Clinical manifestations of essential tremor.

A clinical study of 42 patients with essential tremor is presented. In the case of 12 patients the family history strongly suggested an autosomal dominant mode of transmission, in four the mode of inheritance was indeterminate, and the remaining 26 patients were sporadic cases without an established genetic basis. The tremor involved the upper extremities in 41 patients, the head in 25, lower limbs in 15, and trunk in two. Seven patients showed involvement of speech. Variations were found in the speed and regularity of the tremor. Leg involvement took a variety of forms: (1) direct involvement by tremor; (2) a painful limp associated with forearm tremor; (3) associated dyskinetic movements; (4) ataxia; (5) foot clubbing; and (6) evidence of peroneal muscular atrophy. Several minor symptoms-hyperhidrosis, cramps, dyskinetic movements, and ataxia-were associated with essential tremor. Other features were linked phenotypically to the ataxias and system degenerations. Apart from minor alterations in tone, expression, and arm swing, features of Parkinsonism were notably absent.