Essential (hereditary or senile) tremor.

Sixteen cases (eight in males and eight in females) of essential (hereditary or senile) tremor were collected over a two-year period. Ten patients had near relatives with a similar disorder. All but one patient had a tremor of the upper limbs which was absent when the arms were at rest, but which appeared on movement, and was made worse by emotion. The severity of the tremor varied considerably from patient to patient, and often was temporarily lessened by alcohol. The tremor involved the head and neck in six subjects and the legs in two. One subject has associated neurological abnormalities probably due to cerebral arteriosclerosis. Otherwise no neurological abnormality except tremor was present in any patient. No patient showed evidences of Parkinsonism. To the time of collection of the series the tremor had been present for periods of between one and 62 years. Many patients with essential tremor are not severely enough affected to warrant therapy. Propranolol, a beta-adrenergic blocking agent, appears to reduce the tremor in at least some patients who need treatment.