Nystagmus, turning sensations, and illusory movement in motion sickness susceptibility.

The relationships of motion sickness susceptibility to nystagmic eye movements, sensations of turning, and duration of the spiral aftereffect were determined with 48 subjects separated into groups on the basis of sex and extremes of motion sickness susceptibility. When subjective alertness levels were controlled, there was no enhancement of elicited nystagmus nor turning sensations in susceptible individuals. However, spiral aftereffect durations were significantly longer in susceptible individuals than in nonsusceptible individuals. The results are interpreted as favoring Graybiel's model of the structural elements in motion sickness.