Writing tremor: its relationship to benign essential tremor.

Nine patients with tremor on writing and one patient with tremor only on swinging a golf club were investigated. None of the patients had any other neurological symptoms or signs. The frequency of the tremor ranged from 5 to 6 Hz. Rapid passive supination or pronation of the forearm by a torque motor evoked a short burst of alternating tremor in seven patients. The tremor was improved by alcohol or propranolol in six patients. These characteristics of writing tremor (and of other isolated action tremors) suggest that it is a variant of benign essential tremor.