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.