方向交代性上向性頭位眼振の成因の検討 頭部外傷例を中心に

Abstract

Nystagmus towards the upper ear in both lateral head positions is usually considered to appear in patients with central nervous system lesions, especially those in the brain stem or cerebellar posterior vermis. However, its pathogenesis is still obscure, since several reports have suggested that such positional nystagmus may occur in patients with peripheral vestibular disturbances.This report describes a patient with positional nystagmus of this type after head trauma. X-ray examination revealed temporal bone fracture. The origin of positional nystagmus in this case was thought to be a peripheral vestibular lesion because the nystagmus was transient and there was no clinical evidence of any disturbance of the central nervous system. Seven cases of such positional nystagmus seen during the last 3 years in Kitasato University Hospital are summarized. Positional nystagmus towards the upper ear is assumed to be an important sign of central nervous system disturbance, but it may occur with peripheral vestibular lesions. It is necessary in the latter case for the positional nystagmus to disappear in the course of time, and other vestibular and neurological findings may indicate the character of the peripheral vestibular disturbance.