Mood, side of motor symptom onset and pain complaints in Parkinson's disease

Objective: Patients with Parkinson's disease (PD) present with a variety of non-motor symptoms including sensory complaints and mood disturbances. In the current pilot study, we aimed to explore pain complaints and the association between mood and pain in PD. We hypothesized that pain ratings would be elevated in patients with PD relative to controls. As PD is lateralized at onset and studies have found lateralization of some non-motor symptoms in PD, we also hypothesized that PD patients would exhibit differing pain profiles depending on side of onset of the disease. Methods: Twenty-three PD patients (11 right-onset (RPD), 12 left-onset (LPD) disease), and 11 control participants (CS) completed a mood questionnaire (Depression Anxiety Stress Scale; DASS) as well as the short form of the McGill Pain Questionnaire. Results: Both PD groups reported higher present pain intensity scores ( p=0.001), more evaluative pain intensity ( p=0.02), and more overall pain ( p=0.02) than control participants. There was a significant association between mood and all of the McGill pain ratings in the LPD patients, with those reporting more mood symptoms rating higher on all pain scales (all p-values<0.001). This association was not found in the RPD group. Conclusions: Our results suggest an association between mood and pain in patients with PD that may be related to the differential contribution of right-hemispheric neural networks in processing of mood and pain states. These findings merit further investigation into the relation between mood and pain in patients with PD.