Unusual focal dyskinesias: the ears, the shoulders, the back, and the abdomen.

Fourteen patients with focal or segmental involuntary movements affecting the ears, back, shoulder girdle, and upper extremity, as well as the abdomen and pelvic girdle, are presented. The unusual locations and appearance of these dyskinesias distinguishes them from recognized movement disorder syndromes. It is argued that the slow, sinuous, and semirhythmic character of the movements and the variable long-duration bursts of motor unit activity responsible for them most closely fit into the spectrum of dystonia. A history of pain in the affected region and/or peripheral trauma in some cases also suggests that peripheral factors may play a role in their pathogenesis.