Brain Network Changes in Fatigued Drivers: A Longitudinal Study in a Real-World Environment Based on the Effective Connectivity Analysis and Actigraphy Data

Abstract

The analysis of neurophysiological changes during driving can clarify the mechanisms of fatigue, considered an important cause of vehicle accidents. The fluctuations in alertness can be investigated as changes in the brain network connections, reflected in the direction and magnitude of the information transferred. Those changes are induced not only by the time on task but also by the quality of sleep. In an unprecedented 5-month longitudinal study, daily sampling actigraphy and EEG data were collected during a sustained-attention driving task within a near-real-world environment. Using a performance index associated with the subjects' reaction times and a predictive score related to the sleep quality, we identify fatigue levels in drivers and investigate the shifts in their effective connectivity in different frequency bands, through the analysis of the dynamical coupling between brain areas. Study results support the hypothesis that combining EEG, behavioral and actigraphy data can reveal new features of the decline in alertness. In addition, the use of directed measures such as the Convergent Cross Mapping can contribute to the development of fatigue countermeasure devices.

The influence of mental fatigue on brain activity: Evidence from a systematic review with meta‐analyses

“…Evidence also suggests that alpha activity is an index of top‐down processing in frontal, central and posterior regions in which the cortex inhibits non‐essential or conflicting processes, during sustained attention leading to fatigue (Bazanova & Vernon, 2014). Connectivity research has also shown strong brain networks exist between frontal, central, and posterior cortical regions when a person mentally fatigues (Fonseca et al, 2018; Liu, Zhang, & Zheng, 2010; Sun, Lim, Kwok, & Bezerianos, 2014).…”

“…Similar to mental fatigue, mental and cognitive activity has been shown to be associated with EEG 4–13 Hz cortical activity (Fonseca et al, 2018; Kiroy, Warsawskaya, & Voynov, 1996; Sauseng, Griesmayr, Freunberger, & Klimesch, 2010). For instance, increased power in slow‐wave activity in the 4–13 Hz bands has been found to be associated with deterioration in mental performance (Borghini et al, 2014; Kiroy, Warsawskaya, & Voynov, 1996) and the findings of this meta‐analytic study confirm this conclusion, given increased power in theta and alpha activity across the cortex was strongly associated with mental fatigue.…”

“…Connectivity research has shown that while coherence increased (generally believed to be associated with greater neural communication) during a mentally fatiguing task in frontal, central and posterior regions, it was concluded that this increase in coherence was associated with more “economical” but less efficient mental performance (Zhao et al, 2017). Furthermore, Fonseca and Colleagues (2018) have shown the early sleep cycle is associated with enhancement or suppression of EEG activity in different cortical regions (e.g., suppression of theta and alpha activity in occipital areas in those with good sleep vs. activation in those with poor sleep).…”

“…This will normally lead to intentional or unintentional relaxation of mental effort achieved by various means, such as shutting eyes and napping, or redirecting one's attention to less demanding mental tasks. It may, however, also lead to increased effort to maintain mental performance, resulting in increased activity (Craig, Tran, Wijesuriya, & Middleton, 2012; Fonseca et al, 2018). However, activation versus suppression in EEG activity contingent with fatigue requires further research.…”

“…However, definitions of mental fatigue abound. Since fatigue is a dynamic event involving subjective, mental, behavioral, neural, and physiological processes that interact over time across different tasks and environmental contexts, it is often difficult to agree upon an operational definition (Fonseca, Kerick, King, Lin, & Jung, 2018).…”