Motion sickness: effect of the magnitude of roll and pitch oscillation

BACKGROUND: Rotational oscillation in roll and pitch can cause motion sickness, but it is not known how sickness depends on the magnitude of rotational oscillation or whether there is a difference between the two axes of motion. HYPOTHESIS: It was hypothesized that motion sickness would increase similarly with increasing magnitudes of roll and pitch oscillation. METHOD: There were 120 subjects (6 groups of 20 subjects) who were exposed to 30 min of 0.2-Hz sinusoidal roll or pitch oscillation at 1 of 3 magnitudes: 1) +/- 1.830; 2) +/- 3.66 degrees; or 3) +/- 7.32 degrees. Subjects sitting in a closed cabin with their eyes open gave ratings of their illness on a 7-point illness rating scale at 1-min intervals. RESULTS: Over the six conditions, mild nausea was reported by 17.5% of subjects. With both roll oscillation and pitch oscillation, mean illness ratings were least with +/- 1.83 degrees of rotational oscillation and greater with +/- 3.66 degrees and +/- 7.32 degrees of oscillation. At none of the three magnitudes of oscillation was there a significant difference in motion sickness caused by roll and pitch oscillation. CONCLUSIONS: With rotational oscillation about an Earth-horizontal axis, there is a trend for motion sickness to increase with increasing motion magnitude. For the conditions investigated, similar motion sickness was caused by roll and pitch oscillation.