An INSERM study suggests that some symptoms of attention deficit disorder with or without hyperactivity (ADHD), could be explained by the intrusion of slow brain waves, usually associated with sleep, during wakefulness. These slow waves could thus constitute a potential biomarker of ADHDwhich affects approximately 2.5% of adults and remains poorly understood biologically. Ultimately, these results could guide new therapeutic strategies, in particular by acting on the quality of sleep and the regulation of vigilance.
Frequent forgetting, careless errors or difficulty maintaining attention and resisting distractions: attention deficit disorder with or without hyperactivity (ADHD) affects approximately 2.5% of adults, but its biological mechanisms remain poorly understood.
In an international study published on March 16 in the Journal of Neurosciencescientists from Inserm at the Brain Institute (Inserm/CNRS/Sorbonne University), and from Monash University, in Australia, suggest that the symptoms of this disorder could be linked to the intrusion of slow waves, usually observed during sleep, during wakefulness. This phenomenon, called “local sleep,” could offer an explanation for the lapses in attention and sleepiness often observed in people with ADHD.
To achieve these results, the scientists compared the brain activity of 32 adults with ADHD, under drug treatment, to that of 31 neurotypical adults, while the participants carried out a task requiring sustained attention.
Higher slow wave density in adults with ADHD
Result : « Adults with ADHD have a significantly higher density of slow waves, usually seen during deep sleep. However, these waves are not trivial : the higher their density, the more participants commit careless errors and exhibit slower or more variable reaction times », summarizes Thomas Andrillon, Inserm researcher within the DreamTeam at the Brain Institute, and last author of the study.
Participants with ADHD also reported more episodes of “mind wandering” (mind wandering) and “mental blankness” (mind blanking)two states directly correlated with these local sleep intrusions. Furthermore, the level of fatigue felt by the participants increases as these slow waves accumulate during the attentional effort.
« Sleep wave intrusion is a perfectly normal phenomenon. Think about a long run : after a certain time, physical fatigue forces you to take a break. The same goes for mental fatigue: after a day spent awake or after a poor night’s sleep, the brain also takes breaks in the form of slow waves. These brief moments of brain inactivity happen to everyone”explains the researcher.
In people with ADHD, however, this activity is more common. Our results suggest that it could constitute a key brain mechanism explaining their difficulties in maintaining stable attention and performance over time. Thomas Andrillon, Inserm researcher
For scientists, these slow waves could thus constitute a possible explanation linking the diagnosis of ADHD to the behavioral symptoms observed on a daily basis. This discovery suggests that ADHD could be, at least in part, a disorder of the regulation of arousal and vigilance.. « These local sleep waves could become a key biomarker for diagnosis »forward Thomas Andrillon.
These results could also guide the development of new therapeutic strategies, whether pharmacological or non-drug, in particular interventions aimed at improving the quality of sleep or stabilizing vigilance mechanisms.
« In neurotypical people, for example, some research has shown that auditory stimulation during sleep can strengthen nocturnal slow waves, which could reduce the occurrence of sleep-like brain activity during wakefulness the next day. A next step will be to determine whether this approach could also reduce these local sleep intrusions in people with ADHD. », concludes Thomas Andrillon.
Inserm press release, March 16, 2026
