Can Brain Stimulation Reduce VR motion sickness in Healthy Young Adults During an Immersive Relaxation Application? A Study of tACS

This study marks the first exploration of whether a non-invasive transcranial alternating current stimulation (tACS) on the left parietal cortex can reduce VR motion sickness (VRMS) induced by a commercial VR relaxation app. Two VRMS conditions were examined for 36 healthy young adults: 1) pure VRMS without a moving platform; 2) VRMS with a side-to-side rotary chair. Participants underwent three counterbalanced tACS protocols at the beta frequency band (sham, treatment, and control). Contrary to our hypothesis, the treatment protocol did not significantly reduce VRMS in either condition. Given the protocol's prior success in our previous tACS study, we discussed potential factors hindering the replication of our earlier achievement.

1 Introduction

Our recent electroencephalogram (EEG) studies in vestibular cortical areas revealed that there is a significant correlation between VRMS ratings and the phase-locking values in beta frequency band [1]. To assess the casualty between our EEG findings and the severity of VRMS, we previously designed a transcranial alternating current stimulation (tACS) protocol to disrupt that EEG-VRMS correlation and successfully validated its feasibility in mitigating VRMS in healthy young adults (see attached Supplementary Materials). VRMS in this previous study was induced by a visual motion stimulus eliciting linear self-forward vection, with motion sickness susceptibility of participants being well controlled (10<MSSQ<36; Motion Sickness Susceptibility Questionnaire [2]). In the current study, we replicated the successful beta-tACS protocol developed in our previous work to answer the following research question: Does the beta-tACS stimulation mitigate VRMS caused by a commercial immersive VR relaxation application under stationary and dynamic environments in a non-MSSQ-controlled randomly-recruited student population?