Transcutaneous auricular vagus nerve stimulation modulates masseter muscle activity, pain perception, and anxiety levels in university students: a double-blind, randomized, controlled clinical trial.

Introduction: Chronic anxiety is a statemarked by sustained activation of the masseter muscle, manifesting in both mental and physical strain. This prolonged tension can significantly impact mental wellbeing and cognitive abilities, posing a risk for a range of health complications. 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 active 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 2 weeks follow-up. Results: Active TAVNS significantly reduced both left and right masseter activation during resting mandibular position, persisting for 2 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 2-week follow-up. Discussion: 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. Clinical Trial Registration: https://ensaiosclinicos.gov.br/rg/RBR-4s4kt2r.

Possible mechanisms of auricular acupoint stimulation in the treatment of migraine by activating auricular vagus nerve. / 从耳迷走神经探讨耳穴治疗偏头痛的可能机制.

Under the guidance of traditional Chinese medicine theory, the clinical research of auricular acupoint stimulation in the treatment of migraine has gained a lot, and the curative efficacy is definite, but its mechanism remains unclear. In the present paper, we discussed the efficacy of auricular acupoint stimulation including "transcutaneous auricular vagus nerve stimulation" (taVNS) in the treatment of migraine in recent years. Through bibliometric analysis, we screened out top 10 auricular acupoints (Shenmenï¼»TF4ï¼½, Pizhixiaï¼»AT4ï¼½, Jiaoganï¼»AH6aï¼½, Ganï¼»CO12ï¼½, Yidanï¼»CO11ï¼½, Neifenmiï¼»CO18ï¼½, Shenï¼»CO10ï¼½, Nieï¼»AT2ï¼½, Zhenï¼»AT3ï¼½ and Eï¼»AT1ï¼½) which were the most frequently used for migraine. Majority of these auricular acupoints just distributed in the region innervated by auricular vagus nerve. Thus, we thought that the analgesic effect of needling these auricular acupoints for migraine was produced by triggering the auricular vagus nerve, and concluded that the central mechanism underlying induction of analgesic effect by activating auricular vagus nerve may be achieved by activating the descending pain regulation pathway of the locus coeruleus nucleus and dorsal raphe nucleus. In addition, taVNS-induced 1) regulation of the activities of brain's default network and pain matrix, 2) activation of the cortical descending pain regulation pathway, and 3) inhibition of the neuroinflammatory response may also contribute to its ameliorating effect of migraine. This paper may provide ideas for the future research on the mechanism of auricular acupoint treatment of migraine.

Transcutaneous Auricular Vagus Nerve Stimulation Alleviates Monobenzone-Induced Vitiligo in Mice.

Vitiligo is a complex skin disorder that involves oxidative stress and inflammatory responses and currently lacks a definitive cure. Transcutaneous auricular vagus nerve stimulation (taVNS) is a noninvasive method for targeting the auricular branch of the vagus nerve and has gained widespread attention for potential intervention in the autonomic nervous system. Although previous research has suggested that vagus nerve stimulation can potentially inhibit inflammatory responses, its specific role and mechanisms in vitiligo treatment remain unknown. This study aimed to explore the therapeutic effects of taVNS in a mouse model of vitiligo induced by monobenzone. Initially, a quantitative assessment of the treatment effects on vitiligo mice was conducted using a scoring system, revealing that taVNS significantly alleviated symptoms, particularly by reducing the depigmented areas. Subsequent immunohistochemical analysis revealed the impact of taVNS treatment on melanocyte granules, mitigating pigment loss in the skin of monobenzone-induced vitiligo mice. Further analysis indicated that taVNS exerted its therapeutic effects through multiple mechanisms, including the regulation of oxidative stress, enhancement of antioxidant capacity, promotion of tyrosine synthesis, and suppression of inflammatory responses. The conclusions of this study not only emphasize the potential value of taVNS in vitiligo therapy, but also lay a foundation for future research into the mechanisms and clinical applications of taVNS.