Longitudinal profiles of executive function in autistic and non-autistic children at high likelihood of autism.

Abstract

BACKGROUND: Executive functioning (EF) difficulties are common in autistic children and may aggregate in families. Longitudinal studies examining EF development in autistic children and their siblings are limited. In the current study, we characterized EF development from later infancy through school-age in autistic and non-autistic high likelihood (HL; with an older autistic sibling) and low likelihood (LL; without older autistic sibling) children. METHODS: Participants were 83 autistic and 235 non-autistic HL children, and 132 LL children from the Infant Brain Imaging Study. EF was assessed at ages 12 and 24 months using the A-not-B task and ages 5–14 years (school-age) using the Behavior Rating Inventory of Executive Function (BRIEF), Flanker Inhibitory Control and Attention Test (Flanker), and Dimensional Change Card Sort (DCCS). Longitudinal profiles of EF were examined using linear mixed-effects models with three separate models for each school-age EF outcome. RESULTS: From 12–24 months, the LL group showed an increase in standardized EF scores (p < 0.05). The HL-ASD and HL-noASD groups showed no change (ps > .05). From 24 months to school-age, no change was observed for any group (ps > .05). From 12 months to school-age, standardized scores in the LL group increased (p = 0.002) and in the HL-ASD group (p < .001) decreased for the BRIEF GEC outcome. There were no group differences at 12 months in standardized EF scores (ps > .05) but at 24-months both HL groups had lower scores than the LL group (ps < .05). At school-age, the HL-ASD group had lower standardized EF scores than the LL and HL-noASD groups on all measures (ps < or = .050), and the HL-noASD group had lower standardized scores than the LL group on the BRIEF GEC (p = .014). CONCLUSIONS: Autistic and non-autistic HL children and LL children showed distinct EF profiles. On lab-based measures, autistic and non-autistic HL children showed relatively stable EF performance over time while LL children showed initial improvements. Parent report showed accumulating EF difficulties in autistic HL children. Executive function supports starting in toddlerhood may be useful for HL children showing emerging EF difficulties.