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Wyss AM, Baumgartner T, Guizar Rosales E, Soutschek A, Knoch D. Cathodal HD-tDCS above the left dorsolateral prefrontal cortex increases environmentally sustainable decision-making. Front Hum Neurosci 2024; 18:1395426. [PMID: 38946792 PMCID: PMC11212476 DOI: 10.3389/fnhum.2024.1395426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2024] [Accepted: 05/27/2024] [Indexed: 07/02/2024] Open
Abstract
Environmental sustainability is characterized by a conflict between short-term self-interest and longer-term collective interests. Self-control capacity has been proposed to be a crucial determinant of people's ability to overcome this conflict. Yet, causal evidence is lacking, and previous research is dominated by the use of self-report measures. Here, we modulated self-control capacity by applying inhibitory high-definition transcranial current stimulation (HD-tDCS) above the left dorsolateral prefrontal cortex (dlPFC) while participants engaged in an environmentally consequential decision-making task. The task includes conflicting and low conflicting trade-offs between short-term personal interests and long-term environmental benefits. Contrary to our preregistered expectation, inhibitory HD-tDCS above the left dlPFC, presumably by reducing self-control capacity, led to more, and not less, pro-environmental behavior in conflicting decisions. We speculate that in our exceptionally environmentally friendly sample, deviating from an environmentally sustainable default required self-control capacity, and that inhibiting the left dlPFC might have reduced participants' ability to do so.
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Affiliation(s)
- Annika M. Wyss
- Department of Social Neuroscience and Social Psychology, University of Bern, Bern, Switzerland
| | - Thomas Baumgartner
- Department of Social Neuroscience and Social Psychology, University of Bern, Bern, Switzerland
| | - Emmanuel Guizar Rosales
- Department of Social Neuroscience and Social Psychology, University of Bern, Bern, Switzerland
| | - Alexander Soutschek
- Department of Psychology, Ludwig Maximilian University Munich, Munich, Germany
| | - Daria Knoch
- Department of Social Neuroscience and Social Psychology, University of Bern, Bern, Switzerland
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2
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Kumpf U, Stadler M, Plewnia C, Bajbouj M, Langguth B, Zwanzger P, Normann C, Keeser D, Schellhorn K, Egert-Schwender S, Berkes S, Palm U, Hasan A, Padberg F. Transcranial Direct Current Stimulation (tDCS) for major depression - Interim analysis of cloud supervised technical data from the DepressionDC trial. Brain Stimul 2021; 14:1234-1237. [PMID: 34391956 DOI: 10.1016/j.brs.2021.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) of prefrontal cortex regions has been reported to exert antidepressant effects, though large scale multicenter trials in major depressive disorder (MDD) supporting this notion are still lacking. Application of tDCS in multicenter settings, however, requires measurement, storage and evaluation of technical parameters of tDCS sessions not only for safety reasons but also for quality control. To address this issue, we conducted an interim analysis of supervised technical data across study centers in order to monitor technical quality of tDCS in an ongoing multicenter RCT in MDD (DepressionDC trial). METHODS Technical data of 818 active tDCS sessions were recorded, stored in a data cloud, and analysed without violating study blinding. Impedance, voltage and current were monitored continuously with one data point recorded every second of stimulation. RESULTS Variability of impedance was considerable (1,42 kΩ, to 8,23 kΩ), inter-individually and even more intra-individually, but did not significantly differ between the study centre in Munich and all other sites. CONCLUSION Measurement, centralized data storage via data cloud and remote supervision of technical parameters of tDCS are feasible and proposed for future RCTs on therapeutic tDCS in multiple settings.
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Affiliation(s)
- U Kumpf
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University Munich, Nussbaumstr. 7, 80336, Munich, Germany.
| | - M Stadler
- Faculty of Psychology and Educational Sciences, Ludwig Maximilian University Munich, Germany
| | - C Plewnia
- Department of Psychiatry and Psychotherapy, University of Tübingen, Tübingen, Germany
| | - M Bajbouj
- Department of Psychiatry and Psychotherapy, Charité-Campus Benjamin Franklin, Berlin, Germany
| | - B Langguth
- Department of Psychiatry and Psychotherapy, University of Regensburg, Regensburg, Germany
| | - P Zwanzger
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University Munich, Nussbaumstr. 7, 80336, Munich, Germany; kbo-Inn-Salzach-Hospital, Wasserburg am Inn, Germany
| | - C Normann
- Department of Psychiatry and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine & Center for Basics in Neuomodulation NeuroModulBasics, University of Freiburg, Germany
| | - D Keeser
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University Munich, Germany; Department of Radiology, Ludwig Maximilian University Munich, Germany; Munich Center for Neurosciences (MCN) - Brain & Mind, Planegg-Martinsried, Germany
| | | | | | - S Berkes
- NeuroCare Group GmbH, Munich, Germany
| | - U Palm
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University Munich, Nussbaumstr. 7, 80336, Munich, Germany; Medicalpark Chiemseeblick, Bernau-Felden, Germany
| | - A Hasan
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, University of Augsburg, BKH Augsburg, Augsburg, Germany
| | - F Padberg
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University Munich, Germany
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3
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Lee J, Park SM. Parameterization of physical properties of layered body structure into equivalent circuit model. BMC Biomed Eng 2021; 3:9. [PMID: 34016186 PMCID: PMC8139009 DOI: 10.1186/s42490-021-00054-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 04/26/2021] [Indexed: 11/12/2022] Open
Abstract
Background This study presents a novel technique to develop an equivalent circuit model (ECM) for analyzing the responses of the layered body structure to transcutaneous electrical nerve stimulation (TENS) by parameterizing electrical and geometrical properties.Many classical ECMs are non-parametric because of the difficulty in projecting intrapersonal variability in the physical properties into ECM. However, not considering the intrapersonal variability hampers patient-specifically analyzing the body response to TENS and personal optimization of TENS parameter design. To overcome this limitation, we propose a tissue property-based (TPB) approach for the direct parameterization of the physical properties in the layered body structure and thus enable to quantify the effects of intrapersonal variability. Results The proposed method was first validated through in vitro phantom studies and then was applied in-vivo to analyze the TENS on the forearm. The TPB-ECM calculated the impedance network in the forearm and corresponding responses to TENS. In addition, the modelled impedance was in good agreement with well-known impedance properties that have been achieved empirically. Conclusions The TPB approach uses the parameterized circuit components compared to non-parametric conventional ECMs, thus overcoming the intrapersonal variability problem of the conventional ECMs. Therefore, the TPB-ECM has a potential for widely-applicable TENS analysis and could provide impactful guidance in the TENS parameter design. Supplementary Information The online version contains supplementary material available at (10.1186/s42490-021-00054-8).
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Affiliation(s)
- Jiho Lee
- Department of Creative IT Engineering, Pohang University of Science and Technology(POSTECH), Pohang, Republic of Korea.,Medical Device Innovation Center, Pohang University of Science and Technology(POSTECH), Pohang, Republic of Korea
| | - Sung-Min Park
- Department of Creative IT Engineering, Pohang University of Science and Technology(POSTECH), Pohang, Republic of Korea. .,Medical Device Innovation Center, Pohang University of Science and Technology(POSTECH), Pohang, Republic of Korea. .,Department of Electrical Engineering, Pohang University of Science and Technology(POSTECH), Pohang, Republic of Korea.
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4
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Pilloni G, Woods AJ, Charvet L. No risk of skin lesion or burn with transcranial direct current stimulation (tDCS) using standardized protocols. Brain Stimul 2021; 14:511-512. [PMID: 33722658 DOI: 10.1016/j.brs.2021.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/05/2021] [Accepted: 03/10/2021] [Indexed: 12/14/2022] Open
Affiliation(s)
| | - Adam J Woods
- Center for Cognitive Aging and Memory Clinical Translational Research, Department of Clinical and Health Psychology, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Leigh Charvet
- Department of Neurology, NYU Grossman School of Medicine, NY, USA.
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5
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Solomons CD, Shanmugasundaram V. Transcranial direct current stimulation: A review of electrode characteristics and materials. Med Eng Phys 2020; 85:63-74. [PMID: 33081965 DOI: 10.1016/j.medengphy.2020.09.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 09/10/2020] [Accepted: 09/25/2020] [Indexed: 12/15/2022]
Abstract
Electrode characteristics are crucial in transcranial direct current stimulation (tDCS) since electrode design and placement determine the cortical area being modulated, current density and spatial resolution of stimulation. Early research on tDCS sought to determine optimal parameters for stimulation by specifying maximum current, duration and sizes of electrodes. Further research focused on determining efficient ways to deliver stimulation to targeted regions on the cortex with minimal discomfort to the user by altering electrode size, placement, shape and material. This review aims to give an insight on the main characteristics of electrodes used in tDCS and on the variability found in electrode parameters and placements from tDCS to high definition tDCS (HD-tDCS) applications and beyond.
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Affiliation(s)
- Cassandra D Solomons
- School of Electrical Engineering, Vellore Institute of Technology, Vellore 632014, India
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6
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Chen L, Zou X, Tang R, Ke A, He J. Effect of electrode-electrolyte spatial mismatch on transcranial direct current stimulation: a finite element modeling study. J Neural Eng 2019; 16:056012. [DOI: 10.1088/1741-2552/ab29c5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Khadka N, Borges H, Paneri B, Kaufman T, Nassis E, Zannou AL, Shin Y, Choi H, Kim S, Lee K, Bikson M. Adaptive current tDCS up to 4 mA. Brain Stimul 2019; 13:69-79. [PMID: 31427272 DOI: 10.1016/j.brs.2019.07.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/16/2019] [Accepted: 07/29/2019] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Higher tDCS current may putatively enhance efficacy, with tolerability the perceived limiting factor. OBJECTIVE We designed and validated electrodes and an adaptive controller to provide tDCS up to 4 mA, while managing tolerability. The adaptive 4 mA controller included incremental ramp up, impedance-based current limits, and a Relax-mode where current is transiently decreased. Relax-mode was automatically activated by self-report VAS-pain score >5 and in some conditions by a Relax-button available to participants. METHODS In a parallel-group participant-blind design with 50 healthy subjects, we used specialized electrodes to administer 3 daily session of tDCS for 11 min, with a lexical decision task as a distractor, in 5 study conditions: adaptive 4 mA, adaptive 4 mA with Relax-button, adaptive 4 mA with historical-Relax-button, 2 mA, and sham. A tablet-based stimulator with a participant interface regularly queried VAS pain score and also limited current based on impedance and tolerability. An Abort-button provided in all conditions stopped stimulation. In the adaptive 4 mA with Relax-button and adaptive 4 mA with historical-Relax-button conditions, participants could trigger a Relax-mode ad libitum, in the latter case with incrementally longer current reductions. Primary outcome was the average current delivered during each session, VAS pain score, and adverse event questionnaires. Current delivered was analyzed either excluding or including dropouts who activated Abort (scored as 0 current). RESULTS There were two dropouts each in the adaptive 4 mA and sham conditions. Resistance based current attenuation was rarely activated, with few automatic VAS pain score triggered relax-modes. In conditions with Relax-button option, there were significant activations often irrespective of VAS pain score. Including dropouts, current across conditions were significantly different from each other with maximum current delivered during adaptive 4 mA with Relax-button. Excluding dropouts, maximum current was delivered with adaptive 4 mA. VAS pain score and adverse events for the sham was only significantly lower than the adaptive 4 mA with Relax-button and adaptive 4 mA with historical-Relax-button. There was no difference in VAS pain score or adverse events between 2 mA and adaptive 4 mA. CONCLUSIONS Provided specific electrodes and controllers, adaptive 4 mA tDCS is tolerated and effectively blinded, with acceptability likely higher in a clinical population and absence of regular querying. Indeed, presenting participants with overt controls increases rumination on sensation.
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Affiliation(s)
- Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA
| | - Helen Borges
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA
| | - Bhaskar Paneri
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA
| | - Trynia Kaufman
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA
| | - Electra Nassis
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA
| | - Adantchede L Zannou
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA
| | | | | | | | - Kiwon Lee
- Ybrain Inc., Seongnam-si, Republic of Korea
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, 10031, USA.
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8
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Khadka N, Zannou AL, Zunara F, Truong DQ, Dmochowski J, Bikson M. Minimal Heating at the Skin Surface During Transcranial Direct Current Stimulation. Neuromodulation 2017; 21:334-339. [PMID: 28111832 DOI: 10.1111/ner.12554] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/11/2016] [Accepted: 10/28/2016] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To assess if transcranial direct current stimulation (tDCS) produces a temperature change at the skin surface, if any change is stimulation polarity (anode or cathode) specific, and the contribution of passive heating (joule heat) or blood flow on such change. MATERIAL AND METHODS Temperature differences (ΔTs) in an agar phantom study and an in vivo study (forearm stimulation) including 20 volunteers with both experimental measures and finite element method (FEM) multiphysics prediction (current flow and bioheat) models of skin comprising three tissue layers (epidermis, dermis, and subcutaneous layer with blood perfusion) or of the phantom for active stimulation and control cases were compared. Temperature was measured during pre, post, and stimulation phases for both phantom and subject's forearms using thermocouples. RESULTS In the phantom, ΔT under both anode and cathode, compared to control, was not significantly different and less than 0.1°C. Stimulation of subjects resulted in a gradual increase in temperature under both anode and cathode electrodes, compared to control (at t = 20 min: ΔTanode = 0.9°C, ΔTcathode = 1.1°C, ΔTcontrol = 0.05°C). The FEM phantom model predicted comparable maximum ΔT of 0.27°C and 0.28°C (at t = 20 min) for the control and anode/cathode cases, respectively. The FEM skin model predicted a maximum ΔT at t = 20 min of 0.98°C for control and 1.36°C under anode/cathode electrodes. CONCLUSIONS Taken together, our results indicate a moderate and nonhazardous increase in temperature at the skin surface during 2 mA tDCS that is independent of polarity, and results from stimulation induced blood flow rather than joule heat.
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Affiliation(s)
- Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA
| | - Adantchede L Zannou
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA
| | - Fatima Zunara
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA
| | - Dennis Q Truong
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA
| | - Jacek Dmochowski
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA
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9
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Ezquerro F, Moffa AH, Bikson M, Khadka N, Aparicio LVM, de Sampaio-Junior B, Fregni F, Bensenor IM, Lotufo PA, Pereira AC, Brunoni AR. The Influence of Skin Redness on Blinding in Transcranial Direct Current Stimulation Studies: A Crossover Trial. Neuromodulation 2016; 20:248-255. [PMID: 27704654 DOI: 10.1111/ner.12527] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/08/2016] [Accepted: 08/17/2016] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate whether and to which extent skin redness (erythema) affects investigator blinding in transcranial direct current stimulation (tDCS) trials. MATERIAL AND METHODS Twenty-six volunteers received sham and active tDCS, which was applied with saline-soaked sponges of different thicknesses. High-resolution skin images, taken before and 5, 15, and 30 min after stimulation, were randomized and presented to experienced raters who evaluated erythema intensity and judged on the likelihood of stimulation condition (sham vs. active). In addition, semi-automated image processing generated probability heatmaps and surface area coverage of erythema. Adverse events were also collected. RESULTS Erythema was present, but less intense in sham compared to active groups. Erythema intensity was inversely and directly associated to correct sham and active stimulation group allocation, respectively. Our image analyses found that erythema also occurs after sham and its distribution is homogenous below electrodes. Tingling frequency was higher using thin compared to thick sponges, whereas erythema was more intense under thick sponges. CONCLUSIONS Optimal investigator blinding is achieved when erythema after tDCS is mild. Erythema distribution under the electrode is patchy, occurs after sham tDCS and varies according to sponge thickness. We discuss methods to address skin erythema-related tDCS unblinding.
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Affiliation(s)
- Fernando Ezquerro
- Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil
| | - Adriano H Moffa
- Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil.,Service of Interdisciplinary Neuromodulation (SIN), Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of City University of New York, New York, NY, USA
| | - Niranjan Khadka
- Department of Biomedical Engineering, The City College of City University of New York, New York, NY, USA
| | - Luana V M Aparicio
- Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil.,Service of Interdisciplinary Neuromodulation (SIN), Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
| | - Bernardo de Sampaio-Junior
- Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil.,Service of Interdisciplinary Neuromodulation (SIN), Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
| | - Felipe Fregni
- Spaulding Neuromodulation Center, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - Isabela M Bensenor
- Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil.,Service of Interdisciplinary Neuromodulation (SIN), Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
| | - Paulo A Lotufo
- Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil.,Service of Interdisciplinary Neuromodulation (SIN), Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
| | | | - Andre R Brunoni
- Interdisciplinary Center for Applied Neuromodulation (CINA), University Hospital, University of São Paulo, São Paulo, Brazil.,Service of Interdisciplinary Neuromodulation (SIN), Laboratory of Neurosciences (LIM-27), Department and Institute of Psychiatry, University of São Paulo, São Paulo, Brazil
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10
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Khadka N, Truong DQ, Bikson M. Principles of Within Electrode Current Steering1. J Med Device 2015. [DOI: 10.1115/1.4030126] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY 10031
| | - Dennis Q. Truong
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY 10031
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY 10031
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