Executive function mediates effects of gestational age on functional outcomes and behavior in preschoolers

Abstract

Objective: To investigate the role of executive function (EF) skills, measured by parent-rating and performance-based instruments, as mediators of the effects of gestational age (GA) on functional outcomes and behavior symptoms in preterm (PT) and full-term (FT) preschoolers.

Patients and methods: Children born PT (n = 70; mean GA, 29.6 weeks; mean birth weight, 1365 g) were compared to children born FT (n = 79) on composite measures of EF (using the Behavior Rating Inventory of Executive Function and a performance-based EF battery), adaptive function, prereading skills, and behavior symptoms. For the entire sample, mediation analyses examined the effect of GA on the outcomes with EF as mediator.

Results: Compared to children born FT, children born PT had significantly higher parent-rated EF scores and lower performance-based EF scores, both indicating more problems; furthermore, children born PT had lower adaptive function and prereading scores and more problematic behavior. GA contributed to adaptive function, prereading skills, and behavior symptoms for all children. EF acted as a mediator of GA for all 3 outcomes; different patterns emerged for parent-rated and performance-based EF evaluations. For adaptive function, both EF measures significantly mediated the effects of GA; for prereading skills, only performance-based EF was significant; for behavior symptoms, only parent-rated EF was significant.

Conclusions: We propose standard assessment of EF, using both parent-rating and performance-based EF measures, in young PT children and other children at the risk of EF impairments. EF skills are measurable, mediate important functional outcomes, and may serve as intervention targets.

Figure 1

1a. Total Effects Model—shows the relationship (c) between predictor X and outcome Y. 1b. A simple mediation model in path diagram form includes the mediator and its relationship to predictor X (a) and outcome Y (b), or indirect effect. The direct effect between X and Y (accounting for the mediator in the model) is illustrated by c’.

Figure 2

The Total Effects Model is in the lower part of the figure; the multiple mediation model in path diagram form with both parent-rated EF and performance-based EF in the model is directly above. T-statistics and significance level are presented for each path (inner values correspond to performance-based EF and outer values to parent-rated EF). Indirect effects of gestational age on the Adaptive Behavior Composite through both parent-rated and performance-based EF were significant.

Figure 3

The Total Effects Model is in the lower part of the figure; the multiple mediation model in path diagram form with both parent-rated EF and performance-based EF in the model is directly above. T-statistics and significance level are presented for each path (inner values correspond to performance-based EF and outer values to parent-rated EF). Indirect effect of gestational age on the Phonologic Awareness Score through performance-based EF was significant.

Figure 4

The Total Effects Model is in the lower part of the figure; the multiple mediation model in path diagram form with both parent-rated EF and performance-based EF in the model is directly above. T-statistics and significance level are presented for each path (inner values correspond to performance-based EF and outer values to parent-rated EF). Indirect effect of gestational age on the Total Behavior Problems score through parent-rated EF was significant. **p significant at <.05 Abbreviations: GA, gestational age; EF, executive function