Quantifying Changes in Balance, Gait, Fall Risk, and Sensory Reweighting in Older Adults Following Multi-Session Electrical Vestibular Stimulation Therapy

Objective: To assess the utility of digital biomarkers derived from a head-mounted wearable physiological vibration acceleration (phybrata) sensor for quantifying changes in balance, gait, fall risk, and sensory reweighting in older adults undergoing multi-session electrical vestibular stimulation therapy (eVST). Methods: Data were collected and analyzed from 32 residents aged 60– 98 yrs from a continuing care retirement community before, during, and after the administration of an 18-session eVST treatment protocol delivered over a 4– 6-week period. Each session included subthreshold wideband stochastic electrical vestibular stimulation (swsEVS) for 20 minutes delivered using a wearable device. Balance performance, sensory reweighting, and fall risk were assessed immediately before and after treatment using a head-mounted phybrata sensor. Two additional standard balance tests, along with wearable-sensor-based gait assessments, were administered before the 1 st and after the 18 th treatment session. Results: 30 of the 32 participants demonstrated significantly improved balance and gait performance and reduced fall risk following the 18-session eVST treatment protocol. Phybrata sensory reweighting profiles for the study participants as a group revealed significant recovery of vestibular balance regulation and decreased reliance on proprioception. Phybrata biomarkers were found to identify the 2 non-responders in the study population within the first 2 treatment sessions. The number of participants classified as “high fall risk” decreased from 19 to 4 following treatment. Significant stabilization of head movement was observed following eVST treatment using head-mounted sensors during gait tests over distances as short as 7.6m, with the largest reductions observed in the medial-lateral direction. Head-acceleration based gait biomarkers were found to be more sensitive to eVST-induced improvements than stride-to-stride gait parameters measured using foot-mounted sensors. Conclusion: Phybrata digital biomarkers enable rapid objective assessment of changes in balance, gait, fall risk, and sensory reweighting in older adults before, during, and after a multi-session eVST treatment protocol.