Analysis of EEG Seizure using Fractal Dimensions by the Application of ECT Stimulus to Cerebral Cortex

Abstract

Stimulus is an external agent which produces excitability in tissues. Electroconvulsive therapy (ECT) is a form of medical treatment for severe depression, bipolar disorder and psychotic illnesses such as schizophrenia. An electroencephalogram (EEG) signal is generated from the natural currents of billion nerve cells in the cerebral cortex. Seizure occurs when there is an excessive synchronous discharge of neurons within the central nervous system (CNS). Response of the brain is high at the given point of stimulus and gradually decreases as time elapses, which can be observed as early, mid and post seizure respectively. In this paper, EEG seizure using fractal dimensions (FD) were measured and an attempt is made by comparing the FD values with the subjective conclusion taken clinically. The FD values were measured on four channels of recorded EEG during ECT by a volunteer. The fractal method is successful in detecting low amplitude spikes and the changes in the patterns of the EEG. Fractal characterization is not only an useful tool in analyzing EEG but also can be employed in analyzing and comparing various complex biological signals.