[A case of periodic ataxia].

We report a sporadic case of periodic ataxia characterized by recurrent attacks of vertigo and ataxia. A 62-year-old male was known to have nystagmus at the age of 18. He has had recurrent episodes of vertigo and ataxia since the age of 48. During an attack remarkable downbeat nystagmus, limb ataxia predominant in the lower extremities and ataxic gait were present. MRI demonstrated an atrophy of the anterosuperior region of the cerebellar vermis. Vertical nystagmus, dysesthesia of gloves and stocking type and deep sensory disorder persisted during interictal intervals. There is no finding which supports this case to be vascular disorder, congenital anomaly, tumor, infection or demyelinating disease. We thought this case to be periodic ataxia and to belong to vestibulocerebellar ataxia reported by Farmer and his colleagues.