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Nguyen H, Li CQ, Hoffman S, Deng ZD, Yang Y, Lu H. Ultra-high frequency repetitive TMS at subthreshold intensity induces suprathreshold motor response via temporal summation. J Neural Eng 2024; 21:046044. [PMID: 39079555 PMCID: PMC11307324 DOI: 10.1088/1741-2552/ad692f] [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: 01/18/2024] [Revised: 06/27/2024] [Accepted: 07/30/2024] [Indexed: 08/10/2024]
Abstract
Objective.The transcranial magnetic stimulation (TMS) coil induces an electric field that diminishes rapidly upon entering the brain. This presents a challenge in achieving focal stimulation of a deep brain structure. Neuronal elements, including axons, dendrites, and cell bodies, exhibit specific time constants. When exposed to repetitive TMS pulses at a high frequency, there is a cumulative effect on neuronal membrane potentials, resulting in temporal summation. This study aims to determine whether TMS pulse train at high-frequency and subthreshold intensity could induce a suprathreshold response.Approach.As a proof of concept, we developed a TMS machine in-house that could consistently output pulses up to 250 Hz, and performed experiments on 22 awake rats to test whether temporal summation was detectable under pulse trains at 100, 166, or 250 Hz.Main results.Results revealed that TMS pulses at 55% maximum stimulator output (MSO, peak dI/dt= 68.5 A/μs at 100% MSO, pulse width = 48μs) did not induce motor responses with either single pulses or pulse trains. Similarly, a single TMS pulse at 65% MSO failed to evoke a motor response in rats; however, a train of TMS pulses at frequencies of 166 and 250 Hz, but not at 100 Hz, successfully triggered motor responses and MEP signals, suggesting a temporal summation effect dependent on both pulse intensities and pulse train frequencies.Significance.We propose that the temporal summation effect can be leveraged to design the next-generation focal TMS system: by sequentially driving multiple coils at high-frequency and subthreshold intensity, areas with the most significant overlapping E-fields undergo maximal temporal summation effects, resulting in a suprathreshold response.
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Affiliation(s)
- Hieu Nguyen
- Magnetic Resonance Imaging and Spectroscopy Section, Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States of America
| | - Charlotte Qiong Li
- Magnetic Resonance Imaging and Spectroscopy Section, Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States of America
| | - Samantha Hoffman
- Magnetic Resonance Imaging and Spectroscopy Section, Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States of America
| | - Zhi-De Deng
- Computational Neurostimulation Research Program, Noninvasive Neuromodulation Unit, Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States of America
| | - Yihong Yang
- Magnetic Resonance Imaging and Spectroscopy Section, Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States of America
| | - Hanbing Lu
- Magnetic Resonance Imaging and Spectroscopy Section, Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD, United States of America
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Fang X, Zhang T, Luo Y, Wang S. An Efficient Pulse Circuit Design for Magnetic Stimulation with Diversified Waveforms and Adjustable Parameters. SENSORS (BASEL, SWITZERLAND) 2024; 24:3839. [PMID: 38931623 PMCID: PMC11207347 DOI: 10.3390/s24123839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/03/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024]
Abstract
As a noninvasive neuromodulation technique, transcranial magnetic stimulation (TMS) has important applications both in the exploration of mental disorder causes and the treatment of mental disorders. During the stimulation, the TMS system generates the intracranial time-varying induced E-field (E-field), which alters the membrane potential of neurons and subsequently exerts neural regulatory effects. The temporal waveform of the induced E-fields is directly related to the stimulation effect. To meet the needs of scientific research on diversified stimulation waveforms and flexible adjustable stimulation parameters, a novel efficient pulse magnetic stimulation circuit (the EPMS circuit) design based on asymmetric cascaded multilevel technology is proposed in this paper. Based on the transient analysis of the discharge circuit, this circuit makes it possible to convert the physical quantity (the intracranial induced E-field) that needs to be measured after magnetic stimulation into easily analyzable electrical signals (the discharge voltage at both ends of the stimulation coil in the TMS circuit). This EPMS circuit can not only realize monophasic and biphasic cosine-shaped intracranial induced E-fields, which are widely used in the market, but also realize three types of new intracranial induced E-field stimulation waveform with optional amplitude and adjustable pulse width, including monophasic near-rectangular, biphasic near-rectangular and monophasic/biphasic ladder-shaped stimulation waveform, which breaks through the limitation of the stimulation waveform of traditional TMS systems. Among the new waveforms produced by the EPMS circuit, further research was conducted on the dynamic response characteristics of neurons under the stimulation of the biphasic four-level waveform (the BFL waveform) with controllable parameters. The relationship between TMS circuit parameters (discharge voltage level and duration) and corresponding neural response characteristics (neuron membrane potential change and neuronal polarizability ratio) was explained from a microscopic perspective. Accordingly, the biological physical quantities (neuronal membrane potential) that are difficult to measure can be transformed into easily analyzable electrical signals (the discharge voltage level and duration). Results showed that compared with monophasic and biphasic cosine induced E-fields with the same energy loss, the neuron polarization ratio is decreased by 54.5% and 87.5%, respectively, under the stimulation of BFL waveform, which could effectively enhance the neuromodulation effect and improve the stimulation selectivity.
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Affiliation(s)
- Xiao Fang
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China
- High Field Magnetic Resonance Brain Imaging Laboratory of Sichuan, Chengdu 611731, China
- Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
- State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Tao Zhang
- High Field Magnetic Resonance Brain Imaging Laboratory of Sichuan, Chengdu 611731, China
| | - Yaoyao Luo
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China
| | - Shaolong Wang
- College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059, China
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Gutiérrez-Muto AM, Bestmann S, Sánchez de la Torre R, Pons JL, Oliviero A, Tornero J. The complex landscape of TMS devices: A brief overview. PLoS One 2023; 18:e0292733. [PMID: 38015924 PMCID: PMC10684101 DOI: 10.1371/journal.pone.0292733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/27/2023] [Indexed: 11/30/2023] Open
Abstract
The increasing application of TMS in research and therapy has spawned an ever-growing number of commercial and non-commercial TMS devices and technology development. New CE-marked devices appear at a rate of approximately one every two years, with new FDA-approved application of TMS occurring at a similar rate. With the resulting complex landscape of TMS devices and their application, accessible information about the technological characteristics of the TMS devices, such as the type of their circuitry, their pulse characteristics, or permitted protocols would be beneficial. We here present an overview and open access database summarizing key features and applications of available commercial and non-commercial TMS devices (http://www.tmsbase.info). This may guide comparison and decision making about the use of these devices. A bibliometric analysis was performed by identifying commercial and non-commercial TMS devices from which a comprehensive database was created summarizing their publicly available characteristics, both from a technical and clinical point of view. In this document, we introduce both the commercial devices and prototypes found in the literature. The technical specifications that unify these devices are briefly analysed in two separate tables: power electronics, waveform, protocols, and coil types. In the prototype TMS systems, the proposed innovations are focused on improving the treatment regarding the patient: noise cancellation, controllable parameters, and multiple stimulation. This analysis shows that the landscape of TMS is becoming increasingly fragmented, with new devices appearing ever more frequently. The review provided here can support development of benchmarking frameworks and comparison between TMS systems, inform the choice of TMS platforms for specific research and therapeutic applications, and guide future technology development for neuromodulation devices. This standardisation strategy will allow a better end-user choice, with an impact on the TMS manufacturing industry and a homogenisation of patient samples in multi-centre clinical studies. As an open access repository, we envisage the database to grow along with the dynamic development of TMS devices and applications through community-lead curation.
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Affiliation(s)
| | - Sven Bestmann
- Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | | | - José L. Pons
- Legs and Walking Lab, Shirley Ryan Ability Laboratory (Formerly Rehabilitation Institute of Chicago), Chicago, IL, United States of America
- Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States of America
| | - Antonio Oliviero
- Center for Clinical Neuroscience, Hospital Los Madroños, Brunete, Madrid, Spain
- Advanced Neurorehabilitation Unit, Hospital Los Madroños, Brunete, Madrid, Spain
| | - Jesús Tornero
- Center for Clinical Neuroscience, Hospital Los Madroños, Brunete, Madrid, Spain
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4
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Wang B, Zhang J, Li Z, Grill WM, Peterchev AV, Goetz SM. Optimized monophasic pulses with equivalent electric field for rapid-rate transcranial magnetic stimulation. J Neural Eng 2023; 20:10.1088/1741-2552/acd081. [PMID: 37100051 PMCID: PMC10464893 DOI: 10.1088/1741-2552/acd081] [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: 10/02/2022] [Accepted: 04/26/2023] [Indexed: 04/28/2023]
Abstract
Objective.Transcranial magnetic stimulation (TMS) with monophasic pulses achieves greater changes in neuronal excitability but requires higher energy and generates more coil heating than TMS with biphasic pulses, and this limits the use of monophasic pulses in rapid-rate protocols. We sought to design a stimulation waveform that retains the characteristics of monophasic TMS but significantly reduces coil heating, thereby enabling higher pulse rates and increased neuromodulation effectiveness.Approach.A two-step optimization method was developed that uses the temporal relationship between the electric field (E-field) and coil current waveforms. The model-free optimization step reduced the ohmic losses of the coil current and constrained the error of the E-field waveform compared to a template monophasic pulse, with pulse duration as a second constraint. The second, amplitude adjustment step scaled the candidate waveforms based on simulated neural activation to account for differences in stimulation thresholds. The optimized waveforms were implemented to validate the changes in coil heating.Main results.Depending on the pulse duration and E-field matching constraints, the optimized waveforms produced 12%-75% less heating than the original monophasic pulse. The reduction in coil heating was robust across a range of neural models. The changes in the measured ohmic losses of the optimized pulses compared to the original pulse agreed with numeric predictions.Significance.The first step of the optimization approach was independent of any potentially inaccurate or incorrect model and exhibited robust performance by avoiding the highly nonlinear behavior of neural responses, whereas neural simulations were only run once for amplitude scaling in the second step. This significantly reduced computational cost compared to iterative methods using large populations of candidate solutions and more importantly reduced the sensitivity to the choice of neural model. The reduced coil heating and power losses of the optimized pulses can enable rapid-rate monophasic TMS protocols.
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Affiliation(s)
- Boshuo Wang
- Department of Psychiatry and Behavior Sciences, School of Medicine, Duke University, Durham, NC, USA
| | - Jinshui Zhang
- Department of Electrical and Computer Engineering, School of Engineering, Duke University, Durham, NC, USA
| | - Zhongxi Li
- Department of Electrical and Computer Engineering, School of Engineering, Duke University, Durham, NC, USA
| | - Warren M. Grill
- Department of Electrical and Computer Engineering, School of Engineering, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, School of Engineering, Duke University, Durham, NC, USA
- Department of Neurosurgery, School of Medicine, Duke University, NC, USA
- Department of Neurobiology, School of Medicine, Duke University, NC, USA
| | - Angel V. Peterchev
- Department of Psychiatry and Behavior Sciences, School of Medicine, Duke University, Durham, NC, USA
- Department of Electrical and Computer Engineering, School of Engineering, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, School of Engineering, Duke University, Durham, NC, USA
- Department of Neurosurgery, School of Medicine, Duke University, NC, USA
| | - Stefan M. Goetz
- Department of Psychiatry and Behavior Sciences, School of Medicine, Duke University, Durham, NC, USA
- Department of Electrical and Computer Engineering, School of Engineering, Duke University, Durham, NC, USA
- Department of Neurosurgery, School of Medicine, Duke University, NC, USA
- Department of Engineering, School of Technology, University of Cambridge, Cambridge, UK
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5
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Ali K, Wendt K, Sorkhabi MM, Benjaber M, Denison T, Rogers DJ. xTMS: A Pulse Generator for Exploring Transcranial Magnetic Stimulation Therapies. CONFERENCE PROCEEDINGS. IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION 2023; 2023:1875-1880. [PMID: 37342241 PMCID: PMC7614672 DOI: 10.1109/apec43580.2023.10131554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/22/2023]
Abstract
A cascaded H-bridge based pulse generator for transcranial magnetic stimulation is introduced. The system demonstrates complete flexibility for producing different shape, duration, direction, and rate of repetition of stimulus pulses within its electrical limits, and can emulate all commercial and research systems available to-date in this application space. An offline model predictive control algorithm, used to generate pulses and sequences, shows superior performance compared to conventional carrier-based pulse width modulation. A fully functioning laboratory prototype delivers up to 1.5 kV, 6 kA pulses, and is ready to be used as a research tool for the exploration of transcranial magnetic stimulation therapies by leveraging the many degrees-of-freedom offered by the design.
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Affiliation(s)
- Kawsar Ali
- Department o fEngineering Science, University of Oxford, UK
| | - Karen Wendt
- Department o fEngineering Science, University of Oxford, UK
- MRC Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, UK
| | | | - Moaad Benjaber
- Department o fEngineering Science, University of Oxford, UK
| | - Timothy Denison
- Department o fEngineering Science, University of Oxford, UK
- MRC Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, UK
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Wang T, Yan L, Yang X, Geng D, Xu G, Wang A. Optimal Design of Array Coils for Multi-Target Adjustable Electromagnetic Brain Stimulation System. Bioengineering (Basel) 2023; 10:bioengineering10050568. [PMID: 37237638 DOI: 10.3390/bioengineering10050568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/29/2023] [Accepted: 05/07/2023] [Indexed: 05/28/2023] Open
Abstract
Temporal interference magnetic stimulation is a novel noninvasive deep brain neuromodulation technology that can solve the problem of balance between focus area and stimulation depth. However, at present, the stimulation target of this technology is relatively single, and it is difficult to realize the coordinated stimulation of multiple brain regions, which limits its application in the modulation of multiple nodes in the brain network. This paper first proposes a multi-target temporal interference magnetic stimulation system with array coils. The array coils are composed of seven coil units with an outer radius of 25 mm, and the spacing between coil units is 2 mm. Secondly, models of human tissue fluid and the human brain sphere are established. Finally, the relationship between the movement of the focus area and the amplitude ratio of the difference frequency excitation sources under time interference is discussed. The results show that in the case of a ratio of 1:5, the peak position of the amplitude modulation intensity of the induced electric field has moved 45 mm; that is, the movement of the focus area is related to the amplitude ratio of the difference frequency excitation sources. The conclusion is that multi-target temporal interference magnetic stimulation with array coils can simultaneously stimulate multiple network nodes in the brain region; rough positioning can be performed by controlling the conduction of different coils, fine-tuning the position by changing the current ratio of the conduction coils, and realizing accurate stimulation of multiple targets in the brain area.
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Affiliation(s)
- Tingyu Wang
- School of Electrical Engineering, Hebei University of Technology, Tianjin 300130, China
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China
| | - Lele Yan
- School of Electrical Engineering, Hebei University of Technology, Tianjin 300130, China
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China
| | - Xinsheng Yang
- School of Electrical Engineering, Hebei University of Technology, Tianjin 300130, China
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China
| | - Duyan Geng
- School of Electrical Engineering, Hebei University of Technology, Tianjin 300130, China
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China
| | - Guizhi Xu
- School of Electrical Engineering, Hebei University of Technology, Tianjin 300130, China
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China
| | - Alan Wang
- Auckland Bioengineering Institute, University of Auckland, Auckland 1010, New Zealand
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1010, New Zealand
- Centre for Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1010, New Zealand
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7
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Staat C, Gattinger N, Gleich B. PLUSPULS: A transcranial magnetic stimulator with extended pulse protocols. HARDWAREX 2023; 13:e00380. [PMID: 36578972 PMCID: PMC9791927 DOI: 10.1016/j.ohx.2022.e00380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Transcranial magnetic stimulation (TMS) is increasingly applied in basic neuroscience while its field of usage for diagnosing and treating various neurological diseases broadens steadily. A TMS device generates a current pulse in the reach of several thousand ampére to produce a magnetic pulse which induces an electric field around neurons. This electric field, if high enough to depolarize the neuron membrane, generates an action potential at the neuron which travels down the neurons connected to it. The PLUSPULS TMS generates this magnetic pulse by pre-charging a pulse capacitor C with the voltage V C 0 and connecting it with a stimulation coil L . The oscillation of the resonance circuit is cut off after one period and is called a biphasic pulse. PLUSPULS is a high frequency stimulator with inter stimulus intervals (ISI) down to 1ms which enables different pulse protocols as paired pulse or quadri theta burst stimulation. A GUI on PC allows a flexible control of PLUSPULS with varying amplitudes and ISI in one burst. The modular hardware and the control via GUI on PC allows for an easier adjustment on requirements to come. The article provides design considerations, hardware, firmware and software to reconstruct a modular biphasic TMS with enhanced charging network to enable extended pulse protocols.
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8
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Multi-objective optimization method for coil current waveform of transcranial magnetic stimulation. Heliyon 2023; 9:e13541. [PMID: 36873139 PMCID: PMC9975103 DOI: 10.1016/j.heliyon.2023.e13541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 02/07/2023] Open
Abstract
Transcranial magnetic stimulation (TMS) has been proved to be effective in the treatment of many kinds of mental diseases. However, the clicking noise produced by the pulse current with large amplitude and short duration in the TMS coil may damage the hearing of patients. The heat produced by the high-frequency pulse current in the coil also reduces the efficiency of TMS equipment. A multi-objective waveform optimization method to improve heat and noise problems at the same time is presented. By analyzing the current waveforms of TMS, the relationship between the current and the vibration energy/Joule heating is established. Taking the Joule heating and the vibration energy as the optimization objectives, exceeding the same amount of neuronal membrane potential as the limiting condition, the Pareto fronts of different current models are obtained by applying the multi-objective particle swarm optimization algorithm (MOPSO). Therefore, the corresponding current waveforms are inversely deduced. A ringing suppression cTMS (RS-cTMS) proof-of-principle experimental platform is constructed. The feasibility of the proposed method is validated through experiments. The results show that the optimized current waveforms can greatly reduce the vibration and heating of the coil compared with the conventional full-sine, recified sine and half-sine waveforms, thus reducing the pulse noise and prolonging the using time of the equipment. The optimized diversified waveforms also provide a reference for the diversity of TMS.
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Li Z, Zhang J, Peterchev AV, Goetz SM. Modular pulse synthesizer for transcranial magnetic stimulation with fully adjustable pulse shape and sequence. J Neural Eng 2022; 19:10.1088/1741-2552/ac9d65. [PMID: 36301685 PMCID: PMC10206176 DOI: 10.1088/1741-2552/ac9d65] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 10/25/2022] [Indexed: 01/11/2023]
Abstract
The temporal shape of a pulse in transcranial magnetic stimulation (TMS) influences which neuron populations are activated preferentially as well as the strength and even direction of neuromodulation effects. Furthermore, various pulse shapes differ in their efficiency, coil heating, sensory perception, and clicking sound. However, the available TMS pulse shape repertoire is still very limited to a few biphasic, monophasic, and polyphasic pulses with sinusoidal or near-rectangular shapes. Monophasic pulses, though found to be more selective and stronger in neuromodulation, are generated inefficiently and therefore only available in simple low-frequency repetitive protocols. Despite a strong interest to exploit the temporal effects of TMS pulse shapes and pulse sequences, waveform control is relatively inflexible and only possible parametrically within certain limits. Previously proposed approaches for flexible pulse shape control, such as through power electronic inverters, have significant limitations: The semiconductor switches can fail under the immense electrical stress associated with free pulse shaping, and most conventional power inverter topologies are incapable of generating smooth electric fields or existing pulse shapes. Leveraging intensive preliminary work on modular power electronics, we present a modular pulse synthesizer (MPS) technology that can, for the first time, flexibly generate high-power TMS pulses (one-side peak ∼4000 V, ∼8000 A) with user-defined electric field shape as well as rapid sequences of pulses with high output quality. The circuit topology breaks the problem of simultaneous high power and switching speed into smaller, manageable portions, distributed across several identical modules. In consequence, the MPS TMS techology can use semiconductor devices with voltage and current ratings lower than the overall pulse voltage and distribute the overall switching of several hundred kilohertz among multiple transistors. MPS TMS can synthesize practically any pulse shape, including conventional ones, with fine quantization of the induced electric field (⩽17% granularity without modulation and ∼300 kHz bandwidth). Moreover, the technology allows optional symmetric differential coil driving so that the average electric potential of the coil, in contrast to conventional TMS devices, stays constant to prevent capacitive artifacts in sensitive recording amplifiers, such as electroencephalography. MPS TMS can enable the optimization of stimulation paradigms for more sophisticated probing of brain function as well as stronger and more selective neuromodulation, further expanding the parameter space available to users.
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Affiliation(s)
- Z Li
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, United States of America
| | - J Zhang
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, United States of America
| | - A V Peterchev
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, United States of America
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, 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
- Duke Institute for Brain Sciences, Duke University, Durham, NC 27708, United States of America
| | - S M Goetz
- Department of Electrical and Computer Engineering, Duke University, Durham, NC 27708, United States of America
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, United States of America
- Department of Neurosurgery, Duke University, Durham, NC 27710, United States of America
- Duke Institute for Brain Sciences, Duke University, Durham, NC 27708, United States of America
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom
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10
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Jafari S, Baum IS, Udalov OG, Lee Y, Rodriguez O, Fricke ST, Jafari M, Amini M, Probst R, Tang X, Chen C, Ariando DJ, Hevaganinge A, Mair LO, Albanese C, Weinberg IN. Opening the Blood Brain Barrier with an Electropermanent Magnet System. Pharmaceutics 2022; 14:1503. [PMID: 35890398 PMCID: PMC9317373 DOI: 10.3390/pharmaceutics14071503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 12/03/2022] Open
Abstract
Opening the blood brain barrier (BBB) under imaging guidance may be useful for the treatment of many brain disorders. Rapidly applied magnetic fields have the potential to generate electric fields in brain tissue that, if properly timed, may enable safe and effective BBB opening. By tuning magnetic pulses generated by a novel electropermanent magnet (EPM) array, we demonstrate the opening of tight junctions in a BBB model culture in vitro, and show that induced monophasic electrical pulses are more effective than biphasic ones. We confirmed, with in vivo contrast-enhanced MRI, that the BBB can be opened with monophasic pulses. As electropermanent magnets have demonstrated efficacy at tuning B0 fields for magnetic resonance imaging studies, our results suggest the possibility of implementing an EPM-based hybrid theragnostic device that could both image the brain and enhance drug transport across the BBB in a single sitting.
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Affiliation(s)
- Sahar Jafari
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
| | - Ittai S. Baum
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
| | - Oleg G. Udalov
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
| | - Yichien Lee
- Department of Oncology, Georgetown University Medical Center, Washington, DC 20057, USA; (Y.L.); (O.R.); (S.T.F.); (C.A.)
| | - Olga Rodriguez
- Department of Oncology, Georgetown University Medical Center, Washington, DC 20057, USA; (Y.L.); (O.R.); (S.T.F.); (C.A.)
- Center for Translational Imaging, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Stanley T. Fricke
- Department of Oncology, Georgetown University Medical Center, Washington, DC 20057, USA; (Y.L.); (O.R.); (S.T.F.); (C.A.)
- Center for Translational Imaging, Georgetown University Medical Center, Washington, DC 20057, USA
- Department of Radiology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Maryam Jafari
- Independent Consultant, Oklahoma City, OK 73134, USA;
| | - Mostafa Amini
- Department of Management Science and Information Systems, Oklahoma State University, Stillwater, OK 74078, USA;
| | | | - Xinyao Tang
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
| | - Cheng Chen
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
| | - David J. Ariando
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA;
| | - Anjana Hevaganinge
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
| | - Lamar O. Mair
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
| | - Christopher Albanese
- Department of Oncology, Georgetown University Medical Center, Washington, DC 20057, USA; (Y.L.); (O.R.); (S.T.F.); (C.A.)
- Center for Translational Imaging, Georgetown University Medical Center, Washington, DC 20057, USA
- Department of Radiology, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Irving N. Weinberg
- Weinberg Medical Physics, Inc., North Bethesda, MD 20852, USA; (S.J.); (I.S.B.); (O.G.U.); (X.T.); (C.C.); (A.H.); (L.O.M.)
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11
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Meng Q, Nguyen H, Vrana A, Baldwin S, Li CQ, Giles A, Wang J, Yang Y, Lu H. A high-density theta burst paradigm enhances the aftereffects of transcranial magnetic stimulation: Evidence from focal stimulation of rat motor cortex. Brain Stimul 2022; 15:833-842. [DOI: 10.1016/j.brs.2022.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 05/18/2022] [Accepted: 05/25/2022] [Indexed: 11/28/2022] Open
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12
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Sorkhabi MM, Denison T. A neurostimulator system for real, sham, and multi-target transcranial magnetic stimulation. J Neural Eng 2022; 19:10.1088/1741-2552/ac60c9. [PMID: 35325879 PMCID: PMC7614713 DOI: 10.1088/1741-2552/ac60c9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/24/2022] [Indexed: 11/11/2022]
Abstract
Objective.Transcranial magnetic stimulation (TMS) is a clinically effective therapeutic instrument used to modulate neural activity. Despite three decades of research, two challenging issues remain, the possibility of changing the (a) stimulated spot and (b) stimulation type (real or sham) without physically moving the coil. In this study, a second-generation programmable TMS device with advanced stimulus shaping is introduced that uses a five-level cascaded H-bridge inverter and phase-shifted pulse-width modulation. The principal idea of this research is to obtain real, sham, and multi-locus stimulation using the same TMS system.Approach.We propose a two-channel modulation-based magnetic pulse generator and a novel coil arrangement, consisting of two circular coils with a physical distance of 20 mm between the coils and a control method for modifying the effective stimulus intensity, which leads to the live steerability of the target and type of stimulation.Main results.Based on the measured system performance, the stimulation profile can be steered ±20 mm along a line from the centroid of the coil locations by modifying the modulation index.Significance.The proposed system supports electronic control of the stimulation spot without physical coil movement, resulting in tunable modulation of targets, which is a crucial step towards automated TMS machines.
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Affiliation(s)
- Majid Memarian Sorkhabi
- MRC Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, UK
| | - Timothy Denison
- MRC Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, UK
- Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK
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13
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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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14
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Nieminen JO, Sinisalo H, Souza VH, Malmi M, Yuryev M, Tervo AE, Stenroos M, Milardovich D, Korhonen JT, Koponen LM, Ilmoniemi RJ. Multi-locus transcranial magnetic stimulation system for electronically targeted brain stimulation. Brain Stimul 2022; 15:116-124. [PMID: 34818580 PMCID: PMC8807400 DOI: 10.1016/j.brs.2021.11.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/17/2021] [Accepted: 11/19/2021] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) allows non-invasive stimulation of the cortex. In multi-locus TMS (mTMS), the stimulating electric field (E-field) is controlled electronically without coil movement by adjusting currents in the coils of a transducer. OBJECTIVE To develop an mTMS system that allows adjusting the location and orientation of the E-field maximum within a cortical region. METHODS We designed and manufactured a planar 5-coil mTMS transducer to allow controlling the maximum of the induced E-field within a cortical region approximately 30 mm in diameter. We developed electronics with a design consisting of independently controlled H-bridge circuits to drive up to six TMS coils. To control the hardware, we programmed software that runs on a field-programmable gate array and a computer. To induce the desired E-field in the cortex, we developed an optimization method to calculate the currents needed in the coils. We characterized the mTMS system and conducted a proof-of-concept motor-mapping experiment on a healthy volunteer. In the motor mapping, we kept the transducer placement fixed while electronically shifting the E-field maximum on the precentral gyrus and measuring electromyography from the contralateral hand. RESULTS The transducer consists of an oval coil, two figure-of-eight coils, and two four-leaf-clover coils stacked on top of each other. The technical characterization indicated that the mTMS system performs as designed. The measured motor evoked potential amplitudes varied consistently as a function of the location of the E-field maximum. CONCLUSION The developed mTMS system enables electronically targeted brain stimulation within a cortical region.
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Affiliation(s)
- Jaakko O Nieminen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
| | - Heikki Sinisalo
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Victor H Souza
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; School of Physiotherapy, Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil
| | - Mikko Malmi
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Mikhail Yuryev
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Aino E Tervo
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; AMI Centre, Aalto NeuroImaging, Aalto University School of Science, Espoo, Finland
| | - Matti Stenroos
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Diego Milardovich
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Institute for Microelectronics, Technische Universität Wien, Vienna, Austria
| | - Juuso T Korhonen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Lari M Koponen
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland
| | - Risto J Ilmoniemi
- Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; BioMag Laboratory, HUS Medical Imaging Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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15
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Halawa I, Reichert K, Aberra AS, Sommer M, Peterchev AV, Paulus W. Effect of Pulse Duration and Direction on Plasticity Induced by 5 Hz Repetitive Transcranial Magnetic Stimulation in Correlation With Neuronal Depolarization. Front Neurosci 2021; 15:773792. [PMID: 34899173 PMCID: PMC8661453 DOI: 10.3389/fnins.2021.773792] [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: 09/10/2021] [Accepted: 10/28/2021] [Indexed: 11/20/2022] Open
Abstract
Introduction: High frequency repetitive transcranial magnetic stimulation applied to the motor cortex causes an increase in the amplitude of motor evoked potentials (MEPs) that persists after stimulation. Here, we focus on the aftereffects generated by high frequency controllable pulse TMS (cTMS) with different directions, intensities, and pulse durations. Objectives: To investigate the influence of pulse duration, direction, and amplitude in correlation to induced depolarization on the excitatory plastic aftereffects of 5 Hz repetitive transcranial magnetic stimulation (rTMS) using bidirectional cTMS pulses. Methods: We stimulated the hand motor cortex with 5 Hz rTMS applying 1,200 bidirectional pulses with the main component durations of 80, 100, and 120 μs using a controllable pulse stimulator TMS (cTMS). Fourteen healthy subjects were investigated in nine sessions with 80% resting motor threshold (RMT) for posterior-anterior (PA) and 80 and 90% RMT anterior-posterior (AP) induced current direction. We used a model approximating neuronal membranes as a linear first order low-pass filter to estimate the strength–duration time constant and to simulate the membrane polarization produced by each waveform. Results: PA and AP 5 Hz rTMS at 80% RMT produced no significant excitation. An exploratory analysis indicated that 90% RMT AP stimulation with 100 and 120 μs pulses but not 80 μs pulses led to significant excitation. We found a positive correlation between the plastic outcome of each session and the simulated peak neural membrane depolarization for time constants >100 μs. This correlation was strongest for neural elements that are depolarized by the main phase of the AP pulse, suggesting the effects were dependent on pulse direction. Conclusions: Among the tested conditions, only 5 Hz rTMS with higher intensity and wider pulses appeared to produce excitatory aftereffects. This correlated with the greater depolarization of neural elements with time constants slower than the directly activated neural elements responsible for producing the motor output (e.g., somatic or dendritic membrane). Significance: Higher intensities and wider pulses seem to be more efficient in inducing excitation. If confirmed, this observation could lead to better results in future clinical studies performed with wider pulses.
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Affiliation(s)
- Islam Halawa
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany.,Medical Research Division, National Research Center, Cairo, Egypt
| | - Katharina Reichert
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany
| | - Aman S Aberra
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Martin Sommer
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany.,Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.,Department of Geriatrics, University Medical Center Göttingen, Göttingen, Germany
| | - Angel V Peterchev
- Department of Biomedical Engineering, Duke University, Durham, NC, United States.,Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, United States.,Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States.,Department of Neurosurgery, Duke University, Durham, NC, United States
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany.,Department of Neurology, Ludwig-Maximilians University of Munich, Munich, Germany
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16
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Asbeck P, Alluri S, Leung V, Stambaugh M, Abbasi S, Makale M. A Compact Circuit for Boosting Electric Field Intensity in Repetitive Transcranial Magnetic Stimulation (rTMS). ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:6458-6464. [PMID: 34892590 DOI: 10.1109/embc46164.2021.9631054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The concept of a portable, wearable system for repetitive transcranial stimulation (rTMS) has attracted widespread attention, but significant power and field intensity requirements remain a key challenge. Here, a circuit topology is described that significantly increases induced electric field intensity over that attainable with similar current levels and coils in conventional rTMS systems. The resultant electric field is essentially monophasic, and has a controllable, shortened duration. The system is demonstrated in a compact circuit implementation for which an electric field of 94 V/m at a depth of 2 cm is measured (147 V/m at 1 cm depth) with a power supply voltage of 80 V, a maximum current of 500 A, and an effective pulse duration (half amplitude width) of 7 µsec. The peak electric field is on the same order as that of commercially available systems at full power and comparable depths. An electric field boost of 5x is demonstrated in comparison with our system operated conventionally, employing a 70 µsec rise time. It is shown that the power requirements for rTMS systems depend on the square of the product of electric field Ep and pulse duration tp, and that the proposed circuit technique enables continuous variation and optimization of the tradeoff between Ep and tp. It is shown that the electric field induced in a medium such as the human brain cortex at a specific depth is proportional to the voltage generated in a given loop of the generating coil, which allows insights into techniques for its optimization. This rTMS electric field enhancement strategy, termed 'boost rTMS (rbTMS)' is expected to increase the effectiveness of neural stimulation, and allow greater flexibility in the design of portable rTMS power systems.Clinical Relevance- This study aims to facilitate a compact, battery-powered rTMS prototype with enhanced electric field which will permit broader and more convenient rTMS treatment at home, in a small clinic, vessel, or field hospital, and potentially, on an ambulatory basis.
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17
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Sorkhabi MM, Benjaber M, Wendt K, West TO. Programmable Transcranial Magnetic Stimulation: A Modulation Approach for the Generation of Controllable Magnetic Stimuli. IEEE Trans Biomed Eng 2021; 68:1847-1858. [PMID: 32946379 PMCID: PMC7610606 DOI: 10.1109/tbme.2020.3024902] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE A transcranial magnetic stimulation system with programmable stimulus pulses and patterns is presented. The stimulus pulses of the implemented system expand beyond conventional damped cosine or near-rectangular pulses and approach an arbitrary waveform. METHODS The desired stimulus waveform shape is defined as a reference signal. This signal controls the semiconductor switches of an H-bridge inverter to generate a high-power imitation of the reference. The design uses a new paradigm for TMS, applying pulse-width modulation with a non-resonant, high-frequency switching architecture to synthesize waveforms that leverages the low-pass filtering properties of neuronal cells. The modulation technique enables control of the waveform, frequency, pattern, and intensity of the stimulus. RESULTS A system prototype was developed to demonstrate the technique. The experimental measurements demonstrate that the system is capable of generating stimuli up to 4 kHz with peak voltage and current values of ±1000 V and ±3600 A, respectively. The maximum transferred energy measured in the experimental validation was 100.4 Joules. To characterize repetitive TMS modalities, the efficiency of generating consecutive pulse triplets and quadruplets with interstimulus intervals of 1 ms was tested and verified. CONCLUSION The implemented TMS device can generate consecutive rectangular pulses with a predetermined time interval, widths and polarities, enables the synthesis of a wide range of magnetic stimuli. SIGNIFICANCE New waveforms promise functional advantages over the waveforms generated by current-generation TMS systems for clinical neuroscience research.
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Affiliation(s)
| | - Moaad Benjaber
- MRC Brain Network Dynamics Unit, University of Oxford, Oxford, OX1 3TH, UK
| | - Karen Wendt
- MRC Brain Network Dynamics Unit, University of Oxford, Oxford, OX1 3TH, UK
| | - Timothy O. West
- MRC Brain Network Dynamics Unit, University of Oxford, Oxford, OX1 3TH, UK
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18
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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: 558] [Impact Index Per Article: 186.0] [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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19
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Opie GM, Semmler JG. Preferential Activation of Unique Motor Cortical Networks With Transcranial Magnetic Stimulation: A Review of the Physiological, Functional, and Clinical Evidence. Neuromodulation 2020; 24:813-828. [PMID: 33295685 DOI: 10.1111/ner.13314] [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: 08/10/2020] [Revised: 09/30/2020] [Accepted: 10/19/2020] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The corticospinal volley produced by application of transcranial magnetic stimulation (TMS) over primary motor cortex consists of a number of waves generated by trans-synaptic input from interneuronal circuits. These indirect (I)-waves mediate the sensitivity of TMS to cortical plasticity and intracortical excitability and can be assessed by altering the direction of cortical current induced by TMS. While this methodological approach has been conventionally viewed as preferentially recruiting early or late I-wave inputs from a given populations of neurons, growing evidence suggests recruitment of different neuronal populations, and this would strongly influence interpretation and application of these measures. The aim of this review is therefore to consider the physiological, functional, and clinical evidence for the independence of the neuronal circuits activated by different current directions. MATERIALS AND METHODS To provide the relevant context, we begin with an overview of TMS methodology, focusing on the different techniques used to quantify I-waves. We then comprehensively review the literature that has used variations in coil orientation to investigate the I-wave circuits, grouping studies based on the neurophysiological, functional, and clinical relevance of their outcomes. RESULTS Review of the existing literature reveals significant evidence supporting the idea that varying current direction can recruit different neuronal populations having unique functionally and clinically relevant characteristics. CONCLUSIONS Further research providing greater characterization of the I-wave circuits activated with different current directions is required. This will facilitate the development of interventions that are able to modulate specific intracortical circuits, which will be an important application of TMS.
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Affiliation(s)
- George M Opie
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, Adelaide, Australia
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Roth Y, Pell GS, Barnea-Ygael N, Ankry M, Hadad Y, Eisen A, Burnishev Y, Tendler A, Moses E, Zangen A. Rotational field TMS: Comparison with conventional TMS based on motor evoked potentials and thresholds in the hand and leg motor cortices. Brain Stimul 2020; 13:900-907. [PMID: 32289723 DOI: 10.1016/j.brs.2020.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/20/2020] [Accepted: 03/16/2020] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) is a rapidly expanding technology utilized in research and neuropsychiatric treatments. Yet, conventional TMS configurations affect primarily neurons that are aligned parallel to the induced electric field by a fixed coil, making the activation orientation-specific. A novel method termed rotational field TMS (rfTMS), where two orthogonal coils are operated with a 90° phase shift, produces rotation of the electric field vector over almost a complete cycle, and may stimulate larger portion of the neuronal population within a given brain area. OBJECTIVE To compare the physiological effects of rfTMS and conventional unidirectional TMS (udTMS) in the motor cortex. METHODS Hand and leg resting motor thresholds (rMT), and motor evoked potential (MEP) amplitudes and latencies (at 120% of rMT), were measured using a dual-coil array based on the H7-coil, in 8 healthy volunteers following stimulation at different orientations of either udTMS or rfTMS. RESULTS For both target areas rfTMS produced significantly lower rMTs and much higher MEPs than those induced by udTMS, for comparable induced electric field amplitude. Both hand and leg rMTs were orientation-dependent. CONCLUSIONS rfTMS induces stronger physiologic effects in targeted brain regions at significantly lower intensities. Importantly, given the activation of a much larger population of neurons within a certain brain area, repeated application of rfTMS may induce different neuroplastic effects in neural networks, opening novel research and clinical opportunities.
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Affiliation(s)
- Yiftach Roth
- Brainsway Ltd, Israel; Department of Life Sciences, Ben-Gurion University, Beer Sheva, Israel
| | - Gaby S Pell
- Brainsway Ltd, Israel; Department of Life Sciences, Ben-Gurion University, Beer Sheva, Israel
| | - Noam Barnea-Ygael
- Department of Life Sciences, Ben-Gurion University, Beer Sheva, Israel
| | | | | | - Ami Eisen
- The Department of Physics of Complex Systems, The Weizmann Institute of Science, Rehovot, Israel
| | - Yuri Burnishev
- The Department of Physics of Complex Systems, The Weizmann Institute of Science, Rehovot, Israel
| | - Aron Tendler
- Brainsway Ltd, Israel; Department of Life Sciences, Ben-Gurion University, Beer Sheva, Israel; Advanced Mental Health Care Inc., Israel
| | - Elisha Moses
- The Department of Physics of Complex Systems, The Weizmann Institute of Science, Rehovot, Israel
| | - Abraham Zangen
- Department of Life Sciences, Ben-Gurion University, Beer Sheva, Israel.
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Chen Y, Gao G, Xiong H, Liu J, Wang Y. A multi-channel parameters adjustable magnetic field generator. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:024709. [PMID: 32113457 DOI: 10.1063/1.5125152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/27/2020] [Indexed: 06/10/2023]
Abstract
In order to increase the security and flexibility of the magnetic field generator, a multi-channel parameters adjustable (MCPA) magnetic field generator is designed and implemented in this paper. The circuit topology of the MCPA magnetic field generator is presented. The working principle of MCPA is analyzed. The pulse current is measured and verified by experiments. The results show that the pulsed current amplitude is adjustable under 1000 A, the adjustment range of the effective pulse width is 0-160 µs, and the adjustment range of the frequency is 1-10 Hz. The magnetic field intensity at 2.5 cm below the scalp of the brain was measured when the three channels were working at the same time. It can be seen that the intensity of the magnetic field in the central area is apparently higher than that in the surrounding. The channels of MCPA can also be chosen flexibly as needed. Therefore, it has a very high application and research value in the field of biological magnetism therapy.
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Affiliation(s)
- Yimei Chen
- School of Electrical Engineering and Automation, Tiangong University, Tianjin 300387, China
| | - Guohui Gao
- School of Electrical Engineering and Automation, Tiangong University, Tianjin 300387, China
| | - Hui Xiong
- School of Electrical Engineering and Automation, Tiangong University, Tianjin 300387, China
| | - Jinzhen Liu
- School of Electrical Engineering and Automation, Tiangong University, Tianjin 300387, China
| | - Yuling Wang
- School of Electrical Engineering and Automation, Tiangong University, Tianjin 300387, China
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22
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Hui J, Lioumis P, Blumberger DM, Daskalakis ZJ. Non-invasive Central Neuromodulation with Transcranial Magnetic Stimulation. Stereotact Funct Neurosurg 2020. [DOI: 10.1007/978-3-030-34906-6_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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23
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Tsuboyama M, Lee Kaye H, Rotenberg A. Biomarkers Obtained by Transcranial Magnetic Stimulation of the Motor Cortex in Epilepsy. Front Integr Neurosci 2019; 13:57. [PMID: 31736722 PMCID: PMC6837164 DOI: 10.3389/fnint.2019.00057] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 09/23/2019] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is associated with numerous neurodevelopmental disorders. Transcranial magnetic stimulation (TMS) of the motor cortex coupled with electromyography (EMG) enables biomarkers that provide measures of cortical excitation and inhibition that are particularly relevant to epilepsy and related disorders. The motor threshold (MT), cortical silent period (CSP), short interval intracortical inhibition (SICI), intracortical facilitation (ICF), and long interval intracortical inhibition (LICI) are among TMS-derived metrics that are modulated by antiepileptic drugs. TMS may have a practical role in optimization of antiepileptic medication regimens, as studies demonstrate dose-dependent relationships between TMS metrics and acute medication administration. A close association between seizure freedom and normalization of cortical excitability with long-term antiepileptic drug use highlights a plausible utility of TMS in measures of anti-epileptic drug efficacy. Finally, TMS-derived biomarkers distinguish patients with various epilepsies from healthy controls and thus may enable development of disorder-specific biomarkers and therapies both within and outside of the epilepsy realm.
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Affiliation(s)
- Melissa Tsuboyama
- Neuromodulation Program, Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, United States.,FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston, MA, United States
| | - Harper Lee Kaye
- Neuromodulation Program, Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, United States.,FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston, MA, United States
| | - Alexander Rotenberg
- Neuromodulation Program, Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, United States.,FM Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston, MA, United States.,Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Boston, MA, United States
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24
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Goetz SM, Alavi SMM, Deng ZD, Peterchev AV. Statistical Model of Motor-Evoked Potentials. IEEE Trans Neural Syst Rehabil Eng 2019; 27:1539-1545. [PMID: 31283508 DOI: 10.1109/tnsre.2019.2926543] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Motor-evoked potentials (MEPs) are widely used for biomarkers and dose individualization in transcranial stimulation. The large variability of MEPs requires sophisticated methods of analysis to extract information fast and correctly. Development and testing of such methods relies on the availability for realistic models of MEP generation, which are presently lacking. This paper presents a statistical model that can simulate long sequences of individualized MEP amplitude data with properties matching experimental observations. The MEP model includes three sources of trial-to-trial variability: excitability fluctuations, variability in the neural and muscular pathways, and physiological and measurement noise. It also generates virtual human subject data from statistics of population variability. All parameters are extracted as statistical distributions from experimental data from the literature. The model exhibits previously described features, such as stimulus-intensity-dependent MEP amplitude distributions, including bimodal ones. The model can generate long sequences of test data for individual subjects with specified parameters or for subjects from a virtual population. The presented MEP model is the most detailed to date and can be used for the development and implementation of dosing and biomarker estimation algorithms for transcranial stimulation.
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25
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Kagan ZB, Mize JT, Kosta P, Lazzi G, Normann RA, Warren DJ. Reduced Heat Generation During Magnetic Stimulation of Rat Sciatic Nerve Using Current Waveform Truncation. IEEE Trans Neural Syst Rehabil Eng 2019; 27:937-946. [DOI: 10.1109/tnsre.2019.2911054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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26
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Halawa I, Shirota Y, Neef A, Sommer M, Paulus W. Neuronal tuning: Selective targeting of neuronal populations via manipulation of pulse width and directionality. Brain Stimul 2019; 12:1244-1252. [PMID: 31085123 DOI: 10.1016/j.brs.2019.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 04/22/2019] [Accepted: 04/25/2019] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION Motor evoked potentials (MEP) in response to anteroposterior transcranial (AP) magnetic stimulation (TMS) are sensitive to the TMS pulse shape. We are now able to isolate distinct pulse properties, such as pulse width and directionality and evaluate them individually. Different pulse shapes induce different effects, likely by stimulating different populations of neurons. This implies that not all neurons respond in the same manner to stimulation, possibly, because individual segments of neurons differ in their membrane properties. OBJECTIVES To investigate the effect of different pulse widths and directionalities of TMS on MEP latencies, motor thresholds and plastic aftereffects of rTMS. METHODS Using a controllable pulse stimulator TMS (cTMS), we stimulated fifteen subjects with quasi-unidirectional TMS pulses of different pulse durations (40 μs, 80 μs and 120 μs) and determined thresholds and MEP AP latencies. We then compared the effects of 80 μs quasi-unidirectional pulses to those of 80 μs pulses with different pulse directionality characteristics (0.6 and 1.0 M ratios). We applied 900 pulses of the selected pulse shapes at 1 Hz. RESULTS The aftereffects of 1 Hz rTMS depended on pulse shape and duration. 40 and 80 μs wide unidirectional pulses induced inhibition, 120 μs wide pulses caused excitation. Bidirectional pulses induced inhibition during the stimulation but had facilitatory aftereffects. Narrower pulse shapes caused longer latencies and higher resting motor thresholds (RMT) as compared to wider pulse shapes. CONCLUSIONS We can tune the aftereffects of rTMS by manipulating pulse width and directionality; this may be due to the different membrane properties of the various neuronal segments such as dendrites. SIGNIFICANCE To date, rTMS frequency has been the main determinant of the plastic aftereffects. However, we showed that pulse width also plays a major role, probably by recruiting novel neuronal targets.
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Affiliation(s)
- I Halawa
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany; Medical Research Center of Excellence, National Research Center, Cairo, Egypt.
| | - Y Shirota
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany; Department of Neurology, The University of Tokyo Hospital, Tokyo, Japan
| | - A Neef
- Center for Biostructural Imaging of Neurodegeneration (BIN), Göttingen, Germany; Campus Institute for the Dynamics of Biological Networks, Göttingen, Germany
| | - M Sommer
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
| | - W Paulus
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Robert Koch Str. 40, 37075, Göttingen, Germany
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Casula E, Rocchi L, Hannah R, Rothwell J. Effects of pulse width, waveform and current direction in the cortex: A combined cTMS-EEG study. Brain Stimul 2018; 11:1063-1070. [DOI: 10.1016/j.brs.2018.04.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 02/16/2018] [Accepted: 04/19/2018] [Indexed: 10/17/2022] Open
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Wilson MT, Tang AD, Iyer K, McKee H, Waas J, Rodger J. The challenges of producing effective small coils for transcranial magnetic stimulation of mice. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aab525] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Xiong H, Sun W, Liu J, Shi J. A multifunctional energy-saving magnetic field generator. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:034704. [PMID: 29604796 DOI: 10.1063/1.4990629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
To improve the energy utilization of magnetic field generators for biological applications, a multifunctional energy-saving magnetic field generator (ESMFG) is presented. It is capable of producing both an alternating magnetic field (AMF) and a bipolar pulse magnetic field (BPMF) with high energy-saving and energy-reuse rates. Based on a theoretical analysis of an RLC second-order circuit, the energy-saving and energy-reuse rates of both types of magnetic fields can be calculated and are found to have acceptable values. The results of an experimental study using the proposed generator show that for the BPMF, the peak current reaches 130 A and the intensity reaches 70.3 mT. For the AMF, the intensity is 11.0 mT and the RMS current is 20 A. The energy-saving and energy-reuse rates for the AMF generator are 61.3% and 63.5%, respectively, while for the BPMF generator, the energy-saving rate is 33.6%. Thus, the proposed ESMFG has excellent potential for use in biomedical applications.
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Affiliation(s)
- Hui Xiong
- School of Electrical Engineering and Automation, Tianjin Polytechnic University, Tianjin 300387, China
| | - Wanpeng Sun
- School of Electrical Engineering and Automation, Tianjin Polytechnic University, Tianjin 300387, China
| | - Jinzhen Liu
- School of Electrical Engineering and Automation, Tianjin Polytechnic University, Tianjin 300387, China
| | - Jinhua Shi
- School of Electrical Engineering and Automation, Tianjin Polytechnic University, Tianjin 300387, China
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Yanamadala J, Noetscher GM, Makarov SN, Pascual-Leone A. Estimates of peak electric fields induced by Transcranial magnetic stimulation in pregnant women as patients using an FEM full-body model. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2017:1441-1444. [PMID: 29060149 DOI: 10.1109/embc.2017.8037105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Transcranial magnetic stimulation (TMS) for treatment of depression during pregnancy is an appealing alternative to fetus-threatening drugs. However, no studies to date have been performed that evaluate the safety of TMS for a pregnant mother patient and her fetus. A full-body FEM model of a pregnant woman with about 100 tissue parts has been developed specifically for the present study. This model allows accurate computations of induced electric field in every tissue given different locations of a shape-eight coil, a biphasic pulse, common TMS pulse durations, and using different values of the TMS intensity measured in SMT (Standard Motor Threshold) units. Our simulation results estimate the maximum peak values of the electric field in the fetal area for every fetal tissue separately and for the TMS intensity of one SMT unit.
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Shirota Y, Dhaka S, Paulus W, Sommer M. Current direction-dependent modulation of human hand motor function by intermittent theta burst stimulation (iTBS). Neurosci Lett 2017; 650:109-113. [PMID: 28435045 DOI: 10.1016/j.neulet.2017.04.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/08/2017] [Accepted: 04/18/2017] [Indexed: 11/17/2022]
Abstract
BACKGROUND Transcranial magnetic stimulation (TMS) with different current directions can activate different sets of neurons. Current direction can also affect the results of repetitive TMS. OBJECTIVE To test the influence of uni-directional intermittent theta burst stimulation (iTBS) using different current directions, namely posteroanterior (PA) and anteroposterior (AP), on motor behaviour. METHODS In a cross-over design, PA- and AP-iTBS was applied over the left primary motor cortex in 19 healthy, right-handed volunteers. Performance of a finger-tapping task was recorded before and 0, 10, 20, and 30min after the iTBS. The task was conducted with the right and left hands separately at each time point. As a control, AP-iTBS with reduced intensity was applied to 14 participants in a separate session (APweak condition). RESULTS The finger-tapping count with the left hand was decreased after PA-iTBS. Neither AP- nor APweak-iTBS altered the performance. CONCLUSIONS Current direction had a significant impact on the after-effects of iTBS.
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Affiliation(s)
- Yuichiro Shirota
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany.
| | - Suman Dhaka
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany; Indian Institute of Technology, Guwahati, Assam, India.
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany.
| | - Martin Sommer
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, Germany.
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Goetz SM, Deng ZD. The development and modelling of devices and paradigms for transcranial magnetic stimulation. Int Rev Psychiatry 2017; 29:115-145. [PMID: 28443696 PMCID: PMC5484089 DOI: 10.1080/09540261.2017.1305949] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 03/03/2017] [Accepted: 03/09/2017] [Indexed: 12/20/2022]
Abstract
Magnetic stimulation is a non-invasive neurostimulation technique that can evoke action potentials and modulate neural circuits through induced electric fields. Biophysical models of magnetic stimulation have become a major driver for technological developments and the understanding of the mechanisms of magnetic neurostimulation and neuromodulation. Major technological developments involve stimulation coils with different spatial characteristics and pulse sources to control the pulse waveform. While early technological developments were the result of manual design and invention processes, there is a trend in both stimulation coil and pulse source design to mathematically optimize parameters with the help of computational models. To date, macroscopically highly realistic spatial models of the brain, as well as peripheral targets, and user-friendly software packages enable researchers and practitioners to simulate the treatment-specific and induced electric field distribution in the brains of individual subjects and patients. Neuron models further introduce the microscopic level of neural activation to understand the influence of activation dynamics in response to different pulse shapes. A number of models that were designed for online calibration to extract otherwise covert information and biomarkers from the neural system recently form a third branch of modelling.
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Affiliation(s)
- Stefan M Goetz
- a Department of Psychiatry & Behavioral Sciences, Division for Brain Stimulation & Neurophysiology , Duke University , Durham , NC , USA
- b Department of Electrical & Computer Engineering , Duke University , Durham , NC , USA
- c Department of Neurosurgery , Duke University , Durham , NC , USA
| | - Zhi-De Deng
- a Department of Psychiatry & Behavioral Sciences, Division for Brain Stimulation & Neurophysiology , Duke University , Durham , NC , USA
- d Intramural Research Program, Experimental Therapeutics & Pathophysiology Branch, Noninvasive Neuromodulation Unit , National Institutes of Health, National Institute of Mental Health , Bethesda , MD , USA
- e Duke Institute for Brain Sciences , Duke University , Durham , NC , USA
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Peterchev AV, Murphy DLK, Goetz SM. Quiet transcranial magnetic stimulation: Status and future directions. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:226-9. [PMID: 26736241 DOI: 10.1109/embc.2015.7318341] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A significant limitation of transcranial magnetic stimulation (TMS) is that the magnetic pulse delivery is associated with a loud clicking sound as high as 140 dB resulting from electromagnetic forces. The loud noise significantly impedes both basic research and clinical applications of TMS. It effectively makes TMS less focal since every click activates auditory cortex, brainstem, and other connected regions, synchronously with the magnetic pulse. The repetitive clicking sound can induce neuromodulation that can interfere with and confound the intended effects at the TMS target. As well, there are known concerns regarding blinding of TMS studies, hearing loss, induction of tinnitus, as well as tolerability. Addressing this need, we are developing a quiet TMS (qTMS) device that incorporates two key concepts: First, the dominant frequency components of the TMS pulse sound (typically 2-5 kHz) are shifted to higher frequencies that are above the human hearing upper threshold of about 20 kHz. Second, the TMS coil is designed electrically and mechanically to generate suprathreshold electric field pulses while minimizing the sound emitted at audible frequencies (<; 20 kHz). The enhanced acoustic properties of the coil are accomplished with a novel, layered coil design. We summarize a proof-of-concept qTMS prototype demonstrating noise loudness reduction by 19 dB(A) with ultrabrief pulses at conventional amplitudes. Further, we outline next steps to accomplish further sound reduction and suprathreshold pulse amplitudes.
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Peterchev AV, Luber B, Westin GG, Lisanby SH. Pulse Width Affects Scalp Sensation of Transcranial Magnetic Stimulation. Brain Stimul 2016; 10:99-105. [PMID: 28029593 DOI: 10.1016/j.brs.2016.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 09/24/2016] [Accepted: 09/26/2016] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Scalp sensation and pain comprise the most common side effect of transcranial magnetic stimulation (TMS), which can reduce tolerability and complicate experimental blinding. OBJECTIVE We explored whether changing the width of single TMS pulses affects the quality and tolerability of the resultant somatic sensation. METHODS Using a controllable pulse parameter TMS device with a figure-8 coil, single monophasic magnetic pulses inducing electric field with initial phase width of 30, 60, and 120 µs were delivered in 23 healthy volunteers. Resting motor threshold of the right first dorsal interosseus was determined for each pulse width, as reported previously. Subsequently, pulses were delivered over the left dorsolateral prefrontal cortex at each of the three pulse widths at two amplitudes (100% and 120% of the pulse-width-specific motor threshold), with 20 repetitions per condition delivered in random order. After each pulse, subjects rated 0-to-10 visual analog scales for Discomfort, Sharpness, and Strength of the sensation. RESULTS Briefer TMS pulses with amplitude normalized to the motor threshold were perceived as slightly more uncomfortable than longer pulses (with an average 0.89 point increase on the Discomfort scale for pulse width of 30 µs compared to 120 µs). The sensation of the briefer pulses was felt to be substantially sharper (2.95 points increase for 30 µs compared to 120 µs pulse width), but not stronger than longer pulses. As expected, higher amplitude pulses increased the perceived discomfort and strength, and, to a lesser degree the perceived sharpness. CONCLUSIONS Our findings contradict a previously published hypothesis that briefer TMS pulses are more tolerable. We discovered that the opposite is true, which merits further study as a means of enhancing tolerability in the context of repetitive TMS.
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Affiliation(s)
- Angel V Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA; Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
| | - Bruce Luber
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - Gregory G Westin
- Division of Vascular and Endovascular Surgery, New York University Langone Medical Center, New York, NY, USA
| | - Sarah H Lisanby
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA; Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
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Makarov SN, Yanamadala J, Piazza MW, Helderman AM, Thang NS, Burnham EH, Pascual-Leone A. Preliminary Upper Estimate of Peak Currents in Transcranial Magnetic Stimulation at Distant Locations From a TMS Coil. IEEE Trans Biomed Eng 2016; 63:1944-1955. [PMID: 26685221 PMCID: PMC5845790 DOI: 10.1109/tbme.2015.2507572] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
GOALS Transcranial magnetic stimulation (TMS) is increasingly used as a diagnostic and therapeutic tool for numerous neuropsychiatric disorders. The use of TMS might cause whole-body exposure to undesired induced currents in patients and TMS operators. The aim of this study is to test and justify a simple analytical model known previously, which may be helpful as an upper estimate of eddy current density at a particular distant observation point for any body composition and any coil setup. METHODS We compare the analytical solution with comprehensive adaptive mesh refinement-based FEM simulations of a detailed full-body human model, two coil types, five coil positions, about 100 000 observation points, and two distinct pulse rise times; thus, providing a representative number of different datasets for comparison, while also using other numerical data. RESULTS Our simulations reveal that, after a certain modification, the analytical model provides an upper estimate for the eddy current density at any location within the body. In particular, it overestimates the peak eddy currents at distant locations from a TMS coil by a factor of 10 on average. CONCLUSION The simple analytical model tested in this study may be valuable as a rapid method to safely estimate levels of TMS currents at different locations within a human body. SIGNIFICANCE At present, safe limits of general exposure to TMS electric and magnetic fields are an open subject, including fetal exposure for pregnant women.
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Shirota Y, Sommer M, Paulus W. Strength-Duration Relationship in Paired-pulse Transcranial Magnetic Stimulation (TMS) and Its Implications for Repetitive TMS. Brain Stimul 2016; 9:755-761. [PMID: 27234142 DOI: 10.1016/j.brs.2016.04.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/25/2016] [Accepted: 04/27/2016] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Paired-pulse protocols have played a pivotal role in neuroscience research using transcranial magnetic stimulation (TMS). Stimulus parameters have been optimized over the years. More recently, pulse width (PW) has been introduced to this field as a new parameter, which may further fine-tune paired-pulse protocols. The relationship between the PW and effectiveness of a stimulus is known as the "strength-duration relationship". OBJECTIVE To test the "strength-duration relationship", so as to improve paired-pulse TMS protocols, and to apply the results to develop new repetitive TMS (rTMS) methods. METHODS Four protocols were investigated separately: short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), short-interval intracortical facilitation (SICF) and long-interval intracortical inhibition (LICI). First, various stimulus parameters were tested to identify those yielding the largest facilitation or inhibition of the motor evoked potential (MEP) in each participant. Using these parameters, paired-pulse stimulations were repeated every five seconds for 30 minutes (repetitive paired-pulse stimulation, rPPS). The after-effects of rPPS were measured using MEP amplitude as an index of motor-cortical excitability. RESULTS Altogether, the effect of changing PW was similar to that of changing the stimulus intensity in the conventional settings. The best parameters were different for each participant. When these parameters were used, rPPS based on either SICF or ICF induced an increase in MEP amplitude. CONCLUSIONS PW was introduced as a new parameter in paired-pulse TMS. Modulation of PW influenced the results of paired-pulse protocols. rPPS using facilitatory protocols can be a good candidate to induce enhancement of motor-cortical excitability.
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Affiliation(s)
- Yuichiro Shirota
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Robert-Koch Straße 40, Göttingen 37075, Germany.
| | - Martin Sommer
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Robert-Koch Straße 40, Göttingen 37075, Germany
| | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Robert-Koch Straße 40, Göttingen 37075, Germany
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Goetz SM, Luber B, Lisanby SH, Murphy DLK, Kozyrkov IC, Grill WM, Peterchev AV. Enhancement of Neuromodulation with Novel Pulse Shapes Generated by Controllable Pulse Parameter Transcranial Magnetic Stimulation. Brain Stimul 2016; 9:39-47. [PMID: 26460199 PMCID: PMC5517314 DOI: 10.1016/j.brs.2015.08.013] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 07/28/2015] [Accepted: 08/27/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Standard repetitive transcranial magnetic stimulation (rTMS) devices generate bidirectional biphasic sinusoidal pulses that are energy efficient, but may be less effective than monophasic pulses that induce a more unidirectional electric field. To enable pulse shape optimization, we developed a controllable pulse parameter TMS (cTMS) device. OBJECTIVE We quantified changes in cortical excitability produced by conventional sinusoidal bidirectional pulses and by three rectangular-shaped cTMS pulses, one bidirectional and two unidirectional (in opposite directions), and compared their efficacy in modulating motor evoked potentials (MEPs) produced by stimulation of motor cortex. METHODS Thirteen healthy subjects completed four sessions of 1 Hz rTMS of the left motor cortex. In each session, the rTMS electric field pulse had one of the four shapes. Excitability changes due to rTMS were measured by applying probe TMS pulses before and after rTMS, and comparing resultant MEP amplitudes. Separately, we measured the latency of the MEPs evoked by each of the four pulses. RESULTS While the three cTMS pulses generated significant mean inhibitory effects in the subject group, the conventional biphasic cosine pulses did not. The strongest inhibition resulted from a rectangular unidirectional pulse with dominant induced current in the posterior-anterior direction. The MEP latency depended significantly on the pulse shape. CONCLUSIONS The pulse shape is an important factor in rTMS-induced neuromodulation. The standard cosine biphasic pulse showed the smallest effect on cortical excitability, while the greatest inhibition was observed for an asymmetric, unidirectional, rectangular pulse. Differences in MEP latency across the various rTMS pulse shapes suggest activation of distinct subsets of cortical microcircuitry.
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Affiliation(s)
- Stefan M Goetz
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA
| | - Bruce Luber
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA; Department of Psychology and Neuroscience, Duke University, Durham, NC 27710, USA
| | - Sarah H Lisanby
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA; Department of Psychology and Neuroscience, Duke University, Durham, NC 27710, USA
| | - David L K Murphy
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA
| | - I Cassie Kozyrkov
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA; Department of Neurobiology, Duke University, Durham, NC 27710, USA; Department of Surgery, Duke University, Durham, NC 27710, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC 27710, USA
| | - Angel V Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC 27710, USA; Department of Biomedical Engineering, Duke University, Durham, NC 27710, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC 27710, USA.
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Peterchev AV, Deng ZD, Goetz SM. Advances in Transcranial Magnetic Stimulation Technology. Brain Stimul 2015. [DOI: 10.1002/9781118568323.ch10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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D'Ostilio K, Goetz SM, Hannah R, Ciocca M, Chieffo R, Chen JCA, Peterchev AV, Rothwell JC. Effect of coil orientation on strength-duration time constant and I-wave activation with controllable pulse parameter transcranial magnetic stimulation. Clin Neurophysiol 2015; 127:675-683. [PMID: 26077634 PMCID: PMC4727502 DOI: 10.1016/j.clinph.2015.05.017] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 05/08/2015] [Accepted: 05/13/2015] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare the strength-duration (S-D) time constants of motor cortex structures activated by current pulses oriented posterior-anterior (PA) or anterior-posterior (AP) across the central sulcus. METHODS Motor threshold and input-output curve, along with motor evoked potential (MEP) latencies, of first dorsal interosseus were determined at pulse widths of 30, 60, and 120 μs using a controllable pulse parameter (cTMS) device, with the coil oriented PA or AP. These were used to estimate the S-D time constant and we compared with data for responses evoked by cTMS of the ulnar nerve at the elbow. RESULTS The S-D time constant with PA was shorter than for AP stimulation (230.9 ± 97.2 vs. 294.2 ± 90.9 μs; p<0.001). These values were similar to those calculated after stimulation of ulnar nerve (197 ± 47 μs). MEP latencies to AP, but not PA stimulation were affected by pulse width, showing longer latencies following short duration stimuli. CONCLUSION PA and AP stimuli appear to activate the axons of neurons with different time constants. Short duration AP pulses are more selective than longer pulses in recruiting longer latency corticospinal output. SIGNIFICANCE More selective stimulation of neural elements may be achieved by manipulating pulse width and orientation.
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Affiliation(s)
- Kevin D'Ostilio
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK; MoVeRe Group, Cyclotron Research Centre, University of Liege, Belgium
| | - Stefan M Goetz
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA; Technical University Munich, Munich, Germany
| | - Ricci Hannah
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK
| | - Matteo Ciocca
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK; Department of Neurological Science, University of Milan, Milan, Italy
| | - Raffaella Chieffo
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK; Department of Neurology, Scientific Institute Hospital San Raffaele, Milan, Italy
| | - Jui-Cheng A Chen
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK; Neuroscience Laboratory, Department of Neurology, China Medical University Hospital, Taichung, Taiwan; School of Medicine, China Medical University, Taichung, Taiwan
| | - Angel V Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA; Department of Biomedical Engineering, Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - John C Rothwell
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, London, UK
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Grehl S, Viola HM, Fuller-Carter PI, Carter KW, Dunlop SA, Hool LC, Sherrard RM, Rodger J. Cellular and Molecular Changes to Cortical Neurons Following Low Intensity Repetitive Magnetic Stimulation at Different Frequencies. Brain Stimul 2015; 8:114-23. [DOI: 10.1016/j.brs.2014.09.012] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 09/05/2014] [Accepted: 09/21/2014] [Indexed: 10/24/2022] Open
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Peterchev AV, D’Ostilio K, Rothwell JC, Murphy DL. Controllable pulse parameter transcranial magnetic stimulator with enhanced circuit topology and pulse shaping. J Neural Eng 2014; 11:056023. [PMID: 25242286 PMCID: PMC4208275 DOI: 10.1088/1741-2560/11/5/056023] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE This work aims at flexible and practical pulse parameter control in transcranial magnetic stimulation (TMS), which is currently very limited in commercial devices. APPROACH We present a third generation controllable pulse parameter device (cTMS3) that uses a novel circuit topology with two energy-storage capacitors. It incorporates several implementation and functionality advantages over conventional TMS devices and other devices with advanced pulse shape control. cTMS3 generates lower internal voltage differences and is implemented with transistors with a lower voltage rating than prior cTMS devices. MAIN RESULTS cTMS3 provides more flexible pulse shaping since the circuit topology allows four coil-voltage levels during a pulse, including approximately zero voltage. The near-zero coil voltage enables snubbing of the ringing at the end of the pulse without the need for a separate active snubber circuit. cTMS3 can generate powerful rapid pulse sequences (< 10 ms inter pulse interval) by increasing the width of each subsequent pulse and utilizing the large capacitor energy storage, allowing the implementation of paradigms such as paired-pulse and quadripulse TMS with a single pulse generation circuit. cTMS3 can also generate theta (50 Hz) burst stimulation with predominantly unidirectional electric field pulses. The cTMS3 device functionality and output strength are illustrated with electrical output measurements as well as a study of the effect of pulse width and polarity on the active motor threshold in ten healthy volunteers. SIGNIFICANCE The cTMS3 features could extend the utility of TMS as a research, diagnostic, and therapeutic tool.
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Affiliation(s)
- Angel V Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Kevin D’Ostilio
- Cyclotron Research Centre, University of Liege, Belgium
- Institute of Neurology, University College London, London, UK
| | - John C Rothwell
- Institute of Neurology, University College London, London, UK
| | - David L Murphy
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
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Activation of the central nervous system induced by micro-magnetic stimulation. Nat Commun 2014; 4:2463. [PMID: 24030203 PMCID: PMC3845906 DOI: 10.1038/ncomms3463] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 08/16/2013] [Indexed: 11/09/2022] Open
Abstract
Electrical and transcranial magnetic stimulations have proven to be therapeutically beneficial for patients suffering from neurological disorders. Moreover, these stimulation technologies have provided invaluable tools for investigating nervous system functions. Despite this success, these technologies have technical and practical limitations impeding the maximization of their full clinical and preclinical potential. Recently, micro-magnetic stimulation, which may offer advantages over electrical and transcranial magnetic stimulation, has proven effective in activating the neuronal circuitry of the retina in vitro. Here we demonstrate that this technology is also capable of activating neuronal circuitry on a systems level using an in vivo preparation. Specifically, the application of micro-magnetic fields to the dorsal cochlear nucleus activates inferior colliculus neurons. Additionally, we demonstrate the efficacy and characteristics of activation using different magnetic stimulation parameters. These findings provide a rationale for further exploration of micro-magnetic stimulation as a prospective tool for clinical and preclinical applications.
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Roth Y, Levkovitz Y, Pell GS, Ankry M, Zangen A. Safety and Characterization of a Novel Multi-channel TMS Stimulator. Brain Stimul 2014; 7:194-205. [DOI: 10.1016/j.brs.2013.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 09/15/2013] [Accepted: 09/16/2013] [Indexed: 11/29/2022] Open
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Rotem A, Neef A, Neef NE, Agudelo-Toro A, Rakhmilevitch D, Paulus W, Moses E. Solving the orientation specific constraints in transcranial magnetic stimulation by rotating fields. PLoS One 2014; 9:e86794. [PMID: 24505266 PMCID: PMC3914799 DOI: 10.1371/journal.pone.0086794] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 12/13/2013] [Indexed: 11/19/2022] Open
Abstract
Transcranial Magnetic Stimulation (TMS) is a promising technology for both neurology and psychiatry. Positive treatment outcome has been reported, for instance in double blind, multi-center studies on depression. Nonetheless, the application of TMS towards studying and treating brain disorders is still limited by inter-subject variability and lack of model systems accessible to TMS. The latter are required to obtain a deeper understanding of the biophysical foundations of TMS so that the stimulus protocol can be optimized for maximal brain response, while inter-subject variability hinders precise and reliable delivery of stimuli across subjects. Recent studies showed that both of these limitations are in part due to the angular sensitivity of TMS. Thus, a technique that would eradicate the need for precise angular orientation of the coil would improve both the inter-subject reliability of TMS and its effectiveness in model systems. We show here how rotation of the stimulating field relieves the angular sensitivity of TMS and provides improvements in both issues. Field rotation is attained by superposing the fields of two coils positioned orthogonal to each other and operated with a relative phase shift in time. Rotating field TMS (rfTMS) efficiently stimulates both cultured hippocampal networks and rat motor cortex, two neuronal systems that are notoriously difficult to excite magnetically. This opens the possibility of pharmacological and invasive TMS experiments in these model systems. Application of rfTMS to human subjects overcomes the orientation dependence of standard TMS. Thus, rfTMS yields optimal targeting of brain regions where correct orientation cannot be determined (e.g., via motor feedback) and will enable stimulation in brain regions where a preferred axonal orientation does not exist.
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Affiliation(s)
- Assaf Rotem
- Department of Physics and SEAS, Harvard University, Cambridge, Massachusetts, United States of America
| | - Andreas Neef
- Bernstein Center for Computational Neuroscience, Goettingen, Germany
| | - Nicole E. Neef
- Department of Clinical Neurophysiology, University Medicine Goettingen, Goettingen, Germany
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Andres Agudelo-Toro
- Max Planck Institute for Dynamics and Self-Organization, Goettingen, Germany
| | | | - Walter Paulus
- Department of Clinical Neurophysiology, University Medicine Goettingen, Goettingen, Germany
| | - Elisha Moses
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
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Deng ZD, Lisanby SH, Peterchev AV. Coil design considerations for deep transcranial magnetic stimulation. Clin Neurophysiol 2013; 125:1202-12. [PMID: 24411523 DOI: 10.1016/j.clinph.2013.11.038] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 10/06/2013] [Accepted: 11/09/2013] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To explore the field characteristics and design tradeoffs of coils for deep transcranial magnetic stimulation (dTMS). METHODS We simulated parametrically two dTMS coil designs on a spherical head model using the finite element method, and compare them with five commercial TMS coils, including two that are FDA approved for the treatment of depression (ferromagnetic-core figure-8 and H1 coil). RESULTS Smaller coils have a focality advantage over larger coils; however, this advantage diminishes with increasing target depth. Smaller coils have the disadvantage of producing stronger field in the superficial cortex and requiring more energy. When the coil dimensions are large relative to the head size, the electric field decay in depth becomes linear, indicating that, at best, the electric field attenuation is directly proportional to the depth of the target. Ferromagnetic cores improve electrical efficiency for targeting superficial brain areas; however magnetic saturation reduces the effectiveness of the core for deeper targets, especially for highly focal coils. Distancing winding segments from the head, as in the H1 coil, increases the required stimulation energy. CONCLUSIONS Among standard commercial coils, the double cone coil offers high energy efficiency and balance between stimulated volume and superficial field strength. Direct TMS of targets at depths of ~4 cm or more results in superficial stimulation strength that exceeds the upper limit in current rTMS safety guidelines. Approaching depths of ~6 cm is almost certainly unsafe considering the excessive superficial stimulation strength and activated brain volume. SIGNIFICANCE Coil design limitations and tradeoffs are important for rational and safe exploration of dTMS.
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Affiliation(s)
- Zhi-De Deng
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - Sarah H Lisanby
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA; Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Angel V Peterchev
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA; Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA.
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Wankhar S, Devasahayam S, Babu S. A Novel Magnetic Stimulator Using Parallel Excited Coils and Capable of High Frequency Stimulation. J Med Device 2013. [DOI: 10.1115/1.4025422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Magnetic stimulators are used for transcranial and peripheral stimulation of nerves for diagnostic, therapeutic, and research purposes. Stimulation is achieved by generating a rapidly changing magnetic field to induce a current at the nerve of interest. Effective nerve stimulation requires a current transient of about 108A/s. This current is obtained by switching the current through a thyristor or an insulated gate bipolar transistor (IGBT). Insulated gate bipolar transistors have better turn off characteristics than thyristors. Due to the large currents, fast switching, and inductive load required in magnetic stimulators, spike voltages can occur and cause device damage. Therefore, they require elaborate protection circuitry. Contemporary magnetic stimulators are large, bulky, and give a current wave that is constrained by the device characteristics rather than decided by physiology. Recent instruments using IGBTs have addressed this question. However, the IGBTs require special considerations to protect them against damage. No magnetic stimulators reported so far can stimulate at rates greater than 60 Hz (Magstim Rapid2, two linked stimulators). A novel magnetic stimulator design is presented in this paper which uses a set of stacked coils driven by independent but synchronized electronic circuits to distribute the current so that only a fraction of the required current flows through any given circuit element. The coils can be arranged in several different geometries, depending on the location and shape of the nerves to be stimulated. While such paralleling of coils and control circuits is not so important for the thyristor circuit design, in the case of the IGBT design it allows the use of smaller IGBTs and better transient control. The design of the coils and independent excitation improves the current control and the magnetic field that is generated. The result is a portable instrument with well controlled rectangular pulse shapes. This stimulator is also capable of much higher frequencies (tested up to 100 Hz) than previously reported. Experimental tests have been compared with the biophysical analysis of stimulation with this instrument. Peripheral nerve stimulation and the elicited compound muscle action potential was used to validate the instrument. The instrument has been tested for the controlled recruitment of a compound nerve at up to 100 Hz. In this paper we present a portable magnetic stimulator capable of high frequency stimulation and rectangular stimulation pulse. These features should give fresh momentum to the use of magnetic stimulation in neurological investigations and interventions. In particular, we expect that it will find wide clinical use such as in pediatric neurology, psychiatry, and neuromodulation.
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Affiliation(s)
| | - Suresh Devasahayam
- e-mail: Department of Bioengineering, Christian Medical College, Tamil Nadu 632004, India
| | - Srinivasa Babu
- Department of Neurological Sciences, Christian Medical College, Tamil Nadu 632004, India e-mail:
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Wang X, Bey AL, Chung L, Krystal AD, Jiang YH. Therapeutic approaches for shankopathies. Dev Neurobiol 2013; 74:123-35. [PMID: 23536326 DOI: 10.1002/dneu.22084] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/21/2013] [Indexed: 12/13/2022]
Abstract
Despite recent advances in understanding the molecular mechanisms of autism spectrum disorders (ASD), the current treatments for these disorders are mostly focused on behavioral and educational approaches. The considerable clinical and molecular heterogeneity of ASD present a significant challenge to the development of an effective treatment targeting underlying molecular defects. Deficiency of SHANK family genes causing ASD represent an exciting opportunity for developing molecular therapies because of strong genetic evidence for SHANK as causative genes in ASD and the availability of a panel of Shank mutant mouse models. In this article, we review the literature suggesting the potential for developing therapies based on molecular characteristics and discuss several exciting themes that are emerging from studying Shank mutant mice at the molecular level and in terms of synaptic function.
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Affiliation(s)
- Xiaoming Wang
- Department of Pediatrics, Duke University School of Medicine Durham, North Carolina, 27710
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Goetz SM, Truong NC, Gerhofer MG, Peterchev AV, Herzog HG, Weyh T. Optimization of magnetic neurostimulation waveforms for minimum power loss. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:4652-5. [PMID: 23366965 DOI: 10.1109/embc.2012.6347004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Magnetic stimulation is a key tool in experimental brain research and several clinical applications. Whereas coil designs and the spatial field properties have been intensively studied in the literature, the temporal dynamics of the field has received little attention. The available pulse shapes are typically determined by the relatively limited capabilities of commercial stimulation devices instead of efficiency or optimality. Furthermore, magnetic stimulation is relatively inefficient with respect to the required energy compared to other neurostimulation techniques. We therefore analyze and optimize the waveform dynamics with a nonlinear model of a mammalian motor axon for the first time, without any pre-definition of waveform candidates. We implemented an unbiased and stable numerical algorithm using variational calculus in combination with a global optimization method. This approach yields very stable results with comprehensible characteristic properties, such as a first phase which reduces ohmic losses in the subsequent pulse phase. We compare the energy loss of these optimal waveforms with the waveforms generated by existing magnetic stimulation devices.
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Affiliation(s)
- S M Goetz
- Department of Psychiatry & Behavioral Sciences, Duke University, Durham, NC 27710, USA.
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Goetz SM, Pfaeffl M, Huber J, Singer M, Marquardt R, Weyh T. Circuit topology and control principle for a first magnetic stimulator with fully controllable waveform. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:4700-3. [PMID: 23366977 DOI: 10.1109/embc.2012.6347016] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Magnetic stimulation pulse sources are very inflexible high-power devices. The incorporated circuit topology is usually limited to a single pulse type. However, experimental and theoretical work shows that more freedom in choosing or even designing waveforms could notably enhance existing methods. Beyond that, it even allows entering new fields of application. We propose a technology that can solve the problem. Even in very high frequency ranges, the circuitry is very flexible and is able generate almost every waveform with unrivaled accuracy. This technology can dynamically change between different pulse shapes without any reconfiguration, recharging or other changes; thus the waveform can be modified also during a high-frequency repetitive pulse train. In addition to the option of online design and generation of still unknown waveforms, it amalgamates all existing device types with their specific pulse shapes, which have been leading an independent existence in the past years. These advantages were achieved by giving up the common basis of all magnetic stimulation devices so far, i.e., the high-voltage oscillator. Distributed electronics handle the high power dividing the high voltage and the required switching rate into small portions.
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Affiliation(s)
- S M Goetz
- Duke University, Durham, NC 27710, USA.
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