EEG-based time-on-task vigilance trajectories in children with and without ADHD

Sustaining attention is a key ability not only for adults in contexts such as driving or monitoring systems, but also for children in educational settings, where it is closely linked to long-term academic achievement. The present study aimed to develop an EEG-based measure of vigilance during a sustained attention task and to use it to identify distinct trajectories of vigilance over time in a sample of children with and without ADHD. The measure was developed using multiple regression and captures time-on-task-related changes in the EEG power spectrum. In typically developing children, it is characterized by an increase in theta, alpha and beta activity and a decrease in gamma activity over time. A k-means cluster analysis identified distinct vigilance trajectories, and the corresponding subgroups of children differed both in various performance metrics and in the number of ADHD symptoms. The normative pattern, characterized by a steadily rising trajectory over time, was associated with better performance, whereas atypical patterns showing pronounced declines either early or late in the task were linked to comparatively weaker performance. The identified vigilance profiles point to different mechanisms of sustained attention regulation in children and may help to detect these differences at the individual level, thereby paving the way for personalized interventions.