Evaluating fluid-filled glasses for motion sickness symptom mitigation in a computer-assisted rehabilitation environment (CAREN)

BACKGROUND: Motion sickness arises from sensory conflict between visual, vestibular, and somatosensory inputs, causing nausea, dizziness, and vomiting. Non-pharmacological interventions are underexplored despite their potential for accessibility and safety. This study evaluated (1) Computer-Assisted Rehabilitation Environment (CAREN) as a novel tool to induce motion sickness and (2) the efficacy of fluid-filled motion sickness glasses which create an artificial horizon to counteract peripheral visual-vestibular mismatch and reduce symptoms. METHODS: A randomized controlled trial was conducted with thirty motion sickness-susceptible participants (23 females, 7 males; median age 34.2 years). Participants were exposed to a standardized "scrambler" ride simulation via CAREN, which combined vestibular and visual motion stimuli. The intervention group (n = 15) wore fluid-filled frames, while the placebo group (n = 14) wore identical glasses with drained fluid. Symptoms were assessed pre/post using the Motion Sickness Assessment Questionnaire (MSAQ) and every 60 s during exposure using the Motion Illness Symptoms Classification (MISC) scale. Wilcoxon signed-rank and Mann-Whitney U tests compared outcomes. RESULTS: CAREN significantly induced motion sickness, with median MSAQ scores increasing from 17.0 (IQR: 16.0-19.0) pre-exposure to 40.5 (IQR: 27.0-57.0) post-exposure (p < 0.001). No significant difference was observed between intervention and placebo groups in symptom reduction (median MSAQ increase: 31.0 vs. 16.0, p = 0.15) or glasses-wearing duration (p = 0.89). CONCLUSIONS: CAREN reliably induced motion sickness, supporting its utility for controlled research. However, the motion sickness glasses did not significantly alleviate symptoms compared to placebo in this pilot study. It is possible that peripheral visual cues from fluid-filled glasses may be insufficient to counteract sensory mismatch. Further research should explore larger sample sizes and alternative non-pharmacological interventions using CAREN's controlled environment. TRAIL REGISTRATION: This trial was not prospectively registered in a public registry as it was a limited internal study within the Midwestern University community. The study received ethical approval from our Institutional Review Board (IRB #24-0155), and informed consent was obtained from all participants.