The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysis

Background: Transcranial direct current stimulation (tDCS) has shown potential as an effective aid to facilitate learning. A popular application of this technology has been in combination with working memory training (WMT) in order to enhance transfer effects to other cognitive measures after traini...

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Main Authors: Valentina Pergher, Jacky Au, Mahsa Alizadeh Shalchy, Emiliano Santarnecchi, Aaron Seitz, Susanne M. Jaeggi, Lorella Battelli
Format: Article
Language:English
Published: Elsevier 2022-11-01
Series:Brain Stimulation
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1935861X2200242X
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author Valentina Pergher
Jacky Au
Mahsa Alizadeh Shalchy
Emiliano Santarnecchi
Aaron Seitz
Susanne M. Jaeggi
Lorella Battelli
author_facet Valentina Pergher
Jacky Au
Mahsa Alizadeh Shalchy
Emiliano Santarnecchi
Aaron Seitz
Susanne M. Jaeggi
Lorella Battelli
author_sort Valentina Pergher
collection DOAJ
description Background: Transcranial direct current stimulation (tDCS) has shown potential as an effective aid to facilitate learning. A popular application of this technology has been in combination with working memory training (WMT) in order to enhance transfer effects to other cognitive measures after training. Objective: This meta-analytic review aims to synthesize the existing literature on tDCS-enhanced WMT to quantify the extent to which tDCS can improve performance on transfer tasks after training. Furthermore, we were interested to evaluate the moderating effects of assessment time point (immediate post-test vs. follow-up) and transfer distance, i.e., the degree of similarity between transfer and training tasks. Methods: Using robust variance estimation, we performed a systematic meta-analysis of all studies to date that compared WMT with tDCS to WMT with sham in healthy adults. All procedures conformed to PRISMA guidelines. Results: Across 265 transfer measures in 18 studies, we found a small positive net effect of tDCS on improving overall performance on transfer measures after WMT. These effects were sustained at follow-up, which ranged from 1 week to one year after training, with a median of 1 month. Additionally, although there were no significant differences as a function of transfer distance, effects were most pronounced for non-trained working memory tasks. Conclusions: This review provides evidence that tDCS can be effective in promoting learning over and above WMT alone, and can durably improve performance on trained and untrained measures for weeks to months after the initial training and stimulation period. In particular, boosting performance on dissimilar working memory tasks may present the most promising target for tDCS-augmented WMT.
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spelling doaj.art-45d217e635754b8ea4080b2d1098b5ba2022-12-23T04:40:35ZengElsevierBrain Stimulation1935-861X2022-11-0115615411551The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysisValentina Pergher0Jacky Au1Mahsa Alizadeh Shalchy2Emiliano Santarnecchi3Aaron Seitz4Susanne M. Jaeggi5Lorella Battelli6Department of Psychology, Harvard University, Cambridge, MA, USA; Laboratory of Neuro and Psychophysiology, KU Leuven University, Belgium; Corresponding author. Department of Psychology, Harvard University, Cambridge, MA, USA.School of Education, University of California, Irvine, Irvine, CA, USADepartment of Psychology, University of California, Riverside, CA, USAPrecision Neuroscience & Neuromodulation Program, Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USADepartment of Psychology, University of California, Riverside, CA, USASchool of Education, University of California, Irvine, Irvine, CA, USA; Department of Cognitive Sciences, University of California, Irvine, Irvine, CA, USA; Corresponding author. School of Education, University of California, Irvine, Irvine, CA, USA.Department of Psychology, Harvard University, Cambridge, MA, USA; Center for Neuroscience and Cognitive Systems@UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy; Berenson-Allen Center for Noninvasive Brain Stimulation and Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USABackground: Transcranial direct current stimulation (tDCS) has shown potential as an effective aid to facilitate learning. A popular application of this technology has been in combination with working memory training (WMT) in order to enhance transfer effects to other cognitive measures after training. Objective: This meta-analytic review aims to synthesize the existing literature on tDCS-enhanced WMT to quantify the extent to which tDCS can improve performance on transfer tasks after training. Furthermore, we were interested to evaluate the moderating effects of assessment time point (immediate post-test vs. follow-up) and transfer distance, i.e., the degree of similarity between transfer and training tasks. Methods: Using robust variance estimation, we performed a systematic meta-analysis of all studies to date that compared WMT with tDCS to WMT with sham in healthy adults. All procedures conformed to PRISMA guidelines. Results: Across 265 transfer measures in 18 studies, we found a small positive net effect of tDCS on improving overall performance on transfer measures after WMT. These effects were sustained at follow-up, which ranged from 1 week to one year after training, with a median of 1 month. Additionally, although there were no significant differences as a function of transfer distance, effects were most pronounced for non-trained working memory tasks. Conclusions: This review provides evidence that tDCS can be effective in promoting learning over and above WMT alone, and can durably improve performance on trained and untrained measures for weeks to months after the initial training and stimulation period. In particular, boosting performance on dissimilar working memory tasks may present the most promising target for tDCS-augmented WMT.http://www.sciencedirect.com/science/article/pii/S1935861X2200242XTranscranial direct current stimulationWorking memory trainingTransfer and training effectsHealthy adultsLearning
spellingShingle Valentina Pergher
Jacky Au
Mahsa Alizadeh Shalchy
Emiliano Santarnecchi
Aaron Seitz
Susanne M. Jaeggi
Lorella Battelli
The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysis
Brain Stimulation
Transcranial direct current stimulation
Working memory training
Transfer and training effects
Healthy adults
Learning
title The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysis
title_full The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysis
title_fullStr The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysis
title_full_unstemmed The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysis
title_short The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and meta-analysis
title_sort benefits of simultaneous tdcs and working memory training on transfer outcomes a systematic review and meta analysis
topic Transcranial direct current stimulation
Working memory training
Transfer and training effects
Healthy adults
Learning
url http://www.sciencedirect.com/science/article/pii/S1935861X2200242X
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