Abstract
BACKGROUND: Transcutaneous auricular vagus nerve stimulation (taVNS) is a safe and feasible treatment for a variety of acute and chronic pain conditions. However, no evidence about taVNS effectiveness in patients with chronic pain associated with temporomandibular disorders (TMD) is available. OBJECTIVE: To evaluate the feasibility of and compliance with taVNS in participants experiencing chronic TMD pain and potential effects on pain, psychological well-being, muscle activity, and kinematics. METHODS: Twenty adults with chronic TMD pain were randomised to receive taVNS (n = 10) or sham (n = 10). In the taVNS group, stimulation was performed on the left tragus for 4 h daily (25 Hz, pulse width 250 μs, 28 s on/32 s off). In the sham group, an inactive non-functional sham electrode was used. Patient-reported outcome measures (GCPS, PHQ-9, GAD-7, PHQ-15, and OHIP-G14), muscle activity, and kinematics were assessed at baseline, 4 weeks, and 8 weeks. Compliance was assessed using a smartphone app, which recorded daily stimulation time and intensity. RESULTS: Recruitment and retention rates were high (100% and 90%, respectively), with 83% adherence to the intervention. Participants receiving taVNS showed a large effect on oral health-related quality of life, and at least a small but potentially important effect on pain intensity, anxiety, depression, severity of somatic symptoms, muscle activity, and kinematics. However, none of these differences were statistically significant. No serious adverse events were identified. CONCLUSION: taVNS proved feasible in participants with chronic TMD pain, suggesting potential benefits for symptom management. Future studies with larger sample sizes and extended follow-up durations are necessary to confirm efficacy and safety.