A Multi-modal Ensemble Framework with Topological GAF Features for Accurate EEG-Based Alzheimer’s Diagnosis
摘要
Early diagnosis of Alzheimer’s disease (AD) is a significant issue because neural changes related to the disease are slow, discrete, and, in most cases, concealed by standard clinical tests. This study introduces a Multi-Perspective Topological Gramian Angular Field (MPT-GAF) system that has the potential to deliver reliable EEG-based AD classification. EEG signals are nonlinear and non-stationary in nature, which implies that the proposed method represents complex spatiotemporal behavior by encoding in a nonlinear phase space and transforming it into a topology. Pre-processing of EEG records entails the application of a fifth-order Butterworth bandpass filter (0.5–45 Hz) and Daubechies-4 wavelet denoising to eliminate artifacts and finally sub-resolution into five major frequency bands. All bands were sampled into image-like MPT-GAFs, and the phase correlation, nonlinear association, and interregional connection patterns were preserved. A weighted ensemble classifier based on a Convolutional Neural Network (CNN), Support Vector Machine (SVM) with Radial Basis Function (RBF) kernel, Random Forest and Bidirectional Long Short-Term Memory (Bi-LSTM) networks was then used to exploit both spatial and temporal representations. The experimental validation blocks in the OpenNeuro dataset achieved outstanding performance with 98.94% accuracy, 98.96% precision, and 98.94% F1-score with a significant statistical value (