[Mirror movements observed in patients skilled in playing the piano--symptomatological study]

We investigated mirror movements observed in two patients skilled in playing the piano and compared these symptoms with those reported in patients associated with frontal lobe, corpus callosum or cervical cord lesion. We found the following common features in our two patients: 1) mirror movements were observed during skilled finger movements such as playing the piano, 2) these were observed in distal parts of the bilateral upper extremities, 3) contralateral imitative associated movements were seen concomitantly, 4) frontal lobe symptoms and callosal disconnection syndrome were not seen, 5) both patients recalled having mirror movements in their infancy, and one had family history. These characteristics of mirror movements in our patients were similar to those in patients associated with cervical cord lesion, but were different from those in patients associated with frontal lobe or corpus callosum lesion. It is suggested that abnormal pathways in the pyramidal tract or cervical cord lesion elicited mirror movements in our patients.