title: Two types of abnormal somatosensory evoked potentials in chronic cerebellar ataxias.
abstract: To investigate subclinical sensory impairment in spinocerebellar degenerations, median nerve somatosensory evoked potentials (SEPs) were examined in 16 patients with chronic cerebellar ataxia who were originally diagnosed by clinical neurologists as having olivopontocerebellar atrophy (OPCA). Two types of abnormal SEP patterns were found in six patients. Two patients had the SEP pattern of peripheral neuropathy, which was also detected by peripheral sensory nerve conduction studies. Four patients had abnormal SEPs seen in patients with the lesions in the central nervous system (dorsal column, medial lemniscus). Magnetic resonance imaging (MRI) showed multiple sclerosis (MS). It is possible that clinically diagnosed OPCA sometimes includes a similar form of Friedreich's ataxia with subclinical sensory fiber neuropathy detected by SEPs and peripheral sensory conduction studies. In cases of lesions in the central nervous system demonstrated by both SEPs and MRI, there must be a follow-up in order to make a final diagnosis. In those cases, an alternative diagnosis of MS must be considered when the temporal profile of symptoms and signs characteristic of MS is observed.
authors.affiliation: Department of Rehabilitation Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Okajima
authors.forename: N
authors.initials: N
authors.lastname: Chino
authors.forename: E
authors.initials: E
authors.lastname: Saitoh
authors.forename: A
authors.initials: A
authors.lastname: Tsubahara
authors.forename: A
authors.initials: A
authors.lastname: Kimura
authors.forename: B
authors.initials: B
authors.lastname: Mihara
mesh_terms: D000328:Adult; D002908:Chronic Disease; D004576:Electromyography; D005069:Evaluation Studies as Topic; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000503:physiopathology; D009431:Neural Conduction / Q000502:physiology; D010525:Peripheral Nerves / Q000503:physiopathology; D013127:Spinal Nerves / Q000503:physiopathology; D013132:Spinocerebellar Degenerations / Q000145:classification / Q000503:physiopathology*