EEG correlates in the three variants of Primary Progressive Aphasia (P13-6.002)

Abstract

<h3>Objective:</h3> The aim of this study is to explore the value of EEG analysis in the characterization of the three clinical presentations of primary progressive aphasia (PPA). <h3>Background:</h3> The analysis of EEG cortical sources is promising for the investigation of neurodegenerative disorders. <h3>Design/Methods:</h3> A resting-state 19-channel EEG was obtained in 48 patients diagnosed with PPA (21 nonfluent/agrammatic variant PPA [nfv-PPA], 18 logopenic variant PPA [lv-PPA], 9 semantic variant PPA [sv-PPA]) and in 21 matched healthy controls. Applying seed-based analysis on 3T fMRI data of an independent group of young healthy controls (n.40), we built the maps of three networks belonging to the left perisylvian language network (nodes: middle temporal gyrus–MTG, inferior frontal gyrus–IFG, anterior temporal lobe–ATL) and the maps of default-mode network (DMN) and salience network (SN). Using eLORETA, EEG current source density (CSD) and linear-lagged connectivity (LLC) values were estimated and compared. CSD and LLC analysis were performed at whole-brain level and at network level, respectively. <h3>Results:</h3> Patients showed a low-to-moderate cognitive impairment. At CSD analysis lv-PPA patients showed a higher delta density than nfvPPA, svPPA and healthy subjects. They also showed a higher theta density relative to controls. Level of statistical significance showed a pronounced descending posterior-to-anterior and left-to-right gradient over the brain cortex at theta band. Also nfvPPA patients deviated from healthy subjects in terms of widespread higher theta density. LLC analysis pointed out a significantly higher connectivity at delta and theta frequency bands characterizing all three groups of patients relative to controls in language networks. Connectivity disruption was also evident in non-language networks. <h3>Conclusions:</h3> Findings in PPA patients suggest that Alzheimer’s disease (AD), but not fronto-temporal degeneration (FTD), might induce a characteristic disruption of the cortical electrical activity in lvPPA patients, detectable by EEG. EEG might thus help in the differential diagnosis between AD-related and FTD-related PPA variants. <b>Disclosure:</b> Giordano Cecchetti has nothing to disclose. Federica Agosta has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for Philips. Federica Agosta has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier INC. Silvia Basaia has nothing to disclose. Dr. Spinelli has nothing to disclose. Ms. Cividini has nothing to disclose. Marco Cursi has nothing to disclose. The institution of Elisa Canu has received research support from Italian Ministry of Health . Dr. Leocadi has nothing to disclose. Roberto Santangelo, 4503 has nothing to disclose. Dr. Caso has nothing to disclose. Dr. Fanelli has nothing to disclose. Dr. Minicucci has nothing to disclose. Giuseppe Magnani has nothing to disclose. Dr. Filippi has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Bayer, Biogen Idec, Merck-Serono, Novartis, Roche, Sanofi Genzyme, Takeda, and Teva Pharmaceutical Industries. Dr. Filippi has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Bayer, Biogen Idec, Merck-Serono, Novartis, Roche, Sanofi Genzyme, Takeda, and Teva Pharmaceutical Industries. Dr. Filippi has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Springer Nature. The institution of Dr. Filippi has received research support from Biogen Idec, Merck-Serono, Novartis, Roche, Teva Pharmaceutical Industries, Italian Ministry of Health, Fondazione Italiana Sclerosi Multipla, and ARiSLA (Fondazione Italiana di Ricerca per la SLA).