Sensory mapping of lip representation in brass musicians with embouchure dystonia

Embouchure dystonia is a focal task-specific disorder involving abnormal non-coordinated movements and involuntary muscle contraction around the mouth. In professional brass players it is often so disabling that patients have to limit or give up their occupation. We examined the somatosensory homuncular representation and measured gap detection sensitivity of the lips in eight former professional musicians affected by embouchure dystonia and eight control subjects. Relative to controls, the patients' digit, and especially the thumb, representations were shifted in a lateral direction towards the lip representational zone. Patients' upper lips showed decreased sensitivity compared to their lower lips (p < 0.01). This asymmetry result was absent in controls. Abnormal somatosensory reorganization may contribute to the disorder.