Atara Lipson¹, Sara Weinberg^1,2, Taylor Cleworth^1,2; ¹School of Kinesiology and Health Science, York University, Toronto ON, Canada, ²Centre for Vision Research, York University, Toronto ON, Canada

INTRODUCTION: Dynamic visual cues, such as circular vection stimuli (CV), influence both balance control and self-motion perception. Furthermore, visual cues impact balance behaviour during dynamic balance tasks. Currently, there is limited work examining self-motion perception when exposed to dynamic visual cues during a dynamic balance task. This study aims to assess actual and perceived self-motion during a dynamic balance task with continuous visual rotation. METHODS: Twenty healthy young adults (mean age 21, 14 female) stood on a platform that continuously tilted forwards (3º) and backwards (3º) for 30 seconds. Participants wore a virtual reality headset displaying white dots on a black background. 3D motion was recorded from markers on 6 bony landmarks. Four balance tasks were randomized, including two static stance (SS) conditions (quiet stance, quiet stance with CV) and two dynamic stance (DS) conditions (platform tilt, platform tilt and CV). Participants completed all balance tasks while tracking their movement using a handheld tracking device, and again while not tracking their movement. Trunk angular (TAD) and linear (TLD) displacement and tracked displacement (TRACK) were assessed using root mean square (RMS). RESULTS: During SS and DS conditions, CV influenced actual movement, where TAD and TLD RMS were larger during CV. CV also influenced tracked movement, where TRACK RMS increased with CV in SS conditions only. Therefore, the ratio between perceived and actual movement increased when exposed to CV during SS conditions, while there was no change during DS conditions. During DS trials, tracking increased TAD and TLD RMS compared to non-tracking trials. No other interaction or main effects were observed. CONCLUSIONS: Exposure to dynamic visual feedback increases postural sway. However, perception of self-motion is disrupted when simultaneously exposed to a dynamic balance task with CV. Further work needs to examine cortical regions involved in perception of self-motion during dynamic balance tasks.

Acknowledgements: This project was funded by NSERC and VISTA at York University (TC).