🧠 Attention disorders linked to the intrusion of sleep waves during wakefulness

Attention deficit hyperactivity disorder (ADHD), which affects approximately 2.5% of adults, remains poorly understood from a biological standpoint.

An international study conducted by scientists from Inserm at the Brain Institute (Inserm/CNRS/Sorbonne University), and Monash University in Australia, suggests that certain symptoms 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 for ADHD. Ultimately, these findings could guide new therapeutic strategies, particularly by acting on sleep quality and the regulation of alertness.


Frequent forgetfulness, inattentive errors, or difficulties maintaining focus and resisting distractions: attention deficit hyperactivity disorder (ADHD) affects approximately 2.5% of adults, but its biological mechanisms are still poorly understood.

In an international study published on March 16 in the Journal of Neuroscience, scientists from Inserm at the Brain Institute (Inserm/CNRS/Sorbonne University), and Monash University in Australia, suggest that the symptoms of this disorder could be linked to the intrusion of slow waves, usually observed during sleep, while awake. This phenomenon, called "local sleep," could provide an explanation for the attention lapses and drowsiness often observed in people with ADHD.

To reach these results, the scientists compared the brain activity of 32 adults with ADHD, under medication, with that of 31 neurotypical adults, while participants performed a task requiring sustained attention.

A higher density of slow waves in adults with ADHD

Result: "Adults with ADHD show a significantly higher density of slow waves, usually observed during deep sleep. However, these waves are not trivial: the higher their density, the more participants make inattentive errors and exhibit slower or more variable reaction times," summarizes Thomas Andrillon, an Inserm researcher within the DreamTeam at the Brain Institute, and the last author of the study.

Participants with ADHD also report more episodes of "mind wandering" and "mind blanking," two states directly correlated with these local sleep intrusions. Furthermore, the level of fatigue reported by participants increases as these slow waves accumulate during attentional effort.

"The intrusion of sleep waves is a perfectly normal phenomenon. Think of a long run: after a certain time, physical fatigue forces you to take a break. It's the same for mental fatigue: after a day spent awake or after a bad night's sleep, the brain also takes breaks in the form of slow waves. These brief moments of brain inactivity occur in everyone," explains the researcher.

For the scientists, these slow waves could thus constitute an explanatory pathway linking the ADHD diagnosis to the behavioral symptoms observed in daily life. This discovery indeed suggests that ADHD could be, at least in part, a disorder of the regulation of wakefulness and alertness. "These local sleep waves could become a key biomarker for diagnosis," proposes Thomas Andrillon.

These results could also guide the development of new therapeutic strategies, whether pharmacological or non-drug, particularly interventions aimed at improving sleep quality or stabilizing alertness mechanisms.

"In neurotypical people, some research has for example shown that auditory stimulation during sleep can strengthen nocturnal slow waves, which might reduce the occurrence of brain activity resembling sleep during wakefulness the next day. A next step will be to determine if this approach could also reduce these local sleep intrusions in people with ADHD," concludes Thomas Andrillon.