Electric Field Characteristics of Rotating Permanent Magnet Stimulation
Neurostimulation devices that use rotating permanent magnets are being explored for their potential therapeutic benefits in patients with psychiatric and neurological disorders. This study aims to characterize the electric field (E-field) for ten configurations of rotating magnets using finite eleme...
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MDPI AG
2024-03-01
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| Series: | Bioengineering |
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| Online Access: | https://www.mdpi.com/2306-5354/11/3/258 |
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| author | Pei L. Robins Sergey N. Makaroff Michael Dib Sarah H. Lisanby Zhi-De Deng |
| author_facet | Pei L. Robins Sergey N. Makaroff Michael Dib Sarah H. Lisanby Zhi-De Deng |
| author_sort | Pei L. Robins |
| collection | DOAJ |
| description | Neurostimulation devices that use rotating permanent magnets are being explored for their potential therapeutic benefits in patients with psychiatric and neurological disorders. This study aims to characterize the electric field (E-field) for ten configurations of rotating magnets using finite element analysis and phantom measurements. Various configurations were modeled, including single or multiple magnets, and bipolar or multipolar magnets, rotated at 10, 13.3, and 350 revolutions per second (rps). E-field strengths were also measured using a hollow sphere (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>r</mi><mo>=</mo><mn>9.2</mn><mtext> </mtext><mi>cm</mi></mrow></semantics></math></inline-formula>) filled with a 0.9% sodium chloride solution and with a dipole probe. The E-field spatial distribution is determined by the magnets’ dimensions, number of poles, direction of the magnetization, and axis of rotation, while the E-field strength is determined by the magnets’ rotational frequency and magnetic field strength. The induced E-field strength on the surface of the head ranged between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.0092</mn></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.52</mn></mrow></semantics></math></inline-formula> V/m. In the range of rotational frequencies applied, the induced E-field strengths were approximately an order or two of magnitude lower than those delivered by conventional transcranial magnetic stimulation. The impact of rotational frequency on E-field strength represents a confound in clinical trials that seek to tailor rotational frequency to individual neural oscillations. This factor could explain some of the variability observed in clinical trial outcomes. |
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| institution | Directory Open Access Journal |
| issn | 2306-5354 |
| language | English |
| last_indexed | 2024-04-24T18:32:45Z |
| publishDate | 2024-03-01 |
| publisher | MDPI AG |
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| series | Bioengineering |
| spelling | doaj.art-d7aa184b295145bc827d301ddca91d6e2024-03-27T13:21:54ZengMDPI AGBioengineering2306-53542024-03-0111325810.3390/bioengineering11030258Electric Field Characteristics of Rotating Permanent Magnet StimulationPei L. Robins0Sergey N. Makaroff1Michael Dib2Sarah H. Lisanby3Zhi-De Deng4Computational Neurostimulation Research Program, Noninvasive Neuromodulation Unit, Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, Bethesda, MD 20892, USADepartment of Electrical and Computer Engineering, Worcester Polytechnic Institute, Worcester, MA 01609, USAFischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USAComputational Neurostimulation Research Program, Noninvasive Neuromodulation Unit, Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, Bethesda, MD 20892, USAComputational Neurostimulation Research Program, Noninvasive Neuromodulation Unit, Experimental Therapeutics and Pathophysiology Branch, National Institute of Mental Health, Bethesda, MD 20892, USANeurostimulation devices that use rotating permanent magnets are being explored for their potential therapeutic benefits in patients with psychiatric and neurological disorders. This study aims to characterize the electric field (E-field) for ten configurations of rotating magnets using finite element analysis and phantom measurements. Various configurations were modeled, including single or multiple magnets, and bipolar or multipolar magnets, rotated at 10, 13.3, and 350 revolutions per second (rps). E-field strengths were also measured using a hollow sphere (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>r</mi><mo>=</mo><mn>9.2</mn><mtext> </mtext><mi>cm</mi></mrow></semantics></math></inline-formula>) filled with a 0.9% sodium chloride solution and with a dipole probe. The E-field spatial distribution is determined by the magnets’ dimensions, number of poles, direction of the magnetization, and axis of rotation, while the E-field strength is determined by the magnets’ rotational frequency and magnetic field strength. The induced E-field strength on the surface of the head ranged between <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.0092</mn></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.52</mn></mrow></semantics></math></inline-formula> V/m. In the range of rotational frequencies applied, the induced E-field strengths were approximately an order or two of magnitude lower than those delivered by conventional transcranial magnetic stimulation. The impact of rotational frequency on E-field strength represents a confound in clinical trials that seek to tailor rotational frequency to individual neural oscillations. This factor could explain some of the variability observed in clinical trial outcomes.https://www.mdpi.com/2306-5354/11/3/258electric fieldfinite element methodpermanent magnetshead phantom measurementrotating magnetsmagnetic stimulation |
| spellingShingle | Pei L. Robins Sergey N. Makaroff Michael Dib Sarah H. Lisanby Zhi-De Deng Electric Field Characteristics of Rotating Permanent Magnet Stimulation Bioengineering electric field finite element method permanent magnets head phantom measurement rotating magnets magnetic stimulation |
| title | Electric Field Characteristics of Rotating Permanent Magnet Stimulation |
| title_full | Electric Field Characteristics of Rotating Permanent Magnet Stimulation |
| title_fullStr | Electric Field Characteristics of Rotating Permanent Magnet Stimulation |
| title_full_unstemmed | Electric Field Characteristics of Rotating Permanent Magnet Stimulation |
| title_short | Electric Field Characteristics of Rotating Permanent Magnet Stimulation |
| title_sort | electric field characteristics of rotating permanent magnet stimulation |
| topic | electric field finite element method permanent magnets head phantom measurement rotating magnets magnetic stimulation |
| url | https://www.mdpi.com/2306-5354/11/3/258 |
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