Supranuclear ophthalmoplegia in olivopontocerebellar degeneration.

Autosomal dominant olivopontocerebellar degeneration was diagnosed in a family of Scottish ancestry by clinical examination and autopsy. In addition to having progressive cerebellar ataxia, head titubation, and severe dysarthria, the patients are unable to initiate saccadic eye movements. Slow pursuit movements are normal. Reflex movements of the eyes caused by passive rotation or caloric labyrinthine stimulation are not impaired but are not associated with nystagmus. The phenomenon can be classified as supranuclear pseudo-ophthalmoplegia. It differs from congenital ocular motor apraxia in age at onset and the absence of random eye movements. The anatomic lesion responsible for the defect of saccadic eye movements remains to be established.