Blinding is compromised for transcranial direct current stimulation at 1 mA for 20 min in young healthy adults

Zsolt Turi; Gábor Csifcsák; Nya Mehnwolo Boayue; Per Aslaksen; Andrea Antal; Walter Paulus; Josephine Groot; Guy E. Hawkins; Birte Forstmann; Alexander Opitz; Axel Thielscher; Matthias Mittner

doi:10.1111/ejn.14403

Blinding is compromised for transcranial direct current stimulation at 1 mA for 20 min in young healthy adults

Zsolt Turi
, Gábor Csifcsák
, Nya Mehnwolo Boayue
, Per Aslaksen
, Andrea Antal
, Walter Paulus
, Josephine Groot
, Guy E. Hawkins
, Birte Forstmann
, Alexander Opitz
, Axel Thielscher
, Matthias Mittner

Biomedical Engineering

Research output: Contribution to journal › Article › peer-review

83 Scopus citations

Abstract

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method that is frequently used to study cortical excitability changes and their impact on cognitive functions in humans. While most stimulators are capable of operating in double-blind mode, the amount of discomfort experienced during tDCS may break blinding. Therefore, specifically designed sham stimulation protocols are being used. The “fade-in, short-stimulation, fade-out” (FSF) protocol has been used in hundreds of studies and is commonly believed to be indistinguishable from real stimulation applied at 1 mA for 20 min. We analysed subjective reports of 192 volunteers, who either received real tDCS (n = 96) or FSF tDCS (n = 96). Participants reported more discomfort for real tDCS and correctly guessed the condition above chance-level. These findings indicate that FSF does not ensure complete blinding and that better active sham protocols are needed.

Original language	English (US)
Pages (from-to)	3261-3268
Number of pages	8
Journal	European Journal of Neuroscience
Volume	50
Issue number	8
DOIs	https://doi.org/10.1111/ejn.14403
State	Published - Oct 1 2019

Bibliographical note

Funding Information:
The writing of this paper was supported by the Research Program, University Medical Center, University of Goettingen awarded to ZT. AT received support from Lundbeckfonden (R118-A11308) and Novo Nordisk Fonden by a synergy grant on Biophysically adjusted state-informed cortex stimulation (BASICS; NNF14OC0011413). This work was supported by the Northern Norway Regional Health Authority (grant no. PFP1237-15) for GC and MM.

Publisher Copyright:
© 2019 Federation of European Neuroscience Societies and John Wiley & Sons Ltd

Keywords

active sham tDCS
blinding
double-blinding
placebo
transcranial direct current stimulation

Publisher link

10.1111/ejn.14403

https://backend.orbit.dtu.dk/ws/files/171275773/Turi_et_al_2019_European_Journal_of_Neuroscience.pdf

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@article{191f70d76d1d45a89051a2da1054919f,

title = "Blinding is compromised for transcranial direct current stimulation at 1 mA for 20 min in young healthy adults",

abstract = "Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method that is frequently used to study cortical excitability changes and their impact on cognitive functions in humans. While most stimulators are capable of operating in double-blind mode, the amount of discomfort experienced during tDCS may break blinding. Therefore, specifically designed sham stimulation protocols are being used. The “fade-in, short-stimulation, fade-out” (FSF) protocol has been used in hundreds of studies and is commonly believed to be indistinguishable from real stimulation applied at 1 mA for 20 min. We analysed subjective reports of 192 volunteers, who either received real tDCS (n = 96) or FSF tDCS (n = 96). Participants reported more discomfort for real tDCS and correctly guessed the condition above chance-level. These findings indicate that FSF does not ensure complete blinding and that better active sham protocols are needed.",

keywords = "active sham tDCS, blinding, double-blinding, placebo, transcranial direct current stimulation",

author = "Zsolt Turi and G{\'a}bor Csifcs{\'a}k and Boayue, \{Nya Mehnwolo\} and Per Aslaksen and Andrea Antal and Walter Paulus and Josephine Groot and Hawkins, \{Guy E.\} and Birte Forstmann and Alexander Opitz and Axel Thielscher and Matthias Mittner",

note = "Funding Information: The writing of this paper was supported by the Research Program, University Medical Center, University of Goettingen awarded to ZT. AT received support from Lundbeckfonden (R118-A11308) and Novo Nordisk Fonden by a synergy grant on Biophysically adjusted state-informed cortex stimulation (BASICS; NNF14OC0011413). This work was supported by the Northern Norway Regional Health Authority (grant no. PFP1237-15) for GC and MM. Publisher Copyright: {\textcopyright} 2019 Federation of European Neuroscience Societies and John Wiley \& Sons Ltd",

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AU - Turi, Zsolt

AU - Csifcsák, Gábor

AU - Boayue, Nya Mehnwolo

AU - Aslaksen, Per

AU - Antal, Andrea

AU - Paulus, Walter

AU - Groot, Josephine

AU - Hawkins, Guy E.

AU - Forstmann, Birte

AU - Opitz, Alexander

AU - Thielscher, Axel

AU - Mittner, Matthias

N1 - Funding Information: The writing of this paper was supported by the Research Program, University Medical Center, University of Goettingen awarded to ZT. AT received support from Lundbeckfonden (R118-A11308) and Novo Nordisk Fonden by a synergy grant on Biophysically adjusted state-informed cortex stimulation (BASICS; NNF14OC0011413). This work was supported by the Northern Norway Regional Health Authority (grant no. PFP1237-15) for GC and MM. Publisher Copyright: © 2019 Federation of European Neuroscience Societies and John Wiley & Sons Ltd

PY - 2019/10/1

Y1 - 2019/10/1

N2 - Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method that is frequently used to study cortical excitability changes and their impact on cognitive functions in humans. While most stimulators are capable of operating in double-blind mode, the amount of discomfort experienced during tDCS may break blinding. Therefore, specifically designed sham stimulation protocols are being used. The “fade-in, short-stimulation, fade-out” (FSF) protocol has been used in hundreds of studies and is commonly believed to be indistinguishable from real stimulation applied at 1 mA for 20 min. We analysed subjective reports of 192 volunteers, who either received real tDCS (n = 96) or FSF tDCS (n = 96). Participants reported more discomfort for real tDCS and correctly guessed the condition above chance-level. These findings indicate that FSF does not ensure complete blinding and that better active sham protocols are needed.

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