Assessment of Motion Sickness Associated with Motor Amplification in a Low-Cost Virtual Reality Rehabilitation System

Effective rehabilitation is critical for individuals with motor deficits, such as following a stroke or brain injury. Although high doses of intensive motor rehabilitation can provide maximal benefit, several barriers can prevent attaining necessary therapy levels, including cost, physical access, clinical resource availability, and patient disengagement. Virtual Reality (VR) offers a potential solution to overcome these challenges and enable home-based, self-directed therapy. Here we present custom software that runs on the low-cost Meta Quest 2 headset to deliver immersive rehabilitation exercises. The system uses movement amplification to virtually reduce motor deficits, enabling successful task completion even in individuals with severe disabilities. This approach leverages reinforcement learning to maintain patient engagement during rehabilitation. The system capitalizes on recent advances in VR technology, including inside-out hand tracking, voice recognition, and a responsive virtual coach, to create a more accessible environment for users with no prior VR experience. We present the custom virtual rehabilitation implementation and test whether motor amplification leads to an increase in visually induced motion sickness experienced by individuals without disabilities. We find that motor amplification does not elevate reported motion sickness levels, suggesting that low-cost VR systems may enable increased access to individualized and guided motor rehabilitation.