Safety of transcutaneous auricular vagus nerve stimulation (taVNS): a systematic review and meta-analysis

Author: Angela Yun Kim#1, Anna Marduy#2,3, Paulo S de Melo#3,4, Anna Carolyna Gianlorenco3,5, Chi Kyung Kim6, Hyuk Choi7,8, Jae-Jun Song1,8, Felipe Fregni9
Affiliation: <sup>1</sup> Department of Otorhinolaryngology-Head and Neck Surgery, Korea University Medical Center, Seoul, Republic of Korea. <sup>2</sup> Uniao Metropolitana de Ensino e Cultura (UNIME) Salvador, Bahia, Brazil. <sup>3</sup> Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 96 13th Street, Charlestown, Boston, MA, USA. <sup>4</sup> Department of Medicine, Escola Bahiana de Medicina e Saude Publica, Salvador, Bahia, Brazil. <sup>5</sup> Department of Physical Therapy, Federal University of Sao Carlos, Sao Carlos, Brazil. <sup>6</sup> Department of Neurology, Korea University Guro Hospital, Seoul, Republic of Korea. <sup>7</sup> Department of Medical Sciences, Graduate School of Medicine, Korea University, Seoul, Republic of Korea. <sup>8</sup> Neurive Co., Ltd., Gimhae, Republic of Korea. <sup>9</sup> Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 96 13th Street, Charlestown, Boston, MA, USA. Fregni.Felipe@mgh.harvard.edu.
Conference/Journal: Sci Rep
Date published: 2022 Dec 21
Other: Volume ID: 12 , Issue ID: 1 , Pages: 22055 , Special Notes: doi: 10.1038/s41598-022-25864-1. , Word Count: 293


Transcutaneous auricular vagus nerve stimulation (taVNS) has been investigated as a novel neuromodulation tool. Although taVNS is generally considered safe with only mild and transient adverse effects (AEs), those specifically caused by taVNS have not yet been investigated. This systematic review and meta-analysis on taVNS aimed to (1) systematically analyze study characteristics and AE assessment, (2) characterize and analyze possible AEs and their incidence, (3) search for predictable risk factors, (4) analyze the severity of AE, and (5) suggest an evidence-based taVNS adverse events questionnaire for safety monitoring. The articles searched were published through April 7, 2022, in Medline, Embase, Web of Science, Cochrane, and Lilacs databases. In general, we evaluated 177 studies that assessed 6322 subjects. From these, 55.37% of studies did not mention the presence or absence of any AEs; only 24.86% of the studies described that at least one adverse event occurred. In the 35 studies reporting the number of subjects with at least one adverse event, a meta-analytic approach to calculate the risk differences of developing an adverse event between active taVNS and controls was used. The meta-analytic overall adverse events incidence rate was calculated for the total number of adverse events reported on a 100,000 person-minutes-days scale. There were no differences in risk of developing an adverse event between active taVNS and controls. The incidence of AE, in general, was 12.84/100,000 person-minutes-days of stimulation, and the most frequently reported were ear pain, headache, and tingling. Almost half of the studies did not report the presence or absence of any AEs. We attribute this to the absence of AE in those studies. There was no causal relationship between taVNS and severe adverse events. This is the first systematic review and meta-analysis of transcutaneous auricular stimulation safety. Overall, taVNS is a safe and feasible option for clinical intervention.


PMID: 36543841 DOI: 10.1038/s41598-022-25864-1