Classification of Alzheimer’s Disease and Lewy Body Dementia using Biomarkers on Resting-State Electroencephalogram Signals through Deep Learning
This Master thesis investigates the application of deep learning techniques to resting-state
electroencephalogram (EEG) signals for the classification of neurologically healthy older
adults (NOLD), patients with Alzheimer’s disease (AD), and patients with Lewy body
dementia (DLB). A dataset comprising 90 participants (30 AD, 30 DLB, and 30 NOLD)
was analyzed, with AD and DLB groups further divided into mild cognitive impairment
(MCI) and dementia (DEM) categories. Preprocessed resting state EEG signals were
decomposed into standard frequency bands (delta, theta, alpha, beta, and gamma), and
normalized power spectral density (PSD) features were extracted from 19 channels. Two
deep learning models — Long Short-Term Memory (LSTM) networks and Transformer-
based architectures — were implemented and validated using the Leave One Subject
Out (LOSO) cross-validation scheme, to simulate real clinical generalization. The LSTM
classifier achieved an average accuracy of 94.97%, with 95.03% sensitivity and 94.96%
specificity across three binary group comparisons (AD vs. DLB, AD vs. NOLD, and DLB vs.
NOLD) and three binary category comparisons (DEM vs. MCI, DEM vs. CTRL, and MCI
vs. CTRL). The Transformer model yielded even higher performance, with 96.40% average
accuracy, 97.29% sensitivity, and 95.56% specificity. In multi-class classification, both
approaches demonstrated robust accuracy: 86.67% (LSTM) and 87.78% (Transformer) for
five-class discrimination (AD-DEM, AD-MCI, DLB-DEM, DLB-MCI, and NOLD-CTRL),
and above 90% for three-class group (AD, DLB, and NOLD) and category (DEM, MCI,
and CTRL) distinctions. These results demonstrate that deep learning applied to resting
state EEG data can effectively distinguish between AD, DLB, MCI, and healthy aging,
providing a non-invasive, accurate, and generalizable approach for early and differential
detection of dementia.