RESUMEN
We report a case of 33-year-old man with multiple sclerosis, showing piano playing movement in both hands. His course of multiple sclerosis was remittent/progressive during 2 years and the clinical manifestation suggested the spinal cord involvement. On July 15, 1991, he was admitted with numbness of the right limbs, and then developed piano playing movement in both hands, more marked in the right side. Neurological examination revealed mild weakness in the right upper extremity, and rough touch, pain, and temperature sensation were slightly decreased. However, there was no deep sensory abnormalities, such as vibration, fine touch, and position senses. Vibration sense was lost below ilium. CSF examination showed elevation of IgG index (1.6), three oligoclonal bands and myelin basic protein content of 2.4 ng/ml. There was no HTLV-I antibody in CSF. SSEP, elicited by median nerve stimulation at the right wrist, showed no N13 and low amplitude of N20. T2-weighted images of cervical MRI revealed area of high signal intensity at the C3-C4 level. The piano playing movement gradually improved and disappeared by the initiation of steroid hormone therapy. It was considered that involuntary movement in this patient was due to the spinal cord lesion caused by multiple sclerosis. These findings suggested that the involuntary movement like pseudoathetosis could present without deep sensory abnormalities.