Late cortical cerebellar atrophy. Clinical and oculographic features.

Ten patients with late cortical cerebellar atrophy documented with computerized tomography (CT) and magnetic resonance (MR) imaging presented a uniform pattern of oculomotor abnormalities. All had deficits in smooth pursuit and fixation suppression of the vestibulo-ocular reflex (VOR). The gain of the VOR was often increased but the dynamics of the VOR were not different from normals. Full-field optokinetic responses and visual-vestibular interaction mediated via the VOR velocity storage element were preserved. Just as in lower primates, the cerebellum in humans is a critical relay station for foveal pursuit and visual-vestibular interaction requiring foveal pursuit. Vestibular responses and visual-vestibular interaction mediated through the VOR velocity storage element are relatively independent of the cerebellum.