Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.
Centre for Multimodal Sensorimotor and Pain Research, University of Toronto, Toronto, ON, Canada.
Headache. 2020 Nov;60(10):2389-2405. doi: 10.1111/head.13971. Epub 2020 Sep 30.
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.
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.
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 (EMG ), and to produce spontaneous awake bruxism episodes (EMG ), 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.
In both groups, EMG 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], EMG 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. EMG 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. EMG 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], EMG 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]. EMG was significantly greater in mTMD participants than controls during the stressful music block [contrast estimate (95% CI): +12.9 (1.6-24.2) %MVC; P = .026). GML did not affect the duration or the frequency of awake bruxism in either group (median [IQR], mTMD: 23.5 [96.7] s, range 1-1300 seconds; Controls: 5.5 [22.5], range 0-246 seconds; P = .108). The frequency of awake bruxism episodes was greater in the mTMD group compared to controls only during the pink noise block (median [IQR], mTMD: 5 [15.3] episodes, range 0-62 episodes; Controls: 1 [3] episode, range 0-27 episodes; P = .046). No significant between-group differences were found in either the overall time spent engaging in awake bruxism (median [IQR], mTMD: 23.5 [96.7] s, range 1-1300 seconds; Controls: 5.5 [22.5], range 0-246 seconds; P = .108), or during each block (all P > .05).
In subjects with chronic mTMD, relaxing music and the individual's favorite music decreased the muscular effort during spontaneous awake bruxism episodes by 26% and 44% (relative changes), respectively. In contrast, stressful music increases it by about 43%. Because of its positive effects on awake bruxism, GML with selected music could be a promising and non-invasive component of a multimodal approach for the management of chronic mTMD.
在这项实验研究中，我们旨在确定引导式音乐聆听（guided music listening，GML）——一种基于情绪调节和注意力调节模型的音乐干预方法——是否会调节慢性疼痛性颞下颌关节紊乱症（temporomandibular disorders with myalgia，TMD myalgia，mTMD）患者的咀嚼肌活动和清醒磨牙症。这种疾病会给患者、其家庭和医疗保健系统带来很大的负担。
清醒磨牙症——一种以牙齿紧咬为特征的应激行为——是导致慢性 mTMD 的重要因素。GML 可调节心理压力和运动反应，因此可以减少包括 mTMD 在内的慢性肌肉骨骼疾病中的肌肉活动。
我们记录了 14 名患有慢性（>6 个月）mTMD 的女性（中位数[IQR] = 39.5.3 [24.3] 岁）和 15 名无痛女性（中位数[IQR] = 30.0 [3.5] 岁）在 GML 期间右侧咬肌的肌电图（electromyography，EMG）活动，包括 3 种音乐（压力音乐、放松音乐和参与者最喜欢的音乐）和 1 种无音乐（粉红噪声）对照块，每个块持续 15 分钟。我们测量了右侧咬肌的运动努力相对于参与者的最大自主收缩（maximum voluntary contraction，MVC）、维持下颌姿势的肌肉努力（EMG）和产生自发清醒磨牙症发作的肌肉努力（EMG），以及自发清醒磨牙症发作的持续时间和频率。我们测试了组间和组内（块间）差异，以及实验块对这些结果的交互作用对群体的影响。
在两组中，组间交互作用对 EMG 都有显著影响（P<0.001）。与粉红噪声相比[均值（95%置信区间）；mTMD：2.2（1.6-2.8）%MVC；对照组：1.1（0.5-1.7）%MVC]，在压力音乐块期间，EMG 增加[对比估计（95%置信区间）；mTMD：+0.8（0.7-0.8）%MVC；对照组：+0.3（0.3-0.4）%MVC；两者均 P<0.001]，而在放松音乐块期间则降低[mTMD：-0.4（-0.5 至-0.4）%MVC；对照组：-0.3（-0.4 至-0.3）%MVC；两者均 P<0.001]和最喜欢的音乐块时降低[mTMD：-0.5（-0.6 至-0.5）%MVC；对照组：-0.5（-0.5 至-0.4）%MVC；两者均 P<0.001]。与对照组相比，mTMD 个体在最喜欢的音乐和粉红噪声块中 EMG 更大[对比估计（95%置信区间）：+1.1（0.2-1.9）%MVC；P=0.019]。EMG 受到组间交互作用的显著影响（P<0.001）。与粉红噪声块相比[mTMD：23.8（16.0-31.6）%MVC]，mTMD 参与者在压力音乐块期间的 EMG 增加[对比估计（95%置信区间）；+10.2（8.6-11.8）%MVC]，在放松音乐块期间减少[-6.2（-8.1 至-4.3）%MVC；P<0.001]和最喜欢的音乐块时减少[-10.2（-12.2 至-9.1）%MVC；P<0.001]。在对照组中没有观察到这些影响[均值（95%置信区间）；粉红噪声：19.3（10.9-27.6）%MVC；压力音乐：21.2（12.9-29.4）%MVC；放松音乐：21.6（13.3-29.9）%MVC；最喜欢的音乐：24.2（15.8-32.7）%MVC；所有 P>0.05]。与对照组相比，mTMD 参与者在压力音乐块期间的 EMG 更大[对比估计（95%置信区间）；+12.9（1.6-24.2）%MVC；P=0.026]。GML 对两组的清醒磨牙症发作的持续时间或频率均无影响（中位数[IQR]，mTMD：23.5[96.7]s，范围 1-1300 秒；对照组：5.5[22.5]s，范围 0-246 秒；P=0.108）。mTMD 组在粉红噪声块期间的清醒磨牙症发作频率高于对照组[中位数[IQR]，mTMD：5[15.3]发作，范围 0-62 发作；对照组：1[3]发作，范围 0-27 发作；P=0.046]。在总清醒磨牙症发作时间或每个块的时间方面，两组之间均无显著差异（所有 P>0.05）。
在患有慢性 mTMD 的患者中，放松音乐和个体最喜欢的音乐可分别使自发清醒磨牙症发作期间的肌肉努力减少 26%和 44%（相对变化）。相比之下，压力音乐会增加约 43%。由于 GML 对清醒磨牙症有积极的影响，因此选择音乐的 GML 可能是慢性 mTMD 管理的多模式方法的一个有前途的非侵入性组成部分。
