Epidemiology and outcome of cervical dystonia (spasmodic torticollis) in Rochester, Minnesota

The natural history of cervical dystonia (spasmodic torticollis) was investigated in a population‐based study in Rochester, Minnesota. Eleven new cases were identified with onset during the 20‐year period 1960–1979. The overall incidence rate was 1.2 per 100,000 person‐years (95% confidence interval 0.5–1.9) with a female: male ratio of age‐adjusted incidence rates of 3.6:1. A unitary etiology was not apparent: injury antedated onset in four of the 11 patients, whereas six had documented thyroid disease and four had diabetes. A family history of movement disorder was recorded for only one subject. Only one of the cases would have been classified as moderate in severity; the others were mild. In follow‐up through 1993, progressive disability was noted in only two patients, and two others went into remission. Three cases of intracranial aneurysm were confirmed, two of which produced fatal subarachnoid hemorrhage. A third death was due to amyotrophic lateral sclerosis.