**1. Introduction**

In a systematic review of 151 studies, there was insufficient evidence that traditional neurological treatment methods were effective in improving muscle strength, synergies, muscle tone, dexterity, or ADLs after stroke [1]. Kollen et al. reviewed 735 available published (clinical) stroke rehabilitation trials [2]. They concluded

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*Assistive and Rehabilitation Engineering*

for stroke rehabilitation: An abridged version of a Cochrane review. European Journal of Physical and Rehabilitation

[23] Rhodesa R, Warburton D, Bredin S. Predicting the effect of interactive video bikes on exercise adherence: An efficacy trial. Psychology, Health & Medicine. 2009;**14**(6):631-640

[24] Mestre D, Maiano C, Dagonneau V, Mercier CS. Does virtual reality enhance exercise performance, enjoyment, and dissociation? An exploratory study on a stationary bike apparatus. Presence.

[25] Fisher J, Thompson K, Nicoli L. Cardio-fitness station with virtual reality capability. US Patent, US 2007/0042868 A1; Feb. 22, 2007

[26] Nusbaum NH. Exercise bicycle virtual reality steering apparatus. US Patent, US 6,918,860 B1; Jul. 19, 2005

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[29] Rybarczyk Y, Kleine Deters J, Cointe C, Esparza D. Smart webbased platform to support physical rehabilitation. Sensors. 2018;**18**(5):1344.

[30] McCoy J, Bates M, Eggett C, Siervo M, Cassidy S, Newman J, et al. Pathophysiology of exercise intolerance in chronic diseases: The role of diminished cardiac performance in mitochondrial and heart failure patients. Open Heart. 2017;**4**(2)

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[16] Rawstorn JC, Gant N, Direito A, Beckmann C, Maddison R. Telehealth exercise-based cardiac rehabilitation: A systematic review and meta-analysis.

[17] Worringham C, Rojek A, Stewart I. Development and feasibility of a smartphone, ECG and GPS based system for remotely monitoring exercise in cardiac rehabilitation. PLoS ONE.

[18] Lear SA, Singer J, Banner-Lukaris D, Horvat D, Park JE, Bates J, et al. Randomized trial of a virtual cardiac rehabilitation program delivered at a distance via the internet. Circulation Cardiovascular Quality and Outcomes.

[19] Psotka J. Immersive training systems: Virtual reality and education and training. Instructional Science.

[20] Annesi J, Mazas J. Effects of virtual reality-enhanced exercise equipment on adherence and exercise-induced feeling states. Perceptual and Motor Skills.

[21] Laver K, George S, Thomas S, Deutsch JE, Crotty M. Cochrane review: Virtual reality for stroke rehabilitation. European Journal of Physical and Rehabilitation Medicine.

[22] Laver K, George S, Thomas S, Deutsch JE, Crotty M. Virtual reality

[15] Smolis-Bąk E, Dąbrowski R, Piotrowicz E, Chwyczko T, Dobraszkiewicz-Wasilewska B, Kowalik I, et al. Hospital-based and telemonitoring guided home-based training programs: Effects on exercise tolerance and quality of life in patients with heart failure (NYHA class III) and cardiac resynchronization therapy. A randomized, prospective observation. International Journal of Cardiology.

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that conventional treatment approaches induce improvements that are confined to impairment level only and do not generalize at a functional improvement level. In contrast, they stated that the treatment strategies that incorporate a strong emphasis on functional training may hold the key to optimal stroke rehabilitation and that appropriate intensity and task-specific exercise therapy are important components of such an approach. This was later reconfirmed to various degrees by others [3, 4].

Several commercially available devices have been built to deliver repetitive movements to an impaired human hand for stroke survivors to regain the use of the hand. However, the dysfunction of the natural afferent feedback pathways and proprioception hampers the sensory learning process of the patient and its conversion to execution of movement. This contributes to an inadequate restoration of functionality despite reducing impairment at a gross motor level [4, 5]. External manifestations of movement such as trajectory, force, acceleration, range of motion and the like are ultimately dependent on adequate, appropriate, and timely self-regulation of brain and muscle activity specific to various tasks. After an event such as stroke, various compensatory strategies come into play to execute the same movements, which, left unaddressed, become learned behavior. Re-engaging the human being's innate sensory learning mechanisms to regain the appropriate muscle and neural strategies is, therefore, a challenge and an unmet need. If high repetitionbased rehabilitation is embarked upon without such re-learning, one runs the risk of post-trauma compensatory strategies being unknowingly reinforced in the brain, thus restoring movement and function in only a limited manner [6, 7].

#### **1.1 Learning in a rehabilitation context**

The body learns coordination for task performance by using all the lessons learnt from neuro-muscular, inter-limb, intra-limb, and eye-hand co-ordination [8, 9]. The specific strategies used are not only different from task to task for a person, but also differ for any one task between persons [10]. Initially, it was thought that the muscle synergies eliminated the redundant degrees of freedom by constraining the movements of certain joints or muscle [10]. But this does not work very well with the initial pathological constraints of an impaired arm. It has also been shown that constraining the movement of certain joints and muscles requires more energy and neural commands, and hence increases the number of neural signals required to perform the task [11]. However, some strategies are fundamental to all movement, such as maintaining an agonist-antagonist balance in the appropriate muscle groups, a moderation of effort to make repetitions possible during rehabilitation without being confounded by fatigue, and an active brain state which allows one to bring attention to the task at hand in a consistent manner. Facilitating such general strategies with technology rather than directly and artificially controlling individual, task-specific strategies is less complex, requires lower computational power and could facilitate a generalization of such useful strategies to other activities. This could in turn result in higher degrees of independence.

As an illustration, let us consider how humans learn handwriting. This is usually done by tracing over an existing alphabet or joining dots in the shape of an alphabet. Here, constraints are mind imposed based on visual cues while no constraints are placed physically on the hand. These mind-imposed constraints involve seeing a pattern and responding with a pencil, like a sort of static imitation. Everyone may choose a different strategy to impose these constraints, based on the kinematics of the more proximal joints and natural synergies of muscles proximal to the point where control is desired. This is like the uncontrolled manifold hypothesis for motor learning and involves a mechanism by which brain and body complement each other in real-time in managing elemental and contextual variables [12]. Hence,

**115**

limb is the result [18].

*Restoring Independent Living after Disability Using a Wearable Device: A Synergistic…*

**1.2 Self-regulation and its impact on learning and neuroplasticity**

it is not very clear whether it can result in improvement in functional tasks.

plasticity in the brain and protects against the erosive effects, and this is one of the fundamental principles of early mobilization and continuing long term therapy. However, not all exercise regimens are adaptive, and some may even be maladaptive. In animal studies, the location and type of injury appear to dictate to some extent whether the intensity of motor rehabilitation training results in proplasticity, neutral or adverse contralesional hemisphere effects [17]. Additionally, the contralesional hemisphere appears to benefit from early, intense, motor enrichment while the perilesional area may be most helped by a gradual, modest increase in therapy. On another note, if the motivation to use the impaired limb after stroke is reduced due to ineptitude, pain or fatigue in that limb and there is a corresponding increased reliance on the other extremity, "learned non-use" of the impaired

While remarkable improvements in function have been reported when the non-impaired arm is constrained, as in constraint-induced therapy [19], excessively intense therapy can also lead to increased chances of secondary tissue loss due to reduction of brain derived neurotrophic factor (BDNF) expression in the brain during recovery [20]. Thus, while early onset of therapy using repetitive practice is vital to recovery, too much of it can exaggerate the extent of injury. This becomes even more significant because commonly used clinical assessment tests are not sensitive to small changes and do not allow the experimenter to distinguish between actual neurological recovery and behavioral compensation [21]. Just as neuroplasticity is a mechanism which can be leveraged to regain function, training of inappropriate, compensatory muscle and neural strategies, adopted unknowingly, can just as easily get ingrained in the brain and may take a long time to undo. The chances of this happening are heightened after stroke, when touch function, proprioception and cognition are adversely affected, and self-regulation ability is reduced due to the disruption of the natural feedback loops. Hence, apart from re-learning brain and muscle strategies, self-regulation of intensity in order to consistently keep compensation at bay and maintain beneficial strategies during training is another

Like in the handwriting example given earlier, any learning model must satisfy the requirements of an experience derived from a sensory-rich system, as well as a motor system free of artificial constraints, which can adequately choose the synergy

important component in this learning-led recovery model.

Exercise is one way of providing an enriched motor environment. It facilitates

there does seem to be some convergence between motor learning theory and how developmental biology describes babies and infants learning in an associative, Hebbian manner using their sensory and motor faculties. The next question is whether such learning can be used as a pathway to undo the maladaptive, compensatory brain-muscle strategies that are common among chronic stroke patients with upper arm disability and help re-educate the adoption of appropriate strategies.

Stroke is an injury that affects not only body but also cognition and cardiovascular health, among others. Hence, it resembles a systemic injury or trauma even in mild to moderate cases. Healing of such systemic injuries has the final pathway of self-management or self-regulation [13, 14]. Self-regulation is ingrained by a biological, natural model of learning driven by the feedback and feedforward of information [13]. Self-regulation essentially requires a measure (absolute or relative), some facility to monitor changes in real-time, and some training to help develop the skill to modify the measure and move it in a desired direction [14, 15]. In the area of motor recovery, similar benefits of "self-control" have been demonstrated [16] but

*DOI: http://dx.doi.org/10.5772/intechopen.86011*

*Restoring Independent Living after Disability Using a Wearable Device: A Synergistic… DOI: http://dx.doi.org/10.5772/intechopen.86011*

there does seem to be some convergence between motor learning theory and how developmental biology describes babies and infants learning in an associative, Hebbian manner using their sensory and motor faculties. The next question is whether such learning can be used as a pathway to undo the maladaptive, compensatory brain-muscle strategies that are common among chronic stroke patients with upper arm disability and help re-educate the adoption of appropriate strategies.

#### **1.2 Self-regulation and its impact on learning and neuroplasticity**

Stroke is an injury that affects not only body but also cognition and cardiovascular health, among others. Hence, it resembles a systemic injury or trauma even in mild to moderate cases. Healing of such systemic injuries has the final pathway of self-management or self-regulation [13, 14]. Self-regulation is ingrained by a biological, natural model of learning driven by the feedback and feedforward of information [13]. Self-regulation essentially requires a measure (absolute or relative), some facility to monitor changes in real-time, and some training to help develop the skill to modify the measure and move it in a desired direction [14, 15]. In the area of motor recovery, similar benefits of "self-control" have been demonstrated [16] but it is not very clear whether it can result in improvement in functional tasks.

Exercise is one way of providing an enriched motor environment. It facilitates plasticity in the brain and protects against the erosive effects, and this is one of the fundamental principles of early mobilization and continuing long term therapy. However, not all exercise regimens are adaptive, and some may even be maladaptive. In animal studies, the location and type of injury appear to dictate to some extent whether the intensity of motor rehabilitation training results in proplasticity, neutral or adverse contralesional hemisphere effects [17]. Additionally, the contralesional hemisphere appears to benefit from early, intense, motor enrichment while the perilesional area may be most helped by a gradual, modest increase in therapy. On another note, if the motivation to use the impaired limb after stroke is reduced due to ineptitude, pain or fatigue in that limb and there is a corresponding increased reliance on the other extremity, "learned non-use" of the impaired limb is the result [18].

While remarkable improvements in function have been reported when the non-impaired arm is constrained, as in constraint-induced therapy [19], excessively intense therapy can also lead to increased chances of secondary tissue loss due to reduction of brain derived neurotrophic factor (BDNF) expression in the brain during recovery [20]. Thus, while early onset of therapy using repetitive practice is vital to recovery, too much of it can exaggerate the extent of injury. This becomes even more significant because commonly used clinical assessment tests are not sensitive to small changes and do not allow the experimenter to distinguish between actual neurological recovery and behavioral compensation [21]. Just as neuroplasticity is a mechanism which can be leveraged to regain function, training of inappropriate, compensatory muscle and neural strategies, adopted unknowingly, can just as easily get ingrained in the brain and may take a long time to undo. The chances of this happening are heightened after stroke, when touch function, proprioception and cognition are adversely affected, and self-regulation ability is reduced due to the disruption of the natural feedback loops. Hence, apart from re-learning brain and muscle strategies, self-regulation of intensity in order to consistently keep compensation at bay and maintain beneficial strategies during training is another important component in this learning-led recovery model.

Like in the handwriting example given earlier, any learning model must satisfy the requirements of an experience derived from a sensory-rich system, as well as a motor system free of artificial constraints, which can adequately choose the synergy

*Assistive and Rehabilitation Engineering*

that conventional treatment approaches induce improvements that are confined to impairment level only and do not generalize at a functional improvement level. In contrast, they stated that the treatment strategies that incorporate a strong emphasis on functional training may hold the key to optimal stroke rehabilitation and that appropriate intensity and task-specific exercise therapy are important components of such an approach. This was later reconfirmed to various degrees by others [3, 4]. Several commercially available devices have been built to deliver repetitive movements to an impaired human hand for stroke survivors to regain the use of the hand. However, the dysfunction of the natural afferent feedback pathways and proprioception hampers the sensory learning process of the patient and its conversion to execution of movement. This contributes to an inadequate restoration of functionality despite reducing impairment at a gross motor level [4, 5]. External manifestations of movement such as trajectory, force, acceleration, range of motion and the like are ultimately dependent on adequate, appropriate, and timely self-regulation of brain and muscle activity specific to various tasks. After an event such as stroke, various compensatory strategies come into play to execute the same movements, which, left unaddressed, become learned behavior. Re-engaging the human being's innate sensory learning mechanisms to regain the appropriate muscle and neural strategies is, therefore, a challenge and an unmet need. If high repetitionbased rehabilitation is embarked upon without such re-learning, one runs the risk of post-trauma compensatory strategies being unknowingly reinforced in the brain,

thus restoring movement and function in only a limited manner [6, 7].

The body learns coordination for task performance by using all the lessons learnt from neuro-muscular, inter-limb, intra-limb, and eye-hand co-ordination [8, 9]. The specific strategies used are not only different from task to task for a person, but also differ for any one task between persons [10]. Initially, it was thought that the muscle synergies eliminated the redundant degrees of freedom by constraining the movements of certain joints or muscle [10]. But this does not work very well with the initial pathological constraints of an impaired arm. It has also been shown that constraining the movement of certain joints and muscles requires more energy and neural commands, and hence increases the number of neural signals required to perform the task [11]. However, some strategies are fundamental to all movement, such as maintaining an agonist-antagonist balance in the appropriate muscle groups, a moderation of effort to make repetitions possible during rehabilitation without being confounded by fatigue, and an active brain state which allows one to bring attention to the task at hand in a consistent manner. Facilitating such general strategies with technology rather than directly and artificially controlling individual, task-specific strategies is less complex, requires lower computational power and could facilitate a generalization of such useful strategies to other activities. This

As an illustration, let us consider how humans learn handwriting. This is usually done by tracing over an existing alphabet or joining dots in the shape of an alphabet. Here, constraints are mind imposed based on visual cues while no constraints are placed physically on the hand. These mind-imposed constraints involve seeing a pattern and responding with a pencil, like a sort of static imitation. Everyone may choose a different strategy to impose these constraints, based on the kinematics of the more proximal joints and natural synergies of muscles proximal to the point where control is desired. This is like the uncontrolled manifold hypothesis for motor learning and involves a mechanism by which brain and body complement each other in real-time in managing elemental and contextual variables [12]. Hence,

**1.1 Learning in a rehabilitation context**

could in turn result in higher degrees of independence.

**114**

and/or strategy necessary to respond to this sensory system [22]. This is very similar to infants who learn in a non-instructional manner rich in sensory experience, using a feedforward-feedback sampling process [23]. Like in infants, the presence of such plasticity may provide an opportunity for functional recovery after stroke, if the most appropriate strategies are learnt and the maladaptive ones unlearnt [24].
