Objective Assessments of Mental Fatigue During a Continuous Long-Term Stress Condition

Abstract

Prolonged periods of cognitive workload will cause mental fatigue, but objective, quantitative, and sensitive measurements that reflect long-term, stress-induced mental fatigue have yet to be elucidated. This study aims to apply a potential marker of Rényi entropy to investigate the mental fatigue changes in a long-term, high-level stress condition and compare three different instruments for assessment of mental fatigue: EEG, the oddball task, and self-scoring. We recruited nine individuals who participated in a 5-day intellectually challenging competition. The participants were assessed for mental fatigue each day of the competition using prefrontal cortex electroencephalogram (EEG). Reaction time in an oddball task and self-rated scoring were used comparatively to evaluate the performance of the EEG. Repeated measures ANOVA was utilized to analyze the differences among score, reaction time, and wavelet Rényi entropy. The results demonstrated that both wavelet Rényi entropy extracted from EEG and self-rated scoring revealed significant increases in mental fatigue during the 5 days of competition (P < 0.001). The reaction time of the oddball task did not show significant changes during the five-day competition (P = 0.066). Moreover, the wavelet Rényi entropy analysis of EEG showed greater sensitivity than the self-rated scoring and reaction time of the oddball task for measuring mental fatigue changes. In conclusion, this study shows that mental fatigue accumulates during long-term, high-level stress situations. The study also indicates that EEG wavelet Rényi entropy is an efficient metric to reflect the change of mental fatigue under a long-term stress condition and that EEG is a better method to assess long-term mental fatigue.

Predictors of Functional School Outcome in Children With Pediatric Acquired Brain Injury

“…Strengths of the present study include the large sample size relative to other pABI studies, robust and standardized assessment methods with both child and proxy report and objective functional school data, and the inclusion of both traumatic and non-traumatic brain injuries, increasing the generalizability and validity our findings. However, future research might also want to consider additional fatigue outcomes, such as objective fatigue measures [e.g., ( 109 )]. In addition to the potential overlap in item content between fatigue and QoL measures, factors such as awareness, social desirability bias, response set bias (tendency to respond similarly to all/many items), and over/under reporting of symptoms may influence the accuracy of questionnaire responding.…”

Mental fatigue decreases complexity: Evidence from multiscale entropy analysis of instantaneous frequency variation in alpha rhythm

“…MF impairs a variety of cognitive functions (Mast and Heimstra, 1964 ) and according to the complexity loss theory (Lipsitz and Goldberger, 1992 ), should induce lower complexity in EEG. However, the few studies that cover this topic report inconsistent results (Chen et al, 2018 ; Zhang et al, 2021 ). In this study, we have applied two strategies in the attempt to test the hypotheses that MF can also cause the complexity loss.…”

“…For example, MF caused by watching 3DTV reveals significant complexity loss in occipital lobe in some scales (Chen et al, 2018 ). Another study shows increased complexity of EEG from subjects after performing days of intellectual competition (Zhang et al, 2021 ). Complexity is often measured by multiscale entropy (MSE) (Costa et al, 2002 ) and its variants (e.g., Wu et al, 2013 ; Shi et al, 2017 ; Han et al, 2020 ) in a variety of research fields by calculating sample entropy at multiple scales of the coarse-grained versions of the original signal.…”

The neuroelectrophysiological and behavioral effects of transcranial direct current stimulation on executive vigilance under a continuous monotonous condition

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