Conditioned pain modulation in temporomandibular disorders (TMD) pain patients

Abstract

The aims were to investigate (1) if temporomandibular disorders (TMD) patients with temporomandibular joint (TMJ) pain had different conditioned pain modulation (CPM) compared with healthy subjects and, (2) if clinical pain characteristics influenced CPM. Sixteen TMD pain patients and 16 age-matched healthy subjects were participated. A mechanical conditioning stimulus (CS) was applied to pericranial muscles provoking a pain intensity of 5/10 on a visual analogue scale. Pressure pain thresholds (PPT) and pressure pain tolerance thresholds (PPTol) were assessed at masseter, forearm and painful TMJ (only PPT) before, during, and 20 min after CS. Data were analyzed with ANOVAs. The correlations between CPM effect and ratings of TMD pain intensity on a numerical rating scale (NRS) or the pain duration were calculated (correlation coefficient; R). The relative PPT and PPTol increases (mean for the three assessment sites) during CS were significantly higher than baseline in healthy subjects (43.0 ± 3.6, 33.0 ± 4.0 %; P < 0.001, P < 0.001) but not in the TMD pain patients (4.9 ± 2.7, -1.4 ± 4.1 %; P = 0.492, P = 1.000) with significant differences between groups (P < 0.001). In the patients, the relative PPT changes during CS were not significantly higher than baseline at TMJ (5.3 ± 3.8 %, P = 0.981) and masseter (-2.8 ± 4.8 %, P = 1.000) but significantly higher at forearm (12.3 ± 4.7 %, P = 0.039). No correlation was detected between TMD pain intensity and CPM effect (R = -0.261; P = 0.337) or between pain duration and CPM effect (R = -0.423; P = 0.103) at painful TMJ. These findings indicate that CPM is impaired in TMD pain patients especially at sites with chronic pain but not at pain-free sites and that the clinical pain characteristics do not influence CPM.

Role of endogenous pain modulation in chronic pain mechanisms and treatment

“…King et al 37 reported less efficient CPM in these patients; Garrett et al 24 reported CPM similar to healthy controls, whereas Kothari et al 42 reported reduced CPM in TMDs after surgery. Oono et al 69 reported reduced CPM in TMD, but only when measured from affected sites. For other disorders, a report on interstitial cystitis found reduced CPM, 60 whereas 2 reports on vestibulodynia found normal CPM.…”

Hypoalgesia After Exercise and the Cold Pressor Test is Reduced in Chronic Musculoskeletal Pain Patients With High Pain Sensitivity

“…63,64 The CPM response was predicted by clinical peak pain intensity, again indicating that ongoing pain affects the balance between inhibitory and excitatory pathways or that the balance between inhibitory and excitatory pathways affects clinical peak pain intensity. The relationship between clinical pain intensity and the CPM response has previously been studied in patients with neuropathy 29,30 and temporomandibular disorder, 65 with 2 studies finding an inverse relationship 29,30 and 1 study reporting no relationship. 65 EIH Impaired EIH has previously been shown in chronic pain conditions such as chronic widespread pain, 12 chronic whiplash-associated disorder.…”

“…The relationship between clinical pain intensity and the CPM response has previously been studied in patients with neuropathy 29,30 and temporomandibular disorder, 65 with 2 studies finding an inverse relationship 29,30 and 1 study reporting no relationship. 65 EIH Impaired EIH has previously been shown in chronic pain conditions such as chronic widespread pain, 12 chronic whiplash-associated disorder. 26 The present study extends these findings by showing reduced hypoalgesia after aerobic and isometric exercises and increased TS of pain after aerobic exercise in patients with high pain sensitivity compared with patients with low pain sensitivity.…”

The impact of premature ejaculation on the subjective perception of orgasmic intensity: validation and standardisation of the ‘Orgasmometer’

“…It is structured based on a well-known, validated tool for the evaluation of the subjective perception of pain intensity (Ferreira-Valente et al, 2011;Oono et al, 2014). The Orgasmometer (Data S1) ranges from 0 to 10, where 0 corresponds with the absence of orgasmic intensity and 10 with the highest level of orgasmic intensity.…”