Abstract
Fatigue state changes have been previously linked to performance changes in attentional tasks. A gradual disengagement of the alertness network reflected in oscillatory activity is likely to drive these changes. Here, we investigated whether older adults show greater performance decline in sustained attention and whether this possible decline is reflected in greater fatigue and oscillatory change. In a pre-registered EEG study, young (n = 18, mean = 22.61, SD = 1.85) and older (n = 16, mean = 66.50, SD = 8.45) participants were tested with the Sustained Attention to Response Task (SART) over 45 minutes and assessed on behavioural performance changes, subjective state fatigue and neural metrics. We found an age-specific performance strategy with older participants showing better performance with fewer commission errors and slower reaction times (with young adults demonstrating the opposite pattern). All participants showed increased subjective state fatigue and mind-wandering over time, which was further reflected in increases in pre-stimulus occipito-parietal alpha (8-12Hz) frequency power band and a significant change in the post-stimulus frontocentral lower beta power band (15-25 Hz). We propose that fatigue changes are reflected in oscillatory changes due to increased efforts in top-down control, and that these oscillatory changes can be mapped and possibly ameliorated with non-invasive neuromodulation.