Abnormalities of resting-state functional cortical connectivity in patients with dementia due to Alzheimer's and Lewy body diseases: an EEG study

Publication date: May 2018
Source:Neurobiology of Aging, Volume 65
Author(s): Claudio Babiloni, Claudio Del Percio, Roberta Lizio, Giuseppe Noce, Susanna Lopez, Andrea Soricelli, Raffaele Ferri, Flavio Nobili, Dario Arnaldi, Francesco Famà, Dag Aarsland, Francesco Orzi, Carla Buttinelli, Franco Giubilei, Marco Onofrj, Fabrizio Stocchi, Paola Stirpe, Peter Fuhr, Ute Gschwandtner, Gerhard Ransmayr, Heinrich Garn, Lucia Fraioli, Michela Pievani, Giovanni B. Frisoni, Fabrizia D'Antonio, Carlo De Lena, Bahar Güntekin, Lutfu Hanoğlu, Erol Başar, Görsev Yener, Derya Durusu Emek-Savaş, Antonio Ivano Triggiani, Raffaella Franciotti, John Paul Taylor, Laura Vacca, Maria Francesca De Pandis, Laura Bonanni
Previous evidence showed abnormal posterior sources of resting-state delta (<4 Hz) and alpha (8–12 Hz) rhythms in patients with Alzheimer's disease with dementia (ADD), Parkinson's disease with dementia (PDD), and Lewy body dementia (DLB), as cortical neural synchronization markers in quiet wakefulness. Here, we tested the hypothesis of additional abnormalities in functional cortical connectivity computed in those sources, in ADD, considered as a "disconnection cortical syndrome", in comparison with PDD and DLB. Resting-state eyes-closed electroencephalographic (rsEEG) rhythms had been collected in 42 ADD, 42 PDD, 34 DLB, and 40 normal healthy older (Nold) participants. Exact low-resolution brain electromagnetic tomography (eLORETA) freeware estimated the functional lagged linear connectivity (LLC) from rsEEG cortical sources in delta, theta, alpha, beta, and gamma bands. The area under receiver operating characteristic (AUROC) curve indexed the classification accuracy between Nold and diseased individuals (only values >0.7 were considered). Interhemispheric and intrahemispheric LLCs in widespread delta sources were abnormally higher in the ADD group and, unexpectedly, normal in DLB and PDD groups. Intrahemispheric LLC was reduced in widespread alpha sources dramatically in ADD, markedly in DLB, and moderately in PDD group. Furthermore, the interhemispheric LLC in widespread alpha sources showed lower values in ADD and DLB than PDD groups. At the individual level, AUROC curves of LLC in alpha sources exhibited better classification accuracies for the discrimination of ADD versus Nold individuals (0.84) than for DLB versus Nold participants (0.78) and PDD versus Nold participants (0.75). Functional cortical connectivity markers in delta and alpha sources suggest a more compromised neurophysiological reserve in ADD than DLB, at both group and individual levels.



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