New Neurotological Test for Detecting Cerebellar Dysfunction

Abstract

Adaptation of the vestibule-ocular reflex (VOR) was studied in 26 normal subjects and 15 patients with cerebellar lesions, using horizontal vision-reversal prisms. In normal subjects, adaptation of gain after wearing prisms for one hour was approximately 50% of the VOR value in the dark. In contrast to this, patients with cerebellar lesions showed less adaptation, approximately 20% after a one-hour forced adaptation task. These cases showed three different types of abnormalities: 1) high gain before wearing prisms and normal adaptation, 2) high gain before wearing prisms and reduction of adaptation, 3) normal gain and reduction of adaptation. From these results, it is suggested that observation of the effect of vision-reversal prisms on the VOR may permit the detection of cerebellar lesions of a type or subtlety which escape established tests.