The cause of benign essential tremor is uncertain, but it is sometimes inherited in an autosomal dominant manner. Tremor may begin at any age and is enhanced by emotional stress. The tremor usually involves one or both hands, the head, or the hands and head, while the legs tend to be spared. Examination reveals no other abnormalities. Ingestion of a small quantity of alcohol commonly provides remarkable but short-lived relief by an unknown mechanism.
Although the tremor may become more conspicuous with time, it generally leads to little disability, and treatment is often unnecessary. Occasionally, it interferes with manual skills and leads to impairment of handwriting. Speech may also be affected if the laryngeal muscles are involved. In such circumstances, propranolol may be helpful but will need to be continued indefinitely in daily doses of 60–240 mg. However, intermittent therapy is sometimes useful in patients whose tremor becomes exacerbated in specific predictable situations. Primidone may be helpful when propranolol is ineffective, but patients with essential tremor are often very sensitive to it. They are therefore started on 50 mg daily, and the daily dose is increased by 50 mg every 2 weeks depending on the response; a maintenance dose of 125 mg three times daily is commonly effective. Occasional patients fail to respond to these measures but are helped by alprazolam (up to 3 mg daily in divided doses).