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.
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2015-02-03
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Abstract
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 neurodegeneration 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 Neurodegeneration 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