CLINICAL CHARACTERISTICS OF ESSENTIAL TREMOR - DATA FROM A COMMUNITY-BASED STUDY

BACKGROUND: 99.5% of individuals with essential tremor (ET) who Live i n the community have mild tremor and do not attend clinics. Clinic-bas ed studies of ET have not allowed investigators to characterize the fu ll clinical spectrum of this disorder. In community-based studies of E T, the primary focus has been the prevalence rather than the clinical characteristics of ET. OBJECTIVE: To describe the clinical characteris tics of ET as seen in a community-based study. METHODS: 73 subjects wi th ET, identified in a community-based study of ET in Washington Heigh ts-Inwood, New York, underwent a standardized 84-item physician-admini stered tremor interview and a 26-item videotaped tremor examination wh ich included 12 bedside tests for ET. Two neurologists who specialized in movement disorders and who demonstrated excellent interrater agree ment rated the severity of tremor using a 0 to +3 clinical rating scal e and assigned a total tremor score (range, 0-36) and a diagnosis of E T. RESULTS: Diagnoses in the 73 cases were: definite ET (18, 24.7%), p robable ET (32, 43.8%), and possible ET (23, 31.5%). The mean total tr emor score was 17.8 of 36. Thirty-six of 73 (49.3%) were asymptomatic, answering, ''no'' to the question ''do you often have shaking or trem or that you can't control?'' Sixty-seven of 73 (91.8%) had not been pr escribed medication for tremor. On average, subjects received tremor r atings of greater than or equal to+2 on only 5.4 of the 12 bedside tes ts for ET. Kinetic tremor was rated as more severe than postural tremo r in 72 (98.6%) of 73 cases. CONCLUSIONS: We present the clinical find ings of a group of largely untreated, unselected cases of ET that woul d not otherwise have come to neurologic attention. The tremor was mild , often asymptomatic, and not uniformly present throughout the examina tion. It was rarely treated. The kinetic component of the tremor was m ore severe than the postural component. These clinical data further ou r understanding of the clinical spectrum of ET.