Isolated high-frequency jaw tremor relieved by botulinum toxin injections.

Jaw tremor can be seen as a component of various neurological disorders such as essential tremor, Parkinson's disease, dystonia, branchial myoclonus, hereditary geniospasm, task-specific tremor, and Whipple's disease, as well as in normal situations such as shivering, and subclinical physiological jaw tremor. In most of these conditions, the jaw tremor is usually associated with tremor or other abnormal involuntary movements affecting additional body parts, and its frequency is lower than 12 Hz. Schrag and colleagues reported a patient with a high-frequency idiopathic jaw tremor, and they speculated it could be related to orthostatic tremor affecting the masseter muscles. We encountered a similar patient with intermittent rapid focal jaw tremor that was successfully treated with botulinum toxin injections to the masseters.