Abstract
Brain functional connectivity in dementia has been assessed with dissimilar EEG connectivity metrics and estimation procedures, thereby increasing results' heterogeneity. In this scenario, joint analyses integrating information from different metrics may allow for a more comprehensive characterization of brain functional interactions in different dementia subtypes. To test this hypothesis, resting-state electroencephalogram (rsEEG) was recorded in individuals with Alzheimer's Disease (AD), behavioral variant frontotemporal dementia (bvFTD), and healthy controls (HCs). Whole-brain functional connectivity was estimated in the EEG source space using 101 different types of functional connectivity, capturing linear and nonlinear interactions in both time and frequency-domains. Multivariate machine learning and progressive feature elimination was run to discriminate AD from HCs, and bvFTD from HCs, based on joint analyses of i) EEG frequency bands, ii) complementary frequency-domain metrics (e.g., instantaneous, lagged, and total connectivity), and iii) time-domain metrics with different linearity assumption (e.g., Pearson correlation coefficient and mutual information). <10% of all possible connections were responsible for the differences between patients and controls, and atypical connectivity was never captured by >1/4 of all possible connectivity measures. Joint analyses revealed patterns of hypoconnectivity (patients<HCs) involving convergent temporo-parieto-occipital regions in AD, and fronto-temporo-parietal areas in bvFTD. Hyperconnectivity (patients>HCs) in both groups was mainly identified in frontotemporal regions. These atypicalities were differently captured by frequency- and time-domain connectivity metrics, in a bandwidth-specific fashion. The multi-metric representation of source space whole-brain functional connectivity evidenced the inadequacy of single-metric approaches, and resulted in a valid alternative for the selection problem in EEG connectivity. These joint analyses reveal patterns of brain functional interdependence that are overlooked with single metrics approaches, contributing to a more reliable and interpretable description of atypical functional connectivity in neurodegeneration.
Original language | English |
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Article number | 106047 |
Journal | Neurobiology of Disease |
Volume | 179 |
DOIs | |
State | Published - 2023 |
Bibliographical note
Funding Information:AI is supported by Takeda Grant CW2680521; CONICET; FONCYT-PICT (2017-1818, 2017-1820); ANID/FONDECYT Regular (1210195, 1210176, 1220995); ANID/FONDAP (15150012); ANID/PIA/ANILLOS ACT210096; ANID/FONDEF ID20I10152, ID22I10029; and the Multi-Partner Consortium to Expand Dementia Research in Latin America (ReDLat), funded by the National Institutes of Aging of the National Institutes of Health under award number R01AG057234, an Alzheimer's Association grant (SG-20-725707-ReDLat), the Rainwater Foundation, and the Global Brain Health Institute. SF is an Atlantic Fellow for Equity in Brain Health at the Global Brain Health Institute (GBHI) and is supported with funding from GBHI, BrainLat, ANID/FONDEF ID22I10029, and CONICET. MO is supported by ANID/FONDECYT Postdoctorado 3210508. The content is solely the responsibility of the authors and does not represent the official views of these institutions.The authors thank the Multi-Partner Consortium to Expand Dementia Research in Latin America (ReDLat), the patients and healthy individuals recruited for the study, and their relatives. The authors recognize the contributors of clinical investigators from Chile (GERO/CMYN, Universidad de Chile), Argentina (CNC, Universidad de San Andrés), and Colombia (Pontificia Universidad Javeriana) that provided partial funding for data collection and access.
Funding Information:
AI is supported by Takeda Grant CW2680521 ; CONICET ; FONCYT-PICT ( 2017-1818 , 2017-1820 ); ANID /FONDECYT Regular ( 1210195 , 1210176 , 1220995 ); ANID/ FONDAP ( 15150012 ); ANID/PIA/ ANILLOS ACT210096 ; ANID/ FONDEF ID20I10152 , ID22I10029 ; and the Multi-Partner Consortium to Expand Dementia Research in Latin America (ReDLat), funded by the National Institutes of Aging of the National Institutes of Health under award number R01AG057234 , an Alzheimer's Association grant ( SG-20-725707-ReDLat ), the Rainwater Foundation , and the Global Brain Health Institute . SF is an Atlantic Fellow for Equity in Brain Health at the Global Brain Health Institute (GBHI) and is supported with funding from GBHI , BrainLat , ANID/ FONDEF ID22I10029 , and CONICET . MO is supported by ANID/FONDECYT Postdoctorado 3210508 . The content is solely the responsibility of the authors and does not represent the official views of these institutions.
Publisher Copyright:
© 2023 The Authors
ASJC Scopus subject areas
- Neurology