Transcutaneous Auricular Vagus Nerve Stimulation Modulates Masseter Muscle Activity, Pain Perception, and Anxiety Levels in University Students: A Double-Blind, Randomized, Controlled Clinical Trial

Background This double-blind, randomized, controlled clinical trial investigated the impact of transcutaneous auricular vagus nerve stimulation (TAVNS) on masseter muscle activity, pressure pain threshold (PPT), and anxiety levels in university students with elevated anxiety. Methods Forty-two participants meeting inclusion criteria were randomly assigned to either true TAVNS or sham TAVNS groups. Various parameters, including masseter muscle electromyographic (EMG) signals, PPT, and Beck Anxiety Inventory (BAI) scores, were assessed before pretreatment, immediately after the intervention week, and two weeks follow-up. Results True TAVNS significantly reduced both left and right masseter activation during resting mandibular position, persisting for two weeks post-intervention. Additionally, TAVNS induced a lasting decrease in both left and right masseter PPT, indicative of altered pain perception. Notably, BAI scores showed a substantial reduction, emphasizing TAVNS as a potential intervention for anxiety, with effects maintained at the two-week follow-up. Conclusion This study provides comprehensive insights into the multifaceted effects of TAVNS on physiological and psychological aspects associated with anxiety in university students. The promising results underscore TAVNS as a potential neuromodulatory intervention for anxiety-related conditions, warranting further research and clinical exploration. Trial registration Brazilian Registry of Clinical Trials (ReBEC) number RBR- 4s4kt2r, retrospectively registered, 09/14/2023.