Influence Of Physical Fatigue On Mental Fatigue Based On EEG Analysis

Fatigue is an exhaustion state caused by prolonged physical work or mental work,which can reduces working efficiency and even cause industrial accidents. In most of the scenarios, physical and mental workloads co-lead operator into fatigue state. Thus, it's very important to study the interaction influence and its neural mechanisms between physical and mental fatigue.In this thesis, we studied the influence of physical fatigue on mental fatigue based on EEG. In the study, we designed the physical-mental fatigue experiment and the compared mental fatigue experiment. In physical-mental fatigue experiment, the subject performed 2-back task meanwhile cycling at 40% peak power output. While in mental fatigue experiment, the subject performed 2-back task meanwhile cycling at 0W. Ten subjects participated in the two experiments and the EEG was recorded before and after the fatigue-inducing tasks. Firstly, the wavelet packet energy,sample entropy and LZC values were extracted for statistical analysis and fatigue classification. Then, the brain networks based on parietal directed coherence(PDC) was calculated and the network parameters was calculated based on network topology analysis.The results showed that, after fatigue, the energy of ? band decreased and the ? band increased. The sample entropy and LZC values were decreased after the fatigue-inducing tasks. After tasks, the brain networks of both experiments became more complex and the clustering coefficient increased. Compare the physical-mental fatigue experiment and mental fatigue experiment, we can see that in initial state, the sample entropy and LZC values were consistent. But the value of sample entropy and LZC were lower in physical-mental fatigue condition than in mental fatigue condition, the difference was significant in central areas, parietal areas and temporal areas. The inflow of frontal area increased after both experiments, and the physical-mental fatigue condition was more than that of the mental fatigue condition. The inflow of temporal region decreased in mental fatigue experiment while it increased in physical-mental fatigue experiment. The result may imply that the information flow between frontal and temporal areas may play an important role to understand the interaction between physical and mental fatigue.The results of this thesis may provide scientific basis and theoretical guidance for complex task designs and fatigue monitoring.