Improved Biomagnetic Signal-To-Noise Ratio and Source Localization Using Optically Pumped Magnetometers with Synthetic Gradiometers

Jing Xiang; Xiaoqian Yu; Scott Bonnette; Manish Anand; Christopher D. Riehm; Bryan Schlink; Jed A. Diekfuss; Gregory D. Myer; Yang Jiang

doi:10.3390/brainsci13040663

Improved Biomagnetic Signal-To-Noise Ratio and Source Localization Using Optically Pumped Magnetometers with Synthetic Gradiometers

Jing Xiang, Xiaoqian Yu, Scott Bonnette, Manish Anand, Christopher D. Riehm, Bryan Schlink, Jed A. Diekfuss, Gregory D. Myer, Yang Jiang

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

2 Scopus citations

Abstract

Optically pumped magnetometers (OPMs) can capture brain activity but are susceptible to magnetic noise. The objective of this study was to evaluate a novel methodology used to reduce magnetic noise in OPM measurements. A portable magnetoencephalography (MEG) prototype was developed with OPMs. The OPMs were divided into primary sensors and reference sensors. For each primary sensor, a synthetic gradiometer (SG) was constructed by computing a secondary sensor that simulated noise with signals from the reference sensors. MEG data from a phantom with known source signals and six human participants were used to assess the efficacy of the SGs. Magnetic noise in the OPM data appeared predominantly in a low frequency range (<4 Hz) and varied among OPMs. The SGs significantly reduced magnetic noise (p < 0.01), enhanced the signal-to-noise ratio (SNR) (p < 0.001) and improved the accuracy of source localization (p < 0.02). The SGs precisely revealed movement-evoked magnetic fields in MEG data recorded from human participants. SGs provided an effective method to enhance SNR and improve the accuracy of source localization by suppressing noise. Software-simulated SGs may provide new opportunities regarding the use of OPM measurements in various clinical and research applications, especially those in which movement is relevant.

Original language	English
Article number	663
Journal	Brain Sciences
Volume	13
Issue number	4
DOIs	https://doi.org/10.3390/brainsci13040663
State	Published - Apr 2023

Bibliographical note

Publisher Copyright:
© 2023 by the authors.

Funding

The project described was supported by the United States National Institutes of Health (NIH) Grant Number R21 NS104459 from the National Institute of Neurological Disorders and Stroke (NINDS). The normative database used in the present study was partially supported by Grant Number R21NS081420 and R21NS072817 from NIH/NINDS. The project described was partially supported by funding from NIH/National Institute of Aging (NIA) 1R56AG060608, the State of Ohio, Ohio Development Services Agency, Ohio Third Frontier, Grant Control No. TECG20170361 and TECG20190159.

Funders	Funder number
Ohio Agricultural Research and Development Center, Ohio State University
National Institutes of Health (NIH)	R21 NS104459
National Institute on Aging	1R56AG060608
National Institute of Neurological Disorders and Stroke	R21NS072817, R21NS081420
Ohio Development Services Agency	TECG20170361, TECG20190159

Keywords

magnetoencephalography
noise cancellation
optically pumped magnetometer
signal-to-noise ratio
synthetic gradiometer
wearable MEG

ASJC Scopus subject areas

General Neuroscience

Access to Document

10.3390/brainsci13040663

Cite this

@article{a9c8e5ecf13943ea959bec8374f59195,

title = "Improved Biomagnetic Signal-To-Noise Ratio and Source Localization Using Optically Pumped Magnetometers with Synthetic Gradiometers",

abstract = "Optically pumped magnetometers (OPMs) can capture brain activity but are susceptible to magnetic noise. The objective of this study was to evaluate a novel methodology used to reduce magnetic noise in OPM measurements. A portable magnetoencephalography (MEG) prototype was developed with OPMs. The OPMs were divided into primary sensors and reference sensors. For each primary sensor, a synthetic gradiometer (SG) was constructed by computing a secondary sensor that simulated noise with signals from the reference sensors. MEG data from a phantom with known source signals and six human participants were used to assess the efficacy of the SGs. Magnetic noise in the OPM data appeared predominantly in a low frequency range (<4 Hz) and varied among OPMs. The SGs significantly reduced magnetic noise (p < 0.01), enhanced the signal-to-noise ratio (SNR) (p < 0.001) and improved the accuracy of source localization (p < 0.02). The SGs precisely revealed movement-evoked magnetic fields in MEG data recorded from human participants. SGs provided an effective method to enhance SNR and improve the accuracy of source localization by suppressing noise. Software-simulated SGs may provide new opportunities regarding the use of OPM measurements in various clinical and research applications, especially those in which movement is relevant.",

keywords = "magnetoencephalography, noise cancellation, optically pumped magnetometer, signal-to-noise ratio, synthetic gradiometer, wearable MEG",

author = "Jing Xiang and Xiaoqian Yu and Scott Bonnette and Manish Anand and Riehm, {Christopher D.} and Bryan Schlink and Diekfuss, {Jed A.} and Myer, {Gregory D.} and Yang Jiang",

note = "Publisher Copyright: {\textcopyright} 2023 by the authors.",

year = "2023",

month = apr,

doi = "10.3390/brainsci13040663",

language = "English",

volume = "13",

number = "4",

}

TY - JOUR

T1 - Improved Biomagnetic Signal-To-Noise Ratio and Source Localization Using Optically Pumped Magnetometers with Synthetic Gradiometers

AU - Xiang, Jing

AU - Yu, Xiaoqian

AU - Bonnette, Scott

AU - Anand, Manish

AU - Riehm, Christopher D.

AU - Schlink, Bryan

AU - Diekfuss, Jed A.

AU - Myer, Gregory D.

AU - Jiang, Yang

PY - 2023/4

Y1 - 2023/4

N2 - Optically pumped magnetometers (OPMs) can capture brain activity but are susceptible to magnetic noise. The objective of this study was to evaluate a novel methodology used to reduce magnetic noise in OPM measurements. A portable magnetoencephalography (MEG) prototype was developed with OPMs. The OPMs were divided into primary sensors and reference sensors. For each primary sensor, a synthetic gradiometer (SG) was constructed by computing a secondary sensor that simulated noise with signals from the reference sensors. MEG data from a phantom with known source signals and six human participants were used to assess the efficacy of the SGs. Magnetic noise in the OPM data appeared predominantly in a low frequency range (<4 Hz) and varied among OPMs. The SGs significantly reduced magnetic noise (p < 0.01), enhanced the signal-to-noise ratio (SNR) (p < 0.001) and improved the accuracy of source localization (p < 0.02). The SGs precisely revealed movement-evoked magnetic fields in MEG data recorded from human participants. SGs provided an effective method to enhance SNR and improve the accuracy of source localization by suppressing noise. Software-simulated SGs may provide new opportunities regarding the use of OPM measurements in various clinical and research applications, especially those in which movement is relevant.

AB - Optically pumped magnetometers (OPMs) can capture brain activity but are susceptible to magnetic noise. The objective of this study was to evaluate a novel methodology used to reduce magnetic noise in OPM measurements. A portable magnetoencephalography (MEG) prototype was developed with OPMs. The OPMs were divided into primary sensors and reference sensors. For each primary sensor, a synthetic gradiometer (SG) was constructed by computing a secondary sensor that simulated noise with signals from the reference sensors. MEG data from a phantom with known source signals and six human participants were used to assess the efficacy of the SGs. Magnetic noise in the OPM data appeared predominantly in a low frequency range (<4 Hz) and varied among OPMs. The SGs significantly reduced magnetic noise (p < 0.01), enhanced the signal-to-noise ratio (SNR) (p < 0.001) and improved the accuracy of source localization (p < 0.02). The SGs precisely revealed movement-evoked magnetic fields in MEG data recorded from human participants. SGs provided an effective method to enhance SNR and improve the accuracy of source localization by suppressing noise. Software-simulated SGs may provide new opportunities regarding the use of OPM measurements in various clinical and research applications, especially those in which movement is relevant.

KW - magnetoencephalography

KW - noise cancellation

KW - optically pumped magnetometer

KW - signal-to-noise ratio

KW - synthetic gradiometer

KW - wearable MEG

UR - http://www.scopus.com/inward/record.url?scp=85156188947&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85156188947&partnerID=8YFLogxK

U2 - 10.3390/brainsci13040663

DO - 10.3390/brainsci13040663

M3 - Article

AN - SCOPUS:85156188947

VL - 13

JO - Brain Sciences

JF - Brain Sciences

IS - 4

M1 - 663

ER -

Improved Biomagnetic Signal-To-Noise Ratio and Source Localization Using Optically Pumped Magnetometers with Synthetic Gradiometers

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this