Pain as a nonmotor symptom of Parkinson disease: evidence from a case-control study.

OBJECTIVE: To determine whether pain is more frequent among people with Parkinson disease (PD) than among age-matched controls. DESIGN: Case-control study. Patients and METHODS: Logistic regression models taking into account type of pain, time between pain and PD onset, and possible confounders were used to compare 402 PD patients with 317 age-matched healthy control subjects. RESULTS: The overall frequency of pain was significantly greater in PD patients than in controls (281 [69.9\%] vs 199 [62.8\%]; P = .04), mainly because the healthy control group lacked dystonic pain. Conversely, the frequency of nondystonic pain was similar among PD patients and controls (267 [66.4\%] vs 199 [62.8\%]; P = .28). Nevertheless, we observed a significant association between PD and nondystonic pain, beginning after the onset of parkinsonian symptoms (odds ratio, 2.1; 95\% confidence interval, 1.4-2.9). Cramping and central neuropathic pain were more frequent among PD patients than controls. About one-quarter of patients who experienced pain reported pain onset before starting antiparkinsonian therapy. CONCLUSION: These data support the hypothesis that pain begins at clinical onset of PD or thereafter as a nonmotor feature of PD.