Unusual forehead tremor in a patient with essential tremor.

Voice and head (neck) tremor commonly occur in patients with essential tremor (ET), but involvement of cranial musculature is generally limited to these specific cranial structures, and action tremor of the forehead has not been reported. We describe a patient with ET who had forehead tremor. The tremor seemed to be task-specific, and neurophysiological features suggested that the forehead tremor was dystonic. The presence of forehead tremor in a patient with ET probably indicates an additional pathophysiologic process. The explanation for the specificity of involvement of cranial musculature in ET is not known, but this clinical observation might help guide investigators who are interested in the underlying pathophysiology of this condition.