Quantitative Study of Brain Electroencephalography Changes during Mental Fatigue Task

Abstract

Mental fatigue or so-called cognitive fatigue refers to a feeling of low motivation and lack of energy in a person, which can be associated with physical weakness and a sense of inability to continue working. In fact, this type of fatigue is a very common psycho-cognitive phenomenon that is caused as a side effect of various mental and neurological diseases or even in normal and healthy people. This phenomenon of mental fatigue has many physiological and biological effects on the brain, and changes in brain waves occur after the occurrence of mental fatigue. Therefore, we decided to evaluate these quantitative changes of electroencephalography of the brain during the execution of the mental fatigue task. Method: 30 participants (15 female and 15 male) aged 18 to 30 years participated in the study. After obtaining informed consent form, all participants were mentally fatigued by Stroop cognitive task for 30 minutes. The electrical activity of the brain was recorded at the same time. Before and after completing the fatigue task, sustained attention task that is sensitive to mental exhaustion status was obtained. Also, mental fatigue was assessed by visual analog scale (VAS) and by asking the subject. Participants were also evaluated for baseline EEG. Subjective fatigue (sense of motivation, reduced attention and concentration, inability to maintain concentration) was also measured during the task and every 10 minutes to confirm the effect of the task execution at each stage. ECG changes were also analyzed during 10-minute intervals during the implementation of the task. Results: The normal values of VAS and the adequacy score of the mental fatigue task have changed significantly before and after the implementation of the Stroop fatigue task. This indicates the successful induction of mental fatigue in people. The only significant effect was related to the time factor. This means that the power of the recorded signal has had significant changes during the consecutive times of the experiment. Other effects and interactions were not significant