Italian researchers suggest that pain is associated with Parkinson’s disease after finding that pain appears more common in people who suffer from the condition than in those who do not. Their results are published in the September issue of Archives of Neurology.
“Patients with Parkinson’s disease often complain of painful sensations that may involve body parts affected and unaffected by dystonia [involuntary muscle contractions],” write author Giovanni Defazio, M.D., Ph.D. (University of Bari, Italy) and colleagues. Patients describe the pain as similar to cramping or arthritis, and the pain has features like pain deriving from nerve damage. The researchers note that, “The high frequency of these pain disorders in the general population makes it hard to establish whether pain is more frequent among people with Parkinson’s disease than among age-matched controls.”
In order to gain further insights into the relationship between Parkinson’s disease and pain, the researchers studied 402 patients with the condition and compared them to 317 healthy individuals of the same age. Participants were asked to provide information about their current age, the age at which they developed Parkinson’s disease, scores on disease rating scales, and details regarding any pain that they felt at the time of the study that lasted for three months or longer.
The researchers found that 69.9% (281) of the patients with Parkinson’s disease reported pain compared to 62.7% (199) of the control group – so pain was more common among Parkinson’s patients. Most of the pain could be attributed to dystonic pain because rates of pain not associated with dystonia were about the same between the two groups (66.4% in the Parkinson’s group and 62.8% in the control group).
“Nevertheless, we observed a significant association between Parkinson’s disease and non-dystonic pain, beginning after the onset of parkinsonian symptoms,” explain the authors. “Cramping and central neuropathic [nervous system-related] pain were more frequent among Parkinson’s disease patients than controls. About one-quarter of patients who experienced pain reported pain onset before starting antiparkinsonian therapy.”
The authors suggest that one reason for the increase in pain associated with Parkinson’s disease can be found in the basal ganglia – structures deep in the brain that are involved with controlling movement, are damaged in Parkinson’s disease patients, and are associated with pain processing.
The authors conclude that: “These data support the hypothesis that pain begins at clinical onset of Parkinson’s disease or thereafter as a non-motor feature of Parkinson’s disease. The findings of this study may have implications for designing studies aimed at understanding pain mechanisms in Parkinson’s disease and identifying specific treatment strategies.”
Pain as a Nonmotor Symptom of Parkinson Disease: Evidence From a Case-Control Study
Giovanni Defazio; Alfredo Berardelli; Giovanni Fabbrini; Davide Martino; Emiliana Fincati; Antonio Fiaschi; Giuseppe Moretto; Giovanni Abbruzzese; Roberta Marchese; Ubaldo Bonuccelli; Paolo Del Dotto; Paolo Barone; Elisa De Vivo; Alberto Albanese; Angelo Antonini; Margherita Canesi; Leonardo Lopiano; Maurizio Zibetti; Giuseppe Nappi; Emilia Martignoni; Paolo Lamberti; Michele Tinazzi
Archives of Neurology (2008). 65(9):1191-1194.
Written by: Peter M Crosta