Essential vocal tremor: clinical characteristics and response to therapy.

We evaluated four patients with an initial and predominant voice tremor. All were referred for evaluation for suspected parkinsonism, though vocal tremor was the only symptom. These three women and one man ranged in age from 37 to 59 years. Neurologic evaluation and laryngeal examination were unremarkable. No signs of parkinsonism were present. All patients had a family history of tremor, though in only one family was vocal tremor the sole manifestation. Tremor was suppressed by alcohol ingestion in all patients and with whisper in two. Duration of tremor before evaluation ranged from eight months to six years. Visual representation of tremor was obtained in three, with frequencies ranging from 4 to 10 cps. Three patients responded to treatment with propranolol (Inderal), and one did well with voice training. Follow-up was six months to ten years. Although previous cases of essential vocal tremor with concurrent tremor elsewhere have been noted, only six cases of isolated voice tremor had been reported and response to therapy was not mentioned. Essential tremor may also be isolated to the head, chin, and hands.