Sound comparison of seven TMS coils at matched stimulation strength

Lari M. Koponen; Stefan M. Goetz; Debara L. Tucci; Angel V. Peterchev

doi:10.1016/j.brs.2020.03.004

Sound comparison of seven TMS coils at matched stimulation strength

Lari M. Koponen, Stefan M. Goetz, Debara L. Tucci, Angel V. Peterchev^*

^*Corresponding author for this work

Psychology

Research output: Contribution to journal › Article › peer-review

13 Citations (Scopus)

Abstract

Background: Accurate data on the sound emitted by transcranial magnetic stimulation (TMS) coils is lacking. Methods: We recorded the sound waveforms of seven coils with high bandwidth. We estimated the neural stimulation strength by measuring the induced electric field and applying a strength–duration model to account for different waveforms. Results: Across coils, at maximum stimulator output and 25 cm distance, the sound pressure level (SPL) was 98–125 dB(Z) per pulse and 76–98 dB(A) for a 20 Hz pulse train. At 5 cm distance, these values were estimated to increase to 112–139 dB(Z) and 90–112 dB(A), respectively. Conclusions: The coils’ airborne sound can exceed some exposure limits for TMS subjects and, in some cases, for operators. These findings are consistent with the current TMS safety guidelines that recommend the use of hearing protection.

Original language	English
Pages (from-to)	873-880
Number of pages	8
Journal	Brain stimulation
Volume	13
Issue number	3
DOIs	https://doi.org/10.1016/j.brs.2020.03.004
Publication status	Published - 1 May 2020

Bibliographical note

Funding Information:
L. M. Koponen, S. M. Goetz, and A. V. Peterchev are inventors on patents and patent applications on TMS technology including TMS devices with reduced acoustic noise. S. M. Goetz has received research funding from Magstim Inc. Related to TMS technology, A. V. Peterchev has received research and travel support as well as patent royalties from Rogue Research; research and travel support, consulting fees, as well as equipment donation from Tal Medical/Neurex; patent application and research support from Magstim; equipment loans and hardware donations from MagVenture; and expert witness compensation from Neuronetics.Research reported in this publication was supported by the National Institute of Mental Health of the National Institutes of Health under Award Number R01MH111865. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Funding Information:
L. M. Koponen, S. M. Goetz, and A. V. Peterchev are inventors on patents and patent applications on TMS technology including TMS devices with reduced acoustic noise. S. M. Goetz has received research funding from Magstim Inc . Related to TMS technology, A. V. Peterchev has received research and travel support as well as patent royalties from Rogue Research; research and travel support, consulting fees, as well as equipment donation from Tal Medical/Neurex; patent application and research support from Magstim; equipment loans and hardware donations from MagVenture; and expert witness compensation from Neuronetics.

Publisher Copyright:
© 2020 The Authors

Keywords

Coil click
Hearing safety
Sound
Stimulation strength
TMS
Transcranial magnetic stimulation

ASJC Scopus subject areas

Biophysics
General Neuroscience
Clinical Neurology

Access to Document

10.1016/j.brs.2020.03.004

Cite this

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title = "Sound comparison of seven TMS coils at matched stimulation strength",

abstract = "Background: Accurate data on the sound emitted by transcranial magnetic stimulation (TMS) coils is lacking. Methods: We recorded the sound waveforms of seven coils with high bandwidth. We estimated the neural stimulation strength by measuring the induced electric field and applying a strength–duration model to account for different waveforms. Results: Across coils, at maximum stimulator output and 25 cm distance, the sound pressure level (SPL) was 98–125 dB(Z) per pulse and 76–98 dB(A) for a 20 Hz pulse train. At 5 cm distance, these values were estimated to increase to 112–139 dB(Z) and 90–112 dB(A), respectively. Conclusions: The coils{\textquoteright} airborne sound can exceed some exposure limits for TMS subjects and, in some cases, for operators. These findings are consistent with the current TMS safety guidelines that recommend the use of hearing protection.",

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note = "Funding Information: L. M. Koponen, S. M. Goetz, and A. V. Peterchev are inventors on patents and patent applications on TMS technology including TMS devices with reduced acoustic noise. S. M. Goetz has received research funding from Magstim Inc. Related to TMS technology, A. V. Peterchev has received research and travel support as well as patent royalties from Rogue Research; research and travel support, consulting fees, as well as equipment donation from Tal Medical/Neurex; patent application and research support from Magstim; equipment loans and hardware donations from MagVenture; and expert witness compensation from Neuronetics.Research reported in this publication was supported by the National Institute of Mental Health of the National Institutes of Health under Award Number R01MH111865. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Funding Information: L. M. Koponen, S. M. Goetz, and A. V. Peterchev are inventors on patents and patent applications on TMS technology including TMS devices with reduced acoustic noise. S. M. Goetz has received research funding from Magstim Inc . Related to TMS technology, A. V. Peterchev has received research and travel support as well as patent royalties from Rogue Research; research and travel support, consulting fees, as well as equipment donation from Tal Medical/Neurex; patent application and research support from Magstim; equipment loans and hardware donations from MagVenture; and expert witness compensation from Neuronetics. Publisher Copyright: {\textcopyright} 2020 The Authors",

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N2 - Background: Accurate data on the sound emitted by transcranial magnetic stimulation (TMS) coils is lacking. Methods: We recorded the sound waveforms of seven coils with high bandwidth. We estimated the neural stimulation strength by measuring the induced electric field and applying a strength–duration model to account for different waveforms. Results: Across coils, at maximum stimulator output and 25 cm distance, the sound pressure level (SPL) was 98–125 dB(Z) per pulse and 76–98 dB(A) for a 20 Hz pulse train. At 5 cm distance, these values were estimated to increase to 112–139 dB(Z) and 90–112 dB(A), respectively. Conclusions: The coils’ airborne sound can exceed some exposure limits for TMS subjects and, in some cases, for operators. These findings are consistent with the current TMS safety guidelines that recommend the use of hearing protection.

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Sound comparison of seven TMS coils at matched stimulation strength

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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