The effects of differential rotation speeds on electrogastrograms and motion sickness in humans

The purpose of this study was to investigate effects of differential speeds of an optokinetic rotating drum on vection, illusory self motion, subjective symptoms of motion sickness (SSMS), and abnormal electrogastrograms (EGGs) in humans. Sixty-four subjects were randomly divided into eight groups of different speeds: 20, 40, 60, 80, 100, 120, 140 or 160 degrees per second (deg/s). Report of vection, SSMS and EGGs were measured in all subjects during the rotation period. Spectral intensity of EGG at the frequencies 4-9 cycles per minute (cpm), gastric tachyarrhythmia was calculated at each drum rotation speed. The ratings of SSMS showed a significant difference among the groups (p .05). The mean SSMS was 1.78, for the group of 20 deg/s, 3.77 for 40 deg/s, 4.58 for 60 deg/s, 3.59 for 80 deg/s, 4.71 for 100 deg/s, 3.98 for 120 deg/s, 2.59 for 140 deg/s and 3.70 for 160 deg/s. Vection was found to be significant among the groups (p .05). Mean vection was 3.91 for the group of 20 deg/s, 6.35 for 40 deg/s, 5.85 for 60 deg/s, 4.51 for 80 deg/s, 6.27 for 100 deg/s, 5.39 for 120 deg/s, 4.44 for 140 deg/s and 5.05 for 160 deg/s. The power of the EGG (4-9 cpm) showed a significant difference among the groups, the 100 deg/s group was the highest and the 20 deg/s group was the lowest. In conclusion, different rotation speeds generated different SSMS, reports of vection, and tachyarrhthmia. The most significant SSMS and tachyarrhythmia was generated at the 100 deg/s.