Essential tremor variants: effect of treatment.

Essential tremor may not represent a single condition. Subclassifications include kinetic predominant tremor; combined resting-postural tremor; primary writing tremor; isolated voice, chin, or tongue tremor; and orthostatic truncal tremor. We report patients with these disorders. An association of these conditions with essential tremor is suggested by a high occurrence of a family history of essential tremor, frequent presence of a mild postural tremor, and tremor reduction with alcohol ingestion. Pharmacologic responsiveness is different for these disorders. Propranolol and primidone often have beneficial effects but clonazepam was the only drug effective in some cases of kinetic predominant tremor and in orthostatic truncal tremor. Combined resting-postural tremor and voice tremor were often unresponsive to treatment.