Investigation of schizophrenic EEG signals using wavelet transform functions

The aim of the present study is to investigate EEG data of schizophrenic patients and healthy individuals using different wavelet transform functions and to utilize those functions as a tool for revealing the brain locus causing schizophrenia. In this study, pretreatment of EEG data of both schizophrenic patients and healthy controls were performed to eliminate artifacts and the data were filtered with a 40 Hz low pass filter. Filtered data were subjected to continuous wavelet transform in order to obtain wavelet coefficients as much points as in EEG signal in a range of 0-256 scale. Scales for different EEG bands ( e.g. delta <; 4Hz) were determined. For each channel standard deviation and mean values of coefficients for delta, theta, alpha, gamma bands and the results for patients and healthy individuals were compared to find out the brain locus the disease is originated from. Same process was performed with different wavelet transform functions, and the results were compared.