Global sensitivity of EEG source analysis to tissue conductivity uncertainties
IntroductionTo reliably solve the EEG inverse problem, accurate EEG forward solutions based on a detailed, individual volume conductor model of the head are essential. A crucial—but often neglected—aspect in generating a volume conductor model is the choice of the tissue conductivities, as these may...
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Frontiers Media S.A.
2024-03-01
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| Series: | Frontiers in Human Neuroscience |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fnhum.2024.1335212/full |
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| author | Johannes Vorwerk Carsten H. Wolters Carsten H. Wolters Daniel Baumgarten |
| author_facet | Johannes Vorwerk Carsten H. Wolters Carsten H. Wolters Daniel Baumgarten |
| author_sort | Johannes Vorwerk |
| collection | DOAJ |
| description | IntroductionTo reliably solve the EEG inverse problem, accurate EEG forward solutions based on a detailed, individual volume conductor model of the head are essential. A crucial—but often neglected—aspect in generating a volume conductor model is the choice of the tissue conductivities, as these may vary from subject to subject. In this study, we investigate the sensitivity of EEG forward and inverse solutions to tissue conductivity uncertainties for sources distributed over the whole cortex surface.MethodsWe employ a detailed five-compartment head model distinguishing skin, skull, cerebrospinal fluid, gray matter, and white matter, where we consider uncertainties of skin, skull, gray matter, and white matter conductivities. We use the finite element method (FEM) to calculate EEG forward solutions and goal function scans (GFS) as inverse approach. To be able to generate the large number of EEG forward solutions, we employ generalized polynomial chaos (gPC) expansions.ResultsFor sources up to a depth of 4 cm, we find the strongest influence on the signal topography of EEG forward solutions for the skull conductivity and a notable effect for the skin conductivity. For even deeper sources, e.g., located deep in the longitudinal fissure, we find an increasing influence of the white matter conductivity. The conductivity variations translate to varying source localizations particularly for quasi-tangential sources on sulcal walls, whereas source localizations of quasi-radial sources on the top of gyri are less affected. We find a strong correlation between skull conductivity and the variation of source localizations and especially the depth of the reconstructed source for quasi-tangential sources. We furthermore find a clear but weaker correlation between depth of the reconstructed source and the skin conductivity.DiscussionOur results clearly show the influence of tissue conductivity uncertainties on EEG source analysis. We find a particularly strong influence of skull and skin conductivity uncertainties. |
| first_indexed | 2024-04-25T00:46:20Z |
| format | Article |
| id | doaj.art-5d93e771e92a4a05a6eefb5e06a369f5 |
| institution | Directory Open Access Journal |
| issn | 1662-5161 |
| language | English |
| last_indexed | 2024-04-25T00:46:20Z |
| publishDate | 2024-03-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Human Neuroscience |
| spelling | doaj.art-5d93e771e92a4a05a6eefb5e06a369f52024-03-12T04:28:39ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612024-03-011810.3389/fnhum.2024.13352121335212Global sensitivity of EEG source analysis to tissue conductivity uncertaintiesJohannes Vorwerk0Carsten H. Wolters1Carsten H. Wolters2Daniel Baumgarten3Institute of Electrical and Biomedical Engineering, UMIT TIROL—Private University for Health Sciences and Health Technology, Hall in Tirol, AustriaInstitute for Biomagnetism and Biosignalanalysis, University of Münster, Münster, GermanyOtto Creutzfeldt Center for Cognitive and Behavioral Neuroscience, University of Münster, Münster, GermanyInstitute of Electrical and Biomedical Engineering, UMIT TIROL—Private University for Health Sciences and Health Technology, Hall in Tirol, AustriaIntroductionTo reliably solve the EEG inverse problem, accurate EEG forward solutions based on a detailed, individual volume conductor model of the head are essential. A crucial—but often neglected—aspect in generating a volume conductor model is the choice of the tissue conductivities, as these may vary from subject to subject. In this study, we investigate the sensitivity of EEG forward and inverse solutions to tissue conductivity uncertainties for sources distributed over the whole cortex surface.MethodsWe employ a detailed five-compartment head model distinguishing skin, skull, cerebrospinal fluid, gray matter, and white matter, where we consider uncertainties of skin, skull, gray matter, and white matter conductivities. We use the finite element method (FEM) to calculate EEG forward solutions and goal function scans (GFS) as inverse approach. To be able to generate the large number of EEG forward solutions, we employ generalized polynomial chaos (gPC) expansions.ResultsFor sources up to a depth of 4 cm, we find the strongest influence on the signal topography of EEG forward solutions for the skull conductivity and a notable effect for the skin conductivity. For even deeper sources, e.g., located deep in the longitudinal fissure, we find an increasing influence of the white matter conductivity. The conductivity variations translate to varying source localizations particularly for quasi-tangential sources on sulcal walls, whereas source localizations of quasi-radial sources on the top of gyri are less affected. We find a strong correlation between skull conductivity and the variation of source localizations and especially the depth of the reconstructed source for quasi-tangential sources. We furthermore find a clear but weaker correlation between depth of the reconstructed source and the skin conductivity.DiscussionOur results clearly show the influence of tissue conductivity uncertainties on EEG source analysis. We find a particularly strong influence of skull and skin conductivity uncertainties.https://www.frontiersin.org/articles/10.3389/fnhum.2024.1335212/fullEEGforward modelingfinite element methodsource analysissensitivity analysisuncertainty quantification |
| spellingShingle | Johannes Vorwerk Carsten H. Wolters Carsten H. Wolters Daniel Baumgarten Global sensitivity of EEG source analysis to tissue conductivity uncertainties Frontiers in Human Neuroscience EEG forward modeling finite element method source analysis sensitivity analysis uncertainty quantification |
| title | Global sensitivity of EEG source analysis to tissue conductivity uncertainties |
| title_full | Global sensitivity of EEG source analysis to tissue conductivity uncertainties |
| title_fullStr | Global sensitivity of EEG source analysis to tissue conductivity uncertainties |
| title_full_unstemmed | Global sensitivity of EEG source analysis to tissue conductivity uncertainties |
| title_short | Global sensitivity of EEG source analysis to tissue conductivity uncertainties |
| title_sort | global sensitivity of eeg source analysis to tissue conductivity uncertainties |
| topic | EEG forward modeling finite element method source analysis sensitivity analysis uncertainty quantification |
| url | https://www.frontiersin.org/articles/10.3389/fnhum.2024.1335212/full |
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