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Pamela E Jeter, Amelie Francoise Nkodo, Jialiang Gu, Crystal Roach, Marilyn Corson, Steffany Haaz Moonaz, Ava K Bittner, Olukemi Adeyemo, Gislin Dagnelie; Yoga increases the sensory contribution to balance in visually impaired persons at risk for falls. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):4768.
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© ARVO (1962-2015); The Authors (2016-present)
Balance is regulated by 3 sensory systems: somatosensory, vestibular, and visual. Individuals with visual impairment (VI) have irreparable damage to the visual input contributing to balance, thus increasing the risk of falls. The present pilot study evaluated the Ashtanga-based Yoga Therapy (AYT) program to develop the remaining sensory inputs to balance as compensation in those with VI.
Seventeen legally blind participants were randomized to an 8-week AYT program (n = 9, mean (SD) age = 54.7(13.2); 3 M) or waitlist control (n=8, mean (SD) age = 53.13 (9.63), 3 M). AYT subjects convened for one group session per week with an instructor and were asked to perform two home-based practice sessions per week for a total of 8 weeks. Subjects completed outcome measures at baseline and post-8 weeks of AYT. Absolute Center of Pressure (COP) was derived from 4 force plate sensors in the Wii Balance Board (WBB) in 4 sensory conditions: firm surface, eyes open (EO); firm surface, eyes closed (EC); foam surface, EO; and foam surface, EC. Stabilization Indices (SI) were computed in order to determine the relative visual (SIfirm, SIfoam), somatosensory (SIEO, SIEC) and vestibular (SIV, i.e., FoamEC vs. FirmEO) contributions to balance. This study was not powered to detect between group differences, so significance of pre-post changes was assessed by paired samples t-tests within each group.
There were no significant differences at baseline between groups (all p > 0.05). In the AYT group, absolute COP significantly increased in the FoamEO (t(8) = -3.66, p = 0.006) and FoamEC (t(8) = -3.90, p = 0.005) conditions, as well as, in the relative somatosensory, SIEO (t(8) = -2.42, p = 0.04) and SIEC (t(8) = -3.96, p = 0.004), and vestibular SIV (t(8) = -2.47, p = 0.04) contributions to balance. As expected, no significant changes from EO to EC conditions were found indicating an absence of visual dependency in VI. No significant pre-post changes were observed in the control group (all p > 0.05).
These preliminary results establish the potential for the AYT to increase the somatosensory and vestibular contribution to balance in a VI population. The AYT group’s absolute COP results suggest an increase in corrective postural strategies to maintain stability. Future studies may employ a prospective study measuring falls to determine the potential of the AYT to reduce fall risk.
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