Ocular, Vestibular, and Otologic Syndromes

Abstract

Strokes involving the brainstem and cerebellum give rise to various abnormal eye movements that would aid in delineation of the involved structures and localization of a stroke. In some strokes, the ocular motor abnormalities are the only or predominant findings that require systematic assessments. Among the vertebrobasilar strokes, medullary and cerebellar strokes mostly cause various patterns of nystagmus and impaired vestibular eye movements without ophthalmoplegia. In contrast, pontine strokes are characterized by horizontal eye movement abnormalities while midbrain strokes typically show pupillary, eyelid, and vertical gaze abnormalities. Determining the patterns and characteristics of abnormal eye movements in patients with vertebrobasilar strokes is important in understanding the roles of each neural structure and circuit in ocular motor control as well as in determining the affected structures.