Transcutaneous auricular vagus nerve stimulation (taVNS): a comprehensive review of mechanisms, clinical applications, and future directions.

PURPOSE: Transcutaneous auricular vagus nerve stimulation (Transcutaneous Vagus Nerve Stimulation, TaVNS) is a non-invasive neuromodulation technique that has garnered significant attention. This article aims to summarize its mechanisms of action, clinical applications, and future challenges.

METHODS

A non-systematic literature seach was performed in PubMed for articles published. Studies investigating taVNS, gastrointestinal function, anesthesia, depression, epilepsy, migraine, and post-stroke rehabilitation were identified. A total of 72 articles were included in this review after full-text assessment. This work is a narrative review rather than a systematic review. No pre-registered search strategy, formal eligibility criteria, or risk-of-bias assessment was performed. Literature was collected via targeted non-systematic retrieval focusing on preclinical and clinical advances of transcutaneous auricular vagus nerve stimulation. Relevant original articles and reviews were selectively included to summarize current evidence, mechanisms, safety status and future perspectives of taVNS.

RESULTS

The analysis revealed that taVNS delivers stimulation to the auricular branch of the vagus nerve, transmitting signals to the nucleus tractus solitarius (NTS). Subsequently, these signals modulate emotional and cognitive processes via ascending pathways and regulate autonomic nervous system function through descending pathways. A key mechanism involves the activation of the "cholinergic anti-inflammatory pathway," which suppresses systemic inflammation. Evidence suggested that taVNS holds potential therapeutic value for a variety of conditions, including depression, epilepsy, migraine, and post-stroke rehabilitation.

CONCLUSIONS

This review demeonstrates that future research should focus on parameter optimization, mechanistic exploration, and the development of personalized treatment protocols to facilitate its clinical translation.