Department of Psychology, The Pennsylvania State University, University Park 16802, USA.
BACKGROUND: It has been reported that females are more susceptible to motion sickness than males, but these reports have failed to take into account the possible effects of the gender of the experimenter and the subjective nature of reports of symptoms of motion sickness. To deal with the first possible confound, we used male and female experimenters. To deal with the second issue, we recorded gastric myoelectric activity so as to be able to quantify gastric tachyarrhythmia, an objective measure that has been shown previously to correlate highly with severity of symptoms. METHOD: There were 34 male and 34 female participants were assigned to either a male or female experimenter. Symptoms of motion sickness were induced by placing participants 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 significant main effects for gender of the subject or experimenter were found. However, on a post-session questionnaire, females reported experiencing significantly more GI symptoms than males. Gender comparisons of the change in gastric tachyarrhythmia power from baseline to rotation yielded no significant differences. CONCLUSIONS: Females report more overall symptoms of motion sickness and significantly more GI symptoms than males, but do not show greater increases in gastric tachyarrhythmia during exposure to a rotating drum