Additional Pain In Parkinson's Patients Due To Involuntary Muscle Contractions

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.

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Written by: Peter M Crosta