Transcranial direct current stimulation (tDCS) modulation of picture naming and word reading: A meta-analysis of single session tDCS applied to healthy participants

Research output: Contribution to journalReview article

View graph of relations Save citation



Research units


Recent reviews quantifying the effects of single sessions of transcranial direct current stimulation (or tDCS) in healthy volunteers find only minor effects on cognition despite the popularity of this technique. Here, we wanted to quantify the effects of tDCS on language production tasks that measure word reading and picture naming. We reviewed 14 papers measuring tDCS effects across a total of 96 conditions to a) quantify effects of conventional stimulation on language regions (i.e., left hemisphere anodal tDCS administered to temporal/frontal areas) under normal conditions or under conditions of cognitive (semantic) interference; b) identify parameters which may moderate the size of the tDCS effect within conventional stimulation protocols (e.g., online vs offline, high vs. low current densities, and short vs. long durations), as well as within types of stimulation not typically explored by previous reviews (i.e., right hemisphere anodal tDCS or left/right hemisphere cathodal tDCS). In all analyses there was no significant effect of tDCS, but we did find a small but significant effect of time and duration of stimulation with stronger effects for offline stimulation and for shorter durations (< 15 min). We also found some indication of publication bias towards reporting positive effects. We encourage further experimentation in order resolve the disparity between the current popularity of tDCS and its poor efficacy in healthy participants.


  • Transcranial direct current stimulation

    Rights statement: © 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (

    Final published version, 1 MB, PDF-document

    Licence: CC BY-NC-ND Show licence


Original languageEnglish
Pages (from-to)234-249
Number of pages16
Early online date27 Jul 2017
Publication statusPublished - 1 Sep 2017

Bibliographic note

© 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license ( Funding: Ministry of Defence, Defence Science and Technology Laboratory.


  • Meta- analysis, Null effects, Picture naming, Review, tDCS, Word reading

Download statistics

No data available

Employable Graduates; Exploitable Research

Copy the text from this field...