Sleep-Like Slow Waves during Wakefulness Mediate Attention and Vigilance Difficulties in Adult Attention-Deficit/Hyperactivity Disorder.

Attention-deficit/hyperactivity disorder (ADHD) is characterized by behavioral variability and heightened inattention associated with increased mind wandering (MW) and mind blanking (MB). Individuals with ADHD frequently experience sleep disorders and excessive daytime sleepiness, suggesting interactions between attention and arousal systems. Research examining brain activity using electroencephalography (EEG) has demonstrated that sleep-like slow waves (SWs) during wakefulness are linked to inattention in neurotypical individuals following sleep deprivation, yet their role in ADHD remains unclear. This study investigated whether individuals with ADHD present with altered waking SW distribution compared with neurotypical controls and whether SWs explain attentional difficulties in ADHD. Adults with (n = 32) and without ADHD (n = 31) completed a sustained attention task while EEG recorded brain activity. Mental state probes (on-task, MW, MB) were embedded within the task. Sleep-like SWs reflect cortical slowing and were detected from EEG activity. Omission/commission errors, reaction time (RT), RT variability, mental state reports, and subjective sleepiness were analyzed. Mediation analysis examined whether SW density explained ADHD-related performance differences. Individuals with ADHD exhibited more commission errors, MW and MB, more theta oscillations over frontotemporal electrodes, and higher SW density (SW/minute) over parietotemporal electrodes. Increased SW density correlated with higher omission errors, slower RTs, greater RT variability, and elevated sleepiness ratings. On-task reports were negatively correlated with SW density. Mediation analysis revealed that SW density significantly accounted for ADHD-related attentional difficulties. Wake SW may explain attentional difficulties in ADHD, providing a potential mechanistic link between sleep disturbances and attentional fluctuations. [ABSTRACT FROM AUTHOR]