Effects of acute mental stress on conditioned pain modulation in temporomandibular disorders patients and healthy individuals

Abstract

Stress is a contributing factor to painful temporomandibular disorders (TMD). Nevertheless, the underpinnings of this relationship are not fully understood. Objective To investigate the effects of acute mental stress on conditioned pain modulation (CPM) in TMD patients compared with healthy individuals. Methodology Twenty women with chronic myofascial TMD diagnosed according to the RDC/TMD and 20 age-matched healthy women had the CPM assessed before and after a stressful task using the Paced Auditory Serial Addition Task (PASAT) in a single session. Subjective stress response was assessed with the aid of visual analog scale (VAS). Pressure pain threshold (PPT) on masseter muscle was the test stimulus (TS) and immersion of the participant’s hand on hot water was the conditioning stimulus (CS) - CPM-sequential paradigm. Results Healthy individuals reported PASAT are more stressful when compared with TMD patients and the stress task did not affect the CPM in neither group. Nonetheless, a negative correlation was observed between change in CPM and change in TS from baseline to post-stress session, which indicates that the greater the increase in PPT after the stress task, the greater was the decrease in CPM magnitude. The correlation was strong for healthy controls (r=- 0.72, p<0.001) and moderate for TMD patients (r=- 0.44, p=0.047). Conclusions The correlation between the change in CPM and the TS change following the stress task may possibly indicate an overlapping pathway between stress-induced analgesia/hyperalgesia and descending pain inhibition.

Preclinical models of deep craniofacial nociception and temporomandibular disorder pain

“…CPM refers to the inhibition of pain response evoked by a tested stimulation due to the interference of a second stimulation applied to a remote area, simultaneously or sequentially. Despite contradicting results being reported [ 55 , 56 ], TMD patients display reduced CPM responses [ 60 , 61 ]. Further, evidence suggests that CPM response in the trigeminal-innervated body regions is weaker compared with those in the extra-trigeminal innervated areas [ 62 ].…”

Evidence for alterations to dynamic quantitative sensory tests in patients with chronic temporomandibular myalgia: A systematic review of observational studies with meta‐analysis

“…Four of the 23 final selected studies assessed conditioned pain modulation with test stimuli on the masseter area (Table 5). 38,39,48,49 …”

“…Three of these assessed conditioned pain modulation with pressure pain thresholds as test stimuli. These three were pooled for meta‐analysis comprising 73 patients and 152 healthy controls (Supplementary material 5) 38,39,49 …”

“…[25][26][27][28][29][30][31][32][33][34] Thirteen studies used the original Research Diagnostic Criteria for TMD (RDC/ TMD). 10,[35][36][37][38][39][40][41][42][43][44][45][46][47] One study used the diagnostic criteria of the American Academy of Orofacial Pain. 48 Dynamic somatosensory function was assessed in the upper limb by 19 studies, 10,25,[27][28][29][30][31][32]34,35,37,38,[40][41][42][43][44][45][46]48 in the jaw area by 11 studies [25][26][27][29][30]…”

“…43,48 Temporal summation was the most studied phenomenon: 14 studies assessed mechanical temporal summation 10,25,26,28,33,36,38,40,41,43,45,[47][48][49] and five studies assessed thermal temporal summation. 10,31,35,44,46 Endogenous pain inhibition was assessed with different modalities: the conditioned pain modulation paradigm (seven studies), [37][38][39]42,45,48,49 exercise-induced hypoalgesia (two studies), 28,29 placebo analgesia (two studies), 32,34 offset analgesia (one study), 30 and stress-induced hypoalgesia (one study). 47…”