Oculomotor characteristics of parkinsonism in comparison with those of cerebellar ataxia.

Oculomotor characteristics of patients with Parkinsonism have been analyzed. 1. The Parkinsonian patients showed relatively high frequency, but mild degree of abnormalities in various oculomotor functions such as pursuit eye movements, saccade and optokinetic nystagmus and frequently had positional and positioning nystagmus, although all of them might not relate to the pathology of parkinsonism. 2. When a visual target was presented laterally to a subject and head was free to move, the Parkinsonian patients showed relatively good eye-head coordination for gaze shift, resulting in accurate and stable gaze. However, the reaction times of head and eyes were prolonged and overt head movement was observed. 3. Ocular dyskinesias, characterized by smooth, slow, to-and-fro deviations with large amplitude and prominent in darkness were observed in 8 patients out of 10 with bodily dyskinesia while taking levodopa. 4. Oculogyric crises, paralysis of downward gaze, prolonged reaction time of saccade and poor optokinetic nystagmus were seen in a patient with juvenile Parkinsonism, whose neuropathological examination revealed the most striking changes in the substantia nigra, central grey and midline portion, and ventral and caudal to the central grey.