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.


METHODS
Cross-sectional design.


METHODS
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.
Nandhagopal
R
R
Pacific Parkinson's Research Centre, 2221 Wesbrook Mall, Vancouver, British Columbia, Canada.
Troiano
Andre R
AR
Mak
Edwin
E
Schulzer
Michael
M
Bushnell
Mary Catherine
MC
Stoessl
Alexander Jon
AJ
D000368:Aged; D000978:Antiparkinson Agents; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000503:physiopathology; D010147:Pain Measurement; D017288:Pain Threshold; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology*
D000978:Antiparkinson Agents; D007980:Levodopa