AUTHOR=Lopez Susanna , Del Percio Claudio , Lizio Roberta , Noce Giuseppe , Padovani Alessandro , Nobili Flavio , Arnaldi Dario , Famà Francesco , Moretti Davide V. , Cagnin Annachiara , Koch Giacomo , Benussi Alberto , Onofrj Marco , Borroni Barbara , Soricelli Andrea , Ferri Raffaele , Buttinelli Carla , Giubilei Franco , Güntekin Bahar , Yener Görsev , Stocchi Fabrizio , Vacca Laura , Bonanni Laura , Babiloni Claudio 

TITLE=Patients with Alzheimer’s disease dementia show partially preserved parietal ‘hubs’ modeled from resting-state alpha electroencephalographic rhythms

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 15 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2023.780014

DOI=10.3389/fnagi.2023.780014

ISSN=1663-4365

ABSTRACT=Graph theory models a network by its nodes and connections. “Degree” hubs reflect node centrality, while “connector” hubs are those linked to several clusters of nodes. Here we compared hubs modelled from measures of interdependencies of between-electrode resting-state eyes-closed electroencephalography (rsEEG) rhythms in normal old (Nold) and Alzheimer’s disease dementia (ADD) participants. As ADD is considered as a “network disease” and is typically associated with abnormal rsEEG delta (< 4 Hz) and alpha rhythms (8-12 Hz) over associative posterior areas, we predicted abnormal posterior hubs from measures of interdependencies of those rhythms in ADD as compared to Nold participants. To report robust results, we measured interdependencies of rsEEG rhythms from delta to gamma bands (2-40 Hz) by both bivariate linear lagged connectivity and multivariate (directional) isolated lagged effective coherence. Furthermore, we used three different definitions of “connector” hub.   
Convergent results showed that in both Nold and ADD groups, there were significant parietal “degree” and “connector” hubs derived from alpha rhythms. These hubs had a prominent outward “directionality” in the two groups but that “directionality” was lower in ADD than Nold participants.
In conclusion, independent methodologies and hub definitions suggest that ADD patients may be characterized by low outward “directionality” of topologically partially resilient parietal “degree” and “connector” hubs derived from rsEEG alpha rhythms. Combined use of independent methodologies in rsEEG studies may produce robust results in clinical applications in ADD patients.