Optokinetic nystagmus, vection, and motion sickness.

BACKGROUND

Two current theories concerning the etiology of motion sickness (MS)-the eye movement hypothesis and sensory conflict theory-were evaluated under conditions that manipulated the degree of optokinetic nystagmus (OKN) and/or vection.

METHOD: Eye movement and perceptual responses were elicited with whole field stimulation in a vertically striped rotating drum and modulated with fixation and/or a restriction of the field of view (FOV). Measures of OKN, vection, and MS were recorded under the various conditions.

RESULTS

Both visual field restriction and/or fixation diminished circular vection, OKN, and MS. Conditions involving both fixation and restricted FOV resulted in greater reductions in MS than did either restriction alone.

CONCLUSIONS

These findings lend support to a multi-factor explanation of MS, involving both sensory conflict and eye movement.