Longitudinal Effects of Congenital Heart Defects in Infants With Down Syndrome: Implications for Developmental Outcomes.

Cooccurring congenital heart defects (CHDs) affect roughly 40% to 58% of infants with Down syndrome (DS). However, evidence on the variation and timing by which CHDs affect neurodevelopmental outcomes, including cognition, motor, and language abilities in DS is limited. The present study investigated effects of CHD on these neurodevelopmental outcomes from 12 to 24 months in N = 47 children with DS (n = 26 with cooccurring CHD). No significant developmental differences were found between infants with DS only and infants with DS+CHD at 12 months. Unexpectedly, children with DS+CHD showed significantly higher expressive language abilities at 24 months compared to children with DS only. Post-hoc analyses investigated possible buffering effects of therapy type and dose across ages, identifying different patterns across groups. Findings highlight the variation in developmental outcomes for children with DS+CHD broadly, and implications for targeted treatment for all children with DS are discussed.