[Clinical study on the mechanism of motion sickness--clinical examination based on trigger factors].

This report deals with factors which trigger motion sickness. The author has focused on the clinical examinations applied to motion sickness cases. Relationships between clinical data and susceptibility to motion sickness were investigated. The following results were obtained: 1. CV R-R(coefficient of variation of R-R intervals on EGG)in the frequent motion sickness group showed higher values than in the occasional motion sickness group. This result suggests a hyperfunction of the vagus nerve. 2. In caloric testing with ENG, the motion sickness group showed lower values of duration and eye speed than the occasional motion sickness group. On the other hand, the frequent group showed higher values of laterality in eye speed than the occasional group. 3. With the visual suppression test, the frequent motion sickness group showed higher values than the occasional motion sickness group. On the other hand, there was a significant difference between the frequent motion sickness group and the occasional motion sickness group in terms of laterality of visual suppression values. 4. In testing fluctuation of CV R-R in response to optokinetic stimuli, the frequent motion sickness group showed elevation of CV R-R values after optokinetic load. On the other hand, the occasional motion sickness group showed depression of CV R-R values after the same load. 5. Among clinical examinations designed to diagnose susceptibility to motion sickness, CV R-R, the caloric test, the visual suppression test and OKP testing can produce sufficiently accurate results for clinical investigation.