Evaluation of the EEG Signals and Eye Tracker Data for Working Different N-Back Modes

Abstract

In this study, it is aimed to determine the effects of different modes N-back test which is one of the measurement tools frequently used in measurement of working memory, on the Electroencephalography (EEG) and Eye-tracker data. Eight healthy volunteers participated in this study. The volunteers performed tasks inducing stress and mental fatigue for almost 4 minutes. Each experimental task consists of 72-seconds stress and fatigue inducing 1-position back, 2-position-color and 2-position-image test sessions and three evaluation sessions performed for task. During these sessions, the volunteers were assessed using EEG, Eye Tracker and Visual analogue scale (VAS). VAS was also used to evaluate perceived stress and mental fatigue before and after the N-back test. Power values of EEG signals from volunteers for different test modes were evaluated according to test scores in theta, alpha, beta, and low gamma bands. According to the obtained results, the power values in each subband of the EEG change according to the test mode and the test scores. Beta, alpha and theta frequency bands' power in the frontal cortex (AF7+AF8) increased with the n back test score and difficulty level of the game. When the task gets harder, it shows that the heat map of eye tracking is spread over a wider area. The VAS scores for both mental fatigue and stress increased after the Nback test with low and high test scores. According to the graphical results obtained from EEG with subjective evaluation, stress and mental fatigue increased with N-back tests. These results help understanding of the physiological changes of stress and mental fatigue and contribute to improve new approaches to assess stress and mental fatigue.

A Hybrid EEG-Based Stress State Classification Model Using Multi-Domain Transfer Entropy and PCANet

“…For example, we have incorporated time constraints and performance feedback to further enhance the stress response. Previous studies [ 13 , 14 ] have demonstrated the effectiveness of the tests in inducing stress.…”