Correlates of functional disability in essential tremor

The decision to treat patients with essential tremor (ET) is based primaril y on the functional impact of the tremor. Correlates of functional disabili ty, apart from the severity of the tremor itself, have not been studied. Th e objective of this work was to study correlates of functional disability i n ET, and to present data on the extent of functional disability in communi ty-dwelling ET cases. ET cases and age-matched control subjects were ascertained from a tertiary referral center at Columbia-Presbyterian Medical Center an a community in n orthern Manhattan, N.Y. Subjects underwent a 2.5-hour evaluation, including a tremor disability questionnaire. a videotaped tremor examination rated b y a neurologist, a performance-based test of function, quantitative compute rized tremor analysis, the Hamilton Anxiety Rating Scale. and the depressio n module of the Structured Clinical Interview for DSM-IV. Seventy-six (85.4%) of 89 cases reported disability on greater than or equa l to1 item on the disability questionnaire. In multivariate linear regressi on analyses, current major depression. Hamilton Anxiety Rating Scale score. age, and tremor severity were independently correlated with performance-ba sed test scores. Twenty-seven (73.0%) of 37 community cases reported disabi lity on greater than or equal to1 (mean = 8.4) item on the questionnaire, a nd 25 (67.6%) demonstrated moderate or greater difficulty on tt (mean 4.2) task in a performance-based test. Depression, anxiety. and age, independent of the severity of tremor. were a ssociated with greater functional disability in ET, so that these factors m ust be considered when assessing the impact of new treatments in ET. Among a group of community-dwelling cases, approximately three-quarters reported disability, suggesting that the number of individuals who might receive som e benefit from advances in the treatment of ET is probably a great deal lar ger than previously thought. (C) 2001 Movement Disorder Society.