Effect of interpersonal synchrony on gait fluctuation characteristics: An analysis of synchronization gait assist system

In a walking rehabilitation, the cooperative walking between therapist and patient is implemented and the synchrony of walking rhythm is often observed. So, we suggest that the interpersonal synchrony is important for walking rehabilitation. Our group has proposed gait assistive system using interactive rhythmic auditory stimulation to emulate interpersonal synchrony. It is called “Walk-Mate”. In the previous study, the improvement effects of walking with the fixed-tempo Rhythmic Auditory Stimulation (RAS) and Walk-Mate were compared. As a result, walking with Walk-Mate had 1/f structure and was more effective than walking with RAS. In this study, the emulated interpersonal cooperative walking between human and auditory stimulation was analyzed to investigate the relationship between synchrony and gait improvement effect. Fixed-tempo RAS were compared to Walk-Mate. Twenty PD patients and 18 younger healthy persons were participated in experiments. We showed that the phase difference with Walk-Mate was less variable and more temporally-stable than with RAS. It meant the walking with Walk-Mate has the higher synchrony than with RAS. The combination of the result and previous result indicates that the synchrony between participants and auditory stimulation were related to the gait dynamics of participants´ stride time. In addition, the PD patients showed the lower synchrony than young healthy people. Therefore, we suggest that it is necessary that the auditory system encourage them to synchronize. We suggested the importance of considering the synchrony in rehabilitation for PD patients.