Stress Identification during Sustained Mental Task and Brain Relaxation Modeling with $\beta/\alpha$ Band Power Ratio

Stress is the non-specific response of human brain which changes according to the demand of day to day life. In this paper stress and relaxation of brain is identified from the activation of alpha ( α) and beta ( β) EEG bands depending on their power spectral density (PSD). Stress occurs due to sustained mental task in a test (Bengali, English, Math) environment and the work has been performed in to Reading, Writing and Mathematical problem-solving stages. When β/α power ratio is 1.5 or more it indicates stress. The relaxation of the brain is estimated taking the PSD at different time interval after the brain activity and when the β/α ratio returns to the value of relax state then it is determined that relaxation is obtained. Finally brain relaxation is modeled with mathematical formulation based on β/α power ratio.