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

Objective: To determine the electrophysiological characteristics of frontotemporal dementia (FTD) and the distinction with Alzheimer's disease (AD).

Methods: We 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).

Results: In 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.

Conclusions: Differential patterns of brain regions and EEG frequency bands were observed between the FTD and AD groups in terms of pathological activity.

Significance: FTD and AD patients in the early stages displayed different patterns in the cortical localization of oscillatory activity across different frequency bands.