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Pain Research and Treatment
Volume 2012, Article ID 938595, 6 pages
Clinical Study

Temporal Summation of Pain Is Not Amplified in a Large Proportion of Fibromyalgia Patients

1Centre de Recherche Fernand-Seguin and Department of Psychiatry, Faculty of Medicine, Université de Montréal, QC, Canada H1N 3V2
2Department of Surgery, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4
3School of Nursing, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1H 5N4

Received 1 February 2012; Revised 10 April 2012; Accepted 13 April 2012

Academic Editor: Jonathan O. Dostrovsky

Copyright © 2012 Stéphane Potvin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Recently, it has been proposed that fibromyalgia (FM), a chronic widespread pain syndrome, results from overactive endogenous excitatory pain mechanisms. Experimental studies using temporal summation paradigms have confirmed this hypothesis but have included small samples of patients, prompting our group to perform a large-scale study. Methods. Seventy-two female FM patients and 39 healthy females participated in the study. The temporal summation test consisted of a 2-minute continuous and constant heat pulse administered with a thermode on the participants’ left forearm. Experimental temperature was set at a value individually predetermined to induce a 50/100 pain rating. Results. Relative to controls, FM patients had lower thermal pain thresholds and lower temporal summation of pain. However, 37 FM patients required experimental temperatures lower than the minimal temperature used in controls (45°C). Nevertheless, temporal summation was not increased in the other FM subgroup, relative to controls, despite equivalent experimental temperatures. Discussion. Our results suggest that temporal summation of pain is normal, rather than increased, in a large proportion of FM patients. Future studies on temporal summation in FM will need to be careful since some FM patients require abnormally low experimental temperatures that may confound results and make necessary to separate patients into subgroups.