Objective
In this experimental study, we aimed to determine whether guided music listening (GML) – a music intervention based on models of mood mediation and attention modulation – modulates masticatory muscle activity and awake bruxism in subjects with chronic painful muscular temporomandibular disorders (TMD myalgia, mTMD), a condition causing a significant burden to patients, their families, and healthcare systems.
Background
Awake bruxism – a stress behavior characterized by clenching of the teeth – is a strong contributor to chronic mTMD. GML modulates psychological stress and motor responses and could thus reduce muscle activity in chronic musculoskeletal conditions, including mTMD.
Methods
We recorded the electromyographic (EMG) activity in the right masseter of 14 women with chronic (>6 months) mTMD (median [IQR] = 39.5.3 [24.3] years) and 15 pain‐free women (median [IQR] = 30.0 [3.5] years) during a GML session, including 3 music (stressful, relaxing, and participants' favorite music) and a no‐music (pink noise) control blocks, each lasting 15 minutes. We measured the motor effort of the right masseter relative to the participants' maximum voluntary contraction (MVC), the muscular effort to maintain mandibular posture (EMGposture), and to produce spontaneous awake bruxism episodes (EMGbruxism), and the duration and frequency of spontaneous awake bruxism episodes. We tested between‐group and within‐group (between blocks) differences, as well as the effect of the interaction group by experimental block on these outcome measures.
Results
In both groups, EMGposture was significantly affected by the interaction group by experimental block (P < .001). Compared to pink noise [mean (95% CI); mTMD: 2.2 (1.6‐2.8) %MVC; Controls: 1.1 (0.5‐1.7) %MVC], EMGposture increased during the stressful music block [contrast estimate (95% CI); mTMD: +0.8 (0.7‐0.8) %MVC; Controls: +0.3 (0.3‐0.4) %MVC; both P < .001], and decreased during the relaxing [mTMD: −0.4 (−0.5 to −0.4) %MVC; Controls: −0.3 (−0.4 to −0.3) %MVC; both P < .001] and favorite [mTMD: −0.5 (−0.6 to −0.5) %MVC; Controls: −0.5 (−0.5 to −0.4) %MVC; both P < .001] music blocks. EMGposture was greater in mTMD individuals than controls during the favorite music [contrast estimate (95% CI): +1.1 (0.2‐1.9) %MVC; P = .019] and the pink noise [+1.1 (0.2‐2.0) %MVC; P = .014] blocks. EMGbruxism was significantly affected by the interaction group by experimental block (P < .001). In mTMD participants, compared to the pink noise block [mean (95% CI); 23.8 (16.0‐31.6) %MVC], EMGbruxism increased during the stressful music block [contrast estimate (95% CI); +10.2 (8.6‐11.8) %MVC], and decreased during the relaxing [−6.2 (−8.1 to −4.3) %MVC; P < .001] and favorite [−10.2 (−12.2 to −9.1) %MVC; P < .001] music blocks. These effects were not observed in the control group [mean (95% CI); pink noise: 19.3 (10.9‐27.6); stressful: 21.2 (12.9‐29.4) %MVC; relaxing: 21.6 (13.3‐29.9) %MVC; favorite: 24.2 (15.8‐32.7) %MVC; all P > .05]. EMGbruxism was significantly greater in mTMD partici...