Effects of gender of subjects and experimenter on susceptibility to motionsickness

Background: It has been reported that females are more susceptible to motio n sickness than males, but these reports have railed to take into account t he possible effects of the gender of the experimenter and the subjective na ture of reports of symptoms of motion sickness. To deal with the first poss ible confound, we used male and female experimenters. To deal with the seco nd issue, we recorded gastric myoelectric activity so as to be able to quan tity gastric tachyarrhythmia, an objective measure that has been shown prev iously to correlate highly with severity of symptoms. Method: There were 34 male and 34 female participants were assigned to either a male or female e xperimenter. Symptoms of motion sickness were induced by placing participan ts in an optokinetic drum for an 8-min baseline period followed by a 16-min rotation period. Electrogastrograms (EGGs) were continuously recorded, and reports of symptoms were obtained from the participants every 3 min during rotation. Results: Comparison of male and female subjects' symptom scores revealed that females had higher symptom scores than males; however, no sig nificant main effects for gender of the subject or experimenter were found. However, on a post-session questionnaire, females reported experiencing si gnificantly more GI symptoms than males. Gender comparisons of the change i n gastric tachyarrhythmia power from baseline to rotation yielded no signif icant differences. Conclusions: Females report more overall symptoms of mot ion sickness and significantly more GI symptoms than males, but do not show greater increases in gastric tachyarrhythmia during exposure to a relating drum.