Similarities and differences in cerebellar alterations between youth born preterm and youth born with congenital heart disease.

Individuals born preterm (PT) or with complex congenital heart disease (CHD) present with comparable prevalence of developmental challenges and patterns of neonatal brain injury. Converging evidence also supports that cerebellar development is altered in PT and in CHD survivors. However, no study compared cerebellar integrity between these two groups. This study aims to assess total and regional cerebellar development between youth born PT or with CHD as compared to controls. Participants aged 16-27 years born before 33 weeks of gestational age or who underwent open-heart surgery for CHD during infancy and a group of healthy term-born controls, underwent a brain MRI. Cerebellums were segmented at the lobular level. Youth born PT or with CHD exhibited a comparable pattern of volume reduction affecting total, regional and lobular cerebellar volumes. After adjusting for total brain volume, no significant differences remained between CHD and controls. Only regions and lobules in the anterior cerebellum remained significantly smaller than controls in the youth born PT. Atypical cerebellar development is present in youth born PT and in youth with CHD. However, our results suggested that premature exposure to the extra-uterine environment alters cerebellar development selectively while the cumulative effect of CHD globally hinders brain development.