Prevalence of essential tremor: a door-to-door survey in Terrasini, Sicily. Sicilian Neuro-Epidemiologic Study Group.

As part of a door-to-door neuroepidemiologic survey, we investigated the frequency and distribution of essential tremor (ET) in a Sicilian municipality. During phase 1, we administered a screening instrument for tremor to 7,653 persons residing in Terrasini (Palermo province). During phase 2, neurologists evaluated those subjects who had screened positive. The diagnoses, based on specified clinical criteria, were reviewed to increase reliability across neurologists. We found 31 subjects affected by ET (17 men, 14 women); 11 patients (35.5%) reported a familial aggregation. The prevalence of ET as of November 1, 1987, was 405.1 per 100,000 for the total population, and 1,074.9 per 100,000 for those 40 years old or older. The prevalence increased with advancing age for both sexes and was slightly but consistently higher in men. Comparison with other studies suggests striking geographic variation, which may reflect genetic differences.