Efficacy and neural mechanisms of transcutaneous auricular vagus nerve stimulation for chronic insomnia: a study protocol for a randomized controlled trial

Background

Traditional auricular therapy for chronic insomnia (Bu Mei in TCM) is used in clinical practice but is limited by insufficient standardization and poorly understood mechanisms. Transcutaneous auricular vagus nerve stimulation (taVNS) provides a quantifiable and reproducible neuromodulatory approach by stimulating vagally innervated regions of the auricular concha, which overlap with auricular acupoints used in TCM. However, evidence in insomnia remains predominantly based on clinical outcomes, whereas longitudinal neuroimaging evidence is limited. Resting-state functional magnetic resonance imaging (rs-fMRI) may complement clinical assessments by characterizing spontaneous brain activity and treatment-related functional changes, thereby providing objective neuroimaging evidence relevant to the potential mechanisms of taVNS.