Response to Heat Pain Stimulation in Idiopathic Parkinson's Disease

Background: Pain is a prominent nonmotor symptom in Parkinson's disease (PD) but has not been well studied. Objective: The aim of this study is to assess thermal experience and emotional content, as well as side-to-side sensory differences in PD " off" and " on" dopaminergic therapy following thermal cutaneous stimulation. Design: Cross-sectional design. Setting: University teaching hospital. Methods: Twelve PD subjects experiencing motor fluctuations but no pain symptoms and 13 healthy controls participated in the study. Heat pain and emotional content were assessed using a thermode and visual analog scales in medication on and off states in PD and without medication in healthy controls. Results: There were no side to side differences in heat pain intensity or between PD medication on state and PD medication off state. Unexpectedly, PD subjects reported a higher degree of unpleasantness in response to heat pain while on medication compared with the off state. Conclusions: These results suggest that the perception of heat pain is mediated, at least in part, by nondopaminergic systems in PD, while dopamine might modulate the affective component of pain. Wiley Periodicals, Inc.