Differences in quantitative EEG between frontotemporal dementia and Alzheimer’s disease as revealed by LORETA

ObjectiveTo determine the electrophysiological characteristics of frontotemporal dementia (FTD) and the distinction with Alzheimer’s disease (AD).MethodsWe performed analyses of global field power (GFP) which is a measure of whole brain electric field strength, and EEG neuroimaging analyses with sLORETA (standardized low resolution electromagnetic tomography), in the mild stages of FTD (n = 19; mean age = 68.11 ± 7.77) and AD (n = 19; mean age = 69.42 ± 9.57) patients, and normal control (NC) subjects (n = 22; mean age = 66.13 ± 6.02).ResultsIn the GFP analysis, significant group effects were observed in the delta (1.5–6.0 Hz), alpha1 (8.5–10.0 Hz), and beta1 (12.5–18.0 Hz) bands. In sLORETA analysis, differences in activity were observed in the alpha1 band (NC > FTD) in the orbital frontal and temporal lobe, in the delta band (AD > NC) in widespread areas including the frontal lobe, and in the beta1 band (FTD > AD) in the parietal lobe and sensorimotor area.ConclusionsDifferential patterns of brain regions and EEG frequency bands were observed between the FTD and AD groups in terms of pathological activity.SignificanceFTD and AD patients in the early stages displayed different patterns in the cortical localization of oscillatory activity across different frequency bands.

Research highlights
► A comparative study of frontotemporal dementia (FTD), Alzheimer’s disease (AD), and healthy control subjects (NC) was carried out in terms of the cortical localization of oscillatory EEG activity.
► As compared to NC, FTD had significantly reduced alpha generators in fronto-temporal cortices, while AD showed significantly stronger delta generators that included the frontal lobes.
► ROC curves demonstrate a moderate separation of FTD, AD, and NC groups.