Family studies of dystonia may be limited in part by small family size and incomplete ascertainment of dystonia in geographically dispersed families. Further, prevalence estimates of dystonia are believed to be underestimates, as most studies are clinic-based and many individuals do not present to a physician or are misdiagnosed. As a low-cost highly sensitive screening tool is needed to improve case detection for genetic and epidemiologic studies, the authors developed the Beth Israel Dystonia Screen (BIDS), a computer-assisted telephone interview.