Abstract
Purpose :
Accurate perception of body position relative to the environment through visual motion cues provides sensory input to control postural sway. Importantly, the role of visual motion information in older adults is not well established. This study evaluated the extent to which visual motion perception affects postural sway in older adults with and without vision impairment and the interaction with physical function.
Methods :
Participants included 234 older adults with vision impairment from a range of eye diseases (mean age =72.6 ± 7.2 years) and 204 with normal vision (71.6 ± 5.7 years). Participants completed a series of vision tests including binocular visual acuity, contrast sensitivity, visual fields and central motion sensitivity, as well as physical function tests to assess aspects of physical frailty and functional mobility, including walking speed, Timed Up and Go Test (TUGT) and grip strength. Postural sway (path length, mm) was measured using an electronic forceplate (HurLabs) on a firm and foam surface with eyes open. Linear regression analysis was used to identify visual predictors of postural sway and moderated linear regression explored whether this relationship was moderated by physical frailty.
Results :
Linear regression models indicated that of the vision tests, impairments in motion sensitivity were most strongly associated with increased sway on foam (standardized β = 0.330; p<0.001), while of the physical function tests, TUGT (standardized β = 0.334; p<0.001) was most strongly associated with sway on foam, where poorer functional mobility was associated with increased sway. A moderated linear regression demonstrated significant main effects of motion sensitivity and TUGT for sway on foam (p<0.001), as well as a significant interaction effect (standardised β = 0.164, p<0.001), such that the relationship between motion sensitivity and sway became stronger when TUGT performance was poorer.
Conclusions :
A combination of impaired motion perception and reduced physical function negatively impact on postural stability in older adults with and without vision impairment. This finding provides insight into the visual input to postural stability in older adults and its interactions with other sensory and physical impairments and has implications for the assessment of falls risk in older adults.
This is a 2021 ARVO Annual Meeting abstract.