Sham tDCS: A hidden source of variability? Reflections for further blinded, controlled trials

Clara Fonteneau, Marine Mondino, Martijn Arns, Chris Baeken, Marom Bikson, Andre R Brunoni, Matthew J Burke, Tuomas Neuvonen, Frank Padberg, Alvaro Pascual-Leone, Emmanuel Poulet, Giulio Ruffini, Emiliano Santarnecchi, Anne Sauvaget, Klaus Schellhorn, Marie-Françoise Suaud-Chagny, Ulrich Palm, Jerome Brunelin*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

83 Citations (Web of Science)

Abstract

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique increasingly used to modulate neural activity in the living brain. In order to establish the neurophysiological, cognitive or clinical effects of tDCS, most studies compare the effects of active tDCS to those observed with a sham tDCS intervention. In most cases, sham tDCS consists in delivering an active stimulation for a few seconds to mimic the sensations observed with active tDCS and keep participants blind to the intervention. However, to date, sham-controlled tDCS studies yield inconsistent results, which might arise in part from sham inconsistencies. Indeed, a multiplicity of sham stimulation protocols is being used in the tDCS research field and might have different biological effects beyond the intended transient sensations. Here, we seek to enlighten the scientific community to this possible confounding factor in order to increase reproducibility of neurophysiological, cognitive and clinical tDCS studies.

Original languageEnglish
Pages (from-to)668-673
Number of pages6
JournalBrain stimulation
Volume12
Issue number3
DOIs
Publication statusPublished - 15 Jan 2019
Externally publishedYes

Keywords

  • Humans
  • Randomized Controlled Trials as Topic
  • Reproducibility of Results
  • Research Design/standards
  • Transcranial Direct Current Stimulation/standards
  • DIRECT-CURRENT STIMULATION
  • RANDOMIZED-CONTROLLED-TRIAL
  • SAFETY
  • Sham
  • Variability
  • HEALTHY-HUMAN SUBJECTS
  • Transcranial direct current stimulation
  • TRANSCRANIAL ELECTRICAL-STIMULATION
  • HUMAN MOTOR CORTEX
  • MAGNETIC STIMULATION
  • MEP AMPLITUDE-MODULATION
  • EXCITABILITY
  • Reproducibility
  • tDCS
  • Placebo
  • POLARIZATION

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