Parametric evaluation of EEG signal during Eyes Close and Eyes Open state

Human Brain is a complex organ which controls the whole body. The largest part of brain is cerebrum whose function is to regulate the mental activity, sensations and controls. The rear part of cerebrum is called occipital lobe. It is for visual processing and is the area of interest for this paper. An effort is made to evaluate the different parameters from the acquired EEG signals. These signals were recorded from frontal and occipital lobes in Eyes Close (EC) and Eyes Open (EO) state. The 10-20 International system for electrode placement was used. Five (3 male, 2 female) subjects were trained and data was acquired from sensory visual areas. The data was analyzed for estimated parameters like Power Spectral Density (PSD), Correlation Dimension (CD) and Lyapunov exponent. PSD, mean and standard deviation were calculated for the comparison between the relaxed (EC) and active (EO) state. CD and Lyapunov exponent were used to analyze the impact of `OM chant' over the brain. It was found that the PSD of alpha rhythm has a higher magnitude value for EC state than in EO state whereas reverse is the case for beta and theta rhythm and remains same without any significant changes with regard to the time of data acquisition. The CD and Lyapunov Exponent (LE) parameters calculated showed respectively a maximum of 20% and 39% more relaxed state for the EEG data acquired in presence of `OM chanting' in background than in the absence of `OM chanting' for present list of subjects.