The effect of tilted stripes in an optokinetic drum on gastric myoelectric activity and subjective reports of motion sickness.
Jeffrey T. Andre, E R Muth, R M Stern, Herschel W. Leibowitz · PubMed · 1996
BACKGROUND: The effects of tilted and vertical optokinetic drum stripes on self-reports of motion sickness and electrogastrograms (EGG's) were measured to investigate possible differences in the effects of stripe orientation. The EGG is a non-invasive measure of gastric myoelectric activity. The normal frequency is 3 cpm, and dysrhythmic 4-9 cpm activity, gastric tachyarrhythmia, has been found to be associated with motion sickness symptoms, particularly nausea. It is theorized that these symptoms are related to a sensory mismatch between the visual and vestibular systems elicited by the drum's rotation. HYPOTHESIS: We hypothesized that tilted stripes would elicit more symptoms than vertical stripes due to an additional sensory mismatch between the visual and vestibular verticals. METHODS: We divided 45 subjects into 2 stripe orientation groups: Vertical, and Tilted 15 degrees in the direction of drum movement. After the subject sat inside the stationary drum for a 6-min baseline, the drum was rotated (10 rpm) for a maximum of 16 min, followed by a 6-min recovery period. Throughout the experiment we measured the subjects' EGG's and subjective symptoms of motion sickness (SSMS). RESULTS: During rotation and recovery, gastric tachyarrhythmic activity was higher for subjects in the Tilted condition; the difference between stripe conditions was significant during rotation (p < 0.05). There were, however, no differences between SSMS scores. CONCLUSIONS: Off-vertical stripes increase the dysrhythmic activity of the stomach that often precedes or accompanies nausea and other symptoms of motion sickness.