The Contribution of EEG to the Diagnosis of Dementia

Changes induced by cerebrovascular damage (CVD) and amigdalo-hippocampal atrophy (AHC) on brain rhythmicity as revelaled by scalp electroencephalography (EEG) were evaluated in a cohort of subjects with mild cognitive impairment (MCI) in order to detect different EEG patterns due to the vascular or degenerative impairment. All subjects underwent EEG recording and magnetic resonance imaging (MRI). EEGs were recorded at rest. Relative power was separately computed for delta, theta, alpha1, alpha2, and alpha 3 frequency bands. Increased delta power and decreased alpha2 power were associated with the load of cerebrovascular damage (CVD). Moreover, the theta/alpha 1 ratio could be a reliable index for the estimation of the individual extent of CV damage. No association of vascular damage was observed with alpha3 power. On the other side, moderate hippocampal atrophy was related to an increase of alpha2 and alpha3 frequency power ratio. Our results show that different EEG markers are associated to vascular dementia and Alzheimer’s disease (AD). EEG markers could be expression of different global network pathological changes, helping in differentiation of prodromal AD from vascular demented patients. MCI stated that EEG markers could have a prospective value in differential diagnosis between vascular and degenerative MCI.