Occipital sources of resting-state alpha rhythms are related to local gray matter density in subjects with amnesic mild cognitive impairment and Alzheimer's disease

Başar, Erol
Yener, Görsev
Emek Savaş, Derya Durusu
Babiloni, Claudio
Del Percio, Claudio
Boccardi, Marin
Lizio, Roberta
Lopez, Susanna
Carducci, Filippo
Marzano, Nicola
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Elsevier Science Inc, 360 Park Ave South, New York, Ny 10010-1710 USA
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Occipital sources of resting-state electroencephalographic (EEG) alpha rhythms are abnormal, at the group level, in patients with amnesic mild cognitive impairment (MCI) and Alzheimer's disease (AD). Here, we evaluated the hypothesis that amplitude of these occipital sources is related to neuro-degeneration in occipital lobe as measured by magnetic resonance imaging. Resting-state eyes-closed EEG rhythms were recorded in 45 healthy elderly (Nold), 100 MCI, and 90 AD subjects. Neuro-degeneration of occipital lobe was indexed by weighted averages of gray matter density, estimated from structural MRIs. EEG rhythms of interest were alpha 1 (8-10.5 Hz) and alpha 2 (10.5-13 Hz). EEG cortical sources were estimated by low-resolution brain electromagnetic tomography. Results showed a positive correlation between occipital gray matter density and amplitude of occipital alpha 1 sources in Nold, MCI, and AD subjects as a whole group (r = 0.3, p = 0.000004, N = 235). Furthermore, there was a positive correlation between the amplitude of occipital alpha 1 sources and cognitive status as revealed by Mini Mental State Examination score across all subjects (r = 0.38, p = 0.000001, N = 235). Finally, amplitude of occipital alpha 1 sources allowed a moderate classification of individual Nold and AD subjects (sensitivity: 87.8%; specificity: 66.7%; area under the receiver operating characteristic curve: 0.81). These results suggest that the amplitude of occipital sources of resting- state alpha rhythms is related to AD neurodegeneration in occipital lobe along pathologic aging. (C) 2015 Elsevier Inc. All rights reserved.

Mild cognitive impairment (MCI) , Alzheimer's disease (AD) , Electroencephalography (EEG) , Magnetic resonance imaging (MRI) , Gray matter density (GMD) , Voxel-based morphometry , Transcranial magnetic stimulation , Electromagnetic tomography loreta , Cerebral-blood-flow , Eeg alpha , Quantitative electroencephalography , Clinical neurophysiology , International workshop , Hippocampal Atrophy , Cortical rhythms