Efficacy and safety of non-invasive neurostimulation for insomnia in adults : protocol of a systematic review and network meta-analysis

Jinxian Lu^1,2Jun Hu³Yi Lu⁴Xuecheng Zhang⁵Qi Wang¹Hongling Jia^1,6*Yongchen Zhang^2,7*

• ¹Department of Acupuncture, Shandong University of Traditional Chinese Medicine Second Affiliated Hospital, Jinan, China
• ²School of Acupuncture-Moxibustion and Tuina, Shandong University of Traditional Chinese Medicine, Jinan, China
• ³Department of Radiology, Shandong University of Traditional Chinese Medicine Second Affiliated Hospital, Jinan, China
• ⁴Department of Physical Therapy, Shandong Mental Health Center, Shandong University, Jinan, China
• ⁵Department of Proctology, China-Japan Friendship Hospital, Beijing, China
• ⁶Second School of Clinical Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
• ⁷Department of Acupuncture, Shandong University of Traditional Chinese Medicine Affiliated Hospital, Jinan, China

Background: Non-invasive neurostimulation therapies have demonstrated broad therapeutic potential in the management of insomnia. However, there remains a paucity of systematically integrated evidence regarding the efficacy of commonly used clinical interventions. To address this gap, this study will employ systematic review and network meta-analysis (NMA) to evaluate the comparative efficacy and safety profiles of different non-invasive neurostimulation for insomnia, with the aim of providing evidence-based guidance for clinical decision-making. Methods: The PubMed/Medline, Web of Science, Embase, CENTRAL, Scopus, and PsycINFO databases will be systematically searched for randomized controlled trials (RCTs) on non-invasive neurostimulation techniques for the treatment of insomnia in adults, published from inception to August 31, 2025, with no language restrictions. The primary outcome measure is the Pittsburgh Sleep Quality Index (PSQI) score. Secondary outcomes include the Insomnia Severity Index (ISI) score, emotional symptoms, quality of life, and incidence of adverse events. Two independent researchers will perform literature screening, data extraction, and risk of bias assessment. The overall quality of evidence will be evaluated using the CINeMA. For NMA, we will use a random-effects model based on the Bayesian approach to integrate direct and indirect evidence. Statistical analysis will be performed using R software, and the consistency and heterogeneity of the model will be tested. Discussion: This study will provide an up-to-date synthesis of evidence from all relevant RCTs, which is crucial for evaluating the therapeutic potential and adverse effects of non-invasive neurostimulation techniques in insomnia treatment. The findings will offer valuable insights to assist clinicians in optimizing evidence-based practice.