A model of visual-vestibular interaction in cerebellar disorders.

The number of saccades, vestibular gain and visual suppression as a function of smooth pursuit gain were determined in 10 cerebellar cases. Visual suppression increased and the number of saccades decreased with increasing smooth pursuit gain while a high vestibular gain was found in most cases but without relation to the gain of smooth pursuit. An eye-motor model is presented according to which all findings could be related to a disturbance of proper cerebellar processing of optic impulses and of impulses to the vestibular nuclei in the paramedian reticular formation.