Hand cramps

Clinical features and electromyographic patterns in a focal dystonia

Cohen, Leonardo G. MD
Hallett, Mark MD

From the Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological and Communicative Disorders and Stroke, National Institutes of Health, Bethesda, MD.

Address correspondence and reprint requests to Dr. Cohen, NINCDS (Building 10, Room 5N226), National Institutes of Health, Bethesda, MD 20892.

Received August 21, 1987. Accepted for publication in final form November 27, 1987.

Presented in part at the thirty-ninth annual meeting of the American Academy of Neurology, New York, NY, April 1987.

Neurology 38(7):p 1005-1012, July 1988.

Article abstract

We studied 19 patients with hand cramps, including writer's cramp, typist's cramp, piano, and guitar player's cramp. EMGs were recorded while patients performed the task triggering the cramps. Ten patients with dystonic cramps had EMGs with generalized muscle spasms with co-contraction of agonist and antagonist muscles. In three patients with simple cramps that involved one to three fingers, specific muscle groups showed co-contracting bursts that lasted longer than normal. The physiological abnormalities support the interpretation that hand cramp is a focal dystonia, characterized by both excessive muscle activity and defective fine motor control.