Individual susceptibility analysis and physical therapy strategies for motion sickness

<p indent="0mm">Motion sickness (MS) is a common and complex syndrome caused by exposure to provocative motion environments. Here, we aimed to explore the biological markers of MS susceptibility to achieve individual susceptibility analysis and propose physical therapy strategies without side effects. We combined the numerical model with the nystagmus test to identify individual susceptibility markers for MS, focusing on the slow-phase angular velocity (SPV) of nystagmus, and applied it to analyze individual differences in susceptibility to MS. Additionally, using the numerical model, we analyzed the mechanical behavior changes of the semicircular canal’s cupula in hypothermic conditions. On the basis of these findings, a local hypothermic strategy was proposed to alleviate MS symptoms. The strategy aims to reduce susceptibility to MS by adjusting the mechanical properties of the cupula, thereby alleviating MS symptoms. We also developed a cooling device and observed 36 subjects’ susceptibility to MS in hypothermic conditions through actual driving experiments. The experimental results indicate that SPV can serve as a crucial biomarker for assessing individual differences in MS susceptibility. We found that individuals affected by MS exhibited a higher SPV of nystagmus under the same angular acceleration stimuli than those unaffected by MS in normothermic conditions. Since the SPV of the nystagmus is approximately proportional to the cupula deformation, and cooling can increase the elasticity modulus of the cupula. We verified that cooling can reduce the cupula deformation under the same angular acceleration stimulus through numerical modeling, thereby reducing the SPV in MS-susceptible individuals to levels similar to non-susceptible individuals. This finding inspired us to explore a physical cooling approach to alleviate MS symptoms. In hypothermic conditions, we confirmed that the SPV of MS-susceptible individuals tended to approximate that of non-susceptible individuals. Consequently, we developed a cooling device and further demonstrated the effectiveness of the therapy strategy through driving experiments. In summary, by combining numerical modeling with nystagmus tests, we proposed a method for analyzing individual MS susceptibility and presented a hypothermia strategy to alleviate MS symptoms, which has shown significant effectiveness.