What features improve the accuracy of clinical diagnosis in Parkinson's disease: A clinicopathologic study

Many authorities have drawn attention to the difficulties in clinically dis tinguishing Parkinson's disease (PD) from other parkinsonian syndromes. We assessed the clinical features of 100 patients diagnosed prospectively by a group of consultant neurologists as having idiopathic PD according to thei r pathologic findings. Seventy-six percent of these cases were confirmed to have PD. By using selected criteria (asymmetrical onset, no atypical featu res, and no possible etiology for another parkinsonian syndrome) the propor tion of true PD cases identified was increased to 93%, but 32% of pathologi cally confirmed cases were rejected on this basis. These observations sugge st that studies based on consultant diagnosis of PD, using standard diagnos tic criteria, will include cases other than PD, thus distorting results fro m clinical trials and epidemiologic studies. The strict use of additional c riteria can reduce misdiagnosis but at the cost of excluding genuine PD cas es.