Accuracy of diagnosis in patients with presumed Parkinson's disease

Objectives: to study the diagnostic accuracy for parkinsonism and Parkinson 's disease in a community-based sample of subjects on anti-parkinsonian med ication. Methods: computerized prescribing records in general practice were used to create a community-based disease register for Parkinson's disease. Subjects were examined to establish the likely diagnosis using recommended clinical diagnostic criteria. Results: of 402 cases, parkinsonism was confirmed in 74% and clinically pro bable Parkinson's disease in 53% The commonest causes of misdiagnosis were essential tremor, Alzheimer's disease and vascular pseudo-parkinsonism. Ove r one-quarter of subjects did not benefit from anti-parkinsonian medication . Conclusions: there is difficulty in diagnosing parkinsonism and Parkinson's disease in elderly subjects and we suggest early referral of those suspect ed of having parkinsonism for specialist assessment.