Byeon H. Further insights into the efficacy and moderators of transcranial alternating current stimulation for working memory. World J Psychiatry 2026; 16(2): 114457 [DOI: 10.5498/wjp.v16.i2.114457]
Corresponding Author of This Article
Haewon Byeon, PhD, Associate Professor, Director, Department of Future Technology, Worker's Care & Digital Health Lab, Korea University of Technology and Education, 1600 Chungjeol-ro, Cheonan 31253, South Korea. bhwpuma@naver.com
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Psychiatry
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Letter to the Editor
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This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Feb 19, 2026 (publication date) through Feb 2, 2026
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Publication Name
World Journal of Psychiatry
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2220-3206
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Baishideng Publishing Group Inc, 7041 Koll Center Parkway, Suite 160, Pleasanton, CA 94566, USA
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Byeon H. Further insights into the efficacy and moderators of transcranial alternating current stimulation for working memory. World J Psychiatry 2026; 16(2): 114457 [DOI: 10.5498/wjp.v16.i2.114457]
World J Psychiatry. Feb 19, 2026; 16(2): 114457 Published online Feb 19, 2026. doi: 10.5498/wjp.v16.i2.114457
Further insights into the efficacy and moderators of transcranial alternating current stimulation for working memory
Haewon Byeon
Haewon Byeon, Department of Future Technology, Worker's Care & Digital Health Lab, Korea University of Technology and Education, Cheonan 31253, South Korea
Author contributions: Byeon H designed the study; Byeon H data interpretation; Byeon H developed methodology and writing the article.
Supported by Basic Science Research Program through the National Research Foundation of Korea (NRF), No. NRF-RS-2023-00237287.
Conflict-of-interest statement: No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.
Open Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Haewon Byeon, PhD, Associate Professor, Director, Department of Future Technology, Worker's Care & Digital Health Lab, Korea University of Technology and Education, 1600 Chungjeol-ro, Cheonan 31253, South Korea. bhwpuma@naver.com
Received: September 19, 2025 Revised: October 30, 2025 Accepted: November 21, 2025 Published online: February 19, 2026 Processing time: 132 Days and 23.2 Hours
Abstract
This letter offers a critical appraisal of the systematic review and meta-analysis by Hou et al, which examined the effect of theta-band transcranial alternating current stimulation (theta-tACS) on working memory in healthy adults. The authors initially reported a moderate, statistically significant enhancement of working memory performance (Hedges’ g = 0.405), although this effect became non-significant following adjustment for publication bias. This commentary highlights key strengths of the meta-analysis, including its targeted focus on a frequency band theoretically relevant to working memory, comprehensive moderator analyses, and task-specific subgroup comparisons (N-back vs delayed match-to-sample). At the same time, it emphasizes the substantial impact of publication bias, the considerable heterogeneity among included studies, and the unexpected finding that fixed-frequency stimulation protocols outperformed individualized approaches. While uncertainty remains regarding the overall efficacy of theta-tACS, the observed task-specific improvements in N-back performance and the identification of critical stimulation parameters (such as frequency, duration, and stimulation timing relative to task performance) offer valuable direction for protocol refinement. Taken together, this meta-analysis provides an important and cautionary synthesis that reinforces the need for pre-registered, methodologically rigorous studies to establish the cognitive and potential clinical benefits of theta-tACS with greater confidence.
Core Tip: The meta-analysis by Hou et al on theta-band transcranial alternating current stimulation (theta-tACS) for working memory in healthy adults reveals a complex picture. An initial moderate effect was nullified after correcting for significant publication bias, urging caution in interpreting efficacy. However, the study's key contribution lies in its detailed moderator analysis. It found that theta-tACS significantly enhances performance on N-back tasks, but not delayed match-to-sample tasks. Furthermore, the effectiveness in N-back tasks was moderated by stimulation parameters like frequency (fixed > personalized) and duration. These nuanced findings are crucial for designing future, more targeted transcranial alternating current stimulation protocols for both cognitive enhancement and potential clinical applications in psychiatric disorders with working memory deficits.
