Vestibular functions in motion sickness susceptible individuals.

There exists no functional guide that can serve as a diagnostic tool for individual susceptibility to motion sickness (MS). We evaluated vestibular system functioning via a caloric test (which assesses functioning of the superior vestibular nerve) and the vestibular-evoked myogenic potentials (VEMP) test (which assesses inferior vestibular nerve functioning) in 20 MS susceptible and 20 nonsusceptible individuals. Susceptibility to MS was determined by self-declaration and with MS susceptibility questionnaire and Hamilton Anxiety Scale (HAS). We found statistically significant differences for scores on the MS susceptibility questionnaire and HAS questionnaire; however, we found no correlation between VEMP and caloric test results. We suggest that VEMP and caloric test results are not affected by individuals' susceptibility to MS. We could not find vestibular system deficits using the VEMP and caloric test combination. Our findings do not support vestibular function asymmetry in MS patients.