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BRIEF RESEARCH REPORT article

Front. Hum. Neurosci.
Sec. Brain Imaging and Stimulation
Volume 18 - 2024 | doi: 10.3389/fnhum.2024.1468538
This article is part of the Research Topic Transcranial Electrical Stimulation (tACS, tDCS, tRNS) in Basic and Clinical Neuroscience: Current Progress and Future Directions View all 3 articles

The Subjective Experience of Transcranial Electrical Stimulation: A within-subject comparison of tolerability and side effects between tDCS, tACS, and otDCS

Provisionally accepted
Jovana Bjekic Jovana Bjekic 1*Marko Živanović Marko Živanović 2Marija Stanković Marija Stanković 1Dunja Paunovic Dunja Paunovic 1Uroš Konstantinović Uroš Konstantinović 1Sasa R. Filipovic Sasa R. Filipovic 1
  • 1 Human Neuroscience Group, Centre for Neuroscience and Neuromodulation, Institute for Medical Research, University of Belgrade, Belgrade, Serbia
  • 2 Institute of Psychology, Department of Psychology, Faculty of Philosophy, University of Belgrade, Belgrade, Serbia

The final, formatted version of the article will be published soon.

    Low-intensity transcranial electrical stimulation (tES), including techniques like transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), and oscillatory transcranial direct current stimulation (otDCS), has been widely explored for its neuromodulatory effects on motor, cognitive, and behavioral processes. Despite well-established safety, these techniques can induce varying degrees of discomfort and side effects, potentially impacting their application. This study presents a within-subject sham-controlled experiment directly comparing the subjective experience and side effects of tDCS, tACS, and otDCS. Participants reported their discomfort levels at multiple time points during 20-minute stimulation sessions and completed a side-effects questionnaire before and after each session. Results indicated that the overall discomfort levels were low across all conditions, with ≥ 95% reporting the absence of discomfort or mild procedure-induced discomfort. Nevertheless, tDCS and otDCS were slightly less comfortable compared to sham, especially at the beginning of stimulation, with tACS-induced discomfort levels being overall comparable to sham. The most common side / adverse effects were mild skin sensations, including itching and tingling, particularly with tDCS and otDCS, while tACS occasionally caused phosphenes and blurred vision. These findings provide a systematic comparison of tES-induced discomfort and side effects between different tES techniques, highlighting the high safety of tES, but also the importance of considering within-and between-person variability and time-course effects in tES applications.

    Keywords: transcranial electrical stimulation (TES), transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS), transcranial oscillatory current stimulation (otDCS), tolerability, side effects, Safety, subjective experience

    Received: 22 Jul 2024; Accepted: 11 Oct 2024.

    Copyright: © 2024 Bjekic, Živanović, Stanković, Paunovic, Konstantinović and Filipovic. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Jovana Bjekic, Human Neuroscience Group, Centre for Neuroscience and Neuromodulation, Institute for Medical Research, University of Belgrade, Belgrade, Serbia

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