A novel task-specific dystonia: running-induced cervical dystonia in a triathlete

Abstract

Dear Editor, Task-specific dystonia usually involves a skilled motor taskrelated muscle [1]. However, running-induced cervical dystonia in an experienced triathlete has never been reported. In our patient, cervical dystonia was found to be running-speed dependent, and the direction of head movement was the same as that of swimming. We review about other task-specific cervical dystonia and discuss possible explanation of this movement. A 51-year-old man who had participated in triathlons (running, swimming, cycling) for 20 years noticed involuntary neck movement while running. The movement involved continuous posturing of head to the right with left sternocleidomastoid muscle contraction and chin lifted outward. The movement occurred while running at a speed of more than 6 km/h, and was faster and more pronounced with higher running speed (Supplemental Video). The chewing, wearing a towel around the neck, and back-ward walking were not helpful. Laboratory findings and brain MRI revealed no abnormalities. Medications (carbamazepine, anticholinergics, and levodopa) did not help; however, botox treatment on the neck muscle ameliorated the symptoms, although the relieving effect did not persist. Over a 3-year followup, parkinsonism did not develop and the dystonia did not progress; however, he had to cease triathlon participation.