Postural stability in people with visual impairment

Abstract

Background: The visual system enables the brain to assess information regarding the position of the body in space. Congenital or acquired blindness leads to the development of abnormal sensory-motor interactions that results in development of typical musculoskeletal deformities and gait patterns that cause disability. Diabetes and related complications are expected to increase exponentially in the next 10 years; thus, the number of people with visual impairment is expected to increase. However, there have been few studies regarding etio-pathogenesis of postural alteration and balance impairment in people with visual impairment; moreover, no previous study has investigated postural stability in this population. This study aimed to assess the center of gravity (COG) velocity in subjects with visual impairment and compared with that in sighted subjects.

Methods: Seventy male subjects, 20-40 years of age, participated in this study; they were divided into sighted (control) and visually impaired groups. COG velocity while standing on an unstable surface was measured using the NeuroCom^® Balance Master Version 8.5.0. For the sighted group, data were recorded with eyes open and then with eyes closed. For the visually impaired group, no instructions were given with respect to eyes during data collection.

Results: Mean COG velocity was significantly higher in the visually impaired group than in the sighted group with eyes open. However, there was no difference in mean COG velocity between the visually impaired group and the sighted group with eyes closed. The difference in mean COG velocity between sighted subjects with eyes open and eyes closed was also significant. Mean COG velocity while standing on a foam surface varied among visually impaired subjects and sighted subjects with eyes open and closed.

Conclusion: This study showed that subjects with visual impairment, regardless of eye opening or closure, behave in the same manner as sighted subjects with eyes closed.

Keywords: COG velocity; postural stability; visual impairment.