Orofacial dystonia triggered by mouth closure

Abstract Focal task-specific dystonia affects one part of the body, occurring only during the performance of a specific task. It usually affects the hand, though it can rarely affect the orofacial region. Treatment with oral medications and botulinum toxin (BTX) usually produces only modest benefit, owing to the complexity of the movements involved. We describe a patient with an unusual form of focal task-specific orofacial dystonia, manifested by asynchronous twitching of the right and left lower hemiface upon closure of the mouth and pursing of the lips. Injection of BTX produced complete resolution of task-specific dystonia for 4.5 months.