are usually seen by lower speeds in performance tasks and assessed using for instance, the Paced Auditory Serial Addition Test where the degree of deficit compares positively with the severity of injury. Individuals suffering mild concussion have been found to be up to three times slower than control group individuals with no concussive injury. Athletes who experienced severe concussion were found to be up to five times slower than control group members with no concussive injury. Sustained attention deficits can be seen as time-on-task deficits. In other words, an individual takes longer than the norm to complete a task. Other neuropsychological tests for sustained attention are for instance, the Letter cancellation test, Vigilance tests and Perceptual Speed tests [4, 5].

Computerised cognitive tests (CCTS) are available that evaluate changes in cognition [46]. For instance, the Post-Concussion Assessment and Cognitive Test (ImPACT). These can be more accurate than pen-paper tests but qualitative data from interviewing patients must also be used to give a complete report on any head injured athlete.

#### 1.17 Reaction time related to head injuries

Reaction time (RT) is the period in milliseconds from when a test stimulus is presented to the time the individual reacts. In simple RT testing (using a computerised programme) there is only one stimulus and one response which measures psychomotor skills [46]. In choice RT testing the testee gives a response when presented with a stimulus on the computer screen [4]. Computerised assessment is more accurate than older pen-paper tests and, because of high overall use of smart phones and computers, all populations are able to complete these tests [45]. The two critical measurements taken during this type of assessment are reaction time (RT) and movement time (MT). RT, according to some pundits, reflects decision time which is defined as the length of time for stimulus evaluation and response programming. Conversely, movement time (MT), is the measure of the time it takes to complete a response. RT is reflective of cognitive processes while

MT is linked to the motor component of the RT. RT can be defined as the sum of RT and MT which equals Total Reaction Time. Good RT is needed by athletes in order to perform well in any given sporting code and a head injury, which results in poorer RT, is a challenge (caused by for instance, CMHI, MHI). Factors that influence good RT are high stimulation, tiredness, alcohol consumption and any type of brain injury [45].

significant association between the actual reported MHIs and intellectual or cogni-

In 2001 an investigation into CMHI amongst schoolboy rugby players and a hockey playing control group revealed more variability, on a battery of neuropsychological tests, amongst the forward rugby playing group (as compared to the backline rugby players) as well as the hockey playing group. Working memory and visuospatial processing skills were more impaired in the rugby forwards than the backline and hockey players and the entire rugby playing sample showed more of

Enduring PCS amongst school boys and adult players (at the national level) was looked at using visuomotor processing speed tests. Results suggested that the rugby playing group had less capability on various tests post-season. It was postulated that this was probably due to unreported concussions and/or the cumulative effect of mild head injuries. It was also reported that the rugby forwards (who engage in more scrummaging and heavy tackling) showed more cognitive deficits than the

In 2010 an investigation, using a neuropsychological test battery, was carried out into the effects of three or more concussive injuries in adult male rugby players. It was found that rugby players who had suffered multiple concussive injuries performed lower on the test-battery than those who had no previous history of concussion. The results suggested that rugby players who had incurred three or

On the other hand, an investigation into CMHI using computerised testing, on a sample of high school rugby players, did not support research which indicates that concussive injury and/or CMHI results in cognitive deficits. The major body of research in SA indicates that CMHI results in some cognitive deficits particularly in rugby forwards. In this research neither rugby forwards or backs showed cognitive dysfunction post-season relative to the hockey controls. It was anticipated that, as the computerised test was very sensitive to diffuse brain injury, some cognitive dysfunction would be found. The research concluded that perhaps MHIs in this group (adolescent boys) does not have a cumulative effect as previously

postulated. It was also suggested that factors such as education and age may mitigate against CMHI [9] however, as this was a small sample results were considered

Conversely, a small 2017 study looking at CMHI in college rugby union players found that there was significant variability on mean scores between rugby frontline and backline players on verbal memory, concept formation, cognitive flexibility, working memory and visual-motor processing speed on a pen-paper neuropsychological test battery. In this research it was postulated that poor scores on PCS might also indicate depression in the rugby playing group as insomnia and anger were

An Australian study found that in a sample of 104 amateur rugby sevens players (males and females) in one season thirty-one injuries occurred. These were mostly caused by contact at speed and tackling. In the investigation it was noted that head, neck and shoulder injuries made up 50% of all injuries however, CMHI was not investigated. It was reported that athletes that were slower and less agile were at more risk of injury as were female 7s players. The study concluded that there are limited studies on risks factors associated with rugby sevens player and that more

A study on school level rugby union players in Australia looked at 332 injuries in different age ranges over a season (10–18 years). It was found that the incidence of supposed concussion injuries was 4.3/1000 players and that the most usual way of

incurring this injury was tacking. Risk factors were that the game itself is a

these deficits than the hockey playing control group [49].

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

more concussions were likely to suffer cognitive dysfunction [3].

tive dysfunction [48].

rugby backline players [50].

provisional [51].

57

frequently reported [52].

pre and post season assessment was required [53].

#### 1.18 Use of neuroimaging techniques in diagnosing MHI deficits

Traditional neuroimaging devices for instance, Magnetic Resonance Imaging (MRI) and Computerised Tomography (CT) scans are not appropriate for MHI and CMHI as they do not pick up the pathophysiological processes in this type of head injury [18]. However, newer structural MRIs which include gradient echo perfusion and diffusion imaging are more sensitive to structural abnormalities so may be more useful [19]. Traditional neuropsychological assessments (pen and paper and computerised tests) have proven their usefulness in diagnosing MHI deficits and are very sensitive to diffuse axonal damage thus are used successfully in the sporting environment.

#### 1.19 Cross-cultural neurological assessment

The culture and ethnicity of an athlete must be looked at carefully when interpreting data from any kind of neuropsychological/neurological assessments. Many of these tests have not been standardised on people from non-westernised Caucasian backgrounds which could prove problematic. Construct equivalence for the assessment of individuals who are not from the culture that a test has been standardised and validated on usually does not exist. The assessment of an athlete's responses on a neurological/neuropsychological evaluation must take into account their socio-cultural context and experiences [4, 5]. If these are overlooked there may be a culturally inappropriate analysis which can result in false positive or false negative results.

#### 1.20 Examples of research on CMHI in the contact sports rugby union, rugby 7s and football

Cumulative mild head injury (CMHI) research, to a large extent, has been conducted on rugby union players. Players are fit, the forwards are heavy (up to 140 kg) and it is described as a very physical sport [4]. Although the sport originated in, and was initially played, in Europe it is a very popular sport in the southern hemisphere (for instance in Australia (AUS), South Africa (SA) and New Zealand (NZ)). It is becoming increasingly popular in Japan and the USA which has prompted more research in the field.

In 2000 an investigation looked at the cumulative effects of concussion and CMHI on professional rugby players. A group of 26 professional rugby players and a control group of non-contact sports (professional cricketers) athletes was used. In the rugby group forward and backline players were compared over a neuropsychological test-battery. Results indicated that rugby players, particularly the forwards, had deficits in verbal, working and visual memory as well as visuoperceptual tracking skills as compared to the cricket playing controls. It was also found that within the rugby group mean score test comparisons indicated that the forwards displayed greater cognitive deficits than the backline players [47]. Conversely, research into intellectual deficits incurred by CMHI in high school rugby players, revealed no

MT is linked to the motor component of the RT. RT can be defined as the sum of RT and MT which equals Total Reaction Time. Good RT is needed by athletes in order to perform well in any given sporting code and a head injury, which results in poorer RT, is a challenge (caused by for instance, CMHI, MHI). Factors that influence good RT are high stimulation, tiredness, alcohol consumption and any type of

Traditional neuroimaging devices for instance, Magnetic Resonance Imaging (MRI) and Computerised Tomography (CT) scans are not appropriate for MHI and CMHI as they do not pick up the pathophysiological processes in this type of head injury [18]. However, newer structural MRIs which include gradient echo perfusion and diffusion imaging are more sensitive to structural abnormalities so may be more

computerised tests) have proven their usefulness in diagnosing MHI deficits and are very sensitive to diffuse axonal damage thus are used successfully in the sporting

useful [19]. Traditional neuropsychological assessments (pen and paper and

The culture and ethnicity of an athlete must be looked at carefully when interpreting data from any kind of neuropsychological/neurological assessments. Many of these tests have not been standardised on people from non-westernised Caucasian backgrounds which could prove problematic. Construct equivalence for the assessment of individuals who are not from the culture that a test has been standardised and validated on usually does not exist. The assessment of an athlete's responses on a neurological/neuropsychological evaluation must take into account their socio-cultural context and experiences [4, 5]. If these are overlooked there may be a culturally inappropriate analysis which can result in false positive or false

1.20 Examples of research on CMHI in the contact sports rugby union, rugby 7s

Cumulative mild head injury (CMHI) research, to a large extent, has been conducted on rugby union players. Players are fit, the forwards are heavy (up to 140 kg) and it is described as a very physical sport [4]. Although the sport originated in, and was initially played, in Europe it is a very popular sport in the southern hemisphere (for instance in Australia (AUS), South Africa (SA) and New Zealand (NZ)). It is becoming increasingly popular in Japan and the USA which has

In 2000 an investigation looked at the cumulative effects of concussion and CMHI on professional rugby players. A group of 26 professional rugby players and a control group of non-contact sports (professional cricketers) athletes was used. In the rugby group forward and backline players were compared over a neuropsychological test-battery. Results indicated that rugby players, particularly the forwards, had deficits in verbal, working and visual memory as well as visuoperceptual tracking skills as compared to the cricket playing controls. It was also found that within the rugby group mean score test comparisons indicated that the forwards displayed greater cognitive deficits than the backline players [47]. Conversely, research into intellectual deficits incurred by CMHI in high school rugby players, revealed no

1.18 Use of neuroimaging techniques in diagnosing MHI deficits

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

brain injury [45].

environment.

negative results.

56

and football

prompted more research in the field.

1.19 Cross-cultural neurological assessment

significant association between the actual reported MHIs and intellectual or cognitive dysfunction [48].

In 2001 an investigation into CMHI amongst schoolboy rugby players and a hockey playing control group revealed more variability, on a battery of neuropsychological tests, amongst the forward rugby playing group (as compared to the backline rugby players) as well as the hockey playing group. Working memory and visuospatial processing skills were more impaired in the rugby forwards than the backline and hockey players and the entire rugby playing sample showed more of these deficits than the hockey playing control group [49].

Enduring PCS amongst school boys and adult players (at the national level) was looked at using visuomotor processing speed tests. Results suggested that the rugby playing group had less capability on various tests post-season. It was postulated that this was probably due to unreported concussions and/or the cumulative effect of mild head injuries. It was also reported that the rugby forwards (who engage in more scrummaging and heavy tackling) showed more cognitive deficits than the rugby backline players [50].

In 2010 an investigation, using a neuropsychological test battery, was carried out into the effects of three or more concussive injuries in adult male rugby players. It was found that rugby players who had suffered multiple concussive injuries performed lower on the test-battery than those who had no previous history of concussion. The results suggested that rugby players who had incurred three or more concussions were likely to suffer cognitive dysfunction [3].

On the other hand, an investigation into CMHI using computerised testing, on a sample of high school rugby players, did not support research which indicates that concussive injury and/or CMHI results in cognitive deficits. The major body of research in SA indicates that CMHI results in some cognitive deficits particularly in rugby forwards. In this research neither rugby forwards or backs showed cognitive dysfunction post-season relative to the hockey controls. It was anticipated that, as the computerised test was very sensitive to diffuse brain injury, some cognitive dysfunction would be found. The research concluded that perhaps MHIs in this group (adolescent boys) does not have a cumulative effect as previously postulated. It was also suggested that factors such as education and age may mitigate against CMHI [9] however, as this was a small sample results were considered provisional [51].

Conversely, a small 2017 study looking at CMHI in college rugby union players found that there was significant variability on mean scores between rugby frontline and backline players on verbal memory, concept formation, cognitive flexibility, working memory and visual-motor processing speed on a pen-paper neuropsychological test battery. In this research it was postulated that poor scores on PCS might also indicate depression in the rugby playing group as insomnia and anger were frequently reported [52].

An Australian study found that in a sample of 104 amateur rugby sevens players (males and females) in one season thirty-one injuries occurred. These were mostly caused by contact at speed and tackling. In the investigation it was noted that head, neck and shoulder injuries made up 50% of all injuries however, CMHI was not investigated. It was reported that athletes that were slower and less agile were at more risk of injury as were female 7s players. The study concluded that there are limited studies on risks factors associated with rugby sevens player and that more pre and post season assessment was required [53].

A study on school level rugby union players in Australia looked at 332 injuries in different age ranges over a season (10–18 years). It was found that the incidence of supposed concussion injuries was 4.3/1000 players and that the most usual way of incurring this injury was tacking. Risk factors were that the game itself is a

physically challenging contact sport where many tackles are made at high speed. Over a third of injuries in this sample were to the head and face and overall there were 61 reported concussion. As this was a high incidence it was recommend that prevention programmes need to be put in place [54].

reaction time training actually improves and develops athletes reaction times. As this was computerised testing any diffuse brain damage should have been seen in the results, this was not the case as no significant deficits in football players were found. Conversely, on PCS over a quarter of the football players and only 6% of the control group experienced symptoms such as headaches, attention problems, memory problems, irritation, nervousness and anxiety. This may suggest that athletes involved in football do sustain some CMHI and/or concussive injury which is not reflected in their reaction time scores. This was a small sample of 15 footballers and

A 2016 study looking at concussion in elite male football players found that this type of injury was a risk factor for incurring another such injury within a year of the first injury. Interestingly, the athletes who had a previous concussive injury also had more other injuries than the non-concussed football players in the study. It was suggested that this may be caused by the type of behaviour these athletes engage in (on the field of play) and due to their inherent personality characteristics [65]. The aforementioned literature indicates why there is a debate in football as to

whether young players should be allowed to head the ball [66] particularly if

This section will present several studies related to head injuries in other sporting codes so that the reader is made aware of the extent of these injuries in

Combat sports such as wrestling, mixed martial arts, taekwondo incur many injuries which are mostly soft-tissue and contusion injuries, however, a metareview found that 15% of injuries in these sports are concussive in nature (90% classified as mild to moderate). Risk factors include age, weight category, experience, training and gender, females more likely to incur this type of injury [68].

Cricket players, although the sport is usually designated a non-contact sport, can also receive craniofacial and head injuries if they are hit by a cricket ball (usually when batting). Although using a helmet helped with neck and head injuries it is possible for possible head injuries to occur [69]. Furthermore, another review which looked at craniofacial injuries between 1870 and 2015 found a relatively small number (36). However, 5 resulted in a fatal injury and 9 resulted in the cricketer no longer being able to play the game. In this study it was also reported that in some instance concussion was difficult to diagnosed. It was concluded that all cricket clubs should have medical professionals available and that concussive injuries

Boxers generally suffer more repetitive chronic traumatic brain injury (CTBI) which is not mild or moderate in nature. However, all repetitive injuries to the brain are cumulative in nature and, in the case of boxing, where many blows to the head are received there is the possibility of SIS. As a result since the early twentieth century boxing careers were, on average, 19 years in length but are now around 5 years long. There are still deaths in the sport however, recent research suggest that CBTI caused by repetitive blows to the head will become fever because of medical interventions such as neuroimaging and the early discovery of these injuries [71]. American football is another sport where there are many concussive injuries as it is a contact sport that is considered both violent and dangerous. In a review of head injuries in the game it was revealed that athletes, who have many concussions are, as they age, at risk of non-resolving cognitive deficits, dementia and depression. Retirement age is not prescribed in the sport however, it was suggested that risk

1.21 Recent literature concussive injuries in other sporting codes

needed early identification and appropriate management [70].

15 volleyball controls thus results are provisional [64].

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

tiredness has an impact on performance [67].

the sporting arena today.

59

A recent study in Ireland looking at recurrent injuries in teenage rugby in 15– 18 year olds (15–18 years) found that recurrent injuries numbered 426. Eighty-one concussions were reported of these, 5% were recurrent (in the season under investigation). Although these were the lowest number of recurrent injuries it was noted that any concussive injury that occurs on multiple occasions could be potentially disastrous [55]. In this regard the evaluation and management of concussive injury in young contact sports players is very important because they may have a longterm effect on the athletes to heal [56, 57] for instance, the development of chronic traumatic encephalopathy [55].

There has been very little research into CMHI in football (soccer) players in South Africa. Originally the sport was a non-contact sport but the contemporary game is a designated contact sport [4]. It has been reported that concussive injuries in football are often not reported (players do not wish to leave the field as they do not want to be 'benched' for 6 weeks or until recovery) and, as a result, are underdiagnosed [4]. Athletes involved in football may incur head-to-head, head-toground (or post) and head-to-ball injuries thus there is the likelihood of CMHI. Although head-to-ball injuries may seem unlikely a ball kicked at half-speed travels between 22 and 83 km an hour and can hit the skull with a force of 116 km an hour [59]. A full powered kick could hit the head at around 200 km an hour. As there are about five possibilities a match for any team member to head the ball [60], there is the possibility of CMHI. As early as 1989 research concluded that 12 of 37 football players in a study had slightly abnormal or abnormal EEG (Electroencephalograph) results compared to only 4 of 37 controls who had never played football [58].

In 1989 a study in Norway found that football players self-reported symptoms of irritability, inability to sleep, poor working memory, dizziness, neck pain and headaches after they had repeatedly headed the ball [58]. This supported another 1993 study using male and female Olympic football players. In this research 55% of female and 54% of male football players in the sample reported concussive symptomology after repeated headings of the ball [59]. These investigations underpin earlier findings in 1983 where it was reported that out of every 10 football players 2 had abnormal EEGs when they had trained for 15 minutes in heading the ball [60]. There is concern that youngsters who play football from an early age, and repeatedly head the ball (or are involved in collisions), can have cognitive deficits in later life, possibly as a result of CMHI and concussive injury in the game [4, 61].

Conversely, a study in 2000 reported no acute cognitive deficits in a sample of male and female football players and any significant differences were reported as due to practice effects [62]. However, a 2001 study did find cognitive dysfunction relating to memory and planning abilities in amateur football players in an American college sample [18]. On the other hand, it was reported that concussion from head to ground injuries and collisions were more likely to cause this type of brain injury than repeated heading of the ball [63].

A 2016 study in South Africa looking at sample football players and a control group of non-contact sport athletes (volleyball) using a computerised assessment package (measuring reaction time) and looking at PCS found the following: preseason volleyball players actually had a better (or faster) reaction time than the football players (not significant). Post-season on a test of simple reaction time there were no significant differences. Both groups reaction times improved in relation to their pre-season results. This may suggest that playing these sports and engaging in

#### Cumulative Mild Head Injury (CMHI) in Contact Sports DOI: http://dx.doi.org/10.5772/intechopen.80668

physically challenging contact sport where many tackles are made at high speed. Over a third of injuries in this sample were to the head and face and overall there were 61 reported concussion. As this was a high incidence it was recommend that

A recent study in Ireland looking at recurrent injuries in teenage rugby in 15– 18 year olds (15–18 years) found that recurrent injuries numbered 426. Eighty-one concussions were reported of these, 5% were recurrent (in the season under investigation). Although these were the lowest number of recurrent injuries it was noted that any concussive injury that occurs on multiple occasions could be potentially disastrous [55]. In this regard the evaluation and management of concussive injury in young contact sports players is very important because they may have a longterm effect on the athletes to heal [56, 57] for instance, the development of chronic

There has been very little research into CMHI in football (soccer) players in South Africa. Originally the sport was a non-contact sport but the contemporary game is a designated contact sport [4]. It has been reported that concussive injuries in football are often not reported (players do not wish to leave the field as they do not want to be 'benched' for 6 weeks or until recovery) and, as a result, are underdiagnosed [4]. Athletes involved in football may incur head-to-head, head-toground (or post) and head-to-ball injuries thus there is the likelihood of CMHI. Although head-to-ball injuries may seem unlikely a ball kicked at half-speed travels between 22 and 83 km an hour and can hit the skull with a force of 116 km an hour [59]. A full powered kick could hit the head at around 200 km an hour. As there are about five possibilities a match for any team member to head the ball [60], there is the possibility of CMHI. As early as 1989 research concluded that 12 of 37 football players in a study had slightly abnormal or abnormal EEG (Electroencephalograph) results compared to only 4 of 37 controls who had never played football [58].

In 1989 a study in Norway found that football players self-reported symptoms of

symptomology after repeated headings of the ball [59]. These investigations underpin earlier findings in 1983 where it was reported that out of every 10 football players 2 had abnormal EEGs when they had trained for 15 minutes in heading the ball [60]. There is concern that youngsters who play football from an early age, and repeatedly head the ball (or are involved in collisions), can have cognitive deficits in later life, possibly as a result of CMHI and concussive injury in the game [4, 61]. Conversely, a study in 2000 reported no acute cognitive deficits in a sample of male and female football players and any significant differences were reported as due to practice effects [62]. However, a 2001 study did find cognitive dysfunction relating to memory and planning abilities in amateur football players in an American college sample [18]. On the other hand, it was reported that concussion from head to ground injuries and collisions were more likely to cause this type of brain

A 2016 study in South Africa looking at sample football players and a control group of non-contact sport athletes (volleyball) using a computerised assessment package (measuring reaction time) and looking at PCS found the following: preseason volleyball players actually had a better (or faster) reaction time than the football players (not significant). Post-season on a test of simple reaction time there were no significant differences. Both groups reaction times improved in relation to their pre-season results. This may suggest that playing these sports and engaging in

irritability, inability to sleep, poor working memory, dizziness, neck pain and headaches after they had repeatedly headed the ball [58]. This supported another 1993 study using male and female Olympic football players. In this research 55% of

female and 54% of male football players in the sample reported concussive

injury than repeated heading of the ball [63].

58

prevention programmes need to be put in place [54].

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

traumatic encephalopathy [55].

reaction time training actually improves and develops athletes reaction times. As this was computerised testing any diffuse brain damage should have been seen in the results, this was not the case as no significant deficits in football players were found. Conversely, on PCS over a quarter of the football players and only 6% of the control group experienced symptoms such as headaches, attention problems, memory problems, irritation, nervousness and anxiety. This may suggest that athletes involved in football do sustain some CMHI and/or concussive injury which is not reflected in their reaction time scores. This was a small sample of 15 footballers and 15 volleyball controls thus results are provisional [64].

A 2016 study looking at concussion in elite male football players found that this type of injury was a risk factor for incurring another such injury within a year of the first injury. Interestingly, the athletes who had a previous concussive injury also had more other injuries than the non-concussed football players in the study. It was suggested that this may be caused by the type of behaviour these athletes engage in (on the field of play) and due to their inherent personality characteristics [65].

The aforementioned literature indicates why there is a debate in football as to whether young players should be allowed to head the ball [66] particularly if tiredness has an impact on performance [67].

#### 1.21 Recent literature concussive injuries in other sporting codes

This section will present several studies related to head injuries in other sporting codes so that the reader is made aware of the extent of these injuries in the sporting arena today.

Combat sports such as wrestling, mixed martial arts, taekwondo incur many injuries which are mostly soft-tissue and contusion injuries, however, a metareview found that 15% of injuries in these sports are concussive in nature (90% classified as mild to moderate). Risk factors include age, weight category, experience, training and gender, females more likely to incur this type of injury [68].

Cricket players, although the sport is usually designated a non-contact sport, can also receive craniofacial and head injuries if they are hit by a cricket ball (usually when batting). Although using a helmet helped with neck and head injuries it is possible for possible head injuries to occur [69]. Furthermore, another review which looked at craniofacial injuries between 1870 and 2015 found a relatively small number (36). However, 5 resulted in a fatal injury and 9 resulted in the cricketer no longer being able to play the game. In this study it was also reported that in some instance concussion was difficult to diagnosed. It was concluded that all cricket clubs should have medical professionals available and that concussive injuries needed early identification and appropriate management [70].

Boxers generally suffer more repetitive chronic traumatic brain injury (CTBI) which is not mild or moderate in nature. However, all repetitive injuries to the brain are cumulative in nature and, in the case of boxing, where many blows to the head are received there is the possibility of SIS. As a result since the early twentieth century boxing careers were, on average, 19 years in length but are now around 5 years long. There are still deaths in the sport however, recent research suggest that CBTI caused by repetitive blows to the head will become fever because of medical interventions such as neuroimaging and the early discovery of these injuries [71].

American football is another sport where there are many concussive injuries as it is a contact sport that is considered both violent and dangerous. In a review of head injuries in the game it was revealed that athletes, who have many concussions are, as they age, at risk of non-resolving cognitive deficits, dementia and depression. Retirement age is not prescribed in the sport however, it was suggested that risk


factors for neurocognitive impairment should be taken into account for instance, age, number of concussive injuries, length of time taken to recover and any non-

Ice-hockey players are also at risk of concussive head injuries. It was found that young and older players are more at risk due to possible lack of skills and in the latter case tiredness causing them to be more careless in their playing style. Overall, it was concluded that this type of MTBI is serious in nature and more research needs

There are many risk factors for CMHI and concussive injury in rugby union, rugby 7s, football and other sporting codes. A summary of these is provided in Table 6. Table 6 is not exhaustive but based on the authors reading of the literature.

Recently in South Africa (as well as internationally) there has been much interest in research into the neuropsychological sequelae following concussive injuries [1, 50, 51, 61, 63–67]. This type of research is vital in contributing to the field of sports psychology and sports medicine in terms of understanding the clinical features and assessment techniques, clinical management, rehabilitation, education of athletes and their health care providers, return-to play guidelines and long-term outcomes of concussive injuries. Although it is widely believed that athletes are fit to return to play when observed symptoms resolve, researchers continue to investigate the prolonged effects of concussion and repeated concussion on cognitive

Thanks to Dr. Patricia Maite, Mr. Christopher Nel and Ms. Mokgadi Rapetsoa for

Thank you to the University of Limpopo Research Office specifically Director Mabila and DVC Singh as well as University Management and Dean of the Humanities Prof Maoto. Director of the School of Social Sciences Prof Sithole and the HOD Psychology Prof Sodi for supporting our research endeavours and the VC Prof

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

difficulties, emotional disturbances and behavioural issues.

their research in the field and Ms. Katy Nel for her original drawings.

resolving functional deficits [72].

Cumulative Mild Head Injury (CMHI) in Contact Sports

DOI: http://dx.doi.org/10.5772/intechopen.80668

undertaken in this sporting code [73].

2. Conclusion

Acknowledgements

Mokgalong.

61

Author details

Kathryn Nel\* and Saraswathie Govender

provided the original work is properly cited.

University of Limpopo, Polokwane, South Africa

\*Address all correspondence to: kathryn.nel@ul.ac.za

#### Table 6.

Risk factors in contact sports for cumulative mild head injury (CMI) and concussive injury.

Cumulative Mild Head Injury (CMHI) in Contact Sports DOI: http://dx.doi.org/10.5772/intechopen.80668

factors for neurocognitive impairment should be taken into account for instance, age, number of concussive injuries, length of time taken to recover and any nonresolving functional deficits [72].

Ice-hockey players are also at risk of concussive head injuries. It was found that young and older players are more at risk due to possible lack of skills and in the latter case tiredness causing them to be more careless in their playing style. Overall, it was concluded that this type of MTBI is serious in nature and more research needs undertaken in this sporting code [73].

There are many risk factors for CMHI and concussive injury in rugby union, rugby 7s, football and other sporting codes. A summary of these is provided in Table 6. Table 6 is not exhaustive but based on the authors reading of the literature.

#### 2. Conclusion

Recently in South Africa (as well as internationally) there has been much interest in research into the neuropsychological sequelae following concussive injuries [1, 50, 51, 61, 63–67]. This type of research is vital in contributing to the field of sports psychology and sports medicine in terms of understanding the clinical features and assessment techniques, clinical management, rehabilitation, education of athletes and their health care providers, return-to play guidelines and long-term outcomes of concussive injuries. Although it is widely believed that athletes are fit to return to play when observed symptoms resolve, researchers continue to investigate the prolonged effects of concussion and repeated concussion on cognitive difficulties, emotional disturbances and behavioural issues.

#### Acknowledgements

Thanks to Dr. Patricia Maite, Mr. Christopher Nel and Ms. Mokgadi Rapetsoa for their research in the field and Ms. Katy Nel for her original drawings.

Thank you to the University of Limpopo Research Office specifically Director Mabila and DVC Singh as well as University Management and Dean of the Humanities Prof Maoto. Director of the School of Social Sciences Prof Sithole and the HOD Psychology Prof Sodi for supporting our research endeavours and the VC Prof Mokgalong.

#### Author details

Kathryn Nel\* and Saraswathie Govender University of Limpopo, Polokwane, South Africa

\*Address all correspondence to: kathryn.nel@ul.ac.za

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Table 6.

60

Risk factors in contact sports for cumulative mild head injury (CMI) and concussive injury.

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

### References

[1] Prien A, Grafe A, Rossler R, Junge A, Verhagen E. Epidemiology of head injuries focusing on concussions in team contact sports: A systematic review. Journal of Sports Medicine. 2018;484: 953-969. DOI: 10.1007/s40279-017- 0854-4

[2] Janda DH, Bir CA, Cheney AL. An evaluation of the cumulative concussive effect of soccer heading in the youth population. Injury Control and Safety Promotion. 2002;91:25-31. DOI: 10.1076/icsp.9.1.25.3324

[3] Gardner A, Shores EA, Batchelor J. Reduced processing speed in Rugby Union players reporting three or more previous concussions. Archives of Clinical Neuropsychology. 2010;253: 174-181. DOI: 10.1093/arclin/acq007

[4] Maite P. Cumulative Mild Head Injuries in football (soccer): A comparison of cognitive deficit and post-concussive symptomology between University of Pretoria (AmaTuks) football players and University of Limpopo volleyball controls in South Africa [thesis]. Ga-Rankuwa, Pretoria: University of Limpopo (Medunsa Campus), South Africa; 2014

[5] Lezak MD, Howieson DB, Loring DW. Neuropsychological Assessment. 4th ed. New York, NY: Oxford University Press; 2004. DOI: 10.4236/ jwarp.2018.101009

[6] Mureriwa JF. Traumatic brain injury and attention: Post-concussion symptoms and indices of reaction time [thesis]. Pretoria: University of South Africa; 1997

[7] Kolb B, Wishaw IQ. Fundamentals of Human Neurology. 5th ed. New York, NY: Worth Publishers; 2004. ISBN:10: 0716795868 2009

[8] Zillmer E, Spiers M, Culbertson WC. Principles of Neuropsychology. Belmont, CA: Thomson-Wadsworth; 2008. ISBN:10: 0-495-00376-X

Medicine. 1992;104:815-847. PMID:

DOI: http://dx.doi.org/10.5772/intechopen.80668

Cumulative Mild Head Injury (CMHI) in Contact Sports

[21] Cantu RC. Guidelines for return to

Sportsmedicine. 1986;1410:75-83. DOI: 10.1080/00913847.1986.11709197

[22] Maroon JC, Lovell MR, Norwig J, Podell K, Powell JW, Hartl R. Cerebral concussion in athletes: Evaluation and

[23] Aubry M, Cantu R, Dvorak J, Graf-Baumann T, Johnston K, Kelly J, et al. Summary and agreement statement of the first International Conference on Concussion in Sport, Vienna 2001. British Journal of Sports Medicine. 2002;361:6-10. PMID: 11867482

[24] Petchprapai N. Adaptation to mild traumatic brain injury among Thai adults [thesis]. Cleveland, Ohio: Case Western Reserve University; 2007

[25] Nell V, Brown DS. Epidemiology of traumatic brain injury in Johannesburg —II. Morbidity, mortality and aetiology. Social Science & Medicine. 1999;333:

[26] Brain injury heads up for the cost of recovery [internet]. 2017. Available from: https://www.fanews.co.za/ article/life-insurance/9/dread-

disease-and-or-disability-critical-ilness/ 1085/brain-injuries-heads-up-forthe-costs-of-recovery/21948 [Accessed:

[27] Pope VJ, Edlow JA. Avoiding misdiagnosis in patients with

[28] Mckee AC, Daneshvar D. The neuropathology of traumatic brain injury. Handbook of Clinical Neurology. 2015;127:45-66. DOI: 10.1016/B978-0-

444-52892-6.00004-0

neurological emergencies. Emergency Medicine International. 2012; ID 949275. DOI: 10.1155/2012/949275

289-296. PMID: 1925693

23.05.2018]

contact sports after a cerebral concussion. Physician and

neuropsychological testing. Neurosurgery. 2009;473:659-669.

PMID: 10981755

Neuropsychological impairment as a consequence of football (soccer) play and football heading: Preliminary analyses and report on university footballers. Journal of Clinical and Experimental Neuropsychology. 2005;

[16] Packard RC. Chronic post-traumatic headache: Associations with mild traumatic brain injury, concussion and post-concussive disorder. Current Pain and Headache Reports. 2008;121:67-73.

[17] Silver J, McAllister T, Arciniegas D. Depression and cognitive complaints following mild traumatic brain injury. American Journal of Psychiatry. 2009; 1666:653-661. DOI: 10.1176/appi.

[18] Echemendia RJ, Julian LJ. Mild traumatic brain injury in sports: Neuropsychology's contribution to a developing field. Neuropsychology Review. 2001;112:69-88. PMID:

[19] McCrory P, Meeuwisse W, Johnston K, Dvorak J, Aubry M, Molloy M, et al. Consensus statement on Concussion in Sport—The 3rd International Conference on Concussion in Sport held in Zurich, November 2008. Clinical Journal of Sports Medicine. 2009;193:

185-200. DOI: 10.1097/JSM.

[20] Silver MJ, McAllister TW, Yudovsky MD. Mild brain injury and the post-concussion syndrome. In: Textbook of Traumatic Brain Injury. Arlington, VA: American Psychiatric Publishing, Inc; 2009. ISBN-10:

0b013e3181a501db

1585623571

63

[15] Rutherford A, Stephens R,

27:299-319. DOI: 10.1080/ 13803390490515504

PMID:18417027

ajp.2009.08111676

11572472

Potter D, Fernie G.

1435659

[9] Nel C, Grace J, Nel K, Govender S. Cumulative mild head injury in schoolboy Rugby players. African Journal for Physical, Health Education, Recreation and Dance. 2015;21:92-102. ISSN: 1117-4315

[10] Finkelstein M. The scrum-down on brain damage effects of Cumulative Mild Head Injury in rugby a comparison of group mean scores between national rugby players and non-contact sport controls [thesis]. Grahamstown: Rhodes University; 1999

[11] Satz P, Alfano MS, Light R, Morgenstern H, Zaucha K, Asarnow RF, et al. Persistent post-concussive syndrome: A proposed methodology and literature review to determine the effects, if any, of mild head and other bodily injury. Journal of Clinical and Experimental Neuropsycholo Physician and Sportsmedicine gy. 1999;215: 620-628. DOI: 10.1076/jcen.21.5.620.870

[12] Binder LM, Rohling ML, Larrabee GJ. A review of mild head trauma. Part I: Meta-analytic review of neuropsychological studies. Journal of Clinical and Experimental Neuropsychology. 1997;193:421-431. DOI: 10.1080/01688639708403870

[13] Arciniegas DB, Anderson CA, Topkoff J, McAllister TW. Mild traumatic brain injury: A neuropsychiatric approach to diagnosis, evaluation, and treatment. Neuropsychiatric Disease and Treatment. 2005;14:311-327. PMC2424119

[14] Evans RW. The post-concussion syndrome. Neurology and General

Cumulative Mild Head Injury (CMHI) in Contact Sports DOI: http://dx.doi.org/10.5772/intechopen.80668

Medicine. 1992;104:815-847. PMID: 1435659

References

0854-4

[1] Prien A, Grafe A, Rossler R, Junge A, Verhagen E. Epidemiology of head injuries focusing on concussions in team contact sports: A systematic review. Journal of Sports Medicine. 2018;484: 953-969. DOI: 10.1007/s40279-017-

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

[8] Zillmer E, Spiers M, Culbertson WC.

[9] Nel C, Grace J, Nel K, Govender S. Cumulative mild head injury in schoolboy Rugby players. African Journal for Physical, Health Education, Recreation and Dance. 2015;21:92-102.

[10] Finkelstein M. The scrum-down on brain damage effects of Cumulative Mild Head Injury in rugby a comparison of group mean scores between national rugby players and non-contact sport controls [thesis]. Grahamstown: Rhodes

Principles of Neuropsychology. Belmont, CA: Thomson-Wadsworth; 2008. ISBN:10: 0-495-00376-X

ISSN: 1117-4315

University; 1999

[11] Satz P, Alfano MS, Light R,

et al. Persistent post-concussive syndrome: A proposed methodology and literature review to determine the effects, if any, of mild head and other bodily injury. Journal of Clinical and Experimental Neuropsycholo Physician and Sportsmedicine gy. 1999;215: 620-628. DOI: 10.1076/jcen.21.5.620.870

Morgenstern H, Zaucha K, Asarnow RF,

[12] Binder LM, Rohling ML, Larrabee GJ. A review of mild head trauma. Part I: Meta-analytic review of neuropsychological studies. Journal of

Neuropsychology. 1997;193:421-431. DOI: 10.1080/01688639708403870

[13] Arciniegas DB, Anderson CA, Topkoff J, McAllister TW. Mild traumatic brain injury: A

neuropsychiatric approach to diagnosis,

[14] Evans RW. The post-concussion syndrome. Neurology and General

Clinical and Experimental

evaluation, and treatment. Neuropsychiatric Disease and Treatment. 2005;14:311-327.

PMC2424119

[2] Janda DH, Bir CA, Cheney AL. An evaluation of the cumulative concussive effect of soccer heading in the youth population. Injury Control and Safety Promotion. 2002;91:25-31. DOI:

[3] Gardner A, Shores EA, Batchelor J. Reduced processing speed in Rugby Union players reporting three or more previous concussions. Archives of Clinical Neuropsychology. 2010;253: 174-181. DOI: 10.1093/arclin/acq007

[4] Maite P. Cumulative Mild Head Injuries in football (soccer): A comparison of cognitive deficit and post-concussive symptomology between University of Pretoria (AmaTuks) football players and University of Limpopo volleyball controls in South Africa [thesis]. Ga-Rankuwa, Pretoria: University of Limpopo (Medunsa Campus), South

[5] Lezak MD, Howieson DB, Loring DW. Neuropsychological Assessment. 4th ed. New York, NY: Oxford University Press; 2004. DOI: 10.4236/

[6] Mureriwa JF. Traumatic brain injury

symptoms and indices of reaction time [thesis]. Pretoria: University of South

[7] Kolb B, Wishaw IQ. Fundamentals of Human Neurology. 5th ed. New York, NY: Worth Publishers; 2004. ISBN:10:

and attention: Post-concussion

10.1076/icsp.9.1.25.3324

Africa; 2014

jwarp.2018.101009

Africa; 1997

0716795868 2009

62

[15] Rutherford A, Stephens R, Potter D, Fernie G. Neuropsychological impairment as a consequence of football (soccer) play and football heading: Preliminary analyses and report on university footballers. Journal of Clinical and Experimental Neuropsychology. 2005; 27:299-319. DOI: 10.1080/ 13803390490515504

[16] Packard RC. Chronic post-traumatic headache: Associations with mild traumatic brain injury, concussion and post-concussive disorder. Current Pain and Headache Reports. 2008;121:67-73. PMID:18417027

[17] Silver J, McAllister T, Arciniegas D. Depression and cognitive complaints following mild traumatic brain injury. American Journal of Psychiatry. 2009; 1666:653-661. DOI: 10.1176/appi. ajp.2009.08111676

[18] Echemendia RJ, Julian LJ. Mild traumatic brain injury in sports: Neuropsychology's contribution to a developing field. Neuropsychology Review. 2001;112:69-88. PMID: 11572472

[19] McCrory P, Meeuwisse W, Johnston K, Dvorak J, Aubry M, Molloy M, et al. Consensus statement on Concussion in Sport—The 3rd International Conference on Concussion in Sport held in Zurich, November 2008. Clinical Journal of Sports Medicine. 2009;193: 185-200. DOI: 10.1097/JSM. 0b013e3181a501db

[20] Silver MJ, McAllister TW, Yudovsky MD. Mild brain injury and the post-concussion syndrome. In: Textbook of Traumatic Brain Injury. Arlington, VA: American Psychiatric Publishing, Inc; 2009. ISBN-10: 1585623571

[21] Cantu RC. Guidelines for return to contact sports after a cerebral concussion. Physician and Sportsmedicine. 1986;1410:75-83. DOI: 10.1080/00913847.1986.11709197

[22] Maroon JC, Lovell MR, Norwig J, Podell K, Powell JW, Hartl R. Cerebral concussion in athletes: Evaluation and neuropsychological testing. Neurosurgery. 2009;473:659-669. PMID: 10981755

[23] Aubry M, Cantu R, Dvorak J, Graf-Baumann T, Johnston K, Kelly J, et al. Summary and agreement statement of the first International Conference on Concussion in Sport, Vienna 2001. British Journal of Sports Medicine. 2002;361:6-10. PMID: 11867482

[24] Petchprapai N. Adaptation to mild traumatic brain injury among Thai adults [thesis]. Cleveland, Ohio: Case Western Reserve University; 2007

[25] Nell V, Brown DS. Epidemiology of traumatic brain injury in Johannesburg —II. Morbidity, mortality and aetiology. Social Science & Medicine. 1999;333: 289-296. PMID: 1925693

[26] Brain injury heads up for the cost of recovery [internet]. 2017. Available from: https://www.fanews.co.za/ article/life-insurance/9/dreaddisease-and-or-disability-critical-ilness/ 1085/brain-injuries-heads-up-forthe-costs-of-recovery/21948 [Accessed: 23.05.2018]

[27] Pope VJ, Edlow JA. Avoiding misdiagnosis in patients with neurological emergencies. Emergency Medicine International. 2012; ID 949275. DOI: 10.1155/2012/949275

[28] Mckee AC, Daneshvar D. The neuropathology of traumatic brain injury. Handbook of Clinical Neurology. 2015;127:45-66. DOI: 10.1016/B978-0- 444-52892-6.00004-0

[29] Busl KM, Greer DM. Hypoxicischemic brain injury: Pathophysiology, neuropathology and mechanisms. NeuroRehabilitation. 2015;26:5-13. DOI: 10.3233/NRE-2010-0531

[30] Bey T, Ostick B. Second impact syndrome. The Western Journal of Emergency Medicine. 2009;101:6-10. PMID: 19561758

[31] Bigler ED. The lesion(s) in traumatic brain injury: Implications for clinical neuropsychology. Archives of Clinical Neuropsychology. 2001;162: 95-131. DOI: 10.1016/S0887-6177(00) 00095-0

[32] Strich SJ. Lesions in the cerebral hemispheres after blunt head injury. Journal of Clinical Pathology. 1970;314: 166-171. PMID: 4123922

[33] Niogi SN, Mukherjee P, Ghajar J, Johnson C, Kolster RA, Sarkar R, et al. Extent of microstructural white matter injury in post-concussive syndrome correlates with impaired cognitive reaction time: A 3T diffusion tensor imaging study of mild traumatic brain injury. American Journal of Neuroradiology. 2008;295:967-973. DOI: 0.3174/ajnr.A0970

[34] Daneshvar DH, O'Riley D, Nowinski CJ, McKee AC, Stern RA, Cantu RC. Long term consequences: Effects on normal development profile after concussion. Physical Medicine and Rehabilitation Clinics of North America. 2012;224:683-700. PMID: 22050943

[35] Medical coding reference [Internet]. 2018. Available from: https://www. icd10data.com/ [Accessed: 18.05.2018]

[36] Diagnostic and Statistical Manual of Mental Disorders—5th ed [Internet]. Available from: https://www. sciencetheearth.com/uploads/2/4/6/5/ 24658156/dsm-v-manual\_pg490.pdf [Accessed: 04.06.2018]

[37] Carroll L, Cassidy JD, Peloso P, Borg J, von Holst H, Holm L, et al. Prognosis for mild traumatic brain injury: Results of the WHO collaborating centre task force on mild traumatic brain injury. Journal of Rehabilitation Medicine. 2004;360: 84-105. PMID: 15083873

[44] Tommasone BA, McLeod TVC. Contact sport concussion incidence. Journal of Athletic Training. 2006;414:

DOI: http://dx.doi.org/10.5772/intechopen.80668

Cumulative Mild Head Injury (CMHI) in Contact Sports

Orthodontics. 2014;19:27-29. PMCID:

[52] Nel K, Govender S, Rapetsoa M, Nel C. Cumulative mild head injury (CMHI)

replication and extension study. Journal of Psychology in Africa. 2017;276: 549-552. DOI: 10.1080/14330237.

[53] Rizi RM, Yeung SS, Stewart NJ, Yeung EW. Risk factors that predict severe injuries in university rugby sevens. Journal of Science and Medicine

in Sport. 2017;20:648-652. DOI: 10.10.16/j.sams.2016.11.022

[54] Leung FT, Smith MMF, Brown M, Rahmann A, Mendis MD, Hides JA. Epidemiology in Australian school level rugby union. Journal of Science and Medicine in Sport. 2017;20:740-744. DOI: 10.1016/j.sa,s.2017.3.006

[55] Archbold HAP, Rankin AT, Webb M, Nicholas R, Eames NWA, Wilson RK, et al. Recurrent injury patterns in adolescent rugby. Physical Therapy in Sport. 2018;33:12-17. DOI: 10.1016/j.

[56] Ahmed OH, Hall EE. It was only a mild concussion: Exploring the description of sports concussion in online news articles. Physical Therapy in Sport. 2018;23:7-13. DOI: 10.1016/j.

[57] Kosoy J, Feinstein MD. Evaluation and management of concussion in young athletes. Current Problems in Pediatric and Adolescent Health Care.

[58] Tysvaer AT, Storli OV, Bachen NI. Soccer injuries to the brain. A neurologic and electroencephalographic study of former players. Acta Neurologica Scandinavica. 1989;802:151-156. DOI:

2018;48:1-11. DOI: 10.1016/j.

10.1177/036354658901700421

cppeds.2018.06.002

ptsp.2018.06.005

ptsp.2016.07.003

among college rugby players. A

PMC4296634

2017.1399571

[45] Zollman FS. Manual of Traumatic Brain Injury Management. 2nd ed. New York, NY: Demos Medical; 2016. ISBN

[46] A literature review on reaction time— Kosinki [internet]. 2012. Available from: https://www.semanticscholar. org/paper/A-Literature-Reviewon-Reaction-Time-Kosinski/ 2cc72c884223f51be27e0e536d1fb 19c1779f513 [Accessed: 25.04.2018]

[47] Ancer RL. Cumulative MHI in Rugby: Cognitive test profiles of professional Rugby and cricket players [thesis]. Grahamstown, South Africa:

[48] Ackermann TR. Minor "Dings"- Major Effects? A Study into the

Cognitive Effects of Mild Head Injuries in High School Rugby. Grahamstown, South Africa: Rhodes University; 2001

[49] Partington-Nel K. Boys and Balls "skoppe en koppe" Cumulative Mild Head Injury in contact sport: An evaluation of the cognitive profile of adolescent rugby players compared with non-contact sport controls [minithesis]. Grahamstown, South Africa:

[50] Shuttleworth-Edwards AB, Noakes TD, Radloff SE, Whitefield VJ, Clark SB, Roberts CO, et al. The comparative incidence of reported concussions presenting for follow-up management in south African Rugby union. Clinical Journal of Sport Medicine. 2008;185:

Rhodes University; 2000

Rhodes University; 2001

403-409. DOI: 10.1097/JSM.

[51] Faber J, Fonseca LM. How small sample size influences research outcomes. Dental Press Journal of

0b013e3181895910

65

470-472. PMID: 17273475

9781620700938

[38] New Zealand Rugby League. New Zealand rugby league concussion policy [Internet]. Available from: http:// websites.sportstg.com/get\_file.cgi?id= 1867985 [Accessed: 28.07.2018]

[39] Ruff T. Two decades of advances in understanding of Mild Traumatic Brain Injury. The Journal of Head Trauma Rehabilitation. 2001;2005:5-18. PMID: 15668567

[40] Paré N, Rabin LA, Fogel J, Pépin M. Mild traumatic brain injury and its sequelae: Characterisation of divided attention deficits. Neuropsychological Rehabilitation. 2009;191:110-137. DOI: 10.1080/09602010802106486

[41] Condor R, Condor AA. Neuropsychological and psychological rehabilitation interventions in refractory sport-related postconcussive syndrome. Brain Injury. 2014;292:1-14. DOI: 0.3109/ 02699052.2014.965209

[42] Boden BP, Tacchetti RL, Cantu RC, Knowles SB, Mueller FO. Catastrophic head injuries in high school and college football players. The American Journal of Sports Medicine. 2007;357: 1075-1081. DOI: 10.1177/0363546507 299239

[43] Carlson NE, Brenner LA, Wierman ME, Harrison-Felix C, Morey C, Gallagher S, et al. Hypogonadism on admission to acute rehabilitation is correlated with lower functional status at admission and discharge. Brain Injury. 2009;234:336-344. DOI: 10.1080/02699050902788535

Cumulative Mild Head Injury (CMHI) in Contact Sports DOI: http://dx.doi.org/10.5772/intechopen.80668

[44] Tommasone BA, McLeod TVC. Contact sport concussion incidence. Journal of Athletic Training. 2006;414: 470-472. PMID: 17273475

[29] Busl KM, Greer DM. Hypoxicischemic brain injury: Pathophysiology, neuropathology and mechanisms. NeuroRehabilitation. 2015;26:5-13. DOI:

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

[37] Carroll L, Cassidy JD, Peloso P, Borg J, von Holst H, Holm L, et al. Prognosis for mild traumatic brain

collaborating centre task force on mild traumatic brain injury. Journal of Rehabilitation Medicine. 2004;360:

[38] New Zealand Rugby League. New Zealand rugby league concussion policy [Internet]. Available from: http:// websites.sportstg.com/get\_file.cgi?id= 1867985 [Accessed: 28.07.2018]

[39] Ruff T. Two decades of advances in understanding of Mild Traumatic Brain Injury. The Journal of Head Trauma Rehabilitation. 2001;2005:5-18. PMID:

[40] Paré N, Rabin LA, Fogel J, Pépin M. Mild traumatic brain injury and its sequelae: Characterisation of divided attention deficits. Neuropsychological Rehabilitation. 2009;191:110-137. DOI:

Neuropsychological and psychological

[42] Boden BP, Tacchetti RL, Cantu RC, Knowles SB, Mueller FO. Catastrophic head injuries in high school and college football players. The American Journal of Sports Medicine. 2007;357: 1075-1081. DOI: 10.1177/0363546507

[43] Carlson NE, Brenner LA, Wierman ME, Harrison-Felix C, Morey C, Gallagher S, et al. Hypogonadism on admission to acute rehabilitation is correlated with lower functional status at admission and discharge. Brain Injury. 2009;234:336-344. DOI: 10.1080/02699050902788535

10.1080/09602010802106486

rehabilitation interventions in refractory sport-related postconcussive syndrome. Brain Injury. 2014;292:1-14. DOI: 0.3109/ 02699052.2014.965209

[41] Condor R, Condor AA.

injury: Results of the WHO

84-105. PMID: 15083873

15668567

299239

[30] Bey T, Ostick B. Second impact syndrome. The Western Journal of Emergency Medicine. 2009;101:6-10.

[31] Bigler ED. The lesion(s) in

traumatic brain injury: Implications for clinical neuropsychology. Archives of Clinical Neuropsychology. 2001;162: 95-131. DOI: 10.1016/S0887-6177(00)

[32] Strich SJ. Lesions in the cerebral hemispheres after blunt head injury. Journal of Clinical Pathology. 1970;314:

[33] Niogi SN, Mukherjee P, Ghajar J, Johnson C, Kolster RA, Sarkar R, et al. Extent of microstructural white matter injury in post-concussive syndrome correlates with impaired cognitive reaction time: A 3T diffusion tensor imaging study of mild traumatic brain

166-171. PMID: 4123922

injury. American Journal of

DOI: 0.3174/ajnr.A0970

22050943

64

Neuroradiology. 2008;295:967-973.

[35] Medical coding reference [Internet]. 2018. Available from: https://www. icd10data.com/ [Accessed: 18.05.2018]

[36] Diagnostic and Statistical Manual of Mental Disorders—5th ed [Internet].

sciencetheearth.com/uploads/2/4/6/5/ 24658156/dsm-v-manual\_pg490.pdf

Available from: https://www.

[Accessed: 04.06.2018]

[34] Daneshvar DH, O'Riley D, Nowinski CJ, McKee AC, Stern RA, Cantu RC. Long term consequences: Effects on normal development profile after concussion. Physical Medicine and Rehabilitation Clinics of North America. 2012;224:683-700. PMID:

10.3233/NRE-2010-0531

PMID: 19561758

00095-0

[45] Zollman FS. Manual of Traumatic Brain Injury Management. 2nd ed. New York, NY: Demos Medical; 2016. ISBN 9781620700938

[46] A literature review on reaction time— Kosinki [internet]. 2012. Available from: https://www.semanticscholar. org/paper/A-Literature-Reviewon-Reaction-Time-Kosinski/ 2cc72c884223f51be27e0e536d1fb 19c1779f513 [Accessed: 25.04.2018]

[47] Ancer RL. Cumulative MHI in Rugby: Cognitive test profiles of professional Rugby and cricket players [thesis]. Grahamstown, South Africa: Rhodes University; 2000

[48] Ackermann TR. Minor "Dings"- Major Effects? A Study into the Cognitive Effects of Mild Head Injuries in High School Rugby. Grahamstown, South Africa: Rhodes University; 2001

[49] Partington-Nel K. Boys and Balls "skoppe en koppe" Cumulative Mild Head Injury in contact sport: An evaluation of the cognitive profile of adolescent rugby players compared with non-contact sport controls [minithesis]. Grahamstown, South Africa: Rhodes University; 2001

[50] Shuttleworth-Edwards AB, Noakes TD, Radloff SE, Whitefield VJ, Clark SB, Roberts CO, et al. The comparative incidence of reported concussions presenting for follow-up management in south African Rugby union. Clinical Journal of Sport Medicine. 2008;185: 403-409. DOI: 10.1097/JSM. 0b013e3181895910

[51] Faber J, Fonseca LM. How small sample size influences research outcomes. Dental Press Journal of

Orthodontics. 2014;19:27-29. PMCID: PMC4296634

[52] Nel K, Govender S, Rapetsoa M, Nel C. Cumulative mild head injury (CMHI) among college rugby players. A replication and extension study. Journal of Psychology in Africa. 2017;276: 549-552. DOI: 10.1080/14330237. 2017.1399571

[53] Rizi RM, Yeung SS, Stewart NJ, Yeung EW. Risk factors that predict severe injuries in university rugby sevens. Journal of Science and Medicine in Sport. 2017;20:648-652. DOI: 10.10.16/j.sams.2016.11.022

[54] Leung FT, Smith MMF, Brown M, Rahmann A, Mendis MD, Hides JA. Epidemiology in Australian school level rugby union. Journal of Science and Medicine in Sport. 2017;20:740-744. DOI: 10.1016/j.sa,s.2017.3.006

[55] Archbold HAP, Rankin AT, Webb M, Nicholas R, Eames NWA, Wilson RK, et al. Recurrent injury patterns in adolescent rugby. Physical Therapy in Sport. 2018;33:12-17. DOI: 10.1016/j. ptsp.2018.06.005

[56] Ahmed OH, Hall EE. It was only a mild concussion: Exploring the description of sports concussion in online news articles. Physical Therapy in Sport. 2018;23:7-13. DOI: 10.1016/j. ptsp.2016.07.003

[57] Kosoy J, Feinstein MD. Evaluation and management of concussion in young athletes. Current Problems in Pediatric and Adolescent Health Care. 2018;48:1-11. DOI: 10.1016/j. cppeds.2018.06.002

[58] Tysvaer AT, Storli OV, Bachen NI. Soccer injuries to the brain. A neurologic and electroencephalographic study of former players. Acta Neurologica Scandinavica. 1989;802:151-156. DOI: 10.1177/036354658901700421

[59] Barnes BC, Cooper L, Kirkendall DT, McDermott TP, Jordan BD, Garrett WE. Concussion history in elite male and female soccer players. The American Journal of Sports Medicine. 1998;263:433-438. DOI: 10.1177/ 03635465980260031601

[60] Kross R, Ohler K, Barolin GS. Effects of heading in soccer on the head— A quantifying study of soccer players. EEG-EMG Zeitschrift fur Elektroenzephalograhie Elektromyographie und Verwandte Gebiete. 1986;144:209-212. PMID: 6418516

[61] Abreau F, Templer DI, Schuyler BA, Hutchison HT. Neuropsychological assessment of soccer players. Neuropsychology. 1990;43:175-181. DOI: 10.1037/0894-4105.4.3.175

[62] Putukian M, Echemendia RJ, Mackin S. The acute neuropsychological effects of heading in soccer: A pilot study. Clinical Journal of Sport Medicine. 2000;102:104-109. PMID: 10798791

[63] Kirkendall DT, Garrett WE. Heading in soccer: Integral skill or grounds for cognitive dysfunction? Journal of Athletic Training. 2001;363: 328-333. PMID: 12937505

[64] Maite P, Nel K, Govender S. Reaction time deficits incurred by cumulative mild head injury (CMHI) and post-concussion symptoms (PCS) between contact and non-contact sports players. A prospective study. Journal of Psychology in Africa. 2017;266:555-557. DOI: 10.1080/14330237.2016.1250415

[65] Nordstrom A, Nordstrom P, Ekstrand J. Sports-related concussion increases the risk of subsequent injury by about 50% in elite male football players. British Journal of Sports Medicine. 2014;48:1447-1450. DOI: 10.1136/BKS[PRTS-2013-093406

[66] Reilly T. Energetics of highintensity exercise (soccer) with particular reference to fatigue. Journal of Sports Sciences. 1989;153:257-263. DOI: 10.1080/026404197367263

[67] Should young soccer players be banned from heading the ball. 2016. Available from: https://www. theguardian.com/sport/2016/jan/22/usyoung-soccer-players-heading-ball [Accessed: 05.05.2018]

[68] Hammami N, Hattabi S, Salhi A, Rezgui T, Oueslati M, Bouassida A. Combat sports injuries profile: A review. Science & Sports. 2018;33:73-79. DOI: 101016/j.scispo.2017.04.014

[69] Mohotti D, Fernando PLN, Zaghoul A. Evaluation of possible head injuries ensuing a cricket ball impact. Computer Methods and Programmes in Biomedicine. 2018;158:193-205. DOI: 10.101016/j.cmpb.2018.02.2017

[70] Tripathi M, Shukla DP, Bhat DI, Bhagavatula ID, Mishra T. Craniofacial injuries in professional cricket: No more a red herring. Neurosurgical Focus. 2016;40:1-11. DOI: 10.317/ 2016.2FOCUS15341

[71] Jordan BD. Chronic traumatic brain injury in boxing. Seminars in Neurology. 2000;20:179-185. DOI: 10.4085/1062-6050.52.2.05

[72] Bentz JE. Concussion in American football and sports. Available from: http://www.jlgh.org/JLGH/ media/Journal-LGH-Media-Library/Past %20Issues/Volume%208%20-%20Issue %203/bentz8\_3.pdf [Accessed: 31.07.2018]

[73] Izraelski J. Concussions in the NHL: A narrative review of the literature. Journal of the Canadian Chiropractic Association. 2014;58:346-352. PCMID: PMC4262814

**67**

**Chapter 4**

Injury

**Abstract**

quantified in blood samples.

after hospitalization with TBI is 3.2 million [1].

Glasgow Coma Scale

**1. Introduction**

Neuronal and Glial Biomarkers

*Alexander Rodríguez, Eliana Cervera and Pedro Villalba*

**Keywords:** acute brain injury, biomarkers, blood-brain barrier, prognosis,

Every year, 1.1 million Americans are treated in emergency rooms for traumatic brain injury (TBI): 235,000 are hospitalized for nonfatal TBI and 50,000 died. In Finland, a prospective study found that 3.8% of the population had experienced at least one hospitalization due to traumatic brain injury before 35 years of age. Similarly, another study in New Zealand found that at 25 years of age, 31.6% of the population had experienced at least one TBI that required medical attention (hospitalization, emergency department, or doctor's office). It is estimated that 43.3% of Americans have residual disability 1 year after the damage. The most recent estimate of the prevalence of the US civilian residents living with disability

TBI is assessed and classified clinically according to the Glasgow Coma Scale (GCS) [2] and by imaging: axial computed tomography (CT) and magnetic resonance imaging (MRI). However, the use of GCS as a diagnostic tool is subject to important limitations, and it is difficult to assess the eye opening in patients with serious lesions on the face; likewise, the verbal response cannot be correctly esti-

mated in individuals who are under the influence of psychoactive drugs

The potential of early neurological inaccurate assessment of severity in patients with traumatic brain injury (TBI) has been highlighted; in some cases, for example, the severity of the injury is overestimated or underestimated. These findings have led to the search of biomarkers associated with early brain injury. Research in this field has exponentially increased over the past 20 years, with most publications on the subject in the last 10 years, whose results range from promising findings to other sometimes inconclusive one. An ideal biomarker should be able to demonstrate high sensitivity and specificity for brain injury, among other aspects. Literature has shown that there is not a single biomarker that predicts the patient's clinical decline with high sensitivity and specificity. Instead, it is required to use a panel of markers that reflect different aspects of head trauma. This chapter gives a review of the most promising biomarkers studied as predictors of severity of TBI, with a special focus on their nature, location, basal concentrations, and methods by which they can be

Research for Traumatic Brain

#### **Chapter 4**

[59] Barnes BC, Cooper L, Kirkendall DT, McDermott TP, Jordan BD, Garrett WE. Concussion history in elite male and female soccer players. The American Journal of Sports Medicine. 1998;263:433-438. DOI: 10.1177/

Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment

[66] Reilly T. Energetics of highintensity exercise (soccer) with particular reference to fatigue. Journal of Sports Sciences. 1989;153:257-263. DOI: 10.1080/026404197367263

[67] Should young soccer players be banned from heading the ball. 2016. Available from: https://www.

[Accessed: 05.05.2018]

101016/j.scispo.2017.04.014

Methods and Programmes in

2016;40:1-11. DOI: 10.317/ 2016.2FOCUS15341

injury in boxing. Seminars in Neurology. 2000;20:179-185. DOI: 10.4085/1062-6050.52.2.05

http://www.jlgh.org/JLGH/

31.07.2018]

PMC4262814

%203/bentz8\_3.pdf [Accessed:

theguardian.com/sport/2016/jan/22/usyoung-soccer-players-heading-ball

[68] Hammami N, Hattabi S, Salhi A, Rezgui T, Oueslati M, Bouassida A. Combat sports injuries profile: A review. Science & Sports. 2018;33:73-79. DOI:

[69] Mohotti D, Fernando PLN, Zaghoul A. Evaluation of possible head injuries ensuing a cricket ball impact. Computer

Biomedicine. 2018;158:193-205. DOI: 10.101016/j.cmpb.2018.02.2017

[70] Tripathi M, Shukla DP, Bhat DI, Bhagavatula ID, Mishra T. Craniofacial injuries in professional cricket: No more a red herring. Neurosurgical Focus.

[71] Jordan BD. Chronic traumatic brain

[72] Bentz JE. Concussion in American football and sports. Available from:

media/Journal-LGH-Media-Library/Past %20Issues/Volume%208%20-%20Issue

[73] Izraelski J. Concussions in the NHL: A narrative review of the literature. Journal of the Canadian Chiropractic Association. 2014;58:346-352. PCMID:

03635465980260031601

EEG-EMG Zeitschrift fur Elektroenzephalograhie

6418516

10798791

66

[60] Kross R, Ohler K, Barolin GS.

Elektromyographie und Verwandte Gebiete. 1986;144:209-212. PMID:

[62] Putukian M, Echemendia RJ, Mackin S. The acute neuropsychological effects of heading in soccer: A pilot study. Clinical Journal of Sport Medicine. 2000;102:104-109. PMID:

[63] Kirkendall DT, Garrett WE. Heading in soccer: Integral skill or grounds for cognitive dysfunction? Journal of Athletic Training. 2001;363:

[64] Maite P, Nel K, Govender S. Reaction time deficits incurred by cumulative mild head injury (CMHI) and post-concussion symptoms (PCS) between contact and non-contact sports players. A prospective study. Journal of Psychology in Africa. 2017;266:555-557. DOI: 10.1080/14330237.2016.1250415

[65] Nordstrom A, Nordstrom P, Ekstrand J. Sports-related concussion increases the risk of subsequent injury by about 50% in elite male football players. British Journal of Sports Medicine. 2014;48:1447-1450. DOI: 10.1136/BKS[PRTS-2013-093406

328-333. PMID: 12937505

Effects of heading in soccer on the head— A quantifying study of soccer players.

[61] Abreau F, Templer DI, Schuyler BA, Hutchison HT. Neuropsychological assessment of soccer players. Neuropsychology. 1990;43:175-181. DOI: 10.1037/0894-4105.4.3.175

## Neuronal and Glial Biomarkers Research for Traumatic Brain Injury

*Alexander Rodríguez, Eliana Cervera and Pedro Villalba*

#### **Abstract**

The potential of early neurological inaccurate assessment of severity in patients with traumatic brain injury (TBI) has been highlighted; in some cases, for example, the severity of the injury is overestimated or underestimated. These findings have led to the search of biomarkers associated with early brain injury. Research in this field has exponentially increased over the past 20 years, with most publications on the subject in the last 10 years, whose results range from promising findings to other sometimes inconclusive one. An ideal biomarker should be able to demonstrate high sensitivity and specificity for brain injury, among other aspects. Literature has shown that there is not a single biomarker that predicts the patient's clinical decline with high sensitivity and specificity. Instead, it is required to use a panel of markers that reflect different aspects of head trauma. This chapter gives a review of the most promising biomarkers studied as predictors of severity of TBI, with a special focus on their nature, location, basal concentrations, and methods by which they can be quantified in blood samples.

**Keywords:** acute brain injury, biomarkers, blood-brain barrier, prognosis, Glasgow Coma Scale

#### **1. Introduction**

Every year, 1.1 million Americans are treated in emergency rooms for traumatic brain injury (TBI): 235,000 are hospitalized for nonfatal TBI and 50,000 died. In Finland, a prospective study found that 3.8% of the population had experienced at least one hospitalization due to traumatic brain injury before 35 years of age. Similarly, another study in New Zealand found that at 25 years of age, 31.6% of the population had experienced at least one TBI that required medical attention (hospitalization, emergency department, or doctor's office). It is estimated that 43.3% of Americans have residual disability 1 year after the damage. The most recent estimate of the prevalence of the US civilian residents living with disability after hospitalization with TBI is 3.2 million [1].

TBI is assessed and classified clinically according to the Glasgow Coma Scale (GCS) [2] and by imaging: axial computed tomography (CT) and magnetic resonance imaging (MRI). However, the use of GCS as a diagnostic tool is subject to important limitations, and it is difficult to assess the eye opening in patients with serious lesions on the face; likewise, the verbal response cannot be correctly estimated in individuals who are under the influence of psychoactive drugs

and/or alcohol, and in those who are intubated or sedated will have limited linguistic capacities [3]. Given that the severity of the neurological injury may be underestimated in some cases and overestimated in others, attention has been focused on early assessment strategies in patients with TBI and their inaccuracy in special and frequent circumstances [4].

In view of the high rate of intubation and difficulties in the proper evaluation of the eye opening, Stocchetti et al. concluded that motor GCS score was more important than eye opening or verbal responses to predict the severity of the neurological injury. Other recent research has provided evidence that the use of sedative drugs avoids the accurate assessment of GCS during the first 24 h [5].

Other challenges for diagnosis are presented by the progressive nature of some brain injuries, which can lead to further neurological deterioration. In addition, neurological responses after TBI may vary over time for reasons unrelated to the injury. For example, trauma is frequently associated with alcohol and drug intoxication [6]. These factors together place the GCS in a position full of limitations that diminish its reliability as a highly sensitive test in specific and not infrequent circumstances such as those already mentioned.

On the other hand, neuroimaging techniques are used to provide objective information about the injury and its location [7] and are not influenced by the aforementioned confounding factors. However, the CT scan has a low sensitivity for diffuse brain injury, when the TBI is mild [8] and the availability and usefulness of MRI in the acute stage is limited. These facts, among others, have led to the search for alternative methods to assess the damage, being of special interest, the search for biomarkers, which are more reliable indicators of neuronal injury, due to its molecular context and its early expression.

Research in this field has increased exponentially in the last 20 years, with most publications on the subject in the last 10 years. Most markers are associated with cell damage. **Table 1** presents a summary of the TBI biomarkers most studied to date, including information about their nature, tissue location, molecular weight, half-life, basal levels, and physiopathological significance.

The main physiopathological mechanisms reflected by the glial or neuronal biomarkers are the disruption of the blood-brain barrier (BBBD) and neuronal injury, respectively. Taking into account this basis, it would be advantageous to have a panel of complementary biomarkers that show different temporal profiles and that reflect different physiopathological conditions subsequent to TBI. In a parallel manner, Papa et al. [9] propose that an ideal biomarker should have the following characteristics:


**69**

**Biomarker**

UCH-L1

NSE αIIespectrina

SBDP S-100B

MBP GFAP

**Table 1.**

*Main biomarkers in TBI and their properties.*

Glial (oligodendrocytes and

18.5 [50]

Myelin sheath component

protein

Cytoskeleton component

—

<0.03 ng/mL [30]

BBBD and neuronal

injury

protein

Schwann cells)

Glial (astrocytes)

40–53 [30]

Glial (astrocytes)

Neuronal

280 [41] 120 [41] 145 [41] 150 [41]

21 [50]

Calcium binding protein

Cytoskeleton component protein

2.9 h [48]

1.5 days [49]

1 day [49]

1 day [49]

97 minutes [47]

0.328–0.01 pg/mL [11]

BBBD

112 minutes [43]

12 h [43]

<0.3 ng/mL [50]

White matter injury

Neuronal

90 [45] 78 [46]

Enzyme

24 h [46] 48 h [41]

<12.5 ng/mL [47]

≤15 ng/mL [46]

—

Apoptosis

**Location** Neuronal

**Molecular mass [KDa]**

20 [41] 24 [42]

**Nature** Ubiquitination enzyme

20 minutes [43]

0.12 ng/mL [44]

**Half life**

**Basal concentrations**

**Significance** Neuronal injury

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

Neuronal injury



*Main biomarkers in TBI and their properties.*

#### *Neuronal and Glial Biomarkers Research for Traumatic Brain Injury DOI: http://dx.doi.org/10.5772/intechopen.85555*

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

avoids the accurate assessment of GCS during the first 24 h [5].

circumstances such as those already mentioned.

molecular context and its early expression.

half-life, basal levels, and physiopathological significance.

1.demonstrate high sensitivity and specificity for brain injury;

2. stratify the patients according to the severity of the injury;

3.have rapid appearance in the accessible biological liquid;

8. easily measured by simple techniques widely available.

6.monitor the progress of the disease and the response to the treatment;

4.provide information about injury mechanisms;

5.have biokinetic properties;

7.predict the functional result; and

frequent circumstances [4].

and/or alcohol, and in those who are intubated or sedated will have limited linguistic capacities [3]. Given that the severity of the neurological injury may be underestimated in some cases and overestimated in others, attention has been focused on early assessment strategies in patients with TBI and their inaccuracy in special and

In view of the high rate of intubation and difficulties in the proper evaluation of the eye opening, Stocchetti et al. concluded that motor GCS score was more important than eye opening or verbal responses to predict the severity of the neurological injury. Other recent research has provided evidence that the use of sedative drugs

Other challenges for diagnosis are presented by the progressive nature of some brain injuries, which can lead to further neurological deterioration. In addition, neurological responses after TBI may vary over time for reasons unrelated to the injury. For example, trauma is frequently associated with alcohol and drug intoxication [6]. These factors together place the GCS in a position full of limitations that diminish its reliability as a highly sensitive test in specific and not infrequent

On the other hand, neuroimaging techniques are used to provide objective information about the injury and its location [7] and are not influenced by the aforementioned confounding factors. However, the CT scan has a low sensitivity for diffuse brain injury, when the TBI is mild [8] and the availability and usefulness of MRI in the acute stage is limited. These facts, among others, have led to the search for alternative methods to assess the damage, being of special interest, the search for biomarkers, which are more reliable indicators of neuronal injury, due to its

Research in this field has increased exponentially in the last 20 years, with most publications on the subject in the last 10 years. Most markers are associated with cell damage. **Table 1** presents a summary of the TBI biomarkers most studied to date, including information about their nature, tissue location, molecular weight,

The main physiopathological mechanisms reflected by the glial or neuronal biomarkers are the disruption of the blood-brain barrier (BBBD) and neuronal injury, respectively. Taking into account this basis, it would be advantageous to have a panel of complementary biomarkers that show different temporal profiles and that reflect different physiopathological conditions subsequent to TBI. In a parallel manner, Papa et al. [9] propose that an ideal biomarker should have the following

**68**

characteristics:

**69**

In this chapter, we present a compendium of the most studied biomarkers in the TBI, its possible applications, and the current techniques for its detection.

#### **2. Most studied biomarkers in TBI**

As explained in previous paragraphs, there is no single biomarker that is sufficiently sensitive and specific to study the physiopathological mechanisms that derive from head trauma. Next, we will mention some of the most studied biomarkers given its rapid elevation after trauma and its relationship with the mechanism of injury. One of the most studied biomarkers is the Ca binder protein S-100β, a glial protein at the astrocyte level that is related to alterations in the blood-brain barrier [10]. Its rapid elevation and its considerable concentration release in the serum facilitate the study of the protein and its correlation with the severity of the injury. Due to the type of cells found in the central nervous system, it is necessary to study biomarkers that allow us to demonstrate not only glial injury but also neuronal. One of the most studied biomarkers in this sense is the C-terminal hydrolase of ubiquitin-L1, which is a highly specific cytoplasmic neuronal enzyme [11, 12]. Finally, we will delve into glial fibrillary acidic protein (GFAP), which is also a glial protein and is part of the cytoskeleton of astrocytes and is also related to the disruption of the blood-brain barrier [11, 13].

#### **2.1 The Ca binder protein S-100β**

S-100 β is a central nervous system (CNS) protein found predominantly in astrocytes and is the most studied peripheral biomarker of BBBD. This calcium binding protein (CBP) S-100β increases initially after the accident and then decreases rapidly after the traumatic injuries. In cell models, their release has been demonstrated from the first 15 seconds after the trauma. In humans, the earliest that has been detected is 30 minutes posttrauma. The approximate half-life of this protein is 97 minutes [10], the peak occurs on day 0, and the concentrations decrease toward the sixth day in both CSF and serum.

Goyal et al. [14] reported basal levels of S-100β in healthy CSF controls of 0.0754–0.0034 ng/mL and in serum of 0.328–0.101 pg/mL. This protein has been studied extensively in mild TBI (mTBI), so that high levels in serum are associated with an increase in the incidence of post-concussion syndrome [15] and neurological dysfunction. There are also several studies that have reported a correlation between serum levels of S-100β and the presence of pathological findings in cerebral magnetic resonance imaging (MRI), as well as abnormalities in neuropsychological exploration after mTBI [16].

Most studies show that the S-100β measurement can distinguish injured patients from noninjured patients with an uncertain degree of utility in predicting mortality either acutely or at several points in time (**Table 2**) [17–19]. In general terms, S-100β is a sensitive but not specific predictor of CT abnormalities. Using low serum cut-off values, the sensitivity oscillates between 90 and 100% with a specificity between 4 and 65%.

Müller et al. [17] reported a sensitivity of 0.95 (95% CI 0.76–1.0) for S-100β measured within the first 12 h with a specificity of 31% (95% CI 0.25–0.38) relative to abnormal findings on skull CT scan in a study of 226 adult patients admitted to the hospital with a diagnosis of mild TBI (GCS 13–15). Biberthaler et al. [19] found similar results using a cut-off level of S-100β of 0.1 ng/mL, measured within the first 3 h posttrauma in 1309 patients with mTBI and correlating them to head CT findings. The sensitivity was 99% (95% CI 0.96–1.0), and the specificity was 30% (95% CI 0.29–0.31).

**71**

0.41–0.59) [20].

cut-off value of 0.08 ng/mL [21].

polytraumatized patient.

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

**Reference Detection method Sample Findings**

ELISA CSF and

serum

Increase in CSF and serum first 6 days

Correlation between serum and CSF levels

Level in CSF is a potential predictor of GOS

Mean and peak are predictors of mortality in

It cannot replace the clinical examination or

It can serve as support for the selection of

using the two measurement techniques; cut-off value calculated: 0.18 ng/mL.

post-trauma

and DRS

severe TBI

decreased over time

Serum Significantly elevated in intracranial injury

Serum Increase was related to findings in the CT

the use of CT in mTBI

patients for TC S: 90–100%, E: 4–65%

S: 100%, E: 46%

scan S: 99%, E: 30%

Long term and Rapid test Serum Concentrations were significantly correlated

The usefulness of S-100β as a marker does not seem to be affected by the concomitant consumption of alcohol. Mussack et al. conducted a study in which they included patients with mild TBI with demonstrated blood alcohol levels (mean = 182 mg/dL), and found that the sensitivity of S-100β in the first 3 h posttrauma was 100% (95% CI 0.83 a 1.0) and the specificity was 50% (95% CI

ELISA Serum S: 80%, E: 40%

On the other hand, Bazarian et al. studied 96 patients with TBI, GCS 13–15 who also presented trauma of extracranial localization, and found a sensitivity of 80% (95% CI 0.36–0.96) and a specificity of 40% (95% CI 0.01–0.09) for S-100β with a

From the studies described above, it can be deduced that the sensitivity increases as the time elapsed between the trauma and the sample taking (window) decreases, as well as an increase in specificity is observed when the cut-off value increases. In contrast, the limitations of the use of S-100β as a marker are due to the marked decrease in sensitivity and specificity in the context of the polytraumatized patient, since the presence of concomitant extracranial trauma also causes the release and plasma elevation of this protein. The presence of S-100β has been reported in tissues other than the nervous one, mainly in adipose tissue [22]. From this observation, a negative effect on the specificity of this marker is expected, due to the increase that would occur in the context of extracranial lesions, as occurs in the

Pham et al. [22] characterized the tissue specificity of S-100β and evaluated the extracranial sources of this marker and how they affect serum levels of this marker. For this purpose, they performed the extraction of proteins from nine different human tissues (liver, bladder, kidney, colon, lung, muscle, pancreas, adipose tissue, brain, tonsils, stomach, and skin) and their subsequent analysis through ELISA

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

Automated LIAISON system [AB DiaSorin, Bromma, Sweden]

Elecsys S100 [Roche Diagnostics, Mannheim,

*Summary of the evidence reported in the literature on biomarkers in S-100B.*

Germany]

Goyal et al. [14]

Berger et al [51]

Biberthaler et al [19]

Biberthaler et al [52]

Bazarian, et al [21]

**Table 2.**


*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury DOI: http://dx.doi.org/10.5772/intechopen.85555*

#### **Table 2.**

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

**2. Most studied biomarkers in TBI**

**2.1 The Ca binder protein S-100β**

the sixth day in both CSF and serum.

chological exploration after mTBI [16].

ficity between 4 and 65%.

(95% CI 0.29–0.31).

In this chapter, we present a compendium of the most studied biomarkers in the

As explained in previous paragraphs, there is no single biomarker that is sufficiently sensitive and specific to study the physiopathological mechanisms that derive from head trauma. Next, we will mention some of the most studied biomarkers given its rapid elevation after trauma and its relationship with the mechanism of injury. One of the most studied biomarkers is the Ca binder protein S-100β, a glial protein at the astrocyte level that is related to alterations in the blood-brain barrier [10]. Its rapid elevation and its considerable concentration release in the serum facilitate the study of the protein and its correlation with the severity of the injury. Due to the type of cells found in the central nervous system, it is necessary to study biomarkers that allow us to demonstrate not only glial injury but also neuronal. One of the most studied biomarkers in this sense is the C-terminal hydrolase of ubiquitin-L1, which is a highly specific cytoplasmic neuronal enzyme [11, 12]. Finally, we will delve into glial fibrillary acidic protein (GFAP), which is also a glial protein and is part of the cytoskeleton of astrocytes and is also related to the disruption of the blood-brain barrier [11, 13].

S-100 β is a central nervous system (CNS) protein found predominantly in astrocytes and is the most studied peripheral biomarker of BBBD. This calcium binding protein (CBP) S-100β increases initially after the accident and then decreases rapidly after the traumatic injuries. In cell models, their release has been demonstrated from the first 15 seconds after the trauma. In humans, the earliest that has been detected is 30 minutes posttrauma. The approximate half-life of this protein is 97 minutes [10], the peak occurs on day 0, and the concentrations decrease toward

Goyal et al. [14] reported basal levels of S-100β in healthy CSF controls of 0.0754–0.0034 ng/mL and in serum of 0.328–0.101 pg/mL. This protein has been studied extensively in mild TBI (mTBI), so that high levels in serum are associated with an increase in the incidence of post-concussion syndrome [15] and neurological dysfunction. There are also several studies that have reported a correlation between serum levels of S-100β and the presence of pathological findings in cerebral magnetic resonance imaging (MRI), as well as abnormalities in neuropsy-

Most studies show that the S-100β measurement can distinguish injured patients from noninjured patients with an uncertain degree of utility in predicting mortality either acutely or at several points in time (**Table 2**) [17–19]. In general terms, S-100β is a sensitive but not specific predictor of CT abnormalities. Using low serum cut-off values, the sensitivity oscillates between 90 and 100% with a speci-

Müller et al. [17] reported a sensitivity of 0.95 (95% CI 0.76–1.0) for S-100β measured within the first 12 h with a specificity of 31% (95% CI 0.25–0.38) relative to abnormal findings on skull CT scan in a study of 226 adult patients admitted to the hospital with a diagnosis of mild TBI (GCS 13–15). Biberthaler et al. [19] found similar results using a cut-off level of S-100β of 0.1 ng/mL, measured within the first 3 h posttrauma in 1309 patients with mTBI and correlating them to head CT findings. The sensitivity was 99% (95% CI 0.96–1.0), and the specificity was 30%

TBI, its possible applications, and the current techniques for its detection.

**70**

*Summary of the evidence reported in the literature on biomarkers in S-100B.*

The usefulness of S-100β as a marker does not seem to be affected by the concomitant consumption of alcohol. Mussack et al. conducted a study in which they included patients with mild TBI with demonstrated blood alcohol levels (mean = 182 mg/dL), and found that the sensitivity of S-100β in the first 3 h posttrauma was 100% (95% CI 0.83 a 1.0) and the specificity was 50% (95% CI 0.41–0.59) [20].

On the other hand, Bazarian et al. studied 96 patients with TBI, GCS 13–15 who also presented trauma of extracranial localization, and found a sensitivity of 80% (95% CI 0.36–0.96) and a specificity of 40% (95% CI 0.01–0.09) for S-100β with a cut-off value of 0.08 ng/mL [21].

From the studies described above, it can be deduced that the sensitivity increases as the time elapsed between the trauma and the sample taking (window) decreases, as well as an increase in specificity is observed when the cut-off value increases. In contrast, the limitations of the use of S-100β as a marker are due to the marked decrease in sensitivity and specificity in the context of the polytraumatized patient, since the presence of concomitant extracranial trauma also causes the release and plasma elevation of this protein. The presence of S-100β has been reported in tissues other than the nervous one, mainly in adipose tissue [22]. From this observation, a negative effect on the specificity of this marker is expected, due to the increase that would occur in the context of extracranial lesions, as occurs in the polytraumatized patient.

Pham et al. [22] characterized the tissue specificity of S-100β and evaluated the extracranial sources of this marker and how they affect serum levels of this marker. For this purpose, they performed the extraction of proteins from nine different human tissues (liver, bladder, kidney, colon, lung, muscle, pancreas, adipose tissue, brain, tonsils, stomach, and skin) and their subsequent analysis through ELISA

and Western blot in 200 subjects receiving chemotherapy for the management of CNS lymphomas. A dose of mannitol (1.4M) was administered intra-arterially in the carotid or vertebral artery, subsequently confirming the presence of BBBD by a head CT performed immediately after chemotherapy.

The results presented in that study showed that extracranial sources of S-100β do not affect serum levels. Therefore, the diagnostic value and the negative predictive value of S-100β are not compromised in the context of patients with neurological diseases, but without traumatic lesions, whether cerebral or extracranial.

Goyal et al. [14] also evaluated S-100β as a prognostic biomarker in adult subjects with severe TBI (sTBI) by comparing the results with the S-100β temporal profiles in both CSF (n = 138 subjects) and serum (n = 80 subjects) for 6 days. The variables used to evaluate the extracerebral sources of S-100β in serum were: long bone fracture, Injury Severity Score (ISS), and isolated skull trauma. After TBI, levels of S-100β in CSF and serum were increased compared to healthy controls during the first 6 days after TBI (p ≤ 0.005 and p ≤ 0.031). Although levels in CSF and serum had a high correlation at the early post-TCE time points, this association decreased with time. The bivariate analysis showed that subjects who had temporary CSF profiles with higher concentrations of S-100B had higher acute mortality (p < 0.001) and worse Glasgow Outcome Scale (GOS; p = 0.002) and disability scores (DRS) (p = 0.039) 6 months after the injury. Temporary profiles in serum were associated with acute mortality (p = 0.015), possibly as a result of the extracerebral sources of S-100β in the serum, represented by high ISSs (p = 0.032).

Due to its temporal elevation profile, and the pathophysiological mechanisms that cause its release toward serum, S-100β constitutes an excellent candidate as an early biomarker of TBI, with the possible limitation in patients with concomitant trauma in other sites that leads to the serum elevation of S-100β from extracranial sources.

#### **2.2 Ubiquitin C-terminal hydrolase-L1 (UCH-L1)**

The C-terminal hydrolase of ubiquitin-L1 (ubiquitin C-terminal hydrolase-L1, UCH-L1) is an E2 conjugation enzyme present in the cytoplasm of almost all neurons [13] and has previously been used as a neuronal histological marker due to its great abundance and specific expression in these cells [11]. Its location has also been shown in neurons of the peripheral nervous system, particularly in the neuromuscular junction [12], as well as in cells of the neuroendocrine system. In addition, the presence of UCH-L1 has been demonstrated in aortic endothelial cells and in smooth muscle and tumor cells [23]. This enzyme accomplishes the function of adding and removing ubiquitin from proteins in order to promote its degradation via the proteasome-dependent pathway [24].

UCH-L1 is one of the most recent biomarkers proposed for TBI, and for this reason, there are still limited data that demonstrate its usefulness (**Table 3**).

Three isoenzymes of UCH (UCH-L1, UCH-L2, and UCH-L3) have been identified, being UCH-L1, the only one present in high concentrations in the central nervous system [24]. In a prospective case-control study with 66 patients, Papa et al. [24] obtained ventricular CSF samples for each patient after 6, 12, 24, 48, 72, 96, 120, 144, and 168 h after TBI for the UCH-L1 detection by ELISA. The severity was determined by the Glasgow Scale (GCS) and CT findings. Mortality and neurological sequelae were evaluated at 6 months. This study showed that patients with TBI had a significant elevation of CSF UCH-L1 levels at each point in time compared to controls, with total mean in TBI patients = 44.2 ng/mL (±7.9) vs. 2.7 ng/mL (±0.7) in controls (p < 0.001). Significantly elevated levels of UCH-L1 were found in

**73**

required to validate these findings.

*Summary of the evidence reported in the literature on UCH-L1.*

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

**Reference Detection method Sample Findings**

ELISA CSF

Sandwich ELISA CSF

Electrochemiluminescence immunoassay (ECL-IA)

ELISA CSF Increase at 6, 12, 24, 48, 72, 96, 120, 144,

and serum

and serum 6 months.

ELISA Serum Elevated in GCS 15 vs. controls without trauma

Sandwich ELISA Serum Measurement <24 h posttrauma distinguished

ELISA Serum There were no significant differences between

received.

and 168 h post-trauma, X = 44.2 ng/mL (±7.9), versus controls X = 2.7 ng/mL (±0.7) (p < 0.001). Also elevated when it exists: lower GCS at 24 h, post-trauma complications, deaths in the first 6 weeks, or serious sequelae at

Significant correlation between biokinetics and means of (UCH-L1) in CSF and serum in severe TBI (rs = 0.59, p < 0.001) (AUC, rs = 0.3, p = 0.027). Increased levels <24 h posttrauma, statistically significant in Cmax (0–24 h) in CSF

It remains elevated up to 7 days after TBI, serum AUC and statistically significant CSF at all-time points up to 24 h (p < 0.001). Levels in <12 h in GCS 3–5 > GCS 6–8 (p = 0.07 and p = 0.02, Mann-Whitney test, respectively). Significantly higher and prolonged serum and CSF levels in non-survivors. A level of >5.22 ng/mL was a

(AUC 0.8) and controls with trauma. Higher elevation in GCS 15 plus TAC or neurosurgical intervention requirement. It provides evidence

injury. Significantly elevated levels in patients in

presence and absence of intracranial lesions (AUC of 0.713). No correlation between levels in mild TCE and recovery at 6 months. Significant increase in levels in moderate/ severe TCE compared with mild TBI. Good sensitivity to discriminate between TCE and controls (AUC 0.87). Combination with GFAP showed greater sensitivity and specificity for

the levels of negative controls and TCE <6 h posttrauma, independent of the CT. The levels were high after each game but without correlation with the number of hits

and serum in those who died.

predictor of mortality (OR 4.8).

as a potential marker of mild TBI.

Serum Complements brain MRI in the detection of

the diagnosis of TBI (AUC 0.94).

the acute state of mild TBI.

patients with a lower score in the GCS at 24 h, in those who had presented posttrauma complications, in those who died within the first 6 weeks, and in those with severe sequelae at 6 months. These data suggest that this marker would be useful in determining severity in patients with TBI. Similar studies with larger samples are

Additional studies have confirmed the positive correlation between the concentrations of UCH-L1 at the CSF level and serum samples [25]. Similarly, Mondello

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

Papa et al. [24]

Brophy et al. [53]

Mondello et al. [26]

Papa et al. [11]

Kou et al. [27]

Diaz-Arrastia et al. [28]

Puvenna et al. [15]

**Table 3.**


*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury DOI: http://dx.doi.org/10.5772/intechopen.85555*

#### **Table 3.**

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

head CT performed immediately after chemotherapy.

**2.2 Ubiquitin C-terminal hydrolase-L1 (UCH-L1)**

via the proteasome-dependent pathway [24].

and Western blot in 200 subjects receiving chemotherapy for the management of CNS lymphomas. A dose of mannitol (1.4M) was administered intra-arterially in the carotid or vertebral artery, subsequently confirming the presence of BBBD by a

The results presented in that study showed that extracranial sources of S-100β do not affect serum levels. Therefore, the diagnostic value and the negative predictive value of S-100β are not compromised in the context of patients with neurological diseases, but without traumatic lesions, whether cerebral or extracranial. Goyal et al. [14] also evaluated S-100β as a prognostic biomarker in adult subjects with severe TBI (sTBI) by comparing the results with the S-100β temporal profiles in both CSF (n = 138 subjects) and serum (n = 80 subjects) for 6 days. The variables used to evaluate the extracerebral sources of S-100β in serum were: long bone fracture, Injury Severity Score (ISS), and isolated skull trauma. After TBI, levels of S-100β in CSF and serum were increased compared to healthy controls during the first 6 days after TBI (p ≤ 0.005 and p ≤ 0.031). Although levels in CSF and serum had a high correlation at the early post-TCE time points, this association decreased with time. The bivariate analysis showed that subjects who had temporary CSF profiles with higher concentrations of S-100B had higher acute mortality (p < 0.001) and worse Glasgow Outcome Scale (GOS; p = 0.002) and disability scores (DRS) (p = 0.039) 6 months after the injury. Temporary profiles in serum were associated with acute mortality (p = 0.015), possibly as a result of the extracerebral sources of S-100β in the serum, represented by high ISSs

Due to its temporal elevation profile, and the pathophysiological mechanisms that cause its release toward serum, S-100β constitutes an excellent candidate as an early biomarker of TBI, with the possible limitation in patients with concomitant trauma in other sites that leads to the serum elevation of S-100β from extracranial

The C-terminal hydrolase of ubiquitin-L1 (ubiquitin C-terminal hydrolase-L1, UCH-L1) is an E2 conjugation enzyme present in the cytoplasm of almost all neurons [13] and has previously been used as a neuronal histological marker due to its great abundance and specific expression in these cells [11]. Its location has also been shown in neurons of the peripheral nervous system, particularly in the neuromuscular junction [12], as well as in cells of the neuroendocrine system. In addition, the presence of UCH-L1 has been demonstrated in aortic endothelial cells and in smooth muscle and tumor cells [23]. This enzyme accomplishes the function of adding and removing ubiquitin from proteins in order to promote its degradation

UCH-L1 is one of the most recent biomarkers proposed for TBI, and for this reason, there are still limited data that demonstrate its usefulness (**Table 3**).

Three isoenzymes of UCH (UCH-L1, UCH-L2, and UCH-L3) have been identified, being UCH-L1, the only one present in high concentrations in the central nervous system [24]. In a prospective case-control study with 66 patients, Papa et al. [24] obtained ventricular CSF samples for each patient after 6, 12, 24, 48, 72, 96, 120, 144, and 168 h after TBI for the UCH-L1 detection by ELISA. The severity was determined by the Glasgow Scale (GCS) and CT findings. Mortality and neurological sequelae were evaluated at 6 months. This study showed that patients with TBI had a significant elevation of CSF UCH-L1 levels at each point in time compared to controls, with total mean in TBI patients = 44.2 ng/mL (±7.9) vs. 2.7 ng/mL (±0.7) in controls (p < 0.001). Significantly elevated levels of UCH-L1 were found in

**72**

(p = 0.032).

sources.

*Summary of the evidence reported in the literature on UCH-L1.*

patients with a lower score in the GCS at 24 h, in those who had presented posttrauma complications, in those who died within the first 6 weeks, and in those with severe sequelae at 6 months. These data suggest that this marker would be useful in determining severity in patients with TBI. Similar studies with larger samples are required to validate these findings.

Additional studies have confirmed the positive correlation between the concentrations of UCH-L1 at the CSF level and serum samples [25]. Similarly, Mondello

et al. [26] conducted a case-control study with 95 patients with severe TBI in order to evaluate the CSF and serum concentrations of UCH-L1 by sandwich ELISA and its association with clinical results. The temporal profile of the marker in both CSF and serum was studied during the first 7 days following the trauma and compared with controls showing significantly higher levels compared to the controls throughout the 7-day period, also confirming a high sensitivity and specificity for the diagnosis of TBI versus controls, with statistically significant serum AUC and CSF values at all-time points up to 24 h (p < 0.001).

The levels of UCH-L1 in the first 12 h in both CSF and serum in patients with GCS 3–5 were also significantly higher than in those with GCS 6–8. In addition, UCH-L1 levels in CSF and serum appeared to distinguish between patients with severe TBI survivors and nonsurvivors within the study, such that those who died had significantly higher CSF and serum UCHL1 levels, as well as greater permanence of these levels over time. In this study, a serum level of UCH-L1 > 5.22 ng/mL was a predictor of mortality (OR 4.8).

Papa et al. [11] also analyzed UCH-L1 in serum taken in the first 4 h posttrauma in patients with mild (n = 86) and moderate (n = 10) TBI, as well as in controls with trauma and controls without trauma. For patients with a GCS of 15, serum UCH-L1 was significantly elevated compared to controls without trauma, with an AUC of 0.87, and was also compared with controls with trauma, and was even higher in those patients with GCS of 15 who also had positive findings on the CT scan or required some neurosurgical intervention, suggesting that UCH-L1 may be a potential marker of mild TBI. Additionally, 5% of patients with GCS of 15 (4/77) required neurosurgical intervention, which was higher than the 1% found in patients with GCS 14–15 reported in the study by Jagoda et al., in which the samples were taken within the first 24 h posttrauma [10].

It is inferred from these data that the earlier it is detected posttrauma, the sensitivity of this marker increases. In a smaller study (n = 9), serum UCHL1 (taken <6 h posttraumatic) was found to be significantly elevated in patients with mild TBI [27].

In another study focused on all levels of severity of TBI, serum UCH-1 measured before 24 h posttrauma could distinguish patients with intracranial lesions from those without intracranial lesions with an AUC = 0.713 [28]. However, there was no correlation between UCH-L1 levels in patients with mTBI and recovery at 6 months as measured by the GOSE scale. While there was a significant increase in UCH-L1 levels in patients with moderate/severe TBI compared to mild TBI, patients with mild TBI were not compared with controls.

In a research carried out in a secondary school, Puvenna et al. [15] selected 15 American football players; they obtained serum samples before and after each of two different games. They did not observe significant differences between the levels of UCH-L1 between the negative controls and the positive individuals for mild TBI within the first 6 h posttrauma, regardless of whether or not positive CT findings existed. In addition to this, there was no correlation between the serum levels of UCH-L1 and the number of impacts received. The levels of UCH-L1 and S-100β, markers of neuronal injury and BBBD, respectively, were both elevated after each game. However, only S-100β, unlike UCH-L1, was correlated with the number of hits received and the UCH-L1 elevation did not correlate with the S-100β increments. The authors suggest that elevated postgame UCH-L1 levels may be due to the release of this protein from the neuromuscular junction.

It can be concluded that there are very divergent data regarding the use of UCH-L1 as a serum biomarker of mild TBI. Some studies suggest that it is a promising marker, while others do not find a correlation with the lesion. Release from sources other than the central nervous system could contribute to elevated serum levels.

**75**

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

sample does not allow the conclusions to be validated.

median of 0.85 and correlated positively with age.

than when it was done late (**Table 4**).

was 0.82 for GFAP and 0.77 for S-100β.

Glial fibrillary acidic protein (GFAP) is a protein derived from glial cells, which is a part of the intermediate filament of the cytoskeleton of astrocytes, where it is the most abundant protein. It is considered a specific marker of CNS diseases, and is also related to several neuronal processes' harmful agents that compromise the integrity of the blood-brain barrier [29], and has been shown to be a potentially useful biomarker for predicting clinical outcomes in TBI. Its normal level in serum is <0.03 ng/mL [30], so any elevation thereof will indicate BBBD (**Table 4**).

Due to its great immunoreactivity, GAFP has been used as an indicator of brain injury in experimental models of mTCE [31]. The first successful measurement of GFAP in human blood was made in 1999 in 12 of 25 patients with severe TBI [32]. Using a weight drop model with mice [33] to evaluate two levels of mTBI, one with hemorrhage (complicated mTBI) and another without bleeding (uncomplicated mTBI), Yang et al. [34] found that serum GFAP was significantly elevated in both injury models at 90 minutes and 6 h after injury, but had returned to normal at 24 h. In the study of Kou et al. [27], significantly elevated serum levels of GFAP in the first 24 h posttrauma in 9 mTBI patients was also reported; this elevation being even more significant in those with hemorrhagic lesions; however, the small size of the

In another study, Mondello et al. [35] evaluated whether the relationship between a neuronal marker (UCH-L1) and a glial marker (GFAP) correlates with the presence of different intracranial pathologies after brain trauma. They obtained serum samples from 59 patients with sTBI on admission to the hospital and measured levels of UCH-L1 and GFAP. The glial/neuronal ratio (GNR) was measured as the quotient between the concentrations of GFAP and UCH-L1. Logistic regression analysis identified variables associated with the type of injury. The increase in GNR was associated independently with the type of injury, but not with the age, gender, GCS, or trauma mechanism. This quotient was significantly higher in the patients who died, but it was not an independent predictor of mortality. The GNR had a

When evaluating the CT scan of the skull on admission, 29 patients presented a diffuse lesion and 30 localized lesions. The GNR was significantly higher in the group with focal lesions compared to the group with diffuse lesions. The receiver operating characteristic (ROC) analysis showed that the GNR discriminated between the two types of injury. GNR was more accurate when performed early

These data indicate that the GNR provides valuable information about the different types of injury, which is of great clinical utility. In addition, the GNR can help to identify the pathophysiological mechanisms subsequent to the different types of TBI. This is very useful when implementing therapeutic measures.

In an investigation carried out by Papa et al. [36], the capacity of the GFAP taken <4 h posttrauma was compared to predict intracranial lesions in the CT compared to S-100β. Although patients had GCS 9–15, only 3 of 209 patients had GCS <13 and only 10% had intracranial lesions, both S-100β and GFAP were significantly elevated in all patients, and even more so in those with intracranial lesions. For those patients with GCS 14–15, the AUC for the identification of intracranial lesions

In the presence of extracranial lesions and using a cut-off value of 0.067 ng/mL, GFAP was 100% sensitive and 55% specific in the prediction of intracranial lesions. With a cut-off value of 0.20 ng/mL, S-100β also had 100% sensitivity but only 5% specificity. This study concludes that GFAP exceeds S-100β in the identification of intracranial lesions in mild and moderate TBI, even in the presence of extracranial lesions.

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

**2.3 The fibrillary acid glial protein (GFAP)**

#### **2.3 The fibrillary acid glial protein (GFAP)**

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

values at all-time points up to 24 h (p < 0.001).

were taken within the first 24 h posttrauma [10].

mild TBI were not compared with controls.

release of this protein from the neuromuscular junction.

was a predictor of mortality (OR 4.8).

et al. [26] conducted a case-control study with 95 patients with severe TBI in order to evaluate the CSF and serum concentrations of UCH-L1 by sandwich ELISA and its association with clinical results. The temporal profile of the marker in both CSF and serum was studied during the first 7 days following the trauma and compared with controls showing significantly higher levels compared to the controls throughout the 7-day period, also confirming a high sensitivity and specificity for the diagnosis of TBI versus controls, with statistically significant serum AUC and CSF

The levels of UCH-L1 in the first 12 h in both CSF and serum in patients with GCS 3–5 were also significantly higher than in those with GCS 6–8. In addition, UCH-L1 levels in CSF and serum appeared to distinguish between patients with severe TBI survivors and nonsurvivors within the study, such that those who died had significantly higher CSF and serum UCHL1 levels, as well as greater permanence of these levels over time. In this study, a serum level of UCH-L1 > 5.22 ng/mL

Papa et al. [11] also analyzed UCH-L1 in serum taken in the first 4 h posttrauma

It is inferred from these data that the earlier it is detected posttrauma, the sensitivity of this marker increases. In a smaller study (n = 9), serum UCHL1 (taken <6 h posttraumatic) was found to be significantly elevated in patients with mild TBI [27]. In another study focused on all levels of severity of TBI, serum UCH-1 measured before 24 h posttrauma could distinguish patients with intracranial lesions from those without intracranial lesions with an AUC = 0.713 [28]. However, there was no correlation between UCH-L1 levels in patients with mTBI and recovery at 6 months as measured by the GOSE scale. While there was a significant increase in UCH-L1 levels in patients with moderate/severe TBI compared to mild TBI, patients with

In a research carried out in a secondary school, Puvenna et al. [15] selected 15 American football players; they obtained serum samples before and after each of two different games. They did not observe significant differences between the levels of UCH-L1 between the negative controls and the positive individuals for mild TBI within the first 6 h posttrauma, regardless of whether or not positive CT findings existed. In addition to this, there was no correlation between the serum levels of UCH-L1 and the number of impacts received. The levels of UCH-L1 and S-100β, markers of neuronal injury and BBBD, respectively, were both elevated after each game. However, only S-100β, unlike UCH-L1, was correlated with the number of hits received and the UCH-L1 elevation did not correlate with the S-100β increments. The authors suggest that elevated postgame UCH-L1 levels may be due to the

It can be concluded that there are very divergent data regarding the use of UCH-L1 as a serum biomarker of mild TBI. Some studies suggest that it is a promising marker, while others do not find a correlation with the lesion. Release from sources other than the central nervous system could contribute to elevated

in patients with mild (n = 86) and moderate (n = 10) TBI, as well as in controls with trauma and controls without trauma. For patients with a GCS of 15, serum UCH-L1 was significantly elevated compared to controls without trauma, with an AUC of 0.87, and was also compared with controls with trauma, and was even higher in those patients with GCS of 15 who also had positive findings on the CT scan or required some neurosurgical intervention, suggesting that UCH-L1 may be a potential marker of mild TBI. Additionally, 5% of patients with GCS of 15 (4/77) required neurosurgical intervention, which was higher than the 1% found in patients with GCS 14–15 reported in the study by Jagoda et al., in which the samples

**74**

serum levels.

Glial fibrillary acidic protein (GFAP) is a protein derived from glial cells, which is a part of the intermediate filament of the cytoskeleton of astrocytes, where it is the most abundant protein. It is considered a specific marker of CNS diseases, and is also related to several neuronal processes' harmful agents that compromise the integrity of the blood-brain barrier [29], and has been shown to be a potentially useful biomarker for predicting clinical outcomes in TBI. Its normal level in serum is <0.03 ng/mL [30], so any elevation thereof will indicate BBBD (**Table 4**).

Due to its great immunoreactivity, GAFP has been used as an indicator of brain injury in experimental models of mTCE [31]. The first successful measurement of GFAP in human blood was made in 1999 in 12 of 25 patients with severe TBI [32]. Using a weight drop model with mice [33] to evaluate two levels of mTBI, one with hemorrhage (complicated mTBI) and another without bleeding (uncomplicated mTBI), Yang et al. [34] found that serum GFAP was significantly elevated in both injury models at 90 minutes and 6 h after injury, but had returned to normal at 24 h.

In the study of Kou et al. [27], significantly elevated serum levels of GFAP in the first 24 h posttrauma in 9 mTBI patients was also reported; this elevation being even more significant in those with hemorrhagic lesions; however, the small size of the sample does not allow the conclusions to be validated.

In another study, Mondello et al. [35] evaluated whether the relationship between a neuronal marker (UCH-L1) and a glial marker (GFAP) correlates with the presence of different intracranial pathologies after brain trauma. They obtained serum samples from 59 patients with sTBI on admission to the hospital and measured levels of UCH-L1 and GFAP. The glial/neuronal ratio (GNR) was measured as the quotient between the concentrations of GFAP and UCH-L1. Logistic regression analysis identified variables associated with the type of injury. The increase in GNR was associated independently with the type of injury, but not with the age, gender, GCS, or trauma mechanism. This quotient was significantly higher in the patients who died, but it was not an independent predictor of mortality. The GNR had a median of 0.85 and correlated positively with age.

When evaluating the CT scan of the skull on admission, 29 patients presented a diffuse lesion and 30 localized lesions. The GNR was significantly higher in the group with focal lesions compared to the group with diffuse lesions. The receiver operating characteristic (ROC) analysis showed that the GNR discriminated between the two types of injury. GNR was more accurate when performed early than when it was done late (**Table 4**).

These data indicate that the GNR provides valuable information about the different types of injury, which is of great clinical utility. In addition, the GNR can help to identify the pathophysiological mechanisms subsequent to the different types of TBI. This is very useful when implementing therapeutic measures.

In an investigation carried out by Papa et al. [36], the capacity of the GFAP taken <4 h posttrauma was compared to predict intracranial lesions in the CT compared to S-100β. Although patients had GCS 9–15, only 3 of 209 patients had GCS <13 and only 10% had intracranial lesions, both S-100β and GFAP were significantly elevated in all patients, and even more so in those with intracranial lesions. For those patients with GCS 14–15, the AUC for the identification of intracranial lesions was 0.82 for GFAP and 0.77 for S-100β.

In the presence of extracranial lesions and using a cut-off value of 0.067 ng/mL, GFAP was 100% sensitive and 55% specific in the prediction of intracranial lesions. With a cut-off value of 0.20 ng/mL, S-100β also had 100% sensitivity but only 5% specificity. This study concludes that GFAP exceeds S-100β in the identification of intracranial lesions in mild and moderate TBI, even in the presence of extracranial lesions.


#### **Table 4.**

*Summary of the evidence reported in the literature on GFAP in TBI.*

In general, GFAP seems to increase in TBI and could represent a more sensitive marker than S-100β for the identification of intracranial lesions. However, for further validation, more studies are needed that focus specifically on mTBI (GCS 13–15), which include appropriate controls and adequate statistical comparisons.

#### **3. Discussions and conclusions**

One of the main purposes of the search for potential biomarkers in the TBI is to predict the presence of pathological findings in head CT and brain MRI; however, the studies published in this regard are inconclusive, and the evidence favors the use of S-100β over other markers in mTBI, as a predictor of negative-CT.

For example, Posti et al. [37] showed that patients with orthopedic trauma had higher levels of GFAP at admission, than those with mTBI and negative-CT (p = 0.026), and did not show that UCH-L1 levels presented significant differences in both groups, performing measurements at different time points, which suggest that these markers are not useful for distinguishing patients with negative-CT mTBI from patients with orthopedic trauma, and that high levels of UCH-L1 or GFAP can

**77**

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

sum of Rotterdam CT score and Stockholm CT score [54].

lead to a false diagnosis of mTBI in polytraumatized patients, leading to the unnec-

On the other hand, the use of the S-100β marker has been recommended in the Scandinavian guidelines for the initial management of minimal, mild, and moderate head injuries in adults [38] as an alternative to reduce the number of CT in the subgroup of mTBI with low risk of intracranial complications or surgical interventions. More studies are needed that show the usefulness of S-100β as a predictor of

The use of neuroimaging is necessary to improve the accuracy of biomarkers in the diagnosis and prognosis of patients who have suffered a TBI, with CT being the first option and the one with the most studies in relation to the release and correlation of biomarkers. Some reviews report higher serum S-100β levels in more severe, focal lesions, compared to diffuse lesions using Marshall scale, and a strong correlation between S100B increasing and the severity of the CT finding when using the

Olivecrona et al. reported how S-100β and neuronal specific enolase (NSE) levels correlate with CT findings using the aforementioned scales. Specifically, S-100β levels, but not to the NSE levels, correlates with Morris-Marshall score for the classification of traumatic subarachnoid hemorrhage (tSAH). This is probably associated with the physiopathological pathways described by each of these biomarkers after a neurotrauma. Likewise, the volume of the parenchymal contusions is also associated with the S-100β levels. Furthermore, in mild TBI, initial low levels of S-100β can be used as a predictor of a stationary injury, suggesting that the CT

Diagnosis of severity and prognosis of CT findings cannot be performed by a single biomarker test. Instead, a combination of biomarkers of diverse origins and pathways displays a better performance. Thereby, the joint use of GFAP, heart fatty acid binding protein (H-FABP), S-100β, and IL-10 results in a more efficient diagnostic tool with a 46% specificity and 100% sensitivity for predicting CT injuries. This biomarker panel increases specificity by 14% compared to the best

The ALERT-TBI study, developed in 22 centers in USA and Europe, validated the ability of the combination of UCH-L1 and GFAP to predict CT injuries within 12 h of mTBI, resulting in a sensitivity of 97.6%, a negative predictive value (NPV) of 99.6%, and a specificity of 36.4%. Therefore, when indicating CT only in those patients with a positive GFAP and UCH-L1 test, the CT use could be reduced by approximately onethird. The extent of these findings to patients with moderate TBI is uncertain [57]. The study of the available evidence on the different serum markers in TBI presented in this chapter allows us to conclude that, currently, there is not a single biomarker capable of predicting the clinical deterioration of patients with high sensitivity and specificity. However, the pathophysiological mechanisms of TBI suggest that instead, a panel of markers that reflect different aspects of traumatic

The literature has shown that the joint use of S-100β and GFAP or UCH-L1 would represent a valuable early prognostic and follow-up tool in TBI in addition to the GCS and the CT, thus guiding the decisions of initial management and aggres-

Likewise, given that the kinetic profile of these markers is different, since it presents peaks of appearance earlier than others and different times of permanence in serum, its usefulness would also be correlated with different post-traumatic stages, so that S-100β and UCH-L1 are better early markers [24, 25], whereas GFAP is a better predictor of CT lesions and surgical interventions in the first 7 days post-

injury should be available, including BBBD and neuronal injury.

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

neurodeterioration in moderate TBI.

classification does not evolve [55].

single biomarker [56].

sive interventions.

trauma in mild and moderate TBI [27].

essary use of neuroimaging.

#### *Neuronal and Glial Biomarkers Research for Traumatic Brain Injury DOI: http://dx.doi.org/10.5772/intechopen.85555*

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

Electrochemiluminescence immunoassay (ECL-IA)

Kou et al. [27]

Mondello et al. [35]

Papa et al. [36]

Papa et al. [54]

Okonkwo et al. [55]

**Table 4.**

**Reference Detection method Sample Findings**

Serum Significantly elevated in all cases of intracranial

validate the conclusions.

extracranial lesions.

of severity at the time.

Sandwich ELISA Serum Evaluation of GNR (GFAP/UCH-L1):

ELISA Serum S-100B and GFAP significantly elevated in all

ELISA Serum GFAP-BDP significantly elevated in mild

ELISA Serum GFAP-BDP <24 h posttrauma distinguished

hemorrhage, with potential screening capacity. Small size of the sample does not allow to

Median = 0.85, positive correlation with age (R = 0.45, p = 0.003). Greater in focalized lesions vs. diffuse lesion (1.77 vs. 0.48, respectively, p = 0.003). Different type of lesions (AUC = 0.72, p = 0.003). More precise early measurement (<12 h posttrauma) vs. late (AUC = 0.80, p = 0.002). Independent association with the type of injury, but not with the GCS. Independent predictor of mortality.

patients, especially in intracranial injuries. For GCS 14–15, AUC = 0.82 in identification of intracranial lesions for GFAP (0.77 for S-100B). With extracranial lesions and cut-off 0.067 ng/ mL, GFAP: S = 100% and E = 55% to predict intracranial lesions. GFAP outperforms S-100B in the identification of intracranial lesions in mild and moderate TBI, even in the presence of

TCE vs. controls with or without trauma. AUC = 0.88 to identify brain injury in GCS 15. Higher levels in GCS 15 with positive CT.

between mild and moderate/severe TBI (AUC of 0.87). Controls were not included, mild to moderate TCE was not compared, and most of the statistical analysis was made with all levels

In general, GFAP seems to increase in TBI and could represent a more sensitive

One of the main purposes of the search for potential biomarkers in the TBI is to predict the presence of pathological findings in head CT and brain MRI; however, the studies published in this regard are inconclusive, and the evidence favors the use

For example, Posti et al. [37] showed that patients with orthopedic trauma had higher levels of GFAP at admission, than those with mTBI and negative-CT (p = 0.026), and did not show that UCH-L1 levels presented significant differences in both groups, performing measurements at different time points, which suggest that these markers are not useful for distinguishing patients with negative-CT mTBI from patients with orthopedic trauma, and that high levels of UCH-L1 or GFAP can

marker than S-100β for the identification of intracranial lesions. However, for further validation, more studies are needed that focus specifically on mTBI (GCS 13–15), which include appropriate controls and adequate statistical comparisons.

of S-100β over other markers in mTBI, as a predictor of negative-CT.

**3. Discussions and conclusions**

*Summary of the evidence reported in the literature on GFAP in TBI.*

**76**

lead to a false diagnosis of mTBI in polytraumatized patients, leading to the unnecessary use of neuroimaging.

On the other hand, the use of the S-100β marker has been recommended in the Scandinavian guidelines for the initial management of minimal, mild, and moderate head injuries in adults [38] as an alternative to reduce the number of CT in the subgroup of mTBI with low risk of intracranial complications or surgical interventions. More studies are needed that show the usefulness of S-100β as a predictor of neurodeterioration in moderate TBI.

The use of neuroimaging is necessary to improve the accuracy of biomarkers in the diagnosis and prognosis of patients who have suffered a TBI, with CT being the first option and the one with the most studies in relation to the release and correlation of biomarkers. Some reviews report higher serum S-100β levels in more severe, focal lesions, compared to diffuse lesions using Marshall scale, and a strong correlation between S100B increasing and the severity of the CT finding when using the sum of Rotterdam CT score and Stockholm CT score [54].

Olivecrona et al. reported how S-100β and neuronal specific enolase (NSE) levels correlate with CT findings using the aforementioned scales. Specifically, S-100β levels, but not to the NSE levels, correlates with Morris-Marshall score for the classification of traumatic subarachnoid hemorrhage (tSAH). This is probably associated with the physiopathological pathways described by each of these biomarkers after a neurotrauma. Likewise, the volume of the parenchymal contusions is also associated with the S-100β levels. Furthermore, in mild TBI, initial low levels of S-100β can be used as a predictor of a stationary injury, suggesting that the CT classification does not evolve [55].

Diagnosis of severity and prognosis of CT findings cannot be performed by a single biomarker test. Instead, a combination of biomarkers of diverse origins and pathways displays a better performance. Thereby, the joint use of GFAP, heart fatty acid binding protein (H-FABP), S-100β, and IL-10 results in a more efficient diagnostic tool with a 46% specificity and 100% sensitivity for predicting CT injuries. This biomarker panel increases specificity by 14% compared to the best single biomarker [56].

The ALERT-TBI study, developed in 22 centers in USA and Europe, validated the ability of the combination of UCH-L1 and GFAP to predict CT injuries within 12 h of mTBI, resulting in a sensitivity of 97.6%, a negative predictive value (NPV) of 99.6%, and a specificity of 36.4%. Therefore, when indicating CT only in those patients with a positive GFAP and UCH-L1 test, the CT use could be reduced by approximately onethird. The extent of these findings to patients with moderate TBI is uncertain [57].

The study of the available evidence on the different serum markers in TBI presented in this chapter allows us to conclude that, currently, there is not a single biomarker capable of predicting the clinical deterioration of patients with high sensitivity and specificity. However, the pathophysiological mechanisms of TBI suggest that instead, a panel of markers that reflect different aspects of traumatic injury should be available, including BBBD and neuronal injury.

The literature has shown that the joint use of S-100β and GFAP or UCH-L1 would represent a valuable early prognostic and follow-up tool in TBI in addition to the GCS and the CT, thus guiding the decisions of initial management and aggressive interventions.

Likewise, given that the kinetic profile of these markers is different, since it presents peaks of appearance earlier than others and different times of permanence in serum, its usefulness would also be correlated with different post-traumatic stages, so that S-100β and UCH-L1 are better early markers [24, 25], whereas GFAP is a better predictor of CT lesions and surgical interventions in the first 7 days posttrauma in mild and moderate TBI [27].

In addition to the above, the literature also shows that these biomarkers are being measured with techniques that demand the use of complex equipment and procedures (such as ELISA) in which the use of labels is necessary [6, 39], displaying the need for the development of rapid and cost-effective techniques that allow the implementation of biomarkers in the clinical setting.

### **Acknowledgements**

We thank Universidad del Norte and Colciencias for the financial support of the research project in which the development of this work is framed.

### **Conflict of interest**

The authors declare no conflict of interest.

#### **Author details**

Alexander Rodríguez\*, Eliana Cervera and Pedro Villalba Department of Medicine, Universidad del Norte, Barranquilla, Colombia

\*Address all correspondence to: alexandersanjuan@uninorte.edu.co

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**79**

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

Press/Taylor and Francis Group; 2016. pp. 263-276. DOI: 10.1201/b18959-13

[9] Papa L et al. Use of biomarkers for diagnosis and management of traumatic brain injury patients. Expert Opinion on Medical Diagnostics. 2008;**2**(8):937-945.

DOI: 10.1517/17530059.2.8.937

[10] Jagoda A et al. Clinical policy: Neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting. Annals of Emergency Medicine. 2008;**52**(6):714-748. DOI: 10.1016/j.annemergmed.2008.08.021

[11] Papa L et al. Serum levels of ubiquitin C-terminal hydrolase

TA.0b013e3182491e3d

pnas.0911516107

BCJ20160082

neu.2012.2579

distinguish mild traumatic brain injury from trauma controls and are elevated in mild and moderate traumatic brain injury patients with intracranial lesions and neurosurgical intervention. Journal of Trauma and Acute Care Surgery. 2012;**72**(5):1335-1344. DOI: 10.1097/

[12] Chen F, Sugiura Y, Myers K, Liu Y, Lin W. Ubiquitin carboxyl-terminal hydrolase L1 is required for maintaining the structure and function of the neuromuscular junction. Proceedings of the National Academy of Sciences of the United States of America. 2010;**107**(4):1636-1641. DOI: 10.1073/

[13] Bishop P, Rocca D, Henley J. Ubiquitin C-terminal hydrolase L1 (UCH-L1): Structure , distribution and roles in brain function and

dysfunction. The Biochemical Journal. 2016;**473**(16):2453-2462. DOI: 10.1042/

[14] Goyal A et al. S100b as a prognostic biomarker in outcome prediction for patients with severe traumatic brain injury. Journal of Neurotrauma. 2013;**30**(11):946-957. DOI: 10.1089/

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

[1] Corrigan J, Selassie A, Orman J. The epidemiology of traumatic brain injury. The Journal of Head Trauma Rehabilitation. 2010;**2**(2):72-80. DOI: 10.1097/HTR.0b013e3181ccc8b4

[2] Matis G, Birbilis T. The Glasgow coma scale—A brief review past, present, future. Acta Neurologica Belgica. 2008;**108**(3):75-89

[3] Forastero P, Echevarria C, Barrera J. Traumatismos craneoencefálicos. Escalas de valoración para la medida de resultados en rehabilitación. Rehabilitación. 2002;**36**(6):408-417. DOI: 10.1016/S0048-7120(02)73314-8

[4] Stocchetti N et al. Inaccurate early assessment of neurological severity in head injury. Journal of Neurotrauma. 2004;**21**(9):1131-1140. DOI: 10.1089/

[5] Livingston B, Mackenzie S, MacKirdy F, Howie J. Should the presedation glasgow coma scale value be used when calculating acute physiology and chronic health evaluation scores for sedated patients? Critical Care Medicine.

[6] Mondello S, Muller U, Jeromin A, Streeter J, Hayes R, Wang K. Bloodbased diagnostics of traumatic brain injuries. Expert Review of Molecular Diagnostics. 2011;**11**(1):65-78. DOI:

[7] Carney N et al. Guidelines for the management of severe traumatic brain injury, fourth edition. Journal of Neurotrauma. 2017;**80**(1):6-15. DOI: 10.1227/NEU.0000000000001432

[8] Zhang J, Puvenna V, Janigro

D. Biomarkers of traumatic brain injury and their relationship to pathology. In: Laskowitz D, Grant G, editors. Translational Research in Traumatic Brain Injury. Boca Raton, FL: CRC

neu.2004.21.1131

2000;**28**(2):389-394

10.1586/erm.10.104

**References**

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury DOI: http://dx.doi.org/10.5772/intechopen.85555*

#### **References**

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

the implementation of biomarkers in the clinical setting.

The authors declare no conflict of interest.

research project in which the development of this work is framed.

**Acknowledgements**

**Conflict of interest**

In addition to the above, the literature also shows that these biomarkers are being measured with techniques that demand the use of complex equipment and procedures (such as ELISA) in which the use of labels is necessary [6, 39], displaying the need for the development of rapid and cost-effective techniques that allow

We thank Universidad del Norte and Colciencias for the financial support of the

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Department of Medicine, Universidad del Norte, Barranquilla, Colombia

\*Address all correspondence to: alexandersanjuan@uninorte.edu.co

**78**

**Author details**

provided the original work is properly cited.

Alexander Rodríguez\*, Eliana Cervera and Pedro Villalba

[1] Corrigan J, Selassie A, Orman J. The epidemiology of traumatic brain injury. The Journal of Head Trauma Rehabilitation. 2010;**2**(2):72-80. DOI: 10.1097/HTR.0b013e3181ccc8b4

[2] Matis G, Birbilis T. The Glasgow coma scale—A brief review past, present, future. Acta Neurologica Belgica. 2008;**108**(3):75-89

[3] Forastero P, Echevarria C, Barrera J. Traumatismos craneoencefálicos. Escalas de valoración para la medida de resultados en rehabilitación. Rehabilitación. 2002;**36**(6):408-417. DOI: 10.1016/S0048-7120(02)73314-8

[4] Stocchetti N et al. Inaccurate early assessment of neurological severity in head injury. Journal of Neurotrauma. 2004;**21**(9):1131-1140. DOI: 10.1089/ neu.2004.21.1131

[5] Livingston B, Mackenzie S, MacKirdy F, Howie J. Should the presedation glasgow coma scale value be used when calculating acute physiology and chronic health evaluation scores for sedated patients? Critical Care Medicine. 2000;**28**(2):389-394

[6] Mondello S, Muller U, Jeromin A, Streeter J, Hayes R, Wang K. Bloodbased diagnostics of traumatic brain injuries. Expert Review of Molecular Diagnostics. 2011;**11**(1):65-78. DOI: 10.1586/erm.10.104

[7] Carney N et al. Guidelines for the management of severe traumatic brain injury, fourth edition. Journal of Neurotrauma. 2017;**80**(1):6-15. DOI: 10.1227/NEU.0000000000001432

[8] Zhang J, Puvenna V, Janigro D. Biomarkers of traumatic brain injury and their relationship to pathology. In: Laskowitz D, Grant G, editors. Translational Research in Traumatic Brain Injury. Boca Raton, FL: CRC

Press/Taylor and Francis Group; 2016. pp. 263-276. DOI: 10.1201/b18959-13

[9] Papa L et al. Use of biomarkers for diagnosis and management of traumatic brain injury patients. Expert Opinion on Medical Diagnostics. 2008;**2**(8):937-945. DOI: 10.1517/17530059.2.8.937

[10] Jagoda A et al. Clinical policy: Neuroimaging and decisionmaking in adult mild traumatic brain injury in the acute setting. Annals of Emergency Medicine. 2008;**52**(6):714-748. DOI: 10.1016/j.annemergmed.2008.08.021

[11] Papa L et al. Serum levels of ubiquitin C-terminal hydrolase distinguish mild traumatic brain injury from trauma controls and are elevated in mild and moderate traumatic brain injury patients with intracranial lesions and neurosurgical intervention. Journal of Trauma and Acute Care Surgery. 2012;**72**(5):1335-1344. DOI: 10.1097/ TA.0b013e3182491e3d

[12] Chen F, Sugiura Y, Myers K, Liu Y, Lin W. Ubiquitin carboxyl-terminal hydrolase L1 is required for maintaining the structure and function of the neuromuscular junction. Proceedings of the National Academy of Sciences of the United States of America. 2010;**107**(4):1636-1641. DOI: 10.1073/ pnas.0911516107

[13] Bishop P, Rocca D, Henley J. Ubiquitin C-terminal hydrolase L1 (UCH-L1): Structure , distribution and roles in brain function and dysfunction. The Biochemical Journal. 2016;**473**(16):2453-2462. DOI: 10.1042/ BCJ20160082

[14] Goyal A et al. S100b as a prognostic biomarker in outcome prediction for patients with severe traumatic brain injury. Journal of Neurotrauma. 2013;**30**(11):946-957. DOI: 10.1089/ neu.2012.2579

[15] Puvenna V et al. Significance of ubiquitin carboxy terminal hydrolase L1 elevations in athletes after subconcussive head hits. PLoS One. 2014;**9**(5):e96296. DOI: 10.1371/journal. pone.0096296

[16] Adrian H et al. Biomarkers of traumatic brain injury: Temporal changes in body fluids. eNeuro. 2016;**3**(6):ENEURO.0294-16.2016. DOI: 10.1523/ENEURO.0294-16.2016

[17] Müller K et al. S100B serum level predicts computed tomography findings after minor head injury. The Journal of Trauma. 2007;**62**(6):1452-1456. DOI: 10.1097/TA.0b013e318047bfaa

[18] Ingebrigtsen T et al. The clinical value of serum S-100 protein measurements in minor head injury: A Scandinavian multicentre study. Brain Injury. 2000;**14**(12):1047-1055

[19] Biberthaler P et al. Serum S100B concentration provides additional information for the indication of computed tomography in patients after minor head injury: A prospective multicenter study. Shock. 2006;**25**(5):446-453. DOI: 10.1097/01. shk.0000209534.61058.35

[20] Mussack T et al. Immediate S-100B and neuron-specific enolase plasma measurements for rapid evaluation of primary brain damage in alcoholintoxicated, minor head-injured patients. Shock. 2002;**18**(5):395-400

[21] Bazarian J, Beck C, Blyth B, Von Ahsen N, Hasselblatt M. Impact of creatine kinase correction on the predictive value of S-100B after mild traumatic brain injury. Restorative Neurology and Neuroscience. 2010;**24**(3):163-172

[22] Pham et al. Extracranial sources of S100B do not affect serum levels. PLoS One. 2010;**5**(9):e12691. DOI: 10.1371/ journal.pone.0012691

[23] Campbell L, Thomas J, Lamps L, Smoller B, Folpe A. Protein gene product 9.5 (PGP 9.5) is not a specific marker of neural and nerve sheath tumors: An immunohistochemical study of 95 mesenchymal neoplasms. Modern Pathology. 2003;**16**(10):963-969. DOI: 10.1097/01.MP.0000087088.88280.B0

[24] Papa et al. Ubiquitin C-terminal hydrolase is a novel biomarker in humans for severe traumatic brain injury. Critical Care Medicine. 2010;**38**(1):138-144. DOI: 10.1097/ CCM.0b013e3181b788a

[25] Brophy G et al. Biokinetic analysis of ubiquitin C-terminal hydrolase-L1 (UCH-L1) in severe traumatic brain injury patient biofluids. Journal of Neurotrauma. 2001;**28**(6):861-870. DOI: 10.1089/neu.2010.156

[26] Mondello S et al. Clinical utility of serum levels of ubiquitin C-terminal hydrolase as a biomarker for severe traumatic brain injury. Neurosurgery. 2012;**70**(3):666-675. DOI: 10.1227/ NEU.0b013e318236a809

[27] Kou Z et al. Combining biochemical and imaging markers to improve diagnosis and characterization of mild traumatic brain injury in the acute setting: Results from a pilot study. PLoS One. 2013;**19**(8):11, e80296. DOI: 10.1371/journal.pone.0080296

[28] Diaz-Arrastia et al. Acute biomarkers of traumatic brain injury: Relationship between plasma levels of ubiquitin C-terminal hydrolase-L1 and glial fibrillary acidic protein. Journal of Neurotrauma. 2014;**31**(1):19-25. DOI: 10.1089/neu.2013.3040

[29] Eng L, Ghirnikar R, Lee Y. Glial fibrillary acidic protein: GFAP-thirtyone years (1969-2000). Neurochemical Research. 2000;**25**(9):1439-1451

**81**

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

[38] Undén L et al. Validation of the Scandinavian guidelines for initial management ofminimal, mild and moderate traumatic brain injury in adults. BMC Medicine. 2015;**13**:292. DOI: 10.1186/s12916-015-0533-y

[39] Strathmann FG et al. Blood-based biomarkers for traumatic brain injury: Evaluation of research approaches, available methods and potential utility from the clinician and clinical laboratory perspectives. Clinical Biochemistry. 2014;**47**(10-11):876-888. DOI: 10.1016/j.clinbiochem.2014.01.028

[40] Papa L, Brophy G, Welch R, Lewis L, Braga C, Tan C, et al. Time course and diagnostic accuracy of glial and neuronal blood biomarkers GFAP and UCH-L1 in a large cohort of trauma patients with and without mild traumatic brain injury. JAMA Neurology. 2016;**73**(5):551-560. DOI: 10.1001/jamaneurol.2016.0039

[41] Kövesdi E, Lückl J, Bukovics P, Farkas O, Pál J, Czeiter E, et al. Update on protein biomarkers in traumatic brain injury with emphasis on clinical use in adults and pediatrics. Acta Neurochirurgica. 2010;**152**:1-17. DOI:

10.1007/s00701-009-0463-6

[42] North S, Shriver-Lake L, Taitt C, Ligler F. Rapid analytical methods for on-site triage for traumatic brain injury. Annual Review of Analytical Chemistry. 2012;**5**(1):35-56. DOI: 10.1146/ annurev-anchem-062011-143105

[43] Mondello S, Akinyi L, Buki A, Robicsek S, Gabrielli A, Tepas J, et al. NIH public access. 2013;**70**(3):666-675

Determinación radioinmunométrica de la enolasa neuronal específica en humor acuoso y suero, en pacientes con retinoblastoma. Revista Española de Medicina Nuclear e Imagen Molecular.

[44] Benito I, Rodríguez J.

2000;**7**:472-478

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

traumatic brain injury. The Journal of

[31] Saatman K, Bolton A. Regional neurodegeneration and gliosis are amplified by mild traumatic brain injury repeated at {24-hour} intervals. Journal of Neuropathology and Experimental Neurology. 2014;**73**(10):933-947. DOI: 10.1097/NEN.0000000000000115

Trauma. 2002;**52**(4):798-808

[32] Missler U, Wiesmann M, Wittmann G, Magerkurth O,

1999;**45**(1):138-141

Hagenström H. Measurement of glial fibrillary acidic protein in human blood: Analytical method and preliminary clinical results. Clinical Chemistry.

[33] Albert-Weissenberger C, Sirén AL. Experimental traumatic brain injury. Experimental & Translational

Stroke Medicine. 2010;**2**(1):16

10.1186/2040-7378-2-16

DOI: 10.1089/neu.2011.2092

DOI: 10.1089/neu.2013.3245

DOI: 10.1089/neu.2016.4442

[34] Yang S et al. A murine model of mild traumatic brain injury exhibiting cognitive and motor deficits. The Journal of Surgical Research. 2013;**184**(2):981-988. DOI:

[35] Mondello S et al. Glial neuronal ratio: A novel index for differentiating injury type in patients with severe traumatic brain injury. Journal of Neurotrauma. 2012;**29**(6):1096-1104.

[36] Papa L et al. GFAP out-performs S100beta in detecting traumatic intracranial lesions on computed tomography in trauma patients with mild traumatic brain injury and those with extracranial lesions. Journal of Neurotrauma. 2014;**31**(22):1815-1822.

[37] Posti JP et al. Glial fibrillary acidic protein and ubiquitin C-terminal hydrolase-L1 are not specific biomarkers for mild CT-negative traumatic brain injury. Journal of Neurotrauma. 2017.

[30] Ingebrigtsen T, Romner B. Biochemical serum markers of *Neuronal and Glial Biomarkers Research for Traumatic Brain Injury DOI: http://dx.doi.org/10.5772/intechopen.85555*

traumatic brain injury. The Journal of Trauma. 2002;**52**(4):798-808

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

[23] Campbell L, Thomas J, Lamps L, Smoller B, Folpe A. Protein gene product 9.5 (PGP 9.5) is not a specific marker of neural and nerve sheath tumors: An immunohistochemical study of 95 mesenchymal neoplasms. Modern Pathology. 2003;**16**(10):963-969. DOI: 10.1097/01.MP.0000087088.88280.B0

[24] Papa et al. Ubiquitin C-terminal hydrolase is a novel biomarker in humans for severe traumatic brain injury. Critical Care Medicine. 2010;**38**(1):138-144. DOI: 10.1097/

[25] Brophy G et al. Biokinetic analysis of ubiquitin C-terminal hydrolase-L1 (UCH-L1) in severe traumatic brain injury patient biofluids. Journal of Neurotrauma. 2001;**28**(6):861-870. DOI:

[26] Mondello S et al. Clinical utility of serum levels of ubiquitin C-terminal hydrolase as a biomarker for severe traumatic brain injury. Neurosurgery. 2012;**70**(3):666-675. DOI: 10.1227/

[27] Kou Z et al. Combining biochemical

and imaging markers to improve diagnosis and characterization of mild traumatic brain injury in the acute setting: Results from a pilot study. PLoS One. 2013;**19**(8):11, e80296. DOI:

10.1371/journal.pone.0080296

[28] Diaz-Arrastia et al. Acute

10.1089/neu.2013.3040

biomarkers of traumatic brain injury: Relationship between plasma levels of ubiquitin C-terminal hydrolase-L1 and glial fibrillary acidic protein. Journal of Neurotrauma. 2014;**31**(1):19-25. DOI:

[29] Eng L, Ghirnikar R, Lee Y. Glial fibrillary acidic protein: GFAP-thirtyone years (1969-2000). Neurochemical

Research. 2000;**25**(9):1439-1451

[30] Ingebrigtsen T, Romner B. Biochemical serum markers of

CCM.0b013e3181b788a

10.1089/neu.2010.156

NEU.0b013e318236a809

[15] Puvenna V et al. Significance of ubiquitin carboxy terminal hydrolase

L1 elevations in athletes after subconcussive head hits. PLoS One. 2014;**9**(5):e96296. DOI: 10.1371/journal.

[16] Adrian H et al. Biomarkers of traumatic brain injury: Temporal changes in body fluids. eNeuro.

10.1523/ENEURO.0294-16.2016

2016;**3**(6):ENEURO.0294-16.2016. DOI:

[17] Müller K et al. S100B serum level predicts computed tomography findings after minor head injury. The Journal of Trauma. 2007;**62**(6):1452-1456. DOI: 10.1097/TA.0b013e318047bfaa

[18] Ingebrigtsen T et al. The clinical value of serum S-100 protein

Injury. 2000;**14**(12):1047-1055

shk.0000209534.61058.35

2010;**24**(3):163-172

journal.pone.0012691

measurements in minor head injury: A Scandinavian multicentre study. Brain

[19] Biberthaler P et al. Serum S100B concentration provides additional information for the indication of computed tomography in patients after minor head injury: A prospective multicenter study. Shock. 2006;**25**(5):446-453. DOI: 10.1097/01.

[20] Mussack T et al. Immediate S-100B and neuron-specific enolase plasma measurements for rapid evaluation of primary brain damage in alcoholintoxicated, minor head-injured patients. Shock. 2002;**18**(5):395-400

[21] Bazarian J, Beck C, Blyth B, Von Ahsen N, Hasselblatt M. Impact of creatine kinase correction on the predictive value of S-100B after mild traumatic brain injury. Restorative Neurology and Neuroscience.

[22] Pham et al. Extracranial sources of S100B do not affect serum levels. PLoS One. 2010;**5**(9):e12691. DOI: 10.1371/

pone.0096296

**80**

[31] Saatman K, Bolton A. Regional neurodegeneration and gliosis are amplified by mild traumatic brain injury repeated at {24-hour} intervals. Journal of Neuropathology and Experimental Neurology. 2014;**73**(10):933-947. DOI: 10.1097/NEN.0000000000000115

[32] Missler U, Wiesmann M, Wittmann G, Magerkurth O, Hagenström H. Measurement of glial fibrillary acidic protein in human blood: Analytical method and preliminary clinical results. Clinical Chemistry. 1999;**45**(1):138-141

[33] Albert-Weissenberger C, Sirén AL. Experimental traumatic brain injury. Experimental & Translational Stroke Medicine. 2010;**2**(1):16

[34] Yang S et al. A murine model of mild traumatic brain injury exhibiting cognitive and motor deficits. The Journal of Surgical Research. 2013;**184**(2):981-988. DOI: 10.1186/2040-7378-2-16

[35] Mondello S et al. Glial neuronal ratio: A novel index for differentiating injury type in patients with severe traumatic brain injury. Journal of Neurotrauma. 2012;**29**(6):1096-1104. DOI: 10.1089/neu.2011.2092

[36] Papa L et al. GFAP out-performs S100beta in detecting traumatic intracranial lesions on computed tomography in trauma patients with mild traumatic brain injury and those with extracranial lesions. Journal of Neurotrauma. 2014;**31**(22):1815-1822. DOI: 10.1089/neu.2013.3245

[37] Posti JP et al. Glial fibrillary acidic protein and ubiquitin C-terminal hydrolase-L1 are not specific biomarkers for mild CT-negative traumatic brain injury. Journal of Neurotrauma. 2017. DOI: 10.1089/neu.2016.4442

[38] Undén L et al. Validation of the Scandinavian guidelines for initial management ofminimal, mild and moderate traumatic brain injury in adults. BMC Medicine. 2015;**13**:292. DOI: 10.1186/s12916-015-0533-y

[39] Strathmann FG et al. Blood-based biomarkers for traumatic brain injury: Evaluation of research approaches, available methods and potential utility from the clinician and clinical laboratory perspectives. Clinical Biochemistry. 2014;**47**(10-11):876-888. DOI: 10.1016/j.clinbiochem.2014.01.028

[40] Papa L, Brophy G, Welch R, Lewis L, Braga C, Tan C, et al. Time course and diagnostic accuracy of glial and neuronal blood biomarkers GFAP and UCH-L1 in a large cohort of trauma patients with and without mild traumatic brain injury. JAMA Neurology. 2016;**73**(5):551-560. DOI: 10.1001/jamaneurol.2016.0039

[41] Kövesdi E, Lückl J, Bukovics P, Farkas O, Pál J, Czeiter E, et al. Update on protein biomarkers in traumatic brain injury with emphasis on clinical use in adults and pediatrics. Acta Neurochirurgica. 2010;**152**:1-17. DOI: 10.1007/s00701-009-0463-6

[42] North S, Shriver-Lake L, Taitt C, Ligler F. Rapid analytical methods for on-site triage for traumatic brain injury. Annual Review of Analytical Chemistry. 2012;**5**(1):35-56. DOI: 10.1146/ annurev-anchem-062011-143105

[43] Mondello S, Akinyi L, Buki A, Robicsek S, Gabrielli A, Tepas J, et al. NIH public access. 2013;**70**(3):666-675

[44] Benito I, Rodríguez J. Determinación radioinmunométrica de la enolasa neuronal específica en humor acuoso y suero, en pacientes con retinoblastoma. Revista Española de Medicina Nuclear e Imagen Molecular. 2000;**7**:472-478

[45] Test ID: NSESF. Neuron-Specific Enolase (NSE), Spinal Fluid [Internet]. 2018. Available from: https://www. mayocliniclabs.com/test-catalog/ pod/MayoTestCatalog-Rochester-LaboratoryReferenceEdition-SortedByTestName-duplex.pdf [Accessed: 7 December 2018]

[46] Dash P, Zhao J, Hergenroeder G, Moore A. Biomarkers for the diagnosis, prognosis, and evaluation of treatment efficacy for traumatic brain injury. Neurotherapeutics. 2010;**7**(1):100-114. DOI: 10.1016/j.nurt.2009.10.019

[47] Wang K, Posmantur R, Nath R, McGinnis K, Whitton M, Talanian R, et al. Simultaneous degradation of alphaII and betaII-spectrin by caspase 3 (CPP32) in apoptotic cells. The Journal of Biological Chemistry. 1998;**273**(35):22490-22497

[48] Brophy G, Pineda J, Papa L, Lewis S, Valadka A, Hannay H, et al. alphaII-Spectrin breakdown product cerebrospinal fluid exposure metrics suggest differences in cellular injury mechanisms after severe traumatic brain injury. Journal of Neurotrauma. 2009;**26**(4):471-479. DOI: 10.1089/ neu.2008.0657

[49] Berger R, Hymel K, Gao W. The use of biomarkers after inflicted traumatic brain injury: Insight into Etiology, pathophysiology, and biochemistry. Clinical Pediatric Emergency Medicine. 2006;**7**(3):186-193. DOI: 10.1016/j. cpem.2006.06.001

[50] Biberthaler P, Mussack T, Wiedemann E, Kanz K-G, Mutschler W, Linsenmaier U, et al. Rapid identification of high-risk patients after minor head trauma (MHT) by assessment of S-100β: Ascertainment of a cut-off level. European Journal of Medical Research. 2002;**7**(4):164-170

[51] Brophy G, Mondello S, Papa L, Robicsek S, Gabrielli A, Tepas J,

et al. Biokinetic analysis of ubiquitin C-terminal hydrolase-L1 (UCH-L1) in severe traumatic brain injury pa¬tient biofluids. Journal of Neurotrauma. 2011;**28**(6):861-870. DOI: 10.1089/ neu.2010.1564

[52] Papa L, Lewis L, Falk J, Zhang SS, Giordano P, et al. Elevated levels of serum glial fibrillary acidic protein breakdown products in mild and moderate traumatic brain injury are associated with intracranial lesions and neurosurgical intervention. Annals of Emergency Medicine. 2012;**59**:471-483. DOI: 10.1016/j. annemergmed.2011.08.021

[53] Okonkwo D, Yue J, Puccio A, Panczykowski D, Inoue T, Mcmahon P, et al. GFAP-BDP as an acute diagnostic marker in traumatic brain injury: Results from the pros¬pective transforming research and clinical knowledge in traumatic brain injury study. Journal of Neurotrauma. 2013;**30**(17):1490-1497. DOI: 10.1089/ neu.2013.2883

[54] Thelin E et al. A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury. Acta Neurochirurgica. 2017;**159**(2):209-225. DOI: 10.1007/ s00701-016-3046-3

[55] Olivecrona Z et al. Association of ICP, CPP, CT findings and S-100B and NSE in severe traumatic head injury. Prognostic value of the biomarkers. Brain Injury. 2014:29. DOI: 10.3109/02699052.2014.989403

[56] Lagerstedt L, Egea-Guerrero JJ, Bustamante A, Rodríguez-Rodríguez A, El Rahal A, Quintana-Diaz M, et al. Combining H-FABP and GFAP increases the capacity to differentiate between CT-positive and CT-negative patients with mild traumatic brain injury. PLoS One. 2018;**13**(7):e0200394. DOI: 10.1371/journal.pone.0200394

**83**

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury*

*DOI: http://dx.doi.org/10.5772/intechopen.85555*

[57] Bazarian JJ, Biberthaler P, Welch RD, Lewis LM, Barzo P, Bogner-Flatz V, et al. Serum GFAP and UCH-L1 for prediction of absence of intracranial injuries on head CT (ALERT-TBI): A multicentre observational study. Lancet Neurology. 2018;**17**(9):782-789. DOI: 10.1016/S1474-4422(18)30231-X

*Neuronal and Glial Biomarkers Research for Traumatic Brain Injury DOI: http://dx.doi.org/10.5772/intechopen.85555*

[57] Bazarian JJ, Biberthaler P, Welch RD, Lewis LM, Barzo P, Bogner-Flatz V, et al. Serum GFAP and UCH-L1 for prediction of absence of intracranial injuries on head CT (ALERT-TBI): A multicentre observational study. Lancet Neurology. 2018;**17**(9):782-789. DOI: 10.1016/S1474-4422(18)30231-X

*Traumatic Brain Injury - Neurobiology, Diagnosis and Treatment*

et al. Biokinetic analysis of ubiquitin C-terminal hydrolase-L1 (UCH-L1) in severe traumatic brain injury pa¬tient biofluids. Journal of Neurotrauma. 2011;**28**(6):861-870. DOI: 10.1089/

[52] Papa L, Lewis L, Falk J, Zhang SS, Giordano P, et al. Elevated levels of serum glial fibrillary acidic protein breakdown products in mild and moderate traumatic brain injury are associated with intracranial lesions and neurosurgical intervention. Annals of Emergency Medicine. 2012;**59**:471-483. DOI: 10.1016/j. annemergmed.2011.08.021

[53] Okonkwo D, Yue J, Puccio A, Panczykowski D, Inoue T, Mcmahon P, et al. GFAP-BDP as an acute diagnostic marker in traumatic brain injury: Results from the pros¬pective transforming research and clinical knowledge in traumatic brain injury study. Journal of Neurotrauma. 2013;**30**(17):1490-1497. DOI: 10.1089/

[54] Thelin E et al. A review of the clinical utility of serum S100B protein levels in the assessment of traumatic brain injury. Acta Neurochirurgica. 2017;**159**(2):209-225. DOI: 10.1007/

[55] Olivecrona Z et al. Association of ICP, CPP, CT findings and S-100B and NSE in severe traumatic head injury. Prognostic value of the

10.3109/02699052.2014.989403

Combining H-FABP and GFAP increases the capacity to differentiate between CT-positive and CT-negative patients with mild traumatic brain injury. PLoS One. 2018;**13**(7):e0200394. DOI: 10.1371/journal.pone.0200394

[56] Lagerstedt L, Egea-Guerrero JJ, Bustamante A, Rodríguez-Rodríguez A, El Rahal A, Quintana-Diaz M, et al.

biomarkers. Brain Injury. 2014:29. DOI:

neu.2010.1564

neu.2013.2883

s00701-016-3046-3

[45] Test ID: NSESF. Neuron-Specific Enolase (NSE), Spinal Fluid [Internet]. 2018. Available from: https://www. mayocliniclabs.com/test-catalog/ pod/MayoTestCatalog-Rochester-LaboratoryReferenceEdition-SortedByTestName-duplex.pdf [Accessed: 7 December 2018]

[46] Dash P, Zhao J, Hergenroeder G, Moore A. Biomarkers for the diagnosis, prognosis, and evaluation of treatment efficacy for traumatic brain injury. Neurotherapeutics. 2010;**7**(1):100-114. DOI: 10.1016/j.nurt.2009.10.019

[47] Wang K, Posmantur R, Nath R, McGinnis K, Whitton M, Talanian R, et al. Simultaneous degradation of alphaII and betaII-spectrin by caspase 3 (CPP32) in apoptotic cells. The Journal of Biological Chemistry.

1998;**273**(35):22490-22497

neu.2008.0657

cpem.2006.06.001

[50] Biberthaler P, Mussack T, Wiedemann E, Kanz K-G, Mutschler W, Linsenmaier U, et al. Rapid identification of high-risk patients after minor head trauma (MHT) by assessment of S-100β: Ascertainment of a cut-off level. European Journal of Medical Research. 2002;**7**(4):164-170

[51] Brophy G, Mondello S, Papa L, Robicsek S, Gabrielli A, Tepas J,

[48] Brophy G, Pineda J, Papa L, Lewis S, Valadka A, Hannay H, et al. alphaII-Spectrin breakdown product cerebrospinal fluid exposure metrics suggest differences in cellular injury mechanisms after severe traumatic brain injury. Journal of Neurotrauma. 2009;**26**(4):471-479. DOI: 10.1089/

[49] Berger R, Hymel K, Gao W. The use of biomarkers after inflicted traumatic brain injury: Insight into Etiology, pathophysiology, and biochemistry. Clinical Pediatric Emergency Medicine. 2006;**7**(3):186-193. DOI: 10.1016/j.

**82**

Section 3

Treatment and Multiple

Therapeutic Strategies

85

Section 3
