**2. Diagnosis**

Often RBD is a missed diagnosis, likely due to under reporting. While some patients have no recollection of their nighttime behaviors, others may simply not view these are abnormal. Obtaining an accurate clinical history then depends on corroborative information gathered from the patient's bed partner, as they may witness the dream enactment behavior. Of note, spouses may comment on the patient's night time behaviors being out of character as compared to how they behave during the daytime. For patients who do not have a regular bed partner, questions regarding vivid dreams (specifically of being attacked or engaged in combat) and unexplained night time injuries such as falling out of bed should be explored.

Differential diagnoses for complex nocturnal behaviors can be divided into several categories (see **Table 1**) including: partial arousal parasomnias, nightmare disorder, sleep related respiratory disorders, sleep related movement disorders, seizure disorders, and psychiatric disease. *Partial arousal parasomnias* occur mostly from slow wave sleep (happening during the first half of the night as noted in **Table2**) and pathophysiology is presumed to be an incomplete transition from sleep to wakefulness [6]. These episodes consist of an arousal with associated disorientation and amnesia. Behaviors are quite primitive such as walking and eating. Episodes may be exacerbated by factors that increase the threshold for arousal (e.g. sleep deprivation, sedating medications). *Confusional arousals* are part of this category; however, these are rare in adults. As opposed to sleep walking and sleep related eating disorder,

Partial arousal parasomnias (arising from slow wave sleep):


Nightmares Obstructive sleep apnea Periodic limb movements of sleep Nocturnal frontal lobe epilepsy Nocturnal panic attacks

Sleep-related groaning (Catathrenia)

#### **Table 1.**

*Differential diagnoses of RBD.*


**79**

*REM-Behavior Disorder*

**Table 3.**

trunk or proximal extremities

*Nocturnal frontal lobe epilepsy vs RBD.*

*DOI: http://dx.doi.org/10.5772/intechopen.86277*

Stereotyped asymmetric hypermotor behaviors of

**NFLE RBD**

Short duration 5–60 s Duration is seconds to 2 min Patient is amnestic to the event Patient recalls the event Occurs from NREM stages Occurs during REM sleep May have nightly clusters Rare, sporadic events Age of onset first or second decade Age of onset fifth decade

confusional arousals are associated with poor responsiveness and amnesia but during confusional arousals there is no ambulation. *Nightmare disorder* consists of recurrent awakenings during which the patient is able to recall a disturbing dream and experiences associated intense emotions such as fear, anxiety, or sadness. It is important to note that in nightmares there is preservation of REM atonia, therefore body movement is rare and the patient is fully alert after awakening (as opposed to a confusional arousal). *Obstructive sleep* apnea should be investigated if patient has a history notable for excessive daytime sleepiness. *Periodic limb movements of sleep* and other *sleep fragmenting conditions* may precipitate partial arousal parasomnias, which can be misinterpreted as RBD. Lastly, while parasomnias are largely a disorder of childhood,

Variable dream enacting behaviors in a self-defense

manner including vocalizations

primary RBD (as described below) almost exclusively occurs in older adults.

*Nocturnal frontal lobe epilepsy* (NFLE) is one of the most important differential diagnosis for complex nocturnal behaviors that may mimic RBD (see **Table 3**) [7]. NFLE also presents with complex, exclusively nocturnal, bizarre behaviors; the hallmark of this disorder is that each episode is stereotyped (like with all epilepsies), where actions occurring during parasomnias or RBD are varied. The "classic" example is bicycling of the legs at night time out of sleep. Unlike RBD or parasomnias, there is no particular predilection for a time of night for these seizures to occur. Similar to parasomnias (but unlike RBD), the patient will be amnestic to the events themselves. Preferred treatment for nocturnal frontal lobe epilepsy includes anticonvulsant agents such as carbamazepine, oxcarbazepine, and lamotrigine. Once suspicion for RBD is raised, confirmatory polysomnogram (PSG) should be pursued as this will provide a definite diagnosis. A full attended polysomnogram set up includes: abbreviated electroencephalography leads, eye movement monitoring, nasal airflow monitoring, oronasal thermistor, mental/submental EMG, snore sensor, single ECG lead, chest/abdomen respiratory effort belts, pulse oximetry, and bilateral tibialis anterior EMG monitoring. When testing for RBD additional monitoring includes surface electromyography (EMG) preferably of the upper extremities as lower extremity movements are less specific [8]. The most sensitive information is obtained from monitoring of the chin (mental/submental electrodes) and flexor digitorum superficialis. Diagnostic features on PSG include increased muscle activity on surface EMG, specifically of both the chin and upper extremities. Activity on EMG is categorized as tonic or phasic. Tonic activity lasts longer than 15 s, while phasic activity is much shorter lasting less than 5 s. Typically, tonic activity is observed in the chin, while phasic activity is observed in both the chin and upper extremity EMG. Additionally, combined chin/arm activity should be present for at least 27% of a 30 s epoch (as per the International Classification of Sleep Disorders Guidelines). This is a highly specialized test and its interpretation relies on visual quantification, therefore technical quality is of the utmost importance [9]. Performing a full


#### **Table 3.**

*Updates in Sleep Neurology and Obstructive Sleep Apnea*

**NREM parasomnias RBD**

Partial arousal parasomnias (arising from slow wave sleep):

• Sleep talking/somniloquy • Sleep walking/somnambulism

• Night terrors

Nightmares

**Table 1.**

• Confusional arousals • Sleep related eating disorder

Obstructive sleep apnea Periodic limb movements of sleep Nocturnal frontal lobe epilepsy Nocturnal panic attacks

*Differential diagnoses of RBD.*

Sleep-related groaning (Catathrenia)

Occur in the first part of the night Occur in the second part of the night

Higher prevalence among children Higher prevalence among older adults

Patient is amnestic of event Patient recalls the event Variable duration (minutes or longer) Last seconds to minutes Patient is difficult to arouse Patient easily arousable Male predominance Male predominance Provoked by sleep deprivation, stress Unprovoked

Often RBD is a missed diagnosis, likely due to under reporting. While some patients have no recollection of their nighttime behaviors, others may simply not view these are abnormal. Obtaining an accurate clinical history then depends on corroborative information gathered from the patient's bed partner, as they may witness the dream enactment behavior. Of note, spouses may comment on the patient's night time behaviors being out of character as compared to how they behave during the daytime. For patients who do not have a regular bed partner, questions regarding vivid dreams (specifically of being attacked or engaged in combat) and unex-

Differential diagnoses for complex nocturnal behaviors can be divided into several

plained night time injuries such as falling out of bed should be explored.

categories (see **Table 1**) including: partial arousal parasomnias, nightmare disorder, sleep related respiratory disorders, sleep related movement disorders, seizure disorders, and psychiatric disease. *Partial arousal parasomnias* occur mostly from slow wave sleep (happening during the first half of the night as noted in **Table2**) and pathophysiology is presumed to be an incomplete transition from sleep to wakefulness [6]. These episodes consist of an arousal with associated disorientation and amnesia. Behaviors are quite primitive such as walking and eating. Episodes may be exacerbated by factors that increase the threshold for arousal (e.g. sleep deprivation, sedating medications). *Confusional arousals* are part of this category; however, these are rare in adults. As opposed to sleep walking and sleep related eating disorder,

**2. Diagnosis**

**78**

**Table 2.**

*SWS parasomnias vs RBD.*

*Nocturnal frontal lobe epilepsy vs RBD.*

confusional arousals are associated with poor responsiveness and amnesia but during confusional arousals there is no ambulation. *Nightmare disorder* consists of recurrent awakenings during which the patient is able to recall a disturbing dream and experiences associated intense emotions such as fear, anxiety, or sadness. It is important to note that in nightmares there is preservation of REM atonia, therefore body movement is rare and the patient is fully alert after awakening (as opposed to a confusional arousal). *Obstructive sleep* apnea should be investigated if patient has a history notable for excessive daytime sleepiness. *Periodic limb movements of sleep* and other *sleep fragmenting conditions* may precipitate partial arousal parasomnias, which can be misinterpreted as RBD. Lastly, while parasomnias are largely a disorder of childhood, primary RBD (as described below) almost exclusively occurs in older adults.

*Nocturnal frontal lobe epilepsy* (NFLE) is one of the most important differential diagnosis for complex nocturnal behaviors that may mimic RBD (see **Table 3**) [7]. NFLE also presents with complex, exclusively nocturnal, bizarre behaviors; the hallmark of this disorder is that each episode is stereotyped (like with all epilepsies), where actions occurring during parasomnias or RBD are varied. The "classic" example is bicycling of the legs at night time out of sleep. Unlike RBD or parasomnias, there is no particular predilection for a time of night for these seizures to occur. Similar to parasomnias (but unlike RBD), the patient will be amnestic to the events themselves. Preferred treatment for nocturnal frontal lobe epilepsy includes anticonvulsant agents such as carbamazepine, oxcarbazepine, and lamotrigine.

Once suspicion for RBD is raised, confirmatory polysomnogram (PSG) should be pursued as this will provide a definite diagnosis. A full attended polysomnogram set up includes: abbreviated electroencephalography leads, eye movement monitoring, nasal airflow monitoring, oronasal thermistor, mental/submental EMG, snore sensor, single ECG lead, chest/abdomen respiratory effort belts, pulse oximetry, and bilateral tibialis anterior EMG monitoring. When testing for RBD additional monitoring includes surface electromyography (EMG) preferably of the upper extremities as lower extremity movements are less specific [8]. The most sensitive information is obtained from monitoring of the chin (mental/submental electrodes) and flexor digitorum superficialis. Diagnostic features on PSG include increased muscle activity on surface EMG, specifically of both the chin and upper extremities. Activity on EMG is categorized as tonic or phasic. Tonic activity lasts longer than 15 s, while phasic activity is much shorter lasting less than 5 s. Typically, tonic activity is observed in the chin, while phasic activity is observed in both the chin and upper extremity EMG. Additionally, combined chin/arm activity should be present for at least 27% of a 30 s epoch (as per the International Classification of Sleep Disorders Guidelines). This is a highly specialized test and its interpretation relies on visual quantification, therefore technical quality is of the utmost importance [9]. Performing a full

18 channel EEG montage during routine diagnostic PSG can help rule out NFLE, especially if a complex behavior is captured on the PSG study night.

Diagnostic criteria as established by the International Classification of Sleep Disorders, Third Edition include [10]:

