[A case of superficial siderosis of the central nervous system--findings of the neuro-otological tests and evoked potentials].

We report a 57-year-old woman with superficial siderosis of the central nervous system. On physical examination, sensorineural hearing impairment, cerebellar ataxia, pyramidal tract signs, dysarthria, and neurogenic bladder were seen. Brain and spinal cord MRI (T2 and proton weighted images) revealed cerebellar atrophy and marginal hypointensity of the Sylvian fissure and brain stem, cerebellum and spinal cord. We diagnosed this patient as superficial siderosis because of the clinical course and specific findings on MRI. We consider this case idiopathic superficial siderosis because the source of the bleeding was unknown. Neuro-otological tests and BAEP disclosed retrocochlear deafness. Her central motor conduction time on MEP was delayed. We discussed the pathogenic mechanism of these conditions, and we concluded that we must take notice of myelinopathy in superficial siderosis and that MEP was useful for detecting them.