Mental fatigue refers to a state of exhaustion or weariness that affects cognitive functioning and emotional well-being (Hockey, 2013), and generally leads to impaired cognitive and behavioural performance, including difficulty concentrating, making decisions, and retaining information.

Mental fatigue can result from prolonged periods of cognitive effort, as well as large monotonous and boredom activities (Boksem et al, 2006). The concept of mental fatigue is sometimes used interchangeably with the terms drowsiness and sleepiness, to the extent that they can be considered as different levels of a common scale.

Research suggests that mental fatigue may involve alterations in brain activity and neurotransmitter levels, impacting various cognitive processes (Lorist et al., 2005). For such a reason, a large set of correlations between mental fatigue and physiological markers has been proven so far by scientific community, both at the level of central nervous system, i.e. brain, especially in terms of alpha rhythms synchronization phenomena (Simon et al., 2011), and at the level of autonomic nervous system, such as the increasing of ocular blinks and decreasing of heart rate (Borghini et al., 2014).

According to previous studies and by performing a deep investigation of such a phenomenon, BrainSigns developed and validated an EEG-based index of mental fatigue (Di Flumeri et al., 2022) based on the episodic synchronization of alpha rhythms over parietal sites. This neurometric is useful in contexts where it is important to assess whether a specific task or system may induce user fatigue—and how rapidly this may occur. It can also serve as a valuable tool to assess whether specific training programs or targeted mitigation strategies enhance fatigue resilience. Such index is now largely deployed in automotive and road safety research (Giorgi et al., 2023).

REFERENCES

• Boksem, M. A. S., Meijman, T. F., & Lorist, M. M. (2006). Mental fatigue, motivation and action monitoring. Biological Psychology, 72(2), 123–132.
• Borghini, G., Astolfi, L., Vecchiato, G., Mattia, D., & Babiloni, F. (2014). Measuring neurophysiological signals in aircraft pilots and car drivers for the assessment of mental workload, fatigue and drowsiness. Neuroscience & Biobehavioral Reviews, 44, 58-75.
• Di Flumeri, G., Ronca, V., Giorgi, A., Vozzi, A., Aricò, P., Sciaraffa, N., ... & Borghini, G. (2022). EEG-based index for timely detecting user’s drowsiness occurrence in automotive applications. Frontiers in Human Neuroscience, 16, 866118.
• Giorgi, A., Ronca, V., Vozzi, A., Aricò, P., Borghini, G., Capotorto, R., ... & Di Flumeri, G. (2023). Neurophysiological mental fatigue assessment for developing user-centered Artificial Intelligence as a solution for autonomous driving. Frontiers in Neurorobotics, 17.
• Hockey, G. R. J. (2013). The psychology of fatigue: Work, effort, and control. Cambridge University Press.
• Lorist, M. M., Boksem, M. A. S., & Ridderinkhof, K. R. (2005). Impaired cognitive control and reduced cingulate activity during mental fatigue. Cognitive Brain Research, 24(2), 199–205.
• Simon, M., Schmidt, E. A., Kincses, W. E., Fritzsche, M., Bruns, A., Aufmuth, C., ... & Schrauf, M. (2011). EEG alpha spindle measures as indicators of driver fatigue under real traffic conditions. Clinical Neurophysiology, 122(6), 1168-1178.