The prevalence of primary dystonia in the general community.

The prevalence of primary dystonia was assessed in a random population sample of individuals aged 50 and over in Bruneck, South Tyrol. The diagnosis of primary dystonia was confirmed by videotaped review. Primary dystonia was present in 6 of 707 cases resulting in a prevalence rate of 732 per 100,000 (95% CI 319-1,564) in the general population aged 50 and over. Only two cases (33%) had been previously diagnosed. These results indicate that the true prevalence of primary dystonia is significantly higher than published rates.