Role of Virtual Reality in Improving Balance in Patients With Myelopathy

Balance of the body is achieved by the coordination of three major systems, visual, vestibular and proprioceptive sensation and by the reflexive control of the limbs. Static balance which determines the ability to maintain postural stability during sitting or standing is important to perform daily functional activities. Dynamic balance on the other hand is the ability to respond and adjust to a moving floor or any external stimuli or perturbation and is a requirement for successful gait performance.

In myelopathy, factors like balance and posture, range of motion, muscle strength, coordinated motor control, muscle tone and proprioception are affected. Lack of normal postural synergy and sensory motor integration of lower limbs and trunks and spatial information that regulate upright position and sitting balance leads to balance dysfunction in the population. Hence patient develops compensatory strategies. But ambulation involves the intricate coordination of leg movements, regulating upright posture and balance and adaptation to environmental changes. Hence balance and gait rehabilitation is an important goal in myelopathy.

Virtual reality (VR) is a computer based technology that is used for task oriented biofeedback therapy in rehabilitation. It constructs a virtual environment resembling a situation in the real world and provides multimodal sensory cues. VR ranges from non immersive to semi immersive to fully immersive, depending on the degree to which the user is isolated from the physical surroundings when interacting with the virtual environment.

In virtual reality training, participants perform functional stretching of their extremities, learn postural control of the trunk and practice weight shifting. As the level of difficulty and speed are increased for various tasks, the movement of the body's center of gravity beyond the base of support increases thus increasing the proprioceptive sensations to the joints and improves the subject's ability to adjust balance. Hence it encourages dynamic motions and functional mobility. The VR environment can be controlled and manipulated in advance to fine tune the exercises and meet individual needs. It is interactive as well as enjoyable.

Studies indicate that spinal reflex circuitry exhibits activity dependent plasticity (the capacity of the nervous system to modify its organization). Intensive task specific training is one of the most effective ways to promote neuroplasticity and develop more normalized movement patterns. VR uses this principle of neuroplasticity to promote motor relearning. Literature supports the use of VR as an effective rehabilitative tool in individuals with stroke, spinal cord injury, cerebral palsy, multiple sclerosis and other neurological disorders.