Spectral density analysis: theta wave as mental stress indicator

Abstract

This paper aims to investigate the correlation between mental tasks and the emanated theta and alpha brain waves. Electroencephalogram (EEG) signal is a highly random, complex and non linear in nature. The analysis of Electroencephalogram remains problematic due to the limited understanding of the signal origin. In spite of these shortcomings, the EEG is valuable tool to evaluate the overall cerebral activity. Advanced signal processing technique is required to extract hidden features carried by the signal. These features are useful to determine the mental state condition. Analysis was carried out using five adult right handed subjects, healthy and non smokers. Subjects were asked to perform mental arithmetic (MA) task in a period of time to induce the mental stress. To ensure the subjects performed all the MA tasks with full effort, a honorarium was given for every correct response. Using Burg's Method, power spectral density (PSD) were extracted from the emanate brain signal. Statistical analysis using correlation was performed and a positive relationship (r=0.625, p<0.05) has been observed between the highest PSD theta waves to the mental stress condition. © 2011 Springer-Verlag.