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Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling

BACKGROUND: Unique amongst brain stimulation tools, transcranial direct current stimulation (tDCS) currently lacks an easy or widely implemented method for individualizing dosage. OBJECTIVE: We developed a method of reverse-calculating electric-field (E-field) models based on Magnetic Resonance Imag...

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Autores principales: Caulfield, Kevin A., Badran, Bashar W., DeVries, William H., Summers, Philipp M., Kofmehl, Emma, Li, Xingbao, Borckardt, Jeffrey J., Bikson, Marom, George, Mark S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906246/
https://www.ncbi.nlm.nih.gov/pubmed/32330607
http://dx.doi.org/10.1016/j.brs.2020.04.007
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author Caulfield, Kevin A.
Badran, Bashar W.
DeVries, William H.
Summers, Philipp M.
Kofmehl, Emma
Li, Xingbao
Borckardt, Jeffrey J.
Bikson, Marom
George, Mark S.
author_facet Caulfield, Kevin A.
Badran, Bashar W.
DeVries, William H.
Summers, Philipp M.
Kofmehl, Emma
Li, Xingbao
Borckardt, Jeffrey J.
Bikson, Marom
George, Mark S.
author_sort Caulfield, Kevin A.
collection PubMed
description BACKGROUND: Unique amongst brain stimulation tools, transcranial direct current stimulation (tDCS) currently lacks an easy or widely implemented method for individualizing dosage. OBJECTIVE: We developed a method of reverse-calculating electric-field (E-field) models based on Magnetic Resonance Imaging (MRI) scans that can estimate individualized tDCS dose. We also evaluated an MRI-free method of individualizing tDCS dose by measuring transcranial magnetic stimulation (TMS) motor threshold (MT) and single pulse, suprathreshold transcranial electrical stimulation (TES) MT and regressing it against E-field modeling. Key assumptions of reverse-calculation E-field modeling, including the size of region of interest (ROI) analysis and the linearity of multiple E-field models were also tested. METHODS: In 29 healthy adults, we acquired TMS MT, TES MT, and anatomical T1-weighted MPRAGE MRI scans with a fiducial marking the motor hotspot. We then computed a “reverse-calculated tDCS dose” of tDCS applied at the scalp needed to cause a 1.00 V/m E-field at the cortex. Finally, we examined whether the predicted E-field values correlated with each participant’s measured TMS MT or TES MT. RESULTS: We were able to determine a reverse-calculated tDCS dose for each participant using a 5 × 5 x 5 voxel grid region of interest (ROI) approach (average = 6.03 mA, SD = 1.44 mA, range = 3.75–9.74 mA). The Transcranial Electrical Stimulation MT, but not the Transcranial Magnetic Stimulation MT, significantly correlated with the ROI-based reverse-calculated tDCS dose determined by E-field modeling (R(2) = 0.45, p < 0.001). CONCLUSIONS: Reverse-calculation E-field modeling, alone or regressed against TES MT, shows promise as a method to individualize tDCS dose. The large range of the reverse-calculated tDCS doses between subjects underscores the likely need to individualize tDCS dose. Future research should further examine the use of TES MT to individually dose tDCS as an MRI-free method of dosing tDCS.
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spelling pubmed-79062462021-02-25 Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling Caulfield, Kevin A. Badran, Bashar W. DeVries, William H. Summers, Philipp M. Kofmehl, Emma Li, Xingbao Borckardt, Jeffrey J. Bikson, Marom George, Mark S. Brain Stimul Article BACKGROUND: Unique amongst brain stimulation tools, transcranial direct current stimulation (tDCS) currently lacks an easy or widely implemented method for individualizing dosage. OBJECTIVE: We developed a method of reverse-calculating electric-field (E-field) models based on Magnetic Resonance Imaging (MRI) scans that can estimate individualized tDCS dose. We also evaluated an MRI-free method of individualizing tDCS dose by measuring transcranial magnetic stimulation (TMS) motor threshold (MT) and single pulse, suprathreshold transcranial electrical stimulation (TES) MT and regressing it against E-field modeling. Key assumptions of reverse-calculation E-field modeling, including the size of region of interest (ROI) analysis and the linearity of multiple E-field models were also tested. METHODS: In 29 healthy adults, we acquired TMS MT, TES MT, and anatomical T1-weighted MPRAGE MRI scans with a fiducial marking the motor hotspot. We then computed a “reverse-calculated tDCS dose” of tDCS applied at the scalp needed to cause a 1.00 V/m E-field at the cortex. Finally, we examined whether the predicted E-field values correlated with each participant’s measured TMS MT or TES MT. RESULTS: We were able to determine a reverse-calculated tDCS dose for each participant using a 5 × 5 x 5 voxel grid region of interest (ROI) approach (average = 6.03 mA, SD = 1.44 mA, range = 3.75–9.74 mA). The Transcranial Electrical Stimulation MT, but not the Transcranial Magnetic Stimulation MT, significantly correlated with the ROI-based reverse-calculated tDCS dose determined by E-field modeling (R(2) = 0.45, p < 0.001). CONCLUSIONS: Reverse-calculation E-field modeling, alone or regressed against TES MT, shows promise as a method to individualize tDCS dose. The large range of the reverse-calculated tDCS doses between subjects underscores the likely need to individualize tDCS dose. Future research should further examine the use of TES MT to individually dose tDCS as an MRI-free method of dosing tDCS. 2020-04-21 2020 /pmc/articles/PMC7906246/ /pubmed/32330607 http://dx.doi.org/10.1016/j.brs.2020.04.007 Text en This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Article
Caulfield, Kevin A.
Badran, Bashar W.
DeVries, William H.
Summers, Philipp M.
Kofmehl, Emma
Li, Xingbao
Borckardt, Jeffrey J.
Bikson, Marom
George, Mark S.
Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling
title Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling
title_full Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling
title_fullStr Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling
title_full_unstemmed Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling
title_short Transcranial electrical stimulation motor threshold can estimate individualized tDCS dosage from reverse-calculation electric-field modeling
title_sort transcranial electrical stimulation motor threshold can estimate individualized tdcs dosage from reverse-calculation electric-field modeling
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906246/
https://www.ncbi.nlm.nih.gov/pubmed/32330607
http://dx.doi.org/10.1016/j.brs.2020.04.007
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