Spatiotemporal Gait Guidance Using Audiovisual Cues of Synchronized Walking Avatar in Augmented Reality

There has been a growing interest in augmented reality (AR) methods for gait guidance and rehabilitation. These methods have been effective in guiding spatial gait parameters, such as stride length, and temporal cycle times when paired with rhythmic stimuli. However, few studies have explored the simultaneous spatial and temporal guidance of gaits and have primarily focused on one of several aspects. Gait parameters are related, and changing one might have unintended effects on others; thus, simultaneous guidance is required. In this study, we designed and evaluated a system that provides simultaneous spatial and temporal guidance using a synchronized walking avatar in AR. The system requires a head-mounted display (HMD) and presents a walking avatar involving auditory cues synchronized with the foot-contact timing of the participant via a mutual entrainment model. Spatial feedback is provided by distance changes between the participant and avatar, and the effects on stride length are observed. Phase difference changes between the avatar and participant serve as temporal cues that are used to guide the cycle time. The stride length and cycle-time of eight participants walking along a straight corridor wearing the HMD were recorded and analyzed. Four experimental conditions were applied comprising combinations of increases and decreases in the spatial and temporal cues. Furthermore, the results demonstrated that spatial and temporal feedback had almost independent effects on respective gait parameters. These findings reveal that this combination of spatiotemporal cueing can be extremely effective in gait guidance without loss of effectiveness from single modality cues.