A new neurotological test for detecting cerebellar dysfunction.
The adaptation of the vestibulo-ocular reflex (VOR) was studied in 26 normal subjects and 26 patients with cerebellar lesions, using horizontal vision-reversal prisms. In normal subjects, the 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 were type A, higher gain in the initial level and abnormal adaptation (10 cases); type B, higher gain in the initial level and normal adaptation (5 cases); and type C, normal initial level and abnormal adaptation (11 cases). The cases showing the typical type-A responses tended to have severe widespread or midline lesions of the cerebellum. Typical type-B cases had mild cerebellar lesions, and typical type-C cases tended to have lesions restricted to one side of the cerebellum. From these results, it can be speculated that reduction of VOR adaptation occurs when one side of the cerebellum has severe lesions, but it is sufficient to produce a normal vestibulo-ocular reflex if at least half of the cerebellum is intact.
D000328:Adult; D002526:Cerebellar Diseases / Q000175:diagnosis* / Q000503:physiopathology; D002531:Cerebellum / Q000502:physiology*; D005133:Eye Movements; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008297:Male; D009460:Neurologic Examination / Q000379:methods*; D010469:Perceptual Distortion / Q000502:physiology; D012018:Reflex / Q000502:physiology; D014724:Vestibular Function Tests / Q000379:methods*; D014726:Vestibular Nuclei / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology