Skip to main content
bioRxiv
  • Home
  • About
  • Submit
  • ALERTS / RSS
Advanced Search
New Results

The Time Course of Ineffective Sham Blinding During 1mA tDCS

Robert Greinacher, Larissa Buhôt, Lisa Möller, Gemma Learmonth
doi: https://doi.org/10.1101/462424
Robert Greinacher
1School of Psychology, University of Glasgow, Glasgow, UK
2Quality and Usability Lab, Technische Universität Berlin, Berlin, Germany
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Larissa Buhôt
1School of Psychology, University of Glasgow, Glasgow, UK
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Lisa Möller
1School of Psychology, University of Glasgow, Glasgow, UK
3Department of Neurology, University of Lübeck, Lübeck, Germany
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Gemma Learmonth
1School of Psychology, University of Glasgow, Glasgow, UK
4Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, UK
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Abstract
  • Full Text
  • Info/History
  • Metrics
  • Preview PDF
Loading

Abstract

Background Studies using transcranial direct current stimulation (tDCS) typically compare the effects of an active (10-30min) relative to a shorter sham (placebo) protocol. Both active and sham tDCS are presumed to be perceptually identical on the scalp, and thus represent an effective method of delivering double-blinded experimental designs. However, participants often show above-chance accuracy when asked which condition involved active/sham retrospectively.

Objective/Hypothesis We aimed to assess the time course of sham-blinding during active and sham tDCS. We predicted that 1) Participants will be aware that the current is switched on for a longer duration in the active versus the sham protocol, 2) Active anodal tDCS will reduce reaction times more effectively than sham.

Methods 32 adults were tested in a pre-registered, double-blinded, within-subjects design. A forced-choice reaction time task was undertaken before, during and after active (10min 1mA) and sham (20s 1mA) tDCS. The anode was placed over the left primary motor cortex (C3) to target the right hand, and the cathode on the right forehead. Two probe questions were asked every 30s: “Is the stimulation on? “and “How sure are you?”.

Results Distinct periods of non-overlapping confidence intervals were identified between the active and sham conditions, totalling 5min (57.1% of the total difference in stimulation time). These began immediately after sham ramp-down and lasted until the active protocol had ended. Active tDCS had no effect on reaction times compared to sham (ΔRT active vs sham p>0.38 in all blocks).

Conclusions We show a failure of placebo control during low-intensity tDCS.

Copyright 
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY 4.0 International license.
Back to top
PreviousNext
Posted November 05, 2018.
Download PDF
Email

Thank you for your interest in spreading the word about bioRxiv.

NOTE: Your email address is requested solely to identify you as the sender of this article.

Enter multiple addresses on separate lines or separate them with commas.
The Time Course of Ineffective Sham Blinding During 1mA tDCS
(Your Name) has forwarded a page to you from bioRxiv
(Your Name) thought you would like to see this page from the bioRxiv website.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Share
The Time Course of Ineffective Sham Blinding During 1mA tDCS
Robert Greinacher, Larissa Buhôt, Lisa Möller, Gemma Learmonth
bioRxiv 462424; doi: https://doi.org/10.1101/462424
Digg logo Reddit logo Twitter logo Facebook logo Google logo LinkedIn logo Mendeley logo
Citation Tools
The Time Course of Ineffective Sham Blinding During 1mA tDCS
Robert Greinacher, Larissa Buhôt, Lisa Möller, Gemma Learmonth
bioRxiv 462424; doi: https://doi.org/10.1101/462424

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Subject Area

  • Neuroscience
Subject Areas
All Articles
  • Animal Behavior and Cognition (3484)
  • Biochemistry (7336)
  • Bioengineering (5308)
  • Bioinformatics (20225)
  • Biophysics (9991)
  • Cancer Biology (7717)
  • Cell Biology (11280)
  • Clinical Trials (138)
  • Developmental Biology (6426)
  • Ecology (9930)
  • Epidemiology (2065)
  • Evolutionary Biology (13298)
  • Genetics (9354)
  • Genomics (12566)
  • Immunology (7687)
  • Microbiology (18979)
  • Molecular Biology (7428)
  • Neuroscience (40944)
  • Paleontology (300)
  • Pathology (1226)
  • Pharmacology and Toxicology (2132)
  • Physiology (3146)
  • Plant Biology (6850)
  • Scientific Communication and Education (1272)
  • Synthetic Biology (1893)
  • Systems Biology (5306)
  • Zoology (1087)