Amplified Brain Processing of Dentoalveolar Pressure Stimulus in Persistent Dentoalveolar Pain Disorder Patients

Abstract

Aims (1) To determine the brain regions activated by dentoalveolar pressure stimulation in persistent dentoalveolar pain disorder (PDAP) patients, and (2) to compare these activation patterns to those seen in pain-free control subjects. Methods A total of 13 PDAP patients and 13 matched controls completed the study. Clinical pain characteristics and psychosocial data were collected. Dentoalveolar mechanical pain thresholds were determined with a custom-made device over the painful area for patients and were used as the stimulation level during functional magnetic resonance imaging (fMRI) data acquisition. Control subjects received two stimulation levels over matched locations during fMRI scanning: one determined (as above) that evoked equally subjective pain ratings matching those of patients (subjective-pain match) and another nonpainful stimulation level matching the average stimulus intensity provided to patients (stimulus-intensity match). Clinical and psychosocial data were analyzed using independent samples t tests, Mann-Whitney U test, and Spearman rank-order correlation coefficient. fMRI data were analyzed using validated neuroimaging software and tested using a general linear model. Results PDAP patients had greater anxiety (P < .0001) and depression scores (P = .001), more jaw function impairment (P < .0001), and greater social impact (P < .0001) than controls. No significant differences were found for brain activation spatial extent (PDAP × Controls subjective pain: P = .48; PDAP × Controls stimulus intensity: P = .12). Brain activations were significantly increased for PDAP patients compared to control subjects when matched to stimulus intensity in several regions related to the sensory-discriminative and cognitive components of pain perception, including the primary and secondary somatosensory cortices, inferior parietal lobule, insula, premotor cortex, prefrontal cortex, and thalamus. When matched to subjective pain ratings, increased brain activations were still present for PDAP patients compared to controls, although to a lesser extent. Conclusion The present results suggest that dentoalveolar pressure is processed differently in the brain of PDAP patients, and the increased activation in several brain areas is consistent with amplified pain processing.

Altered Brain Responses to Noxious Dentoalveolar Stimuli in High-Impact Temporomandibular Disorder Pain Patients

“…A coordinate-based meta-analysis investigating brain responses to orofacial pain stimuli in healthy controls revealed consistent activations in bilateral SII [12]. Previously, when applying noxious dentoalveolar stimuli to PDAP patients and controls with matched subjective stimulus intensity, we found greater activation in right SII in PDAP patients relative to controls [39].…”

“…One study revealed decreased brain activations in regions of the frontoparietal attention network in TMD patients subjected to forearm heat [24] while another found no brain activation differences between TMD patients and controls in response to thumbnail pressure pain [33]. In a previous sfMRI study done by our group, noxious dentoalveolar pressure stimuli was applied to patients with persistent dentoalveolar pain disorder (PDAP), a chronic orofacial pain condition affecting the dentoalveolar structures [39] which is commonly comorbid with TMD pain [40]. Compared to controls, PDAP patients exhibited a greater extent of brain activations over several brain areas including SI, SII, insula, prefrontal cortex, and thalamus.…”

Cortical representation of experimental periodontal pain: a functional magnetic resonance imaging study

“…While the posterior insula is part of the lateral pain system, the anterior insula is part of the mesial pain system and is involved in affective pain processing 35 , 37 . Similarly, elevated insular activity was found during ‘amplified pain processing’ in persistent dentoalveolar pain disorder (PDAP) patients (compared to matched controls) induced by dentoalveolar pressure stimulation 38 . In this context, it is interesting that reductions of insular activity associated with decreased pain percepts under orthodontic treatment were reported: in patients with orofacial pain, mandibular splint therapy caused a decrease in left anterior insula activity and the magnitude of the decrease in perceived pain correlates with the magnitude of the decrease in insular activation 39 .…”

Persistent dentoalveolar pain disorder: A putative intraoral chronic overlapping pain condition

“…However, a different study that tested CPM in PDAP cases and controls did not find such endogenous pain inhibition impairment (Baad-Hansen, List, Kaube, et al, 2006). Other study supporting central amplification of pain in PDAP patients showed greater activation in brain regions related to the sensory-discriminative and cognitive components of pain perception in patients relative to pain-free controls following matched dentoalveolar pressure intensity stimulation during functional magnetic resonance imaging (Moana-Filho, Bereiter, & Nixdorf, 2015). Put together, these findings suggest dysfunction of endogenous pain modulation mechanisms and brain-related pain amplification following dentoalveolar mechanical painful stimulus (Moana-Filho et al, 2015;Nasri-Heir et al, 2015)…”