The Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Sleep Quality in Insomnia: A Systematic Review and Meta-Analysis Publisher



Hasani A ; Sani SM ; Kamroo A ; Parsaei M ; Sarvi MM ; Amirifard H
Source: Current Sleep Medicine Reports Published:2025

Abstract

Purpose of Review: In this systematic review and meta-analysis, we aim to determine the potential therapeutic roles of transcutaneous auricular vagus nerve stimulation (taVNS) as an innovative treatment for patients with primary insomnia. Considering the restrictions and fallbacks of the conventionally used strategies, such as the pharmacological and psychological approaches, we aim to assess the feasibility of utilizing taVNS as a non-invasive neuromodulation technique for improving the indices of sleep quality. Recent Findings: We conducted a systematic search in the three major databases, including a total of seven clinical studies with 282 participants, both healthy and insomniac. Meta-analysis was performed based on the data from the clinical outcomes of insomnia patients based on the four of the included studies (n = 91); indicating the substantially improved Pittsburgh Sleep Quality Index (PSQI) scores in comparison to the baseline data (Cohen’s d = 1.33, p < 0.001). Additionally, our secondary outcomes of sleep latency, disturbances, fatigue, and comorbid anxiety/depression have been improved as a result of taVNS intervention. Functional MRI (fMRI) studies have also indicated taVNS-associated alterations in brain connectivity, especially in the medial prefrontal cortex, thalamus, and occipital cortex, and a change in low-frequency brain activity. Despite the scant reports of mild to moderate side effects, taVNS was depicted as a strongly safe intervention. Summary: TaVNS neuromodulation is a safe alternative for the management of patients suffering from primary insomnia. By modifying the neuronal circuits governing sleep, taVNS can improve sleep quality and other associated symptoms accompanied by insomnia. Despite the efficacy, the generalizability of the results of the current study faces numerous limitations, mainly due toa predominance of studies centered on the Chinese population. For the future, multicenter randomized trials are suggested to comprehensively investigate the therapeutic role, possible side effects, and the optimization of device electrical parameters. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.