WRITE A NOTE ON VIRTUAL REALITY BASED REHABILITATION ?
A 7 INTRODUCTION
1 Recovery after a stroke relies on neuronal plasticity that allows other areas of the brain to take over functions of the ischemic zone, the complexity of this reorganization strongly depends on the severity of the anatomical and functional lesion
2 Therefore, the main target of rehabilitation after stroke should be to maximize the effect of plasticity and functional reorganization.
3 Several methods and therapy concepts have been proposed and many of them aim at promoting functional changes within surviving motor networks
4 However, it is not always clear how effective these different approaches are and how they exactly influence recovery.
5 Relatively novel tools in neurorehabilitation are based on Virtual Reality (VR) technologies, these have the advantage of flexibly deploying scenarios that can be directed towards specific needs.
6 Is specifically advantageous for distal upper extremity which in turn acts as an end effector , thus promoting all activities of upper limb ( vv imp )
7 Regaining upper extremity function is one of the major goals in stroke survivors, as it is important for performing activities of daily living (ADLs).
8 However, approximately 80 % of stroke survivors have upper extremity limitations, and these limitations persist in approximately half of these survivors in the chronic phase
9 Distal upper extremity function is vital for performing ADLs, such as holding objects like utensils, turning a doorknob or key in a lock, telephone or computer use, and writing, and is strongly related to quality of life (QoL) in stroke survivors
10 In stroke survivors, the distal upper extremity is severely affected and is the last body part to recover .
11 Therefore, improving distal upper extremity function is of primary importance in the rehabilitation of stroke survivors.
DEFINITION
1 Virtual rehabilitation is a concept in psychology in which a therapeutic patient’s training is based entirely on, or is augmented by, virtual reality simulation exercises.
2 The term Virtual Rehabilitation was coined in 2002 by Professor Daniel Thalmann of EPFL (Switzerland) and Professor Grigore Burdea of Rutgers University(USA )
3 Virtual rehabilitation offers a number of advantages compared to conventional therapeutic methods such as -
A ) It is entertaining, thus motivating the patient
B ) It provides objective outcome measures of therapy efficacy (limb velocity, range of movement, error rates, game scores, etc.)
C ) These data are transparently stored by the computer running the simulation and can be made available on the Internet.
D ) Thus virtual rehabilitation can be performed in the patient’s home and monitored at a distance (becoming telerehabilitation)
E ) The client feels more actively involved in the desensitization
MECHANISM OF ACTION
A ) The RGS tracks arm and finger movements and maps them onto a virtual environment.
B ) In this manner, the user controls the movements of two virtual limbs that are viewed in a first person perspective.
C ) The rehabilitation scenario described here, Spheroids, consists of intercepting, capturing and placing spheres that move towards the user.
D ) The main rationale behind this rehabilitation scenario of RGS is the hypothesis that bimanual task oriented action execution combined with the observation of virtual limbs that mirror the executed or intended movement create conditions that facilitate the functional reorganization of the motor and pre-motor systems affected by stroke.
E ) In the action execution and observation paradigm, recovery could be promoted through the engagement of undamaged primary or secondary motor areas or by recruiting alternative perilesional or contralesional networks.
F ) This, however, requires that an information channel must exist that allows external modulation of the states of these alternative circuits.
G ) So , such an interface could be provided by neurons such as those found in the mirror neuron system, which have the property of being active both during the execution of goal-oriented actions with a biological effector and during the observation of the same actions performed by biological effectors of other agents .
H ) It is exactly this cognitive transduction channel between the perception and execution of action that RGS exploits even when motor actions themselves cannot be performed due to a lesion
I ) recent studies have suggested a benefit of using passive action observation for rehabilitation following stroke
J ) In the mirror neuron literature, the perceptual frame of reference is often not considered and the mirror neurons are mainly reported in a third person perspective.
K ) However, it has been acknowledged that these neurons essentially follow the statistics of the multi-modal inputs the acting brain is exposed to
L ) This is consistent with current theories of perceptual learning that emphasize the role of sampling statistics in the development of perceptual structures
M ) For instance, it has been proposed that through statistical inference, associating motor intention and actions, the mirror neurons facilitate the encoding of the intentions of others
N ) Based on these observations, RGS assumes that the first person view should provide the most effective drive onto these multi-modal populations of neurons simply because this is the perspective that the system is most frequently exposed to.
O ) Indeed, it has been observed that the first person view of a virtual representation of the hand induces stronger activation of primary and secondary motor areas associated with sensory motor control as opposed to only performing hand movements in the absence of such a representation
P ) More concretely, the response is stronger when the orientation of the hand is similar to the one of the first person perceiver
Q ) Since the Yerkes-Dodson law established the relationship between motivation and learning, it has been acknowledged that human performance is optimal at intermediate levels of arousal vv imp
R ) This means that the optimum experience in any task is the one that is perfectly balanced so as to be neither too hard nor too easy .
S ) Given these considerations individualization means to identify a level of performance, i.e. failure rates, that optimally challenge each user at their own level of competence. Hence, any automated therapy system should be able to assess the performance level of the subject and subsequently tune the therapeutic intervention in relation to this level. ( PTM - PERSONALISED TRAINING MODULE )
T ) Finally, RGS, as any other VR based rehabilitation approach, assumes that training in virtual environments will lead to corresponding improvements in performance in the physical world.
U ) Therefore, to understand the transfer of performance between the virtual and the physical world, stroke patients and controls performed physical and virtual versions of a calibration reaching task.
INDICATIONS
1 first-ever ischemic or hemorrhagic stroke
(2) complaints of unilateral upper extremity functional deficits after stroke
(3) presence of a score of at least 2 points on the medical research council scale for wrist flexion/extension or forearm pronation/supination, as the SG system can be operated only with volitional movements and does not involve external assistance ( vv imp )
CONTRAINDICATIONS
1 age <18 years
(2) uncontrolled hypertension, unstable angina, recent myocardial infarction, or any history of seizure
(3) predisposing psychological disorders that could impede participation
(4) neurological disorders that cause motor deficits, such as Parkinson’s disease and peripheral neuropathy
(5) severe aphasia resulting in communication difficulties that could influence the intervention and outcome measures
(6) cognitive impairment resulting in cooperation difficulties (a score of ≤24 in the Mini-Mental State Examination
and (7) severe pain impeding upper extremity rehabilitation (numeric pain rating scale score ≥ 7)