Evaluation Of Laboratory-driven Mental Fatiguing Protocol Using EEG And Self-reported Fatigue Scale

PURPOSE: Assess physiological effects of a mental fatigue protocol using both subjective (VAS-F) and EEG assessments. METHODS: Subjective evaluation using the VAS-F scale and EEG data were collected from 28 participants (14F, age: 29.1 ± 13.4 yrs) before and after a 40-minute mental fatigue protocol. A working memory dual-task test combining parity judgment and n-back tasks was customized to each participant's cognitive limit to induce mental fatigue. Alpha and Theta band frequencies were analyzed from frontal electrodes (AF7 and AF8), and the Theta Alpha ratio was calculated. A paired-sample t-test was performed to detect differences before and after the fatiguing protocol (p < .05). RESULTS: Significant increases were observed post-fatigue in Theta power at AF7 (p = .001), AF8 (p = .002), and combined AF7 + AF8 (p = .001). Alpha power showed a significant decrease at AF7 (p = .042), AF8 (p = .004), and combined AF7 + AF8 (p = .006). The Theta/Alpha ratio increased significantly at AF7 (p = .002), AF8 (p = .001), and combined AF7 + AF8 (p < .000). Subjectively, participants reported higher fatigue (p < .000) and lower energy levels (p < .000) post-task. These changes reflect a shift from a relaxed, alert state to one characterized by increased cognitive effort and reduced attentional control. The congruence between self-reported fatigue and EEG data reinforces the validity of subjective fatigue measures, especially when complemented with objective EEG analyses. CONCLUSION: The findings demonstrate that the employed mental fatiguing protocol effectively induced physiological changes indicative of increased cognitive load and mental fatigue. These changes were corroborated by both EEG measurements and self-reported assessments, thereby validating the protocol's efficacy and contributing to the growing body of research linking EEG markers to subjective experiences of mental fatigue. Table 1. - EEG Power Spectral Density and Self-reported Fatigue Freq Band EEG sensors Pre-fatigue Post-fatigue θ (μV2/Hz) AF7 0.974 ± 0.225 1.314 ± 0.592* AF8 1.082 ± 0.329 1.517 ± 0.883* AF7 + AF8 2.056 ± 0.477 2.831 ± 1.360* α (μV2/Hz) AF7 0.690 ± 0.256 0.625 ± 0.156* AF8 0.759 ± 0.310 0.627 ± 0.169* AF7 + AF8 1.449 ± 0.534 1.253 ± 0.308* θ/α AF7 1.505 ± 0.391 2.080 ± 0.645* AF8 1.509 ± 0.352 2.361 ± 0.971* AF7 + AF8 1.502 ± 0.341 2.224 ± 0.727* VAS-F Fatigue (/130 pts) 47.9 ± 21.2 73.1 ± 24.2* Energy (/50 pts) 28.6 ± 9.6 21.1 ± 9.5*