Pain Sensitivity Risk Factors for Chronic TMD: Descriptive Data and Empirically Identified Domains from the OPPERA Case Control Study

Abstract

Many studies report that people with temporomandibular disorders (TMD) are more sensitive to experimental pain stimuli than TMD-free controls. Such differences in sensitivity are observed in remote body sites as well as in the orofacial region, suggesting a generalized upregulation of nociceptive processing in TMD cases. This large case-control study of 185 adults with TMD and 1,633 TMD-free controls measured sensitivity to painful pressure, mechanical cutaneous, and heat stimuli, using multiple testing protocols. Based on an unprecedented 36 experimental pain measures, 28 showed statistically significantly greater pain sensitivity in TMD cases than controls. The largest effects were seen for pressure pain thresholds at multiple body sites and cutaneous mechanical pain threshold. The other mechanical cutaneous pain measures and many of the heat pain measures showed significant differences, but with lesser effect sizes. Principal component analysis (PCA) of the pain measures derived from 1,633 controls identified five components labeled: (1) heat pain ratings, (2) heat pain aftersensations and tolerance, (3) mechanical cutaneous pain sensitivity, (4) pressure pain thresholds, and (5) heat pain temporal summation. These results demonstrate that, compared to TMD-free controls, chronic TMD cases are more sensitive to many experimental noxious stimuli at extra-cranial body sites, and provides for the first time the ability to directly compare the case-control effect sizes of a wide range of pain sensitivity measures.

Reliability and validity of a simple and clinically applicable pain stimulus: sustained mechanical pressure with a spring-clamp

“…No correlation was found to CPT tolerance. In other words, clamp pain intensity correlated to other QST to varying degrees, which is in line with the literature which suggests, that different methods of QST measure different aspects of pain sensitivity and modulation [6,7,18,19].…”

“…Different QST procedures measure different aspects of pain sensitivity, whilst others overlap to some degree [6][7][8]. The pressure algometer is often used to assess pain detection thresholds of deep-tissue structures [9], but quantifying the effects of temporal summation or conditioned pain modulation (CPM), require a more complicated set-up [10].…”

“…In any case, a single pain test is most likely insufficient to get an adequate picture of pain sensitivity in a complex clinical context, where different pathways and mechanisms are involved. Rather, it is a question of choosing the right selection and combination of QST procedures [6][7][8]. Obviously, the more QST procedures in such a selection of tests, the more expensive, time-consuming and difficult it becomes and therefore less likely to be adopted in clinical practice.…”

Diagnosing and treating chronic musculoskeletal pain based on the underlying mechanism(s)

“…An individual's pain threshold at baseline (i.e., while asymptomatic) was a strong predictor of the development of TMJD, as any individual on the "hyperalgesic side" of a bell-shaped curve of pain sensitivity at baseline was nearly 3Â as likely to develop TMJD as an individual in the bottom half of pain sensitivity. These results have recently been replicated in a much larger cohort, and they showed that pressure pain threshold was the single experimental measure of pain threshold with respect to predicting the future onset of TMJD [54].…”

Genetics of chronic post-surgical pain: a crucial step toward personal pain medicine

“…The current model of the susceptibility for developing TMD includes anatomical, neuromuscular, and psychological factors that operate in parallel, reflecting the concerted effects of genetic and non-genetic etiological factors. [35][36][37][38] The OPPERA project began by recruiting 3,300 healthy women who were followed up for five years with the expectation that about 10% would develop TMD over the course of the study. By having participants respond to psychological questionnaires, questionnaires that describe various aspects of TMD pain, and a number of psychophysical and cardiovascular assays, this project identified non-genetic risk factors for TMD.…”