Chronic pain associated with temporomandibular disorders (TMDs) may reflect muscle mechanoreceptor afferent barrage and dysregulated sensory processing. This observational study tested for associations between Characteristic Pain Intensity (CPI), physical symptoms (Patient Health Questionnaire–15 [PHQ-15]), and cumulative jaw muscle motor load (mV*s). In accordance with institutional review board oversight and Strengthening the Reporting of Observational Studies in Epidemiology guidelines, adult subjects gave informed consent and were identified via Diagnostic Criteria for TMD (DC-TMD) examination and research protocols. Subjects were assigned to ±Pain groups using DC-TMD criteria for myalgia. CPI scores characterized pain intensity. PHQ-15 scores were surrogate measures of dysregulated sensory processing. Laboratory tests were performed to quantify masseter and temporalis muscle activities (mV) per bite force (N) for each subject. In their natural environments, subjects recorded day- and nighttime electromyography from which cumulative jaw muscle motor loads (mV*s) were determined for activities consistent with bite forces of >1 to ≤2 and >2 to ≤5 N. Data were assessed using univariate analysis of variance, simple effects tests, K-means cluster classification, and 3-dimensional regression analyses. Of 242 individuals screened, 144 enrolled, and 125 with complete data from study protocols, there were 35 females and 15 males for +Pain and 35 females and 40 males for −Pain. Subjects produced 324 daytime and 341 nighttime recordings of average duration 6.9 ± 1.7 and 7.6 ± 1.7 h, respectively. Overall, +Pain compared to −Pain subjects had significantly higher (all P ≤ 0.002) CPI and PHQ-15 scores. Cumulative jaw muscle motor loads showed significant between-subject effects for time, diagnostic group, and sex (all P < 0.003), where motor loads tended to be higher for daytime versus nighttime, +Pain versus −Pain groups, and males versus females. Two clusters were identified, and regression relations showed associations of low-magnitude daytime masseter motor load, PHQ-15, and CPI scores for cluster 1 (n = 105, R² = 0.44) and cluster 2 (n = 18, R² = 0.80). Furthermore, these regression relations showed thresholds of motor load and PHQ-15 scores, above which there were nonlinear increases in reported pain.

与颞下颌疾病 (TMD) 相关的慢性疼痛可能反映了肌肉机械感受器传入屏障和感觉处理失调。这项观察性研究测试了特征疼痛强度 (CPI)、身体症状（患者健康问卷 - 15 [PHQ-15]）和累积下颌肌肉运动负荷 (mV*s) 之间的关联。根据机构审查委员会的监督和加强流行病学观察研究报告指南，成人受试者给予知情同意，并通过 TMD 诊断标准 (DC-TMD) 检查和研究方案进行识别。使用 DC-TMD 肌痛标准将受试者分配至±疼痛组。CPI 评分表征疼痛强度。PHQ-15 分数是感觉处理失调的替代指标。进行实验室测试以量化每位受试者每咬合力 (N) 的咬肌和颞肌活动 (mV)。在自然环境中，受试者记录白天和夜间肌电图，从中确定与咬合力 >1 至 ≤2 和 >2 至 ≤5 N 一致的活动的累积颌肌运动负荷 (mV*s)。使用以下方法评估数据单变量方差分析、简单效应检验、K 均值聚类分类和 3 维回归分析。在 242 名接受筛查、144 名登记和 125 名拥有研究方案完整数据的个体中，有 35 名女性和 15 名男性接受 +Pain，35 名女性和 40 名男性接受 -Pain。受试者产生了 324 个白天和 341 个夜间录音，平均持续时间分别为 6.9 ± 1.7 和 7.6 ± 1.7 小时。总体而言，+Pain 与 −Pain 受试者相比，CPI 和 PHQ-15 得分显着更高（所有P ≤ 0.002）。累积下颌肌肉运动负荷在时间、诊断组和性别方面表现出显着的受试者间影响（所有P < 0.003），其中白天与夜间、+疼痛组与 -疼痛组以及男性与女性的运动负荷往往较高。确定了两个聚类，回归关系显示聚类 1 ( n = 105，R ² = 0.44) 和聚类 2 ( n = 18，R ² = 0.80）。此外，这些回归关系显示了运动负荷和 PHQ-15 评分的阈值，超过该阈值，报告的疼痛就会呈非线性增加。