Validity of a screening question for head tremor: an analysis of four essential tremor case samples.

BACKGROUND The goal of this study was to assess the validity of a screening question for head tremor in essential tremor (ET). There are no published data on this topic, and the knowledge will guide future epidemiological investigations of this disorder. METHODS These analyses utilized four distinct patient samples: a population-based study in northern Manhattan, a study of the environmental epidemiology of ET, a genetics study, and a brain repository. Sensitivity was the proportion of ET cases with head tremor on examination who self-reported head tremor. RESULTS The sensitivity of the screening question for head tremor was lowest in the population-based study (31.6%), and higher as well as somewhat similar across the remaining studies (46.7 to 62.2%). Higher sensitivity was associated with tremor of longer duration, presence of voice tremor on examination, female gender, and lower education. The use of the screening question would have increased case ascertainment during the screening phase of these four studies by 1.9, 4.1, 10.2, and 20.3%. CONCLUSIONS A screening question for head tremor had low-to-moderate sensitivity in ET. The use of such a screening questionnaire, however, has the potential to increase case ascertainment by as much as 20% in some screening settings.