A Novel Spatial Gait Parameter-Based Vibrotactile Cueing for Freezing of Gait Mitigation Among Parkinson’s Patients

 Objective: Auditory and visual cues have been shown to be efficacious in laboratory-based freezing of gait (FoG) mitigation in Parkinson’s disease (PD). However, the real-life applications of these cues are restricted due to inconvenience to the users and lower social acceptance. Recently developed closed loop vibrotactile cues based on temporal gait events have overcome the shortcomings of auditory and visual cueing. However, spatial gait parameter driven vibrotactile cueing has not been explored yet. Previous studies have suggested spatial gait parameter driven cueing to be more effective than temporal cueing based on FoG pathophysiology. Therefore, we developed and validated a novel cueing scheme in which foot to ground angle at heel strike (FGA_HS) is estimated using indigenous instrumented shoes to drive vibrotactile cueing. Methods: Eight PD freezers underwent a 6-meter timed walk test including reverse counting and hurdles to induce FoG. PD freezers underwent the protocol in the off-medication state with and without cue, and after medication without cue. Indigenous instrumented shoes were used for objective gait assessment. Results: Freezing severity, quantified by the ratio of time spent freezing to the total walking time, reduced with the cue in the off-medication state. The reduced freezing severity was accompanied by increased antero-posterior stance center of pressure excursion (CoP_AP) and FGA_HS.  Conclusion: The novel spatial gait parameter-based cue was effective in mitigating FoG through improvement in associated gait parameters. Significance: With a future comprehensive validation on a larger number of participants, the novel cueing method has significant potential for practical use and commercialization.