Automatic Detection of Schizophrenia by Applying Deep Learning over Spectrogram Images of EEG Signals

This study presents a method that aims to automatically diagnose Schizophrenia (SZ) patients by using EEG recordings. Unlike many literature studies, the proposed method does not manually extract features from EEG recordings, instead it transforms the raw EEG into 2D by using Short-time Fourier Transform (STFT) in order to have a useful representation of frequency-time features. This work is the first in the relevant literature in using 2D time-frequency features for the purpose of automatic diagnosis of SZ patients. In order to extract most useful features out of all present in the 2D space and classify samples with high accuracy, a state-of-art Convolutional Neural Network architecture, namely VGG-16, is trained. The experimental results show that the method presented in the paper is successful in the task of classifying SZ patients and healthy controls with a classification accuracy of 95% and 97% in two datasets of different age groups. With this performance, the proposed method outperforms most of the literature methods. The experiments of the study also reveal that there is a relationship between frequency components of an EEG recording and the SZ disease. Moreover, Grad-CAM images presented in the paper clearly show that mid-level frequency components matter more while discriminating a SZ patient from a healthy control.