RT - Journal of Oral & Facial Pain and Headache ID - 10.11607/jofph.1841 T1 - Evidence for Up-regulated Central Nociceptive Processing in Patients with Masticatory Myofascial Pain A1 - Eleni Sarlani A1 - Edward G. Grace A1 - Mark A. Reynolds A1 - Joel D. Greenspan K1 - myofascial pain syndromes; pain thresholds; temporal summation; temporomandibular disorders; wind-up YR - 2004 SP - 41 AB -

Aims: Previous work suggests that hyperexcitability of central nociceptive neurons may play a role in the pain of temporo-mandibular disorders (TMD). The aim of this study was to test this theory by assessing differences, between myalgic TMD patients and pain-free controls, in temporal summation of mechanically evoked pain and aftersensations following repetitive noxious stimulation. Methods: Sixteen series of 10 repetitive, mildly noxious mechanical stimuli were applied to the fingers of 25 female TMD patients with masticatory myofascial pain and 25 age-matched, pain-free female subjects. All subjects rated the pain intensity and unpleasantness evoked by the first, fifth, and tenth stimuli in the series and their aftersensations at 15 seconds and 1 minute following the last stimulus. Data were analyzed by 3-way repeated-measures analysis of variance. Results: Pain and unpleas-antness ratings increased with repetition of the stimulation (P ＜ .0001). In addition, there was a significant trial number × group interaction for the pain intensity ratings, such that TMD patients provided higher ratings than controls for the tenth stimulus (P ＜ .001). The increase in unpleasantness ratings with repetitive stimu-lation was also higher for the patient group (P ＜ .0001). Moreover, TMD patients rated the intensity of aftersensations as higher (P ＜ .005) and reported painful aftersensations at signifi-cantly greater frequency (P ＜ .05). Conclusion: A generalized hyperexcitability of central nociceptive processing in this TMD patient group is indicated by their more pronounced temporal summation of pain and greater aftersensations following repetitive noxious digital stimulation versus controls. Such hyperexcitability may contribute to the pathophysiology of TMD pain.