Consequence of Stress on Cognitive Performance: An EEG and HRV Study

Frontal cortical activity can be used as an indicator of mental stress. Using the frontal alpha activity in the electroencephalogram (EEG) as a basis, the Frontal Brain Asymmetry, Resting Brain Asymmetry, Frontal Asymmetry Index and Alpha Band Power along with Heart Rate Variability have been used as features in the present work to analyse the level of stress in subjects. Eleven healthy subjects participated in the experiments with 3 tests each based on 4 trials, with each trial posing an added cognitive challenge. Trials consisted of the Hopkins Verbal Learning Test, Trial Making Test, and Corsi Block Tapping Test. They were tested on factors based on verbal understanding, memory, attention, focus and overall cognitive performance. Using a rule-based classification model and combining the results from the features, 3 categories (low, medium and high) of stresses were identified. Partial consistency through the various extracted features indicate that subjects vary in their ability to manage stress. Overall, 2 subjects were indicative of a low stressed state, 6 subjects showed medium stress levels and 3 subjects were categorized under the high stress state.