[Electro-oculographic study of a case of abolition of horizontal saccades with viscosity of eye movements in hereditary cerebellar degeneration].

A case of familial cerebellar ataxia is reported during the course of which horizontal ocular movements were slow, and "viscous". The electro-oculographic study showed complete abolition of horizontal jerks, induced by either voluntary, automatic (optokinetic nystagmus), or reflex (vestibular) stimuli. Slow movements, however, were normal, and voluntary vertical jerks were conserved while being slightly slowed towards the top. The physiopathological interpretation of these facts remains a point for discussion. Results from animal experiments and neuropathological studies suggest that the abolition of jerks in such cases is probably due to loss of facilitating influences from the cerebral cortex and central grey nuclei.