Blinding is compromised for transcranial direct current stimulation at 1 mA for 20 min in young healthy adults
AuthorTuri, Zsolt; Csifcsak, Gabor; Boayue, Nya Mehnwolo; Aslaksen, Per M; Antal, Andrea; Paulus, Walter; Groot, Josephine; Hawkins, Guy E.; Opitz, Alexander; Thielscher, Axel; Mittner, Matthias
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.
This is the pre-peer reviewed version of the following article: Turi, Z., Csifcsak, G., Boayue, N.M., Aslaksen, P., Antal, A., Paulus, W., ... Mittner, M. (2019). Blinding is compromised for transcranial direct current stimulation at 1 mA for 20 min in young healthy adults. European Journal of Neuroscience, which has been published in final form at https://doi.org/10.1111/ejn.14403. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.