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

Yawen Zhai; Yan Li; Shengyi Zhou; Chenxu Zhang; Erping Luo; Chi Tang; Kangning Xie

doi:10.3389/fnhum.2022.906735

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

Front Hum Neurosci. 2022 Oct 26:16:906735. doi: 10.3389/fnhum.2022.906735. eCollection 2022.

Authors

Yawen Zhai^{1

2

3}, Yan Li^{1

2}, Shengyi Zhou^{1

2

4}, Chenxu Zhang^{1

2}, Erping Luo^{1

2}, Chi Tang^{1

2}, Kangning Xie^{1

2}

Affiliations

¹ School of Biomedical Engineering, Air Force Medical University, Xi'an, China.
² Shaanxi Provincial Key Laboratory of Bioelectromagnetic Detection and Intelligent Perception, Xi'an, China.
³ School of Electronics and Information, Xi'an Polytechnic University, Xi'an, China.
⁴ Air Force Hospital of Western Theater Command, Chengdu, China.

Abstract

Mental fatigue (MF) jeopardizes performance and safety through a variety of cognitive impairments and according to the complexity loss theory, should represent "complexity loss" in electroencephalogram (EEG). However, the studies are few and inconsistent concerning the relationship between MF and loss of complexity, probably because of the susceptibility of brain waves to noise. In this study, MF was induced in thirteen male college students by a simulated flight task. Before and at the end of the task, spontaneous EEG and auditory steady-state response (ASSR) were recorded and instantaneous frequency variation (IFV) in alpha rhythm was extracted and analyzed by multiscale entropy (MSE) analysis. The results show that there were significant differences in IFV in alpha rhythm either from spontaneous EEG or from ASSR for all subjects. Therefore, the proposed method can be effective in revealing the complexity loss caused by MF in spontaneous EEG and ASSR, which may serve as a promising analyzing method to mark mild mental impairments.

Keywords: auditory steady-state response; complexity; mental fatigue; multiscale entropy; nonlinear analysis.