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IC‐P‐074: Development of an eeg‐based neurometric battery for the assessment of cognitive decline in patients at risk for Alzheimer's disease
Author(s) -
Graves Kelly,
Cunningham Emily,
Okhravi Hamid,
Kieffaber Paul
Publication year - 2015
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2015.06.095
Subject(s) - audiology , multivariate analysis of variance , psychology , electroencephalography , dementia , discriminant function analysis , montreal cognitive assessment , cognition , analysis of variance , multivariate analysis , quantitative electroencephalography , disease , medicine , cognitive impairment , neuroscience , machine learning , computer science
Background: The posterior cingulate cortex (PCC) is an important brain connectivity network hub which is particularly sensitive to AD. This heterogeneous structure can be subdivided into ventral (vPCC) and dorsal (dPCC) regions that showed distinct connectivity. The aim of the present work was to highlight functional connectivity (FC) disruption, atrophy, and hypometabolism within the vPCC and dPCC networks in patients with amnestic Mild Cognitive Impairment (aMCI) and AD.Methods:Forty-three healthy elderly (HE) (68.76 6 years), 34 aMCI (73.46 6.8) and 24 AD (70.96 9.1) patients underwent resting-state functional MRI, FDG-PET and anatomical T1weighted MRI. FC maps from the vPCC and dPCC were obtained, and compared to identify the ventral and dorsal networks. Functional connectivity, gray matter volume and metabolism within each network were then compared between groups. Results: In HE, the ventral network included the hippocampus and temporo-parietal regions, whereas the dorsal network involved the precuneus, supramarginal, anterior temporal and dorso-medial prefrontal regions. aMCi patients had impaired ventral network FC in the bilateral hippocampus while the dorsal network FC was preserved. In AD, the ventral network FC disruption spread into the left parahippocampal and angular regions and the dorsal network FC was also affected in the right inferior middle temporal region. The ventral network was atrophied in bilateral hippocampus in aMCI and in the vPCC and angular regions as well in AD. The dorsal network was only atrophied in AD in the dPCC, bilateral supramarginal and temporal regions. By contrast, hypometabolism was already present in both the vPCC and the dPCC networks in aMCI patients and further extended to include the whole networks in patients with AD. Conclusions: The vPCC and dPCC connectivity networks are differentially sensitive to AD. In the vPCC network, FC disruption, atrophy and hypometabolism occur early (in aMCI patients) and amplify in AD. By contrast, the dPCC network is only hypometabolic in the aMCI stage and becomes atrophic and FC disrupted in AD. This suggests that atrophy and FC disruption spread from the ventral to the dorsal PCC networks while hypometabolism is not constrained by these networks.