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Vassiliadis P, Stiennon E, Windel F, Wessel MJ, Beanato E, Hummel FC. Safety, tolerability and blinding efficiency of non-invasive deep transcranial temporal interference stimulation: first experience from more than 250 sessions. J Neural Eng 2024; 21:024001. [PMID: 38408385 DOI: 10.1088/1741-2552/ad2d32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/26/2024] [Indexed: 02/28/2024]
Abstract
Objective. Selective neuromodulation of deep brain regions has for a long time only been possible through invasive approaches, because of the steep depth-focality trade-off of conventional non-invasive brain stimulation (NIBS) techniques.Approach. An approach that has recently emerged for deep NIBS in humans is transcranial Temporal Interference Stimulation (tTIS). However, a crucial aspect for its potential wide use is to ensure that it is tolerable, compatible with efficient blinding and safe.Main results. Here, we show the favorable tolerability and safety profiles and the robust blinding efficiency of deep tTIS targeting the striatum or hippocampus by leveraging a large dataset (119 participants, 257 sessions), including young and older adults and patients with traumatic brain injury. tTIS-evoked sensations were generally rated as 'mild', were equivalent in active and placebo tTIS conditions and did not enable participants to discern stimulation type.Significance. Overall, tTIS emerges as a promising tool for deep NIBS for robust double-blind, placebo-controlled designs.
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Affiliation(s)
- Pierre Vassiliadis
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (INX), École Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
- Defitech Chair of Clinical Neuroengineering, INX, EPFL Valais, Clinique Romande de Réadaptation, 1951 Sion, Switzerland
| | - Emma Stiennon
- Louvain School of Engineering, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Fabienne Windel
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (INX), École Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
- Defitech Chair of Clinical Neuroengineering, INX, EPFL Valais, Clinique Romande de Réadaptation, 1951 Sion, Switzerland
| | | | - Elena Beanato
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (INX), École Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
- Defitech Chair of Clinical Neuroengineering, INX, EPFL Valais, Clinique Romande de Réadaptation, 1951 Sion, Switzerland
| | - Friedhelm C Hummel
- Defitech Chair of Clinical Neuroengineering, Neuro-X Institute (INX), École Polytechnique Fédérale de Lausanne (EPFL), 1202 Geneva, Switzerland
- Defitech Chair of Clinical Neuroengineering, INX, EPFL Valais, Clinique Romande de Réadaptation, 1951 Sion, Switzerland
- Clinical Neuroscience, University of Geneva Medical School, 1202 Geneva, Switzerland
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2
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Jones KT, Gallen CL, Ostrand AE, Rojas JC, Wais P, Rini J, Chan B, Lago AL, Boxer A, Zhao M, Gazzaley A, Zanto TP. Gamma neuromodulation improves episodic memory and its associated network in amnestic mild cognitive impairment: a pilot study. Neurobiol Aging 2023; 129:72-88. [PMID: 37276822 PMCID: PMC10583532 DOI: 10.1016/j.neurobiolaging.2023.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 06/07/2023]
Abstract
Amnestic mild cognitive impairment (aMCI) is a predementia stage of Alzheimer's disease associated with dysfunctional episodic memory and limited treatment options. We aimed to characterize feasibility, clinical, and biomarker effects of noninvasive neurostimulation for aMCI. 13 individuals with aMCI received eight 60-minute sessions of 40-Hz (gamma) transcranial alternating current stimulation (tACS) targeting regions related to episodic memory processing. Feasibility, episodic memory, and plasma Alzheimer's disease biomarkers were assessed. Neuroplastic changes were characterized by resting-state functional connectivity (RSFC) and neuronal excitatory/inhibitory balance. Gamma tACS was feasible and aMCI participants demonstrated improvement in multiple metrics of episodic memory, but no changes in biomarkers. Improvements in episodic memory were most pronounced in participants who had the highest modeled tACS-induced electric fields and exhibited the greatest changes in RSFC. Increased RSFC was also associated with greater hippocampal excitability and higher baseline white matter integrity. This study highlights initial feasibility and the potential of gamma tACS to rescue episodic memory in an aMCI population by modulating connectivity and excitability within an episodic memory network.
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Affiliation(s)
- Kevin T Jones
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Neuroscape, University of California-San Francisco, San Francisco, CA.
| | - Courtney L Gallen
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Neuroscape, University of California-San Francisco, San Francisco, CA
| | - Avery E Ostrand
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Neuroscape, University of California-San Francisco, San Francisco, CA
| | - Julio C Rojas
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Weill Institute for Neurosciences, Memory and Aging Center, University of California-San Francisco, San Francisco, CA
| | - Peter Wais
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Neuroscape, University of California-San Francisco, San Francisco, CA
| | - James Rini
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Neuroscape, University of California-San Francisco, San Francisco, CA
| | - Brandon Chan
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Weill Institute for Neurosciences, Memory and Aging Center, University of California-San Francisco, San Francisco, CA
| | - Argentina Lario Lago
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Weill Institute for Neurosciences, Memory and Aging Center, University of California-San Francisco, San Francisco, CA
| | - Adam Boxer
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Weill Institute for Neurosciences, Memory and Aging Center, University of California-San Francisco, San Francisco, CA
| | - Min Zhao
- Departments of Ophthalmology and Vision Science and Dermatology, Institute for Regenerative Cures, University of California-Davis, Davis, CA
| | - Adam Gazzaley
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Neuroscape, University of California-San Francisco, San Francisco, CA; Departments of Physiology and Psychiatry, University of California-San Francisco, San Francisco, CA
| | - Theodore P Zanto
- Department of Neurology, University of California-San Francisco, San Francisco, CA; Neuroscape, University of California-San Francisco, San Francisco, CA.
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Gaugain G, Quéguiner L, Bikson M, Sauleau R, Zhadobov M, Modolo J, Nikolayev D. Quasi-static approximation error of electric field analysis for transcranial current stimulation. J Neural Eng 2023; 20. [PMID: 36621858 DOI: 10.1088/1741-2552/acb14d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 01/06/2023] [Indexed: 01/10/2023]
Abstract
Objective.Numerical modeling of electric fields induced by transcranial alternating current stimulation (tACS) is currently a part of the standard procedure to predict and understand neural response. Quasi-static approximation (QSA) for electric field calculations is generally applied to reduce the computational cost. Here, we aimed to analyze and quantify the validity of the approximation over a broad frequency range.Approach.We performed electromagnetic modeling studies using an anatomical head model and considered approximations assuming either a purely ohmic medium (i.e. static formulation) or a lossy dielectric medium (QS formulation). The results were compared with the solution of Maxwell's equations in the cases of harmonic and pulsed signals. Finally, we analyzed the effect of electrode positioning on these errors.Main results.Our findings demonstrate that the QSA is valid and produces a relative error below 1% up to 1.43 MHz. The largest error is introduced in the static case, where the error is over 1% across the entire considered spectrum and as high as 20% in the brain at 10 Hz. We also highlight the special importance of considering the capacitive effect of tissues for pulsed waveforms, which prevents signal distortion induced by the purely ohmic approximation. At the neuron level, the results point a difference of sense electric field as high as 22% at focusing point, impacting pyramidal cells firing times.Significance.QSA remains valid in the frequency range currently used for tACS. However, neglecting permittivity (static formulation) introduces significant error for both harmonic and non-harmonic signals. It points out that reliable low frequency dielectric data are needed for accurate transcranial current stimulation numerical modeling.
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Affiliation(s)
- Gabriel Gaugain
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Lorette Quéguiner
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, United States of America
| | - Ronan Sauleau
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Maxim Zhadobov
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
| | - Julien Modolo
- Univ Rennes, INSERM, LTSI (Laboratoire traitement du signal et de l'image) - U1099, 35000 Rennes, France
| | - Denys Nikolayev
- Univ Rennes, CNRS, IETR (Institut d'électronique et des technologies du numérique) - UMR 6164, 35000 Rennes, France
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Mulyana B, Tsuchiyagaito A, Misaki M, Kuplicki R, Smith J, Soleimani G, Rashedi A, Shereen D, Bergman TO, Cheng S, Paulus MP, Bodurka J, Ekhtiari H. Online closed-loop real-time tES-fMRI for brain modulation: A technical report. Brain Behav 2022; 12:e2667. [PMID: 36134450 PMCID: PMC9575607 DOI: 10.1002/brb3.2667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 04/29/2022] [Accepted: 05/22/2022] [Indexed: 11/17/2022] Open
Abstract
Recent studies suggest that transcranial electrical stimulation (tES) can be performed during functional magnetic resonance imaging (fMRI). The novel approach of using concurrent tES-fMRI to modulate and measure targeted brain activity/connectivity may provide unique insights into the causal interactions between the brain neural responses and psychiatric/neurologic signs and symptoms, and importantly, guide the development of new treatments. However, tES stimulation parameters to optimally influence the underlying brain activity may vary with respect to phase difference, frequency, intensity, and electrode's montage among individuals. Here, we propose a protocol for closed-loop tES-fMRI to optimize the frequency and phase difference of alternating current stimulation (tACS) for two nodes (frontal and parietal regions) in individual participants. We carefully considered the challenges in an online optimization of tES parameters with concurrent fMRI, specifically in its safety, artifact in fMRI image quality, online evaluation of the tES effect, and parameter optimization method, and we designed the protocol to run an effective study to enhance frontoparietal connectivity and working memory performance with the optimized tACS using closed-loop tES-fMRI. We provide technical details of the protocol, including electrode types, electrolytes, electrode montages, concurrent tES-fMRI hardware, online fMRI processing pipelines, and the optimization algorithm. We confirmed the implementation of this protocol worked successfully with a pilot experiment.
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Affiliation(s)
- Beni Mulyana
- Laureate Institute for Brain ResearchTulsaOklahomaUSA
- Electrical and Computer EngineeringUniversity of OklahomaTulsaOklahomaUSA
| | | | - Masaya Misaki
- Laureate Institute for Brain ResearchTulsaOklahomaUSA
| | | | - Jared Smith
- Laureate Institute for Brain ResearchTulsaOklahomaUSA
| | - Ghazaleh Soleimani
- Department of Biomedical EngineeringAmirkabir University of Technology, Tehran, Iran
- Iranian National Center for Addiction StudiesTehran University of Medical SciencesTehranIran
| | | | - Duke Shereen
- The Graduate Center of the City University of New YorkNew YorkNew YorkUSA
| | - Til Ole Bergman
- Neuroimaging Center (NIC)University Medical Center of the Johannes Gutenberg University MainzGermany
- Leibniz Institute for Resilience Research (LIR)MainzGermany
| | - Samuel Cheng
- Electrical and Computer EngineeringUniversity of OklahomaTulsaOklahomaUSA
| | | | - Jerzy Bodurka
- Laureate Institute for Brain ResearchTulsaOklahomaUSA
- Stephenson School of Biomedical EngineeringUniversity of OklahomaNormanOklahomaUSA
| | - Hamed Ekhtiari
- Laureate Institute for Brain ResearchTulsaOklahomaUSA
- Department of Psychiatry and Behavioral SciencesUniversity of MinnesotaMinneapolisMinnesotaUSA
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5
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Structural and functional network mechanisms of rescuing cognitive control in aging. Neuroimage 2022; 262:119547. [DOI: 10.1016/j.neuroimage.2022.119547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 07/13/2022] [Accepted: 08/04/2022] [Indexed: 11/23/2022] Open
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Zeng Z, Koponen LM, Hamdan R, Li Z, Goetz SM, Peterchev AV. Modular multilevel TMS device with wide output range and ultrabrief pulse capability for sound reduction. J Neural Eng 2022; 19:10.1088/1741-2552/ac572c. [PMID: 35189604 PMCID: PMC9425059 DOI: 10.1088/1741-2552/ac572c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 02/21/2022] [Indexed: 11/12/2022]
Abstract
Objective.This article presents a novel transcranial magnetic stimulation (TMS) pulse generator with a wide range of pulse shape, amplitude, and width.Approach.Based on a modular multilevel TMS (MM-TMS) topology we had proposed previously, we realized the first such device operating at full TMS energy levels. It consists of ten cascaded H-bridge modules, each implemented with insulated-gate bipolar transistors, enabling both novel high-amplitude ultrabrief pulses as well as pulses with conventional amplitude and duration. The MM-TMS device can output pulses including up to 21 voltage levels with a step size of up to 1100 V, allowing relatively flexible generation of various pulse waveforms and sequences. The circuit further allows charging the energy storage capacitor on each of the ten cascaded modules with a conventional TMS power supply.Main results. The MM-TMS device can output peak coil voltages and currents of 11 kV and 10 kA, respectively, enabling suprathreshold ultrabrief pulses (>8.25μs active electric field phase). Further, the MM-TMS device can generate a wide range of near-rectangular monophasic and biphasic pulses, as well as more complex staircase-approximated sinusoidal, polyphasic, and amplitude-modulated pulses. At matched estimated stimulation strength, briefer pulses emit less sound, which could enable quieter TMS. Finally, the MM-TMS device can instantaneously increase or decrease the amplitude from one pulse to the next in discrete steps by adding or removing modules in series, which enables rapid pulse sequences and paired-pulse protocols with variable pulse shapes and amplitudes.Significance.The MM-TMS device allows unprecedented control of the pulse characteristics which could enable novel protocols and quieter pulses.
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Affiliation(s)
- Zhiyong Zeng
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, 27710, United States of America
| | - Lari M Koponen
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, 27710, United States of America
| | - Rena Hamdan
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, 27710, United States of America
| | - Zhongxi Li
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, United States of America
| | - Stefan M Goetz
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, 27710, United States of America.,Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, United States of America.,Duke Institute for Brain Sciences, Duke University, Durham, NC, 27708, United States of America.,Department of Neurosurgery, Duke University, Durham, NC, 27710, United States of America
| | - Angel V Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, 27710, United States of America.,Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708, United States of America.,Duke Institute for Brain Sciences, Duke University, Durham, NC, 27708, United States of America.,Department of Neurosurgery, Duke University, Durham, NC, 27710, United States of America.,Department of Biomedical Engineering, Duke University, Durham, NC, 27708, United States of America
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7
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Kim J, Kim H, Jeong H, Roh D, Kim DH. tACS as a promising therapeutic option for improving cognitive function in mild cognitive impairment: A direct comparison between tACS and tDCS. J Psychiatr Res 2021; 141:248-256. [PMID: 34256276 DOI: 10.1016/j.jpsychires.2021.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 06/17/2021] [Accepted: 07/05/2021] [Indexed: 02/07/2023]
Abstract
Neuromodulation has gained attention as a potential non-pharmacological intervention for mild cognitive impairment (MCI). However, no studies have directly compared the effects of transcranial alternating current stimulation (tACS) with transcranial direct current stimulation (tDCS) on MCI patients. We aimed to identify the more promising and efficient therapeutic option between tACS and tDCS for cognitive enhancement in MCI patients. We compared the effects of gamma-tACS with tDCS on cognitive function and electroencephalography (EEG) in MCI patients. In this sham-controlled, double-blinded, repeated-measures study with the order of the stimulation counterbalanced across patients (n = 20), both gamma-tACS (40 H z) and tDCS were administered at the same intensity (2 mA) in the dorsolateral prefrontal cortex for 30 min. Cognitive tests (Stroop and Trail-Making-Test [TMT]) and EEG were performed before and after single-session stimulation. Gamma-tACS improved the Stroop-color in comparison with tDCS (p = .044) and sham (p = .010) and enhanced the TMT-B in comparison with sham (p = .021). However, tDCS was not significantly different from sham in changes of any cognitive test scores. In EEG analysis, gamma-tACS increased beta activity in comparison with sham and tDCS, whereas tDCS decreased delta and theta activity in comparison with sham. Gamma-tACS also increased beta 2 source activity in the anterior cingulate, compared to sham. The cognitive benefits of tACS in MCI patients appeared superior to those of tDCS. tACS facilitated cognitive function by increasing beta activity, while tDCS delayed the progression of MCI symptoms by decreasing slow-frequency activity. Thus, tACS could be used as a new therapeutic option for MCI.
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Affiliation(s)
- Jiheon Kim
- Department of Psychiatry, Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea; Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Hansol Kim
- Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Hyewon Jeong
- Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Daeyoung Roh
- Department of Psychiatry, Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea; Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea
| | - Do Hoon Kim
- Department of Psychiatry, Chuncheon Sacred Heart Hospital, Chuncheon, Republic of Korea; Mind-Neuromodulation Laboratory, College of Medicine, Hallym University, Chuncheon, Republic of Korea.
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Rossi S, Antal A, Bestmann S, Bikson M, Brewer C, Brockmöller J, Carpenter LL, Cincotta M, Chen R, Daskalakis JD, Di Lazzaro V, Fox MD, George MS, Gilbert D, Kimiskidis VK, Koch G, Ilmoniemi RJ, Lefaucheur JP, Leocani L, Lisanby SH, Miniussi C, Padberg F, Pascual-Leone A, Paulus W, Peterchev AV, Quartarone A, Rotenberg A, Rothwell J, Rossini PM, Santarnecchi E, Shafi MM, Siebner HR, Ugawa Y, Wassermann EM, Zangen A, Ziemann U, Hallett M. Safety and recommendations for TMS use in healthy subjects and patient populations, with updates on training, ethical and regulatory issues: Expert Guidelines. Clin Neurophysiol 2021; 132:269-306. [PMID: 33243615 PMCID: PMC9094636 DOI: 10.1016/j.clinph.2020.10.003] [Citation(s) in RCA: 512] [Impact Index Per Article: 170.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Abstract
This article is based on a consensus conference, promoted and supported by the International Federation of Clinical Neurophysiology (IFCN), which took place in Siena (Italy) in October 2018. The meeting intended to update the ten-year-old safety guidelines for the application of transcranial magnetic stimulation (TMS) in research and clinical settings (Rossi et al., 2009). Therefore, only emerging and new issues are covered in detail, leaving still valid the 2009 recommendations regarding the description of conventional or patterned TMS protocols, the screening of subjects/patients, the need of neurophysiological monitoring for new protocols, the utilization of reference thresholds of stimulation, the managing of seizures and the list of minor side effects. New issues discussed in detail from the meeting up to April 2020 are safety issues of recently developed stimulation devices and pulse configurations; duties and responsibility of device makers; novel scenarios of TMS applications such as in the neuroimaging context or imaging-guided and robot-guided TMS; TMS interleaved with transcranial electrical stimulation; safety during paired associative stimulation interventions; and risks of using TMS to induce therapeutic seizures (magnetic seizure therapy). An update on the possible induction of seizures, theoretically the most serious risk of TMS, is provided. It has become apparent that such a risk is low, even in patients taking drugs acting on the central nervous system, at least with the use of traditional stimulation parameters and focal coils for which large data sets are available. Finally, new operational guidelines are provided for safety in planning future trials based on traditional and patterned TMS protocols, as well as a summary of the minimal training requirements for operators, and a note on ethics of neuroenhancement.
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Affiliation(s)
- Simone Rossi
- Department of Scienze Mediche, Chirurgiche e Neuroscienze, Unit of Neurology and Clinical Neurophysiology, Brain Investigation and Neuromodulation Lab (SI-BIN Lab), University of Siena, Italy.
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center, Georg-August University of Goettingen, Germany; Institue of Medical Psychology, Otto-Guericke University Magdeburg, Germany
| | - Sven Bestmann
- Department of Movement and Clinical Neurosciences, UCL Queen Square Institute of Neurology, London, UK and Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, UK
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - Carmen Brewer
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health (NIH), Bethesda, MD, USA
| | - Jürgen Brockmöller
- Department of Clinical Pharmacology, University Medical Center, Georg-August University of Goettingen, Germany
| | - Linda L Carpenter
- Butler Hospital, Brown University Department of Psychiatry and Human Behavior, Providence, RI, USA
| | - Massimo Cincotta
- Unit of Neurology of Florence - Central Tuscany Local Health Authority, Florence, Italy
| | - Robert Chen
- Krembil Research Institute and Division of Neurology, Department of Medicine, University of Toronto, Canada
| | - Jeff D Daskalakis
- Center for Addiction and Mental Health (CAMH), University of Toronto, Canada
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Università Campus Bio-Medico, Roma, Italy
| | - Michael D Fox
- Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Mark S George
- Medical University of South Carolina, Charleston, SC, USA
| | - Donald Gilbert
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Vasilios K Kimiskidis
- Laboratory of Clinical Neurophysiology, Aristotle University of Thessaloniki, AHEPA University Hospital, Greece
| | | | - Risto J Ilmoniemi
- Department of Neuroscience and Biomedical Engineering (NBE), Aalto University School of Science, Aalto, Finland
| | - Jean Pascal Lefaucheur
- EA 4391, ENT Team, Faculty of Medicine, Paris Est Creteil University (UPEC), Créteil, France; Clinical Neurophysiology Unit, Henri Mondor Hospital, Assistance Publique Hôpitaux de Paris, (APHP), Créteil, France
| | - Letizia Leocani
- Department of Neurology, Institute of Experimental Neurology (INSPE), IRCCS-San Raffaele Hospital, Vita-Salute San Raffaele University, Milano, Italy
| | - Sarah H Lisanby
- National Institute of Mental Health (NIMH), National Institutes of Health (NIH), Bethesda, MD, USA; Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - Carlo Miniussi
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy
| | - Frank Padberg
- Department of Psychiatry and Psychotherapy, University Hospital, LMU Munich, Munich, Germany
| | - Alvaro Pascual-Leone
- Hinda and Arthur Marcus Institute for Aging Research and Center for Memory Health, Hebrew SeniorLife, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA; Guttmann Brain Health Institut, Institut Guttmann, Universitat Autonoma Barcelona, Spain
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center, Georg-August University of Goettingen, Germany
| | - Angel V Peterchev
- Departments of Psychiatry & Behavioral Sciences, Biomedical Engineering, Electrical & Computer Engineering, and Neurosurgery, Duke University, Durham, NC, USA
| | - Angelo Quartarone
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Alexander Rotenberg
- Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - John Rothwell
- Department of Movement and Clinical Neurosciences, UCL Queen Square Institute of Neurology, London, UK and Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, UK
| | - Paolo M Rossini
- Department of Neuroscience and Rehabilitation, IRCCS San Raffaele-Pisana, Roma, Italy
| | - Emiliano Santarnecchi
- Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Mouhsin M Shafi
- Berenson-Allen Center for Noninvasive Brain Stimulation, Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Hartwig R Siebner
- Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Copenhagen, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark; Institute for Clinical Medicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yoshikatzu Ugawa
- Department of Human Neurophysiology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Eric M Wassermann
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Abraham Zangen
- Zlotowski Center of Neuroscience, Ben Gurion University, Beer Sheva, Israel
| | - Ulf Ziemann
- Department of Neurology & Stroke, and Hertie-Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
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9
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Howell B, McIntyre CC. Feasibility of Interferential and Pulsed Transcranial Electrical Stimulation for Neuromodulation at the Human Scale. Neuromodulation 2020; 24:843-853. [PMID: 32147953 DOI: 10.1111/ner.13137] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/06/2020] [Accepted: 02/13/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVES Transcranial electrical stimulation (tES) is a promising tool for modulating neural activity, but tES has poor penetrability and spatiotemporal resolution compared to invasive techniques like deep brain stimulation (DBS). Interferential strategies for alternating-current stimulation (IF-tACS) and pulsed/intersectional strategies for transcranial direct-current stimulation (IS-tDCS) address some of the limitations of tES, but the comparative advantages and disadvantages of these new techniques is not well understood. This study's objective was to evaluate the suprathreshold and subthreshold membrane dynamics of neurons in response to IF-tACS and IS-tDCS. MATERIALS AND METHODS We analyzed the biophysics of IF-tACS and IS-tDCS using a bioelectric field model of tES. Neural responses were quantified for suprathreshold generation of action potentials in axons and for subthreshold modulation of membrane dynamics in spiking pyramidal neurons. RESULTS IF-tACS and IS-tDCS could not directly activate axons at or below 10 mA, but within this current range, these fields were able to modulate, albeit indirectly, spiking activity in the neuron model. IF-tACS facilitated phase synchronization similar to tACS, and IS-tDCS enhanced and suppressed spiking activity similar to tDCS; however, in either case, the modulatory effects of these fields were less potent than their standard counterparts at a matched field intensity. Moreover, neither IF-tACS nor IS-tDCS improved the spatial selectivity of their parent strategies. CONCLUSIONS Enhancing the spatiotemporal precision and penetrability of tES with interferential and intersectional strategies is possible at the human scale. However, IF-tACS or IS-tDCS will likely require spatial multiplexing with multiple simultaneous sources to counteract their reduced potency, compared to standard techniques, to maintain stimulation currents at tolerable levels.
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Affiliation(s)
- Bryan Howell
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Cameron C McIntyre
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
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10
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Abstract
Transcranial electric stimulation (tES) protocols strictly need to keep the safety of stimulations and to avoid the unpleasant feelings of stimulated subjects. Following that, the aim of the paper was to find out both the perception and the pain thresholds of different tES modalities. The perception thresholds and the pain thresholds at AF7 and AF8 electrodes with transcranial direct and alternating current stimulation (tDCS and tACS) were performed. Average perception and pain thresholds did not differ significantly inter-individually but intra-individually. With gradually increasing intensity the analysis of thresholds showed that 1) an average participant perceived as first 20 Hz and 40 Hz tACS, then 10 Hz tACS and cathodal tDCS and then anodal tDCS, and 2) the pain was felt first for anodal tDCS, then for 6, 10 and 20 Hz tACS, then for cathodal tDCS and finally for 40 Hz tACS. Besides that, intensity-dependent regularities in feelings of different tES modalities were found. Perception thresholds for 2 types of tDCS (anodal and cathodal) and 4 types of tACS (6-40 Hz) are arranged in sequence of gradually increased values (threshold current): anodal tDCS - cathodal tDCS - 6 - 10 - 20 - 40 Hz tACS. whereas pain thresholds are arranged with decreased threshold values.
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Affiliation(s)
- E Kvašňák
- Department of Medical Biophysics and Medical Informatics, Third Faculty of Medicine, Charles University, Prague, Czech Republic.
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11
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After-effects of 10 Hz tACS over the prefrontal cortex on phonological word decisions. Brain Stimul 2019; 12:1464-1474. [DOI: 10.1016/j.brs.2019.06.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 05/13/2019] [Accepted: 06/18/2019] [Indexed: 11/23/2022] Open
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12
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Haberbosch L, Datta A, Thomas C, Jooß A, Köhn A, Rönnefarth M, Scholz M, Brandt SA, Schmidt S. Safety Aspects, Tolerability and Modeling of Retinofugal Alternating Current Stimulation. Front Neurosci 2019; 13:783. [PMID: 31440126 PMCID: PMC6692662 DOI: 10.3389/fnins.2019.00783] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 07/12/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND While alternating current stimulation (ACS) is gaining relevance as a tool in research and approaching clinical applications, its mechanisms of action remain unclear. A review by Schutter and colleagues argues for a retinal origin of transcranial ACS' neuromodulatory effects. Interestingly, there is an alternative application form of ACS specifically targeting α-oscillations in the visual cortex via periorbital electrodes (retinofugal alternating current stimulation, rACS). To further compare these two methods and investigate retinal effects of ACS, we first aim to establish the safety and tolerability of rACS. OBJECTIVE The goal of our research was to evaluate the safety of rACS via finite-element modeling, theoretical safety limits and subjective report. METHODS 20 healthy subjects were stimulated with rACS as well as photic stimulation and reported adverse events following stimulation. We analyzed stimulation parameters at electrode level as well as distributed metric estimates from an ultra-high spatial resolution magnetic resonance imaging (MRI)-derived finite element human head model and compared them to existing safety limits. RESULTS Topographical modeling revealed the highest current densities in the anterior visual pathway, particularly retina and optic nerve. Stimulation parameters and finite element modeling estimates of rACS were found to be well below existing safety limits. No serious adverse events occurred. CONCLUSION Our findings are in line with existing safety guidelines for retinal and neural damage and establish the tolerability and feasibility of rACS. In comparison to tACS, retinofugal stimulation of the visual cortex provides an anatomically circumscribed model to systematically study the mechanisms of action of ACS.
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Affiliation(s)
- Linus Haberbosch
- Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Department of Endocrinology, Diabetes and Metabolism, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Abhishek Datta
- Research and Development, Soterix Medical, New York, NY, United States
| | - Chris Thomas
- Research and Development, Soterix Medical, New York, NY, United States
| | - Andreas Jooß
- Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Arvid Köhn
- Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Maria Rönnefarth
- Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Michael Scholz
- Neural Information Processing Group, Technical University of Berlin, Berlin, Germany
| | - Stephan A. Brandt
- Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Sein Schmidt
- Department of Neurology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
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13
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Sabel BA, Hamid AIA, Borrmann C, Speck O, Antal A. Transorbital alternating current stimulation modifies BOLD activity in healthy subjects and in a stroke patient with hemianopia: A 7 Tesla fMRI feasibility study. Int J Psychophysiol 2019; 154:80-92. [PMID: 30978369 DOI: 10.1016/j.ijpsycho.2019.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 03/28/2019] [Accepted: 04/04/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Modifying brain activity using non-invasive, low intensity transcranial electrical brain stimulation (TES) has rapidly increased during the past 20 years. Alternating current stimulation (ACS), for example, has been shown to alter brain rhythm activities and modify neuronal functioning in the visual system. Daily application of transorbital ACS to patients with optic nerve damage induces functional connectivity reorganization, and partially restores vision. While ACS is thought to mainly modify neuronal mechanisms, e.g. changes in brain oscillations that can be detected by EEG, it is still an open question, whether and how it may alter BOLD activity. OBJECTIVE We evaluated whether transorbital ACS modulates BOLD activity in early visual cortex using high-resolution 7 Tesla functional magnetic resonance imaging (fMRI). METHODS In this feasibility study transorbital ACS in the alpha range and sham ACS was applied in a random block design in five healthy subjects for 20 min at 1 mA. Brain activation in the visual areas V1, V2 and V3 were measured using 7 Tesla fMRI-based retinotopic mapping at the time points before (baseline) and after stimulation. In addition, we collected data from one hemianopic stroke patient with visual cortex damage after ten daily sessions with 25-50 min stimulation duration. RESULTS In healthy subjects transorbital ACS increased the activated cortical surface area, decreased the fMRI response amplitude and increased coherence in the visual cortex, which was most prominent in the full field task. In the patient, stimulation improved contrast sensitivity in the central visual field. BOLD amplitudes and coherence values were increased in most early visual areas in both hemispheres, with the most pronounced activation detected during eccentricity testing in retinotopic mapping. CONCLUSIONS This feasibility study showed that transorbital ACS modifies BOLD activity to visual stimulation, which outlasts the duration of the AC stimulation. This is in line with earlier neurophysiological findings of increased power in EEG recordings and functional connectivity reorganization in patients with impaired vision. Accordingly, the larger BOLD response area after stimulation can be explained by more coherent activation and lower variability in the activation. Alternatively, increased neuronal activity can also be taken into account. Controlled trials are needed to systematically evaluate the potential of repetitive transorbital ACS to improve visual function after visual pathway stroke and to determine the cause-effect relationship between neural and BOLD activity changes.
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Affiliation(s)
- Bernhard A Sabel
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany.
| | - Aini Ismafairus Abd Hamid
- Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Neurosciences, School of Medical Sciences Health Campus, Jalan Hospital USM, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Carolin Borrmann
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany
| | - Oliver Speck
- Center for Behavioral Brain Sciences, Magdeburg, Germany; Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Neurosciences, School of Medical Sciences Health Campus, Jalan Hospital USM, 16150 Kubang Kerian, Kelantan, Malaysia; Leibniz Institute for Neurobiology, Magdeburg, Germany; German Center for Neurodegenerative Disease (DZNE), Germany
| | - Andrea Antal
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg, Leipziger Strasse 44, 39120 Magdeburg, Germany; Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
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Negahbani E, Kasten FH, Herrmann CS, Fröhlich F. Targeting alpha-band oscillations in a cortical model with amplitude-modulated high-frequency transcranial electric stimulation. Neuroimage 2018; 173:3-12. [PMID: 29427848 DOI: 10.1016/j.neuroimage.2018.02.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 01/11/2018] [Accepted: 02/03/2018] [Indexed: 12/28/2022] Open
Abstract
Non-invasive brain stimulation to target specific network activity patterns, e.g. transcranial alternating current stimulation (tACS), has become an essential tool to understand the causal role of neuronal oscillations in cognition and behavior. However, conventional sinusoidal tACS limits the ability to record neuronal activity during stimulation and lacks spatial focality. One particularly promising new tACS stimulation paradigm uses amplitude-modulated (AM) high-frequency waveforms (AM-tACS) with a slow signal envelope that may overcome the limitations. Moreover. AM-tACS using high-frequency carrier signals is more tolerable than conventional tACS, e.g. in terms of skin irritation and occurrence of phosphenes, when applied at the same current intensities (e.g. 1-2 mA). Yet, the fundamental mechanism of neuronal target-engagement by AM-tACS waveforms has remained unknown. We used a computational model of cortex to investigate how AM-tACS modulates endogenous oscillations and compared the target engagement mechanism to the case of conventional (unmodulated) low-frequency tACS. Analysis of stimulation amplitude and frequency indicated that cortical oscillations were phase-locked to the envelope of the AM stimulation signal, which thus exhibits the same target engagement mechanism as conventional (unmodulated) low frequency tACS. However, in the computational model substantially higher current intensities were needed for AM-tACS than for low-frequency (unmodulated) tACS waveforms to achieve pronounced phase synchronization. Our analysis of the carrier frequency suggests that there might be a trade-off between the use of high-frequency carriers and the stimulation amplitude required for successful entrainment. Together, our computational simulations support the use of slow-envelope high frequency carrier AM waveforms as a tool for noninvasive modulation of brain oscillations. More empirical data will be needed to identify the optimal stimulation parameters and to evaluate tolerability and safety of both, AM- and conventional tACS.
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Affiliation(s)
- Ehsan Negahbani
- Dept. of Psychiatry, Univ. of North Carolina, Chapel Hill, NC 27514-5307, United States
| | - Florian H Kasten
- Experimental Psychology Lab, Dept. of Psychology, Cluster for Excellence "Hearing for All", European Medical School, Carl von Ossietzky Univ., Oldenburg, Germany
| | - Christoph S Herrmann
- Experimental Psychology Lab, Dept. of Psychology, Cluster for Excellence "Hearing for All", European Medical School, Carl von Ossietzky Univ., Oldenburg, Germany; Res. Ctr. Neurosensory Sci., Carl von Ossietzky Univ., Oldenburg, Germany
| | - Flavio Fröhlich
- Dept. of Psychiatry, Univ. of North Carolina, Chapel Hill, NC 27514-5307, United States; Dept. Cell Biology and Physiology, Univ. of North Carolina, Chapel Hill, NC 27514-5307, United States; Dept. of Biomedical Engineering, Univ. of North Carolina, Chapel Hill, NC 27514-5307, United States; Neuroscience Center, Univ. of North Carolina, Chapel Hill, NC 27514-5307, United States; Dept. of Neurology, Univ. of North Carolina, Chapel Hill, NC 27514-5307, United States; Carolina Center for Neurostimulation, Univ. of North Carolina, Chapel Hill, NC 27514-5307, United States.
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15
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Antal A, Alekseichuk I, Bikson M, Brockmöller J, Brunoni AR, Chen R, Cohen LG, Dowthwaite G, Ellrich J, Flöel A, Fregni F, George MS, Hamilton R, Haueisen J, Herrmann CS, Hummel FC, Lefaucheur JP, Liebetanz D, Loo CK, McCaig CD, Miniussi C, Miranda PC, Moliadze V, Nitsche MA, Nowak R, Padberg F, Pascual-Leone A, Poppendieck W, Priori A, Rossi S, Rossini PM, Rothwell J, Rueger MA, Ruffini G, Schellhorn K, Siebner HR, Ugawa Y, Wexler A, Ziemann U, Hallett M, Paulus W. Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. Clin Neurophysiol 2017; 128:1774-1809. [PMID: 28709880 PMCID: PMC5985830 DOI: 10.1016/j.clinph.2017.06.001] [Citation(s) in RCA: 655] [Impact Index Per Article: 93.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/29/2017] [Accepted: 06/06/2017] [Indexed: 12/11/2022]
Abstract
Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears to be safe. No serious adverse events (SAEs) have been reported so far in over 18,000 sessions administered to healthy subjects, neurological and psychiatric patients, as summarized here. Moderate adverse events (AEs), as defined by the necessity to intervene, are rare, and include skin burns with tDCS due to suboptimal electrode-skin contact. Very rarely mania or hypomania was induced in patients with depression (11 documented cases), yet a causal relationship is difficult to prove because of the low incidence rate and limited numbers of subjects in controlled trials. Mild AEs (MAEs) include headache and fatigue following stimulation as well as prickling and burning sensations occurring during tDCS at peak-to-baseline intensities of 1-2mA and during tACS at higher peak-to-peak intensities above 2mA. The prevalence of published AEs is different in studies specifically assessing AEs vs. those not assessing them, being higher in the former. AEs are frequently reported by individuals receiving placebo stimulation. The profile of AEs in terms of frequency, magnitude and type is comparable in healthy and clinical populations, and this is also the case for more vulnerable populations, such as children, elderly persons, or pregnant women. Combined interventions (e.g., co-application of drugs, electrophysiological measurements, neuroimaging) were not associated with further safety issues. Safety is established for low-intensity 'conventional' TES defined as <4mA, up to 60min duration per day. Animal studies and modeling evidence indicate that brain injury could occur at predicted current densities in the brain of 6.3-13A/m2 that are over an order of magnitude above those produced by tDCS in humans. Using AC stimulation fewer AEs were reported compared to DC. In specific paradigms with amplitudes of up to 10mA, frequencies in the kHz range appear to be safe. In this paper we provide structured interviews and recommend their use in future controlled studies, in particular when trying to extend the parameters applied. We also discuss recent regulatory issues, reporting practices and ethical issues. These recommendations achieved consensus in a meeting, which took place in Göttingen, Germany, on September 6-7, 2016 and were refined thereafter by email correspondence.
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Affiliation(s)
- A Antal
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany.
| | - I Alekseichuk
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - M Bikson
- Department of Biomedical Engineering, The City College of New York, New York, USA
| | - J Brockmöller
- Department of Clinical Pharmacology, University Medical Center Goettingen, Germany
| | - A R Brunoni
- Service of Interdisciplinary Neuromodulation, Department and Institute of Psychiatry, Laboratory of Neurosciences (LIM-27) and Interdisciplinary Center for Applied Neuromodulation University Hospital, University of São Paulo, São Paulo, Brazil
| | - R Chen
- Division of Neurology, Department of Medicine, University of Toronto and Krembil Research Institute, Toronto, Ontario, Canada
| | - L G Cohen
- Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke NIH, Bethesda, USA
| | | | - J Ellrich
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark; Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany; EBS Technologies GmbH, Europarc Dreilinden, Germany
| | - A Flöel
- Universitätsmedizin Greifswald, Klinik und Poliklinik für Neurologie, Greifswald, Germany
| | - F Fregni
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - M S George
- Brain Stimulation Division, Medical University of South Carolina, and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC, USA
| | - R Hamilton
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - J Haueisen
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Germany
| | - C S Herrmann
- Experimental Psychology Lab, Department of Psychology, European Medical School, Carl von Ossietzky Universität, Oldenburg, Germany
| | - F C Hummel
- Defitech Chair of Clinical Neuroengineering, Centre of Neuroprosthetics (CNP) and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland; Defitech Chair of Clinical Neuroengineering, Clinique Romande de Réadaptation, Swiss Federal Institute of Technology (EPFL Valais), Sion, Switzerland
| | - J P Lefaucheur
- Department of Physiology, Henri Mondor Hospital, Assistance Publique - Hôpitaux de Paris, and EA 4391, Nerve Excitability and Therapeutic Team (ENT), Faculty of Medicine, Paris Est Créteil University, Créteil, France
| | - D Liebetanz
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - C K Loo
- School of Psychiatry & Black Dog Institute, University of New South Wales, Sydney, Australia
| | - C D McCaig
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, UK
| | - C Miniussi
- Center for Mind/Brain Sciences CIMeC, University of Trento, Rovereto, Italy; Cognitive Neuroscience Section, IRCCS Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - P C Miranda
- Institute of Biophysics and Biomedical Engineering, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - V Moliadze
- Institute of Medical Psychology and Medical Sociology, University Hospital of Schleswig-Holstein (UKSH), Campus Kiel, Christian-Albrechts-University, Kiel, Germany
| | - M A Nitsche
- Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany; Department of Neurology, University Hospital Bergmannsheil, Bochum, Germany
| | - R Nowak
- Neuroelectrics, Barcelona, Spain
| | - F Padberg
- Department of Psychiatry and Psychotherapy, Munich Center for Brain Stimulation, Ludwig-Maximilian University Munich, Germany
| | - A Pascual-Leone
- Division of Cognitive Neurology, Harvard Medical Center and Berenson-Allen Center for Noninvasive Brain Stimulation at Beth Israel Deaconess Medical Center, Boston, USA
| | - W Poppendieck
- Department of Information Technology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - A Priori
- Center for Neurotechnology and Experimental Brain Therapeutich, Department of Health Sciences, University of Milan Italy; Deparment of Clinical Neurology, University Hospital Asst Santi Paolo E Carlo, Milan, Italy
| | - S Rossi
- Department of Medicine, Surgery and Neuroscience, Human Physiology Section and Neurology and Clinical Neurophysiology Section, Brain Investigation & Neuromodulation Lab, University of Siena, Italy
| | - P M Rossini
- Area of Neuroscience, Institute of Neurology, University Clinic A. Gemelli, Catholic University, Rome, Italy
| | | | - M A Rueger
- Department of Neurology, University Hospital of Cologne, Germany
| | | | | | - H R Siebner
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark
| | - Y Ugawa
- Department of Neurology, Fukushima Medical University, Fukushima, Japan; Fukushima Global Medical Science Center, Advanced Clinical Research Center, Fukushima Medical University, Japan
| | - A Wexler
- Department of Science, Technology & Society, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - U Ziemann
- Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - M Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, USA
| | - W Paulus
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
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Varlet M, Wade A, Novembre G, Keller PE. Investigation of the effects of transcranial alternating current stimulation (tACS) on self-paced rhythmic movements. Neuroscience 2017; 350:75-84. [PMID: 28323009 DOI: 10.1016/j.neuroscience.2017.03.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/07/2017] [Accepted: 03/09/2017] [Indexed: 11/27/2022]
Abstract
Human rhythmic movements spontaneously entrain to external rhythmic stimuli. Such sensory-motor entrainment can attract movements to different tempi and enhance their efficiency, with potential clinical applications for motor rehabilitation. Here we investigate whether entrainment of self-paced rhythmic movements can be induced via transcranial alternating current stimulation (tACS), which uses alternating currents to entrain spontaneous brain oscillations at specific frequencies. Participants swung a handheld pendulum at their preferred tempo with the right hand while tACS was applied over their left or right primary motor cortex at frequencies equal to their preferred tempo (Experiment 1) or in the alpha (10Hz) and beta (20Hz) ranges (Experiment 2). Given that entrainment generally occurs only if the frequency difference between two rhythms is small, stimulations were delivered at frequencies equal to participants' preferred movement tempo (≈1Hz) and ±12.5% in Experiment 1, and at 10Hz and 20Hz, and ±12.5% in Experiment 2. The comparison of participants' movement frequency, amplitude, variability, and phase synchrony with and without tACS failed to reveal entrainment or movement modifications across the two experiments. However, significant differences in stimulation-related side effects reported by participants were found between the two experiments, with phosphenes and burning sensations principally occurring in Experiment 2, and metallic tastes reported marginally more often in Experiment 1. Although other stimulation protocols may be effective, our results suggest that rhythmic movements such as pendulum swinging or locomotion that are low in goal-directedness and/or strongly driven by peripheral and mechanical constraints may not be susceptible to modulation by tACS.
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Affiliation(s)
- Manuel Varlet
- The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Australia.
| | - Alanna Wade
- The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Australia
| | - Giacomo Novembre
- The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Australia; Department of Neuroscience, Physiology, and Pharmacology, University College London, United Kingdom
| | - Peter E Keller
- The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Australia
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17
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Kunz P, Antal A, Hewitt M, Neef A, Opitz A, Paulus W. 5 kHz Transcranial Alternating Current Stimulation: Lack of Cortical Excitability Changes When Grouped in a Theta Burst Pattern. Front Hum Neurosci 2017; 10:683. [PMID: 28119589 PMCID: PMC5222864 DOI: 10.3389/fnhum.2016.00683] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/21/2016] [Indexed: 11/15/2022] Open
Abstract
Background: Suprathreshold transcranial single pulse electrical stimulation (tES) is painful and not applicable in a repetitive mode to induce plastic after-effects. Objective: In order to circumvent this pain problem, we applied here a 5 kHz transcranial alternating current stimulation (tACS) theta burst protocol with a field intensity of up to 10 mA to the primary motor cortex (M1). Furthermore, we were interested in finding out whether electrical theta burst stimulation (eTBS) is able to induce lasting after-effects on cortical plasticity. Methods: Three different eTBS protocols were applied at 5 mA in a sham controlled, double blinded cross-over design on the M1 region of seventeen healthy subjects during the first part of the study. The second study part consists of three different eTBS protocols ranging from 5 mA to 10 mA and 1 ms to 5 ms sinusoidal bursts, applied to the M1 region of 14 healthy subjects. Results: We were able to apply all eTBS protocols in a safe manner, with only six subjects reporting mild side effects related to the stimulation. However, no eTBS protocol induced lasting effects on muscle- evoked potential (MEP) amplitudes when compared to sham stimulation. Significant inhibition of MEP amplitude was only seen in the lower intensity protocols as compared to baseline. Conclusion: eTBS is a safe method to apply high frequency tACS with up to 10 mA intensity. Future studies need to explore the parameter space to a larger extent in order to assure efficacy.
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Affiliation(s)
- Patrik Kunz
- Department of Clinical Neurophysiology, University Medical Center Göttingen Göttingen, Germany
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center Göttingen Göttingen, Germany
| | - Manuel Hewitt
- Department of Clinical Neurophysiology, University Medical Center Göttingen Göttingen, Germany
| | - Andreas Neef
- Department of Nonlinear Dynamics and Network Dynamics Group, Max Planck Institute for Dynamics and Self-Organization Göttingen, Germany
| | - Alexander Opitz
- Nathan Kline Institute for Psychiatric Research Orangeburg, NY, USA
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center Göttingen Göttingen, Germany
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Matsumoto H, Ugawa Y. Adverse events of tDCS and tACS: A review. Clin Neurophysiol Pract 2016; 2:19-25. [PMID: 30214966 PMCID: PMC6123849 DOI: 10.1016/j.cnp.2016.12.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 01/25/2023] Open
Abstract
Transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS) have been applied to many research issues because these stimulation techniques can modulate neural activity in the human brain painlessly and non-invasively with weak electrical currents. However, there are no formal safety guidelines for the selection of stimulus parameters in either tDCS or tACS. As a means of gathering the information that is needed to produce safety guidelines, in this article, we summarize the adverse events of tDCS and tACS. In both stimulation techniques, most adverse effects are mild and disappear soon after stimulation. Nevertheless, several papers have reported that, in tDCS, some adverse events persist even after stimulation. The persistent events consist of skin lesions similar to burns, which can arise even in healthy subjects, and mania or hypomania in patients with depression. Recently, one paper reported a pediatric patient presenting with seizure after tDCS, although the causal relationship between stimulation and seizure is not clear. As this seizure is the only serious adverse events yet reported in connection with tDCS, tDCS is considered safe. In tACS, meanwhile, no persistent adverse events have been reported, but considerably fewer reports are available on the safety of tACS than on the safety of tDCS. Therefore, to establish the safety of tDCS and tACS, we need to scan the literature continuously for information on the adverse events of both stimulation techniques. Further safety investigations are also required.
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Affiliation(s)
| | - Yoshikazu Ugawa
- Department of Neurology, School of Medicine, Fukushima Medical University, Japan.,Fukushima Global Medical Science Center, Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
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Veniero D, Vossen A, Gross J, Thut G. Lasting EEG/MEG Aftereffects of Rhythmic Transcranial Brain Stimulation: Level of Control Over Oscillatory Network Activity. Front Cell Neurosci 2015; 9:477. [PMID: 26696834 PMCID: PMC4678227 DOI: 10.3389/fncel.2015.00477] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 11/23/2015] [Indexed: 11/24/2022] Open
Abstract
A number of rhythmic protocols have emerged for non-invasive brain stimulation (NIBS) in humans, including transcranial alternating current stimulation (tACS), oscillatory transcranial direct current stimulation (otDCS), and repetitive (also called rhythmic) transcranial magnetic stimulation (rTMS). With these techniques, it is possible to match the frequency of the externally applied electromagnetic fields to the intrinsic frequency of oscillatory neural population activity (“frequency-tuning”). Mounting evidence suggests that by this means tACS, otDCS, and rTMS can entrain brain oscillations and promote associated functions in a frequency-specific manner, in particular during (i.e., online to) stimulation. Here, we focus instead on the changes in oscillatory brain activity that persist after the end of stimulation. Understanding such aftereffects in healthy participants is an important step for developing these techniques into potentially useful clinical tools for the treatment of specific patient groups. Reviewing the electrophysiological evidence in healthy participants, we find aftereffects on brain oscillations to be a common outcome following tACS/otDCS and rTMS. However, we did not find a consistent, predictable pattern of aftereffects across studies, which is in contrast to the relative homogeneity of reported online effects. This indicates that aftereffects are partially dissociated from online, frequency-specific (entrainment) effects during tACS/otDCS and rTMS. We outline possible accounts and future directions for a better understanding of the link between online entrainment and offline aftereffects, which will be key for developing more targeted interventions into oscillatory brain activity.
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Affiliation(s)
- Domenica Veniero
- Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow Glasgow, UK
| | | | - Joachim Gross
- Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow Glasgow, UK
| | - Gregor Thut
- Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow Glasgow, UK
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Abd Hamid AI, Gall C, Speck O, Antal A, Sabel BA. Effects of alternating current stimulation on the healthy and diseased brain. Front Neurosci 2015; 9:391. [PMID: 26578858 PMCID: PMC4621306 DOI: 10.3389/fnins.2015.00391] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 10/06/2015] [Indexed: 12/30/2022] Open
Abstract
Cognitive and neurological dysfunctions can severely impact a patient's daily activities. In addition to medical treatment, non-invasive transcranial alternating current stimulation (tACS) has been proposed as a therapeutic technique to improve the functional state of the brain. Although during the last years tACS was applied in numerous studies to improve motor, somatosensory, visual and higher order cognitive functions, our knowledge is still limited regarding the mechanisms as to which type of ACS can affect cortical functions and altered neuronal oscillations seem to be the key mechanism. Because alternating current send pulses to the brain at predetermined frequencies, the online- and after-effects of ACS strongly depend on the stimulation parameters so that “optimal” ACS paradigms could be achieved. This is of interest not only for neuroscience research but also for clinical practice. In this study, we summarize recent findings on ACS-effects under both normal conditions and in brain diseases.
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Affiliation(s)
- Aini Ismafairus Abd Hamid
- Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg Magdeburg, Germany ; Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia Kubang Kerian, Malaysia
| | - Carolin Gall
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg Magdeburg, Germany
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Institute for Experimental Physics, Otto-von-Guericke University Magdeburg Magdeburg, Germany ; Leibniz Institute for Neurobiology Magdeburg, Germany ; Center for Behavioral Brain Sciences Magdeburg, Germany ; German Center for Neurodegenerative Disease (DZNE) Magdeburg, Germany
| | - Andrea Antal
- Department of Clinical Neurophysiology, University Medical Center, Georg-August University Goettingen, Germany
| | - Bernhard A Sabel
- Institute of Medical Psychology, Otto-von-Guericke University Magdeburg Magdeburg, Germany
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Moliadze V, Andreas S, Lyzhko E, Schmanke T, Gurashvili T, Freitag CM, Siniatchkin M. Ten minutes of 1 mA transcranial direct current stimulation was well tolerated by children and adolescents: Self-reports and resting state EEG analysis. Brain Res Bull 2015; 119:25-33. [PMID: 26449209 DOI: 10.1016/j.brainresbull.2015.09.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 09/25/2015] [Accepted: 09/28/2015] [Indexed: 11/18/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a promising and well-tolerated method of non-invasive brain stimulation, by which cortical excitability can be modulated. However, the effects of tDCS on the developing brain are still unknown, and knowledge about its tolerability in children and adolescents is still lacking. Safety and tolerability of tDCS was assessed in children and adolescents by self-reports and spectral characteristics of electroencephalogram (EEG) recordings. Nineteen typically developing children and adolescents aged 11-16 years participated in the study. Anodal and cathodal tDCS as well as sham stimulation were applied for a duration of 10 min over the left primary motor cortex (M1), each with an intensity of 1 mA. Subjects were unable to identify whether they had received active or sham stimulation, and all participants tolerated the stimulation well with a low rate of adverse events in both groups and no serious adverse events. No pathological oscillations, in particular, no markers of epileptiform activity after 1mA tDCS were detected in any of the EEG analyses. In summary, our study demonstrates that tDCS with 1mA intensity over 10 min is well tolerated, and thus may be used as an experimental and treatment method in the pediatric population.
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Affiliation(s)
- Vera Moliadze
- Department of Medical Psychology and Medical Sociology, University Hospital of Schleswig-Holstein (UK-SH), Campus Kiel, Preußerstraße 1-9, 24105 Kiel, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy Goethe-University, Deutschordenstr. 50, D-60528 Frankfurt am Main, Germany.
| | - Saskia Andreas
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy Goethe-University, Deutschordenstr. 50, D-60528 Frankfurt am Main, Germany
| | - Ekaterina Lyzhko
- Department of Medical Psychology and Medical Sociology, University Hospital of Schleswig-Holstein (UK-SH), Campus Kiel, Preußerstraße 1-9, 24105 Kiel, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy Goethe-University, Deutschordenstr. 50, D-60528 Frankfurt am Main, Germany; Institute of Mathematical Problems of Biology, Pushchino, Moscow Region, Russia
| | - Till Schmanke
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy Goethe-University, Deutschordenstr. 50, D-60528 Frankfurt am Main, Germany
| | - Tea Gurashvili
- Department of Medical Psychology and Medical Sociology, University Hospital of Schleswig-Holstein (UK-SH), Campus Kiel, Preußerstraße 1-9, 24105 Kiel, Germany
| | - Christine M Freitag
- Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy Goethe-University, Deutschordenstr. 50, D-60528 Frankfurt am Main, Germany
| | - Michael Siniatchkin
- Department of Medical Psychology and Medical Sociology, University Hospital of Schleswig-Holstein (UK-SH), Campus Kiel, Preußerstraße 1-9, 24105 Kiel, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy Goethe-University, Deutschordenstr. 50, D-60528 Frankfurt am Main, Germany
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Safety Study of Transcranial Static Magnetic Field Stimulation (tSMS) of the Human Cortex. Brain Stimul 2015; 8:481-5. [DOI: 10.1016/j.brs.2014.12.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 12/02/2014] [Accepted: 12/05/2014] [Indexed: 11/23/2022] Open
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Krishnan C, Santos L, Peterson MD, Ehinger M. Safety of noninvasive brain stimulation in children and adolescents. Brain Stimul 2014; 8:76-87. [PMID: 25499471 DOI: 10.1016/j.brs.2014.10.012] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 10/03/2014] [Accepted: 10/21/2014] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Noninvasive brain stimulation (NIBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial current stimulation (tCS) have the potential to mitigate a variety of symptoms associated with neurological and psychiatric conditions, including stroke, cerebral palsy, autism, depression, and Tourette syndrome. While the safety of these modalities has been established in adults, there is a paucity of research assessing the safety of NIBS among children. OBJECTIVE To examine the existing literature regarding the safety of NIBS techniques in children and adolescents with neurologic and neuropsychiatric disorders. METHODS An electronic search was performed on online databases for studies using NIBS in individuals less than 18 years of age. Non-English publications, diagnostic studies, electroconvulsive therapy, single/dual pulse TMS studies, and reviews were excluded. Adverse events reported in the studies were carefully examined and synthesized to understand the safety and tolerability of NIBS among children and adolescents. RESULTS The data from 48 studies involving more than 513 children/adolescents (2.5-17.8 years of age) indicate that the side effects of NIBS were, in general, mild and transient [TMS: headache (11.5%), scalp discomfort (2.5%), twitching (1.2%), mood changes (1.2%), fatigue (0.9%), tinnitus (0.6%); tCS: tingling (11.5%), itching (5.8%), redness (4.7%), scalp discomfort (3.1%)] with relatively few serious adverse events. CONCLUSION Our findings indicate that both repetitive TMS and tCS are safe modalities in children and adolescents with various neurological conditions, especially when safety guidelines are followed. The incidence of adverse events appears to be similar to that observed in adults; however, further studies with longer treatment and follow-up periods are needed to better understand the benefits and tolerance of long-term use of NIBS in children.
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Affiliation(s)
- Chandramouli Krishnan
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Luciana Santos
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Mark D Peterson
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Margaret Ehinger
- Department of Physical Medicine and Rehabilitation, University of Michigan Medical School, Ann Arbor, MI, USA
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