Evaluation of stress and mental fatique with physical and physiological measurements

Stress and mental fatigue are in existence constantly in our daily life, and decrease our productivity while performing our daily routines. It was thought that it would be very important to do research by adding objective measurements about these two situations. In the study, ten volunteers carried out electronic sport (the competitions of organized computer games) which required both physical and mental effort and skills for two minutes, and they were subjected to stress and mental fatigue. Puzzle video game Tetris selected as electronic sport. Volunteers' data of Electroencephalography (EEG), Galvanic Skin Response (GSR) and Heart Rate Variability (HRV) were obtained before and during the game and eye tracking data was obtained only during the game, and then they were analyzed. It was tried to determine the effect of the game on working memory by means of Position, Color 2-Back test and on cognitive performance by means of D2 attention test and the relation of such effects with objective measures before and after the electronic sport applied to the volunteers. VAS evaluation was realized in relation with stress and mental fatigue before and after the electronic sport. The correlation of this subjective evaluation with the objective measures was searched. It was observed that Position, Color 2-Back score averages was decreasing while VAS scores were increasing. As a result of D2 tests, it was seen that the game effected the attention in a positive way. When average normalize powers belonging to frequency band in the AF7 and AF8 sections of the brain of each participants were examined in EEG evaluation, it was understood that game caused stress and mental fatigue. By considering the parameters of heart rate variability, it was observed that game occurred various sympathetic and vagal activities on individuals. During the game, it was seen that feature averages related to GSR increased comparing with the situation of resting. By examining HRV and GSR together, it was determined that the emotional processes of some participants constituted stress, and some constituted excitement. Finally, it was seen that the heat map, which was prepared as per the eye actions of the individuals getting lower points in the game, dispersed to wider area. In the other study, it was aimed to determine the effects of different modes of N-back test on stress and mental fatigue by EEG and eye tracking device. With the increase of N-back test difficulty, the EEG beta, alpha and theta powers were also increased. In addition, HRV, GSR and eye tracking records were taken and analyzed in the study which investigated the effects of tetris playing time. When the playing time of tetris play increased, sympathetic activity and stress increased and the heat map was also spread over a larger area.