What features improve the accuracy of clinical diagnosis in Parkinson's disease

TLDR

Clinically distinguishing Parkinson's disease from other parkinsonian syndromes is difficult, as highlighted by many authorities. The study evaluated the clinical features of 100 prospectively diagnosed idiopathic Parkinson's disease patients using pathological confirmation. Of these patients, 76 % were pathologically confirmed PD; applying strict criteria increased true PD identification to 93 % but excluded 32 % of confirmed cases, showing that standard diagnostic criteria can misclassify PD while stricter criteria reduce misdiagnosis at the expense of excluding genuine cases.

Abstract

Many authorities have drawn attention to the difficulties in clinically distinguishing Parkinson9s 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 their pathologic findings. Seventy-six percent of these cases were confirmed to have PD. By using selected criteria (asymmetrical onset, no atypical features, and no possible etiology for another parkinsonian syndrome) the proportion of true PD cases identified was increased to 93%, but 32% of pathologically confirmed cases were rejected on this basis. These observations suggest that studies based on consultant diagnosis of PD, using standard diagnostic criteria, will include cases other than PD, thus distorting results from clinical trials and epidemiologic studies. The strict use of additional criteria can reduce misdiagnosis but at the cost of excluding genuine PD cases.