Starnberg trial on epidemiology of Parkinsonism and hypertension in the elderly. Prevalence of Parkinson's disease and related disorders assessed by a door-to-door survey of inhabitants older than 65 years.

Objective: To investigate the prevalence of different types of parkinsonism (PS) in the elderly, regardless of health care service or drug prescription, by a door-to-door survey in two German villages.

Design: We investigated the prevalence of PS in a rural Bavarian population of individuals older than 65 years (982 participants; response rate, 82.5%) using a door-to-door-survey and a biphasic approach.

Main Outcome Measures: Two investigators employed a pretest screening questionnaire and motor tests for signs of PS. Individuals suspected of suffering from PS were reinvestigated by two neurologists trained in movement disorders, and computed tomographic scans were performed.

Results: The prevalence of Parkinson's disease in individuals older than 65 years was 0.71% (95% confidence interval, 0.19% to 1.23%), with a male predominance (five men, two women). Parkinsonism of other pathogenesis included drug-induced PS (0.41%, four of 982 inhabitants), vascular PS (0.20%, two of 982), multiple system atrophy (0.31%, three of 982), and Fahr's disease (0.10%, one of 982). The high prevalence of normal-pressure hydrocephalus (0.41%, four of 982 inhabitants) was an unexpected finding that was confirmed by computed tomography. Fifty percent of cases of PS were newly diagnosed.

Conclusions: This study represents the first door-to-door survey on PS in Germany. In addition, for the first time, it includes a clinical differentiation between Parkinson's disease, multiple system atrophy (of the striatonigral type), and PS of other pathogenesis. The prevalence of Parkinson's disease corresponds to that reported in other surveys of people older than 65 years. Normal-pressure hydrocephalus and multiple system atrophy, on the other hand, were more prevalent than expected, and all these cases were newly diagnosed.