1993 Volume 15 Issue 5 Pages 380-385
A 62-year-old man suddenly suffered from cerebral infarction during coronarography. Subsequent examinations revealed right hemiplegia accompanied by lateral deviation of the right eye, vertical oculomotor disorder, and retraction nystagmus in the dounward gaze. An electro-oculogram showed that downward gaze was more prominent than upward gaze, Doll's eye phenomenon, however, was preserved and remained unchanged. A caloric test elicited upward nystagmus in the supine position and pendular nystagmus in the prone position. Bell's phenomenon was positive. Brain MRI demonstrated a discrete infarction in the paramedian midbrain including the rostral interstitial nucleus of MLF (riMLF). It is suggested therefore that the vertical oculomotor disorder was caused by the lesion of the riMLF. Based on MRI, predominantly downward gaze palsy might be ascribable more to a lesion of the mediocaudal part than one of the dorsolateral part of the riMLF.
