Executive function and implications for the Preterm Behavioral Phenotype in very preterm children at age 9-10 years

Children born very preterm (VPT) have greater executive function (EF) challenges and internalizing, inattention, and social communication-interaction differences (the Preterm Behavioral Phenotype [PBP]) than full-term (FT) children. EF and PBP outcomes for VPT children with white matter injury (WMI) are less well understood. Furthermore, the extent that EF challenges serve as a neurocognitive mechanism for the PBP is unknown.

As part of a longitudinal study, 123 VPT infants (≤ 30 weeks gestation) were recruited from a level-III neonatal intensive care unit and underwent developmental follow-up at ages 5 and 9-10 years. Forty-four VPT infants had high-grade WMI. Seventy-nine FT control children were also included. At the 5 and 9-10 year follow-up, children completed EF tasks tapping short-term/working memory, inhibitory control, and flexibility/shifting, which were combined into an EF composite at each timepoint. Parents and children also completed measures assessing children's attention-deficit/ hyperactivity, internalizing/anxiety, and social communication-interaction outcomes to generate parent- and child-informant PBP composites at age 9-10 years. Serial mediation analysis examined EF at ages 5 and 9-10 years as serial mediators linking VPT birth and WMI with the PBP, adjusted for covariate factors.

VPT and WMI children demonstrated lower EF abilities at both timepoints compared to FT children (p≤.02). VPT and WMI children obtained higher child-informant PBP composite scores (p<.001) as well as parent- and child-informant social communication-interaction and ADHD-inattentive problem ratings (p≤.03) at age 9-10 years. Lower EF at both timepoints correlated with higher parent- and child-informant PBP ratings (r -0.2 to -0.45, p<.05). Serial mediation analysis showed that EF development from age 5 to 9-10 years (proportion mediated 3-5%) as well as EF at age 9-10 years (proportion mediated 16-43%) partially mediated associations linking VPT birth and WMI with PBP outcomes.

VPT and WMI children had greater EF and PBP challenges compared to FT children, with WMI children at greatest risk. Disrupted EF development, at least in part, contributed to the PBP. Findings suggest that VPT and WMI children are in need of early and ongoing EF supports, and that EF training interventions may improve mental health outcomes in this population.