Interactions between sleep parameters and heart rate variability in temporomandibular disorders

Temporomandibular disorders (TMD) cause pain and dysfunction in the temporomandibular joints (TMJs) and masticatory muscles and significantly impact quality of life. Temporomandibular disorderrelated pain is associated with sleep disorders and affects heart rate (HR) parameters; however, data from polysomnographic studies remains inconclusive.

The aim of the study was to evaluate the impact of TMD on sleep parameters recorded using video-polysomnography (vPSG) and heart rate variability (HRV) monitored with the use of a 24-hour electrocardiogram (ECG).

A cross-sectional study included 93 patients with TMD diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Video-polysomnography and 24-hour ECG monitoring were conducted. Pain was assessed using the numeric rating scale (NRS) (0-10) and categorized as mild (≤5) or severe (>5).

The study included 93 patients with TMD, divided into groups of low pain intensity (n = 66) and high pain intensity (n = 27). The group with high pain intensity demonstrated lower sleep efficiency (87.7% vs. 90.8%, p = 0.022) and lower oxygen saturation (94.7% vs. 95.2%, p = 0.036). Heart rate variability parameters were similar in both groups. Women reported a higher total pain score (20 vs. 10, p = 0.007) and had a higher percentage of normal-to-normal (NN) intervals differing by more than 50 ms (pNN50) (24 h: 22.5% vs. 14.2%, p = 0.013; daytime: 18.0% vs. 9.8%, p = 0.002), higher daytime root mean square of successive differences (RMSSD) (41.7 vs. 34.8, p = 0.026), and a higher nighttime HR (63.8 vs. 60.5, p = 0.047). Additionally, women demonstrated lower values for very low frequency (VLF) power (1,402.4 vs. 2,214.5, p = 0.010), low frequency (LF) power (1,415.5 vs. 2,494.5, p = 0.028), and the low frequency/high frequency (LF/HF) ratio (1.3 vs. 2.5, p < 0.001).

High TMD-related pain intensity is associated with reduced sleep efficiency and lower mean oxygen saturation during sleep. Women experience higher pain intensity but lower sympathetic activation than men.