抄録
Spinocerebellar degeneration (SCD) is an inherited neurological disorder characterized by the slow degeneration of the brainstem and cerebellum. The Motor Ataxia Research Group has reported that there are more than 36,000 patients in Japan. Previously, SCD was classified by the clinical symptoms so that it was hard to make a distinct diagnosis. After the 1990s, SCD was identified genetically and has been classified into more than 60 different types. This classification has facilitated our approach to the restricted neuronal function of the brain stem and cerebellum. Usually the diagnosis comes after examination by a neurologist, which includes a physical exam, family history, MRI scanning of the brain and spine, and spinal tap. However, the patients frequently reveal unsteadiness of gait associated with nystagmus that could be also observed in the patients with peripheral vestibular impairment. For this, one third of the SCD patients visit otolaryngologists at their first hospital visit. For an accurate diagnosis, an eye movement examination is necessary. Brainstem and cerebellar lesions affect physiological eye movements, e.g., saccade, smooth pursuit and VOR suppression. Eye gains during those physiological eye movements in SCD patients are significantly lower than controls. Although it is not necessary for them to be an expert, otolaryngologists should understand the role of the brain stem and cerebellum, especially how they affect movements of the eye.
