essential tremor

essential tremor n a common usu. hereditary or familial disorder of movement that is characterized by uncontrolled trembling of the hands and often involuntary nodding of the head and tremulousness of the voice, that is exacerbated by anxiety and by activity, that is not associated with Parkinson's disease or any other known disease, and that responds to treatment with propranolol

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a hereditary tremor with onset at varying ages, usually at about 50 years of age, beginning with a fine rapid tremor (as distinct from that of parkinsonism) of the hands, followed by tremor of the head, tongue, limbs, and trunk; it is aggravated by emotional factors, is accentuated by volitional movement, and in some cases is temporarily improved by alcohol. Called also familial t., heredofamilial t., and hereditary essential t.