Illusory self-motion (vection) may be inhibited by hypobaric hypoxia.

Abstract

Previous reports have shown that higher altitudes can alter human perception. We add further evidence to this claim, describing a new finding in which higher altitudes inhibit the perception of illusory self-motion, i.e., vection. We compared vection strength under both normal and high altitude (hypobaric hypoxia) conditions. In the high altitude condition, atmospheric pressure in the climatic chamber was decreased to 13,123 ft (4000 m; 492 ft/150 m x min(-1)) for 28 min and then maintained at the 13,123-ft (4000-m) level for 30 min by a preprogrammed operation. Vection was induced by an optic flow stimulus. Significant differences were observed between the normal and high altitude conditions for all three of the vection strength measurements (latency, duration, and magnitude). Vection was decreased by 14.6%, and Spo2 was decreased by 16.7% in the hypoxia condition. Vection was inhibited in the high altitude condition. Applications of this finding include informing aircraft pilots of this effect of self-motion perception inhibition at higher altitudes to promote safer flying.