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Updated: Aug 19, 2025
Transcranial Direct Current Stimulation tDCS for Memory Enhancement
Published on: September 18, 2021
The benefits of simultaneous tDCS and working memory training on transfer outcomes: A systematic review and
Valentina Pergher1, Jacky Au2, Mahsa Alizadeh Shalchy3
1Department of Psychology, Harvard University, Cambridge, MA, USA; Laboratory of Neuro and Psychophysiology, KU Leuven University, Belgium.
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.
