Altered cortical gyrification in adults who were born very preterm and its associations with cognition and mental health

Abstract

BackgroundThe last trimester of pregnancy is a critical period for the establishment of cortical gyrification and altered folding patterns have been reported following very preterm birth (< 33 weeks of gestation) in childhood and adolescence. However, research is scant on the persistence of such alterations in adulthood and their associations with cognitive and psychiatric outcomes. MethodsWe studied 79 very-preterm adults and 81 age-matched full-term controls. T1-weighted images were used to measure local gyrification index (LGI), indicating the degree of folding across multiple vertices of the reconstructed cortical surface. Group and group-sex LGI differences were assessed using per-vertex adjustment for cortical thickness and overall intracranial volume. Within-group correlations were also computed between LGI and functional outcomes, including general intelligence (IQ) and psychopathology. ResultsVery preterm adults had significantly reduced LGI in extensive cortical regions encompassing the frontal, anterior temporal and occipito-parietal lobes. Alterations in lateral fronto-temporal-parietal and medial occipito-parietal regions were present in both males and females, although males reported more extensive alterations. In both very preterm adults and controls, higher LGI was associated with higher IQ and lower psychopathology scores, with the spatial distribution of these associations substantially differing between the two groups. ConclusionsVery preterm adults brains are characterized by significant and widespread local hypogyria and these abnormalities might be implicated in cognitive and psychiatric outcomes. Gyrification reflects an early developmental process and provides a fingerprint for very preterm birth.