Abstract

The nystagmus of vertebrobasilar insufficiency (VBI) patients is not clearly understood. In this article we report a videonystagmography (VNG) result which had been recorded in a VBI patient during his ictal period. The spontaneous nystagmus was purely torsional toward the left side. During the various positional tests, up beating left torsional and right horizontal nystagmus was found. Right beating horizontal nystagmus was stronger when the head was turned to the left side. But we were not able to explain the exact mechanism of this nystagmus. Although the mechanism is not fully understood the pattern of nystagmus reported in this article may be helpful in distinguishing VBI from other diseases by means of VNG recording.

• Keywords: Vertigo;vertebrobasilar insufficiency;Nystagmus;