Safety of Transcranial Direct Current Stimulation: Evidence Based Update 2016

Marom Bikson; Pnina Grossman; Chris Thomas; Adantchede Louis Zannou; Jimmy Jiang; Tatheer Adnan; Antonios P Mourdoukoutas; Greg Kronberg; Dennis Truong; Paulo Boggio; André R Brunoni; Leigh Charvet; Felipe Fregni; Brita Fritsch; Bernadette Gillick; Roy H Hamilton; Benjamin M Hampstead; Ryan Jankord; Adam Kirton; Helena Knotkova; David Liebetanz; Anli Liu; Colleen Loo; Michael A Nitsche; Janine Reis; Jessica D Richardson; Alexander Rotenberg; Peter E Turkeltaub; Adam J Woods

doi:10.1016/j.brs.2016.06.004

Safety of Transcranial Direct Current Stimulation: Evidence Based Update 2016

Brain Stimul. 2016 Sep-Oct;9(5):641-661. doi: 10.1016/j.brs.2016.06.004. Epub 2016 Jun 15.

Authors

Marom Bikson¹, Pnina Grossman², Chris Thomas², Adantchede Louis Zannou², Jimmy Jiang², Tatheer Adnan², Antonios P Mourdoukoutas², Greg Kronberg², Dennis Truong², Paulo Boggio³, André R Brunoni⁴, Leigh Charvet⁵, Felipe Fregni⁶, Brita Fritsch⁷, Bernadette Gillick⁸, Roy H Hamilton⁹, Benjamin M Hampstead¹⁰, Ryan Jankord¹¹, Adam Kirton¹², Helena Knotkova¹³, David Liebetanz¹⁴, Anli Liu¹⁵, Colleen Loo¹⁶, Michael A Nitsche¹⁷, Janine Reis⁷, Jessica D Richardson¹⁸, Alexander Rotenberg¹⁹, Peter E Turkeltaub²⁰, Adam J Woods²¹

Affiliations

¹ Department of Biomedical Engineering, The City College of New York, New York, NY, USA. Electronic address: bikson@ccny.cuny.edu.
² Department of Biomedical Engineering, The City College of New York, New York, NY, USA.
³ Cognitive Neuroscience Laboratory and Developmental Disorders Program, Center for Health and Biological Sciences, Mackenzie Presbyterian University, Sao Paulo, Brazil.
⁴ Service of Interdisciplinary Neuromodulation, Department and Institute of Psychiatry, Laboratory of Neurosciences (LIM-27), University of São Paulo, São Paulo, Brazil.
⁵ NYU MS Comprehensive Care Center, Department of Neurology, New York University School of Medicine, New York, NY, USA.
⁶ Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
⁷ Department of Neurology, University Medical Center, Freiburg, Germany; BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Germany.
⁸ Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, MN.
⁹ Laboratory for Cognition and Neural Stimulation, University of Pennsylvania, Philadelphia, PA, USA; Center for Cognitive Neuroscience, University of Pennsylvania, Philadelphia, PA, USA; Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA.
¹⁰ Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA.
¹¹ Applied Neuroscience, 711th Human Performance Wing, Air Force Research Laboratory, WPAFB, OH, USA.
¹² Departments of Pediatrics and Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
¹³ MJHS Institute for Innovation in Palliative Care, New York, NY, USA; Department of Social and Family Medicine, Albert Einstein College of Medicine, The Bronx, NY, USA.
¹⁴ Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Goettingen 37075, Germany.
¹⁵ NYU Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY, USA.
¹⁶ Psychiatry, Black Dog Institute, Clinical Academic, St George Hospital, University of New South Wales, Sydney, Australia.
¹⁷ Department of Clinical Neurophysiology, University Medical Center, Georg-August-University, Goettingen 37075, Germany; Leibniz Research Centre for Working Environment and Human Factors at the TU Dortmund, Dortmund, Germany; Department of Neurology, University Medical Hospital Bergmannsheil, Bochum, Germany.
¹⁸ Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA; Department of Communication Sciences & Disorders, The University of South Carolina, Columbia, SC, USA; Department of Speech and Hearing Sciences, The University of New Mexico, Albuquerque, NM, USA.
¹⁹ Berenson-Allen Center for Noninvasive Brain Stimulation, Division of Cognitive Neurology, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA; Pediatric Neuromodulation Program, Division of Epilepsy and Neurophysiology, Department of Neurology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA.
²⁰ Department of Neurology, Georgetown University, Washington, DC, USA; Research Division, MedStar National Rehabilitation Hospital, Washington, DC, USA.
²¹ Center for Cognitive Aging and Memory, Institute on Aging, Department of Aging and Geriatric Research, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.

Abstract

This review updates and consolidates evidence on the safety of transcranial Direct Current Stimulation (tDCS). Safety is here operationally defined by, and limited to, the absence of evidence for a Serious Adverse Effect, the criteria for which are rigorously defined. This review adopts an evidence-based approach, based on an aggregation of experience from human trials, taking care not to confuse speculation on potential hazards or lack of data to refute such speculation with evidence for risk. Safety data from animal tests for tissue damage are reviewed with systematic consideration of translation to humans. Arbitrary safety considerations are avoided. Computational models are used to relate dose to brain exposure in humans and animals. We review relevant dose-response curves and dose metrics (e.g. current, duration, current density, charge, charge density) for meaningful safety standards. Special consideration is given to theoretically vulnerable populations including children and the elderly, subjects with mood disorders, epilepsy, stroke, implants, and home users. Evidence from relevant animal models indicates that brain injury by Direct Current Stimulation (DCS) occurs at predicted brain current densities (6.3-13 A/m(2)) that are over an order of magnitude above those produced by conventional tDCS. To date, the use of conventional tDCS protocols in human trials (≤40 min, ≤4 milliamperes, ≤7.2 Coulombs) has not produced any reports of a Serious Adverse Effect or irreversible injury across over 33,200 sessions and 1000 subjects with repeated sessions. This includes a wide variety of subjects, including persons from potentially vulnerable populations.

Keywords: Electrical stimulation; Mood disorders; Safety; Transcranial Direct Current Stimulation; tDCS; tDCS safety.

Publication types

Review

MeSH terms

Animals
Brain / physiopathology*
Computer Simulation*
Epilepsy / physiopathology
Epilepsy / therapy*
Evidence-Based Practice*
Humans
Models, Animal
Stroke / physiopathology
Stroke / therapy*
Transcranial Direct Current Stimulation / adverse effects*
Transcranial Direct Current Stimulation / methods

Abstract

Publication types

MeSH terms

Grants and funding