OBJECTIVE: To report a patient with genetically proven DYT1 dystonia who shows dramatic improvement in symptoms while playing the piano. DESIGN: Case study. SETTING: Sobell Department for Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, England. Patient A 49-year-old right-handed male civil servant. MAIN OUTCOME MEASURES: The patient was videotaped, and electromyographic activity was recorded from the splenius capitis, sternocleidomastoid, and orbicularis oculi muscles, while he was (1) at rest, (2) playing an electric piano with auditory feedback, and (3) playing an electric piano without auditory feedback (ie, when the sound of the piano is turned off). RESULTS: At baseline, the patient had generalized dystonia with prominent upper limb, neck, and facial involvement. While he was playing the piano, there was an instant and almost complete improvement in dystonia symptoms. The improvement was also noticeable when he played the piano without auditory feedback. There was a significant reduction in electromyographic activity for all recorded muscles when he played the piano, compared with his baseline electromyographic activity. CONCLUSION: This is a unique case of "paradoxical" improvement in dystonia symptoms with activity (ie, playing a piano), in contrast to the typical worsening of dystonia symptoms with activity. We discuss the possible mechanisms underlying this phenomenon.