Association of sleep spindle activity with executive functioning and intellectual ability in children and adolescents

Sleep spindles may serve as a biomarker for neural and cognitive maturation, with developmental differences reflecting key brain maturational changes from childhood to adolescence. While altered in unmedicated psychiatric/behavioral disorders, lower-frequency spindles may provide a protective mechanism for working memory in adolescents with ADHD. Statement of Significance Sleep spindles occur as bursts of activity in the sigma-frequency range during non-rapid eye movement sleep. Due to their thalamocortical origin, spindles have been linked to cognitive functioning. We examined spindle activity in typically developing youth and unmedicated youth with psychiatric/behavioral disorders. In typically developing children, higher spindle density was associated with better verbal intelligence and, as they transitioned to adolescence, with better nonverbal intelligence. In unmedicated children with attention deficit/hyperactivity disorder (ADHD), lower-frequency spindles were associated with better working memory in adolescence. Sleep spindles promote neural plasticity for cognitive growth, with reduced impact in later developmental stages reflecting matured neural pathways. In youth with ADHD, sleep spindles may serve a protective role in mitigating cognitive deficits over time.