Ulnar neuropathy and dystonic flexion of the fourth and fifth digits: clinical correlation in musicians.
Peripheral nerve lesions are sometimes associated with focal dystonia. We diagnosed ulnar neuropathy in 28 of 73 (40%) cases of occupational cramp in musicians. Focal slowing of ulnar conduction across the elbow was identified in 15 of 19 (79%) patients using the near nerve technique and in 5 of 17 (29%) patients using surface recording. Ulnar neuropathy was present in 24 of 31 (77%) cases with flexion dystonia of the fourth and fifth digits and only 4 of the remaining 42 (10%) cases with other patterns of focal dystonia. Focal dystonia improved in 13 of 14 patients whose ulnar neuropathy improved and appeared or worsened in 2 patients following ulnar nerve injury. These data, together with our recent observation of a dystonic pattern of antagonist bursting in patients with isolated ulnar neuropathy (Muscle Nerve 1995, 18:606-611), suggest that ulnar neuropathy may initiate or sustain a specific dystonia, flexion of the fourth and fifth digits, by inducing a central disorder of motor control.
Charness
M E
ME
Department of Neurology, Harvard Medical School, Boston, Massachusetts, USA.
Ross
M H
MH
Shefner
J M
JM
D000293:Adolescent; D000328:Adult; D004421:Dystonia / Q000175:diagnosis / Q000503:physiopathology*; D004594:Electrophysiology; D005260:Female; D005385:Fingers / Q000294:innervation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D009146:Music; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000503:physiopathology; D014459:Ulnar Nerve / Q000503:physiopathology*