[The motion sickness under reversing goggles (1st report)].

We observed locomotion and motion sickness in 10 normal adults wearing reversing goggles while moving outdoors. Horizontal reversal of the visual field produced moderate to severe ataxia and motion sickness in all subjects except one. There was marked variability in the sensitivity among different subjects. In contrast, vertical reversal produced no symptoms. Confusion of information relation to spatial orientation possibly caused both the motion sickness and abnormal locomotion. Horizontal reversal of visual information produces disorientation because visual information is equal in importance to that from the semicircular canals. In the case of vertical reversal of visual information, orientation may be assured by gravity. The present study suggests that motion sickness is a biological signal alerting the organism to loss of spatial orientation rather than a mere autonomic symptom produced by mismatched sensory information. It appears that motion sickness is accompanied by dysequilibrium and abnormality of locomotion.