A community survey of Parkinson's disease.

In a rural community of 80,000 people 69 patients were identified as having a diagnosis of Parkinson's disease. After interview and examination we found that 55 met the generally accepted diagnostic criteria for Parkinson's disease, 4 had possible Parkinson's disease, 6 had essential tremor, 2 had dementia and 2 had other conditions. The patients with Parkinson's disease had clinical and epidemiologic characteristics similar to those of patients in previous, mainly hospital-based, studies. These characteristics included mean age at onset (63 years), frequency rate of dementia (20%) and presence of postural tremor (11%). The pattern of treatment varied, some patients receiving more medication than is usual for the severity of their illness, and some patients receiving less than is usual. Parkinson's disease can be difficult to diagnose and manage because of the clinical variation between patients in presentation and response to treatment.