Interaction of vestibular and optokinetic nystagmus in patients with peripheral vestibular and central nervous disorders.

In 66 patients showing different lesions of the vestibular and central nervous system, the influences of spontaneous and experimentally (rotation) induced vestibular nystagmus on optokinetic nystagmus were investigated. Considering the large interindividual differences in the results of vestibulo-visual interaction, the actual values of nystagmus slow phase velocity obtained by means of a combined vestibular and visual stimulation are only of limited diagnostic value in a single case. But by averaging the results obtained from various nosologic groups of patients very different but distinct patterns of vestibulo-visual interaction can be demonstrated. This observation allows some speculation on the mechanism of how nystagmus might be generated as a common output of the vestibular and the visual system.