Abstract
Background: Abnormal endogenous pain modulation (EPM) was suggested as a pathophysiological characteristic of chronic pain. EPM has been investigated using psychophysical tests for pain facilitation and inhibition such as temporal summation of pain and conditioned pain modulation, respectively. Another psychophysical test for pain inhibition is offset analgesia (OA), where small variations in noxious stimulus intensity over time elicit a disproportionately large analgesic response. OA has been investigated in patients with mixed pain conditions, but not in chronic temporomandibular disorder (TMD) patients. Objective: To compare OA responses in chronic TMD female cases to age-matched, pain-free female controls. Methods: Offset analgesia was assessed by applying noxious heat over the non-dominant forearm of chronic TMD cases (n = 22) and controls (n = 17), using a previously reported paradigm with individualised test temperatures (TT): T1(5 seconds) = TT, T2(5 seconds) = TT + 1°C and T3(20 seconds) = TT. Clinical and psychosocial characteristics were measured. Main outcomes for OA were delta computerised visual analogue scale (COVAS), per cent change (T2-T3/T2-T1) and area under the curve (AUC) ratio of pain ratings controlling for TT. Results: No statistically significant between-group differences were found for delta COVAS (TMD cases mean ± SD = 53.5 ± 22.0; controls = 51.6 ± 22.9, P = 0.876) and per cent change (T2-T3/T2-T1) (cases mean = 327.2 ± 375.1; controls = 226.9 ± 553.4, P = 0.515), with both groups presenting a robust OA response. TMD cases perceived more pain during OA trials than controls, as measured by AUC ratio (mean difference [95% CI] = −15.6 [−26.9, −3.5], P = 0.017). Conclusion: Chronic TMD cases presented with similar OA response over the forearm as controls; however, they experienced greater pain during testing. Future studies including this patient population should investigate OA responses over painful body sites, for example, jaw/face.
Original language | English (US) |
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Pages (from-to) | 1009-1022 |
Number of pages | 14 |
Journal | Journal of Oral Rehabilitation |
Volume | 46 |
Issue number | 11 |
DOIs | |
State | Published - Nov 1 2019 |
Bibliographical note
Funding Information:Funding information This study was partially supported by the Office of the Vice President for Research, University of Minnesota, which played no role in study design, collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the article for publication. We would like to acknowledge Flavia P. Kapos, DDS, MS (University of Washington), for her substantial contribution during study planning, setup and initial data collection, and Eva Counsell, dental student (University of Minnesota), for her assistance during database entry.
Publisher Copyright:
© 2019 John Wiley & Sons Ltd
Keywords
- chronic oro-facial pain
- endogenous pain modulation
- musculoskeletal pain
- offset analgesia
- psychophysics
- temporomandibular disorders
- Humans
- Pain Management
- Temporomandibular Joint Disorders
- Analgesia
- Female
- Pain Measurement
- Chronic Pain
PubMed: MeSH publication types
- Journal Article