Page 83 - MEGIN Book Of Abstracts - 2023

Center Amsterdam, Department of Neurology, Amsterdam between patients with AD dementia and cognitively
Neuroscience, Vrije Universiteit Amsterdam, Amsterdam healthy controls. These two measures likely reflect dif-
UMC, Amsterdam, The Netherlands ferent aspects of neural activity and show differential
sensitivity to changes in neural dynamics.
BACKGROUND Analysis of functional brain networks in
Alzheimer's disease (AD) has been hampered by a lack Keywords: Alzheimer’s disease, Functional connectivity,
of reproducible, yet valid metrics of functional connec- Magnetoencephalography, Reproducibility, Sensitivity,
tivity (FC). This study aimed to assess both the sensi- Subjective cognitive decline
tivity and reproducibility of the corrected amplitude
envelope correlation (AEC-c) and phase lag index (PLI), Alzheimer's research & therapy (2022), Vol. 14, No. 1
two metrics of FC that are insensitive to the effects of (35219327) (0 citations)
volume conduction and field spread, in two separate
cohorts of patients with dementia due to AD versus
healthy elderly controls. Cortical and subcortical changes in resting-
state neuronal activity and connectivity in early
METHODS Subjects with a clinical diagnosis of AD symptomatic ALS and advanced frontotemporal
dementia with biomarker proof, and a control group dementia (2022)
of subjective cognitive decline (SCD), underwent two
5-min resting-state MEG recordings. Data consisted of Govaarts, Rosanne; Beeldman, Emma; Fraschini,
a test (AD = 28; SCD = 29) and validation (AD = 29; SCD Matteo; Griffa, Alessandra; Engels, Marjolein M A; van
= 27) cohort. Time-series were estimated for 90 regions Es, Michael A; Veldink, Jan H; van den Berg, Leonard
of interest (ROIs) in the automated anatomical labelling H; van der Kooi, Anneke J; Pijnenburg, Yolande A L; de
(AAL) atlas. For each of five canonical frequency bands, Visser, Marianne; Stam, Cornelis J; Raaphorst, Joost;
the AEC-c and PLI were calculated between all 90 ROIs, Hillebrand, Arjan
and connections were averaged per ROI. General linear
models were constructed to compare the global FC dif- Amsterdam University Medical Centers, University of
ferences between the groups, assess the reproducibil- Amsterdam, Department of Neurology, Amsterdam Neu-
ity, and evaluate the effects of age and relative power. roscience, Amsterdam, the Netherlands. Electronic address:
Reproducibility of the regional FC differences was as- [email protected]; University of Cagliari,
sessed using the Mann-Whitney U tests, with correction Department of Electrical and Electronic Engineering, Cagliari,
for multiple testing using the false discovery rate (FDR). Italy; Department of Clinical Neurosciences, Division of Neu-
rology, Geneva University Hospitals and Faculty of Medicine,
RESULTS The AEC-c showed significantly and repro- University of Geneva, Geneva, Switzerland; Institute of Bioen-
ducibly lower global FC for the AD group compared to gineering, Center of Neuroprosthetics, École Polytechnique
SCD, in the alpha (8-13 Hz) and beta (13-30 Hz) bands, Fédérale De Lausanne (EPFL), Geneva, Switzerland; Amster-
while the PLI revealed reproducibly lower FC for the AD dam University Medical Centers, Vrije Universiteit Amsterdam,
group in the delta (0.5-4 Hz) band and higher FC for the Department of Clinical Neurophysiology, Magnetoencepha-
theta (4-8 Hz) band. Regionally, the beta band AEC-c lography Centre, Amsterdam Neuroscience, Amsterdam, the
showed reproducibility for almost all ROIs (except for Netherlands; University Medical Centre Utrecht, Department
13 ROIs in the frontal and temporal lobes). For the other of Neurology, Brain Centre Rudolf Magnus, Utrecht, the
bands, the AEC-c and PLI did not show regional repro- Netherlands; Amsterdam University Medical Centers, Vrije
ducibility after FDR correction. The theta band PLI was Universiteit, Alzheimer Center, Amsterdam Neuroscience,
susceptible to the effect of relative power. Amsterdam, the Netherlands

CONCLUSION For MEG, the AEC-c is a sensitive and ABSTRACT The objective of this study was to examine
reproducible metric, able to distinguish FC differences if patterns of resting-state brain activity and functional

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