Does this patient have Parkinson disease?

CONTEXT: Diagnosis of Parkinson disease (PD) remains challenging. An accurate diagnosis is important because effective symptomatic treatment for PD is available.

OBJECTIVE: To systematically review the literature for information on the precision and accuracy of the clinical examination for diagnosing PD.

DATA SOURCES: MEDLINE database was searched for all English-language articles related to the diagnosis of PD published from January 1966 through April 2001. The reference lists of all articles retrieved were searched for additional relevant sources.

STUDY SELECTION: Studies in which patients presented with 1 or more typical features of PD were included if the final diagnosis was confirmed by a suitable criterion standard and data could be extracted to determine the accuracy of 1 or more symptoms or signs. Variability in descriptions of symptoms and signs made it impossible to combine data across existing studies for most findings.

DATA SYNTHESIS: We identified 6 studies that met our criteria. The positive (presence) likelihood ratios (LRs) for tremor as a symptom of PD ranged from 1.3 to 17 (range of negative [absence] LRs, 0.24 to 0.60). Tremor as a sign of PD produced a range of positive LRs from 1.3 to 1.5 (negative LRs, 0.47 to 0.61). Clinical features useful in the diagnosis of PD include a history of the combination of symptoms of rigidity and bradykinesia (positive LR, 4.5; negative LR, 0.12); a history of loss of balance (range of positive LRs, 1.6 to 6.6; range of negative LRs, 0.29 to 0.35), symptoms of micrographia (range of positive LRs, 2.8 to 5.9; range of negative LRs, 0.30 to 0.44), and a history of shuffling gait (range of positive LRs, 3.3 to 15; range of negative LRs, 0.32 to 0.50). Trouble with certain tasks such as turning in bed (positive LR, 13; negative LR, 0.56), opening jars (positive LR, 6.1; negative LR, 0.26), and rising from a chair (range of positive LRs, 1.9 to 5.2; range of negative LRs, 0.39 to 0.58). Useful signs include the glabella tap test (positive LR, 4.5; negative LR, 0.13), difficulty walking heel-to-toe (positive LR, 2.9; negative LR, 0.32), and rigidity (range of positive LRs, 0.53 to 2.8; range of negative LRs, 0.38 to 1.6). Significant selection bias was detected in all studies included for review.

CONCLUSIONS: Symptoms of tremor, rigidity, bradykinesia, micrographia, shuffling gait, and difficulty with the tasks of turning in bed, opening jars, and rising from a chair should be carefully reviewed in all patients with suspected PD. The glabella tap and heel-to-toe tests also should be assessed.