Interpersonal synchrony-based dynamic stabilization of the gait rhythm between human and virtual robot — Clinical application to festinating gait of Parkinson´s disease patient

Recently, robotics attracts attention in field of not only industry and production but also assistive technology and rehabilitation method. It is required how the system generate assistive functions in interaction with the user, while lots of one-sided help forms are in previous researches. From these backgrounds, we have focused on cooperative gait between humans as interpersonal synchronization, and modeled the mechanism of footstep rhythm synchronization. Moreover, we developed an interpersonal synchrony emulation robot named Walk-Mate, which was biped virtual robot synchronizing with the user´s footstep rhythm via walking together. In this study, we evaluated the effect of Walk-Mate in stabilizing gait with Parkinson´s disease (PD), which previously displayed disturbances in rhythm formation and festinating gait (accelerating footsteps). The results showed that the festinating gait, evaluated by stride time reduction rate, significantly stabilized and accelerated less with Walk-Mate compared to unassisted walking. Additionally, carry-over effects were significantly observed. After termination of the auditory stimulation, the gait remained stabilized. These suggested that gait with PD was dynamically stabilized by the interpersonal synchrony process between timing of human´s gait and of external auditory cues. In this paper, we showed significant improvement for the festinating gait in the PD patients.