Vestibular Perceptual Thresholds, Balance Impairment, and Fall Risk in Community-Dwelling Older Adults

BackgroundVestibular complaints are common in older adults and are linked to imbalance and falls. Some older adults show impaired vestibular perception despite preserved peripheral-reflex ("vestibular agnosia"). Yet it remains unclear if vestibular agnosia is independently linked to imbalance and falls in otherwise healthy older adults. We therefore investigated the prevalence of vestibular agnosia in community-dwelling older adults, and examined its association to balance and prospective falls. MethodsVestibular perceptual thresholds were measured during yaw-plane rotational chair testing. Postural sway and instrumented Timed-Up-and-Go were assessed using wearable sensors, and falls were recorded prospectively over six-month. Vestibular agnosia was identified using K-means clustering. Multivariable regressions examined associations between perceptual thresholds and balance outcomes; logistic and negative binomial regressions evaluated associations with prospective falls. ResultsAmong 166 participants (75.4 years; 81.9% female), 18.7% were classified as having vestibular agnosia. These individuals had worse cognition and somatosensation. Elevated (i.e. worse) vestibular perceptual thresholds were independently associated with greater sway velocity when standing on foam with eyes-open (adjusted {beta}=0.002, p=0.03). Associations with other balance outcomes were attenuated after adjustment. Vestibular perceptual thresholds were not associated with prospective falls (odds of [≥]1 fall: adjusted OR=0.99, p=0.65; fall counts: adjusted IRR=1.02, p=0.35). ConclusionsApproximately one-fifth of healthy older adults exhibit vestibular agnosia. While elevated perceptual thresholds are independently associated with poorer balance, they did not predict falls. Vestibular perceptual testing provides complementary insight into age-related balance impairment, although its utility in fall-risk prediction requires further investigation. Key PointsO_LIApproximately one-fifth of healthy older adults had vestibular agnosia (impaired vestibular perception despite intact peripheral function) C_LIO_LIOlder adults with vestibular agnosia have poorer cognition, reduced lower limb somatosensation, and higher anxiety. C_LIO_LIHigher (i.e. worse) vestibular perceptual thresholds were independently associated with greater sway velocity when standing on foam (eyes open). C_LIO_LIHigher vestibular perceptual thresholds were only associated with slower TUG performance and greater eyes-closed foam sway in unadjusted models. C_LIO_LIVestibular perceptual thresholds did not predict prospective falls over 6 months. C_LI