方向交代性頭位眼振の臨床的検討

Abstract

Direction changing positional nystagmus (geotropic and apogeotropic) used to be considered to indicate the presence of central nervous system lesions, especially in the flocculonodular lobe of the cerebellum and the brainstem. Recently, however, several reports have suggested that such positional nystagmus is more likely to be caused by a peripheral vestibular lesion. Particularly, benign paroxysmal positional vertigo, which may originate from the horizontal semicircular canal (HC-BPPV), was first reported by McClure in 1985.The present study reports 23 patients with positional vertigo who were diagnosed as having HC-BPPV in terms of the clinical and roentgenographic findings. Eight patients in the present series showed direction changing apogeotropic positional nystagmus, whereas the remaining 15 had direction changing geotropic positional nystagmus. In most patients, a short latency (less than 5 seconds) was observed between head positioning and the onset of nystagmus, but it tended to be shorter in the former group of patients. In addition, whereas the nystagmus in patients in the former group persisted for more than 1 minute and showed no fatigability with repeated positioning, the nystagmus in the latter group of patients was only transitory and exhibited fatigability.There has been no established physical therapy for positional vertigo with position changing apogeotropic nystagmus. The present study showed that Brandt-Daroff exercise considerably reduced the time to remission, which took an average of 41.3 days in patients with no treatment, and occurred within an average of 12.8 days in those who underwent the physical therapy. The present study also confirmed the effectiveness of Lempert's maneuver for the patients with geotropic nystagmus. This maneuver reduced the time until remission from an average of 11.0 days to 1.9 days.