Neonatal sleep physiology and early executive functioning in preterm children

Background: Executive functioning (EF) deficits are frequently observed in preterms. EF development is linked to the prefrontal cortex and sleep-regulating homeostatic processes. As sleep is an essential driver of early brain maturation, curtailment of sleep in the NICU may be unfavorable. This study examined whether neonatal sleep behavior influences EF at 2 years corrected age in preterm children. Methods: 76 preterm infants (< 34 weeks gestation and/or 1500 g) underwent overnight polysomnography before discharge. Sleep stages—Total Sleep Time, Active Sleep (AS), Quiet Sleep (QS) and Transitional Sleep—were quantified using an automated sleep algorithm. EF was assessed at 2 years corrected age, focusing on spatial working memory, cognitive flexibility, and inhibitory control. General linear models were used, adjusting for confounders. Results: More Total Sleep Time was significantly associated with higher overall EF scores, and the subtest for spatial working memory. AS and QS durations were influenced by postmenstrual age. Longer AS bouts were linked to increased Total Sleep Time. However, individual AS or QS percentages were not directly associated with EF. Higher levels of Transitional Sleep were related to lower EF performance. Conclusions: Neonatal sleep duration is positively associated with better EF outcomes at 2 years. Protecting sleep in the NICU may support early brain development and executive functioning. Impact: This study links objective neonatal sleep measurements—using polysomnography and automated sleep staging—with later executive functioning development in preterm children. Neonatal sleep duration, particularly Total Sleep Time, is positively associated with executive functioning at 2 years in children born preterm. This study highlights neonatal sleep as a potential early marker of altered brain development. The findings support the importance of protecting and improving sleep in the NICU as a possible modifiable factor that could enhance early brain maturation and neurodevelopment.