Reduced hippocampal subfield volumes and memory function in school-aged children born preterm with very low birthweight (VLBW)

Abstract Background The hippocampus, an essential structure for learning and memory, has a reduced volume in preterm born (gestational age  Methods Children born preterm with VLBW ( n  = 34) and term-born controls from the Norwegian Mother and Child Cohort Study (MoBa) ( n  = 104) underwent structural MRI and a neuropsychological assessment of memory function at primary school age. FreeSurfer 6.0 was used to analyze the volumes of hippocampal subfields which were compared between groups, as was memory performance. Correlations between abnormal hippocampal subfields and memory performance were explored in the VLBW group. Results All absolute hippocampal subfield volumes were lower in the children with VLBW compared to MoBa term-born controls, and the volumes of the left and right dentate gyrus and the right subiculum remained significantly lower after correcting for total intracranial volume. The VLBW group had inferior working memory performance and the score on the subtest Spatial Span backwards was positively correlated to the volume of the right dentate gyrus. Conclusions Hippocampal subfield volumes seem to be differently affected by early brain development related to preterm birth. The dentate gyrus appears particularly susceptible to adverse effects of preterm birth. Reduced working memory function among children with VLBW was associated with smaller volume of right dentate gyrus. This finding demonstrates alterations in hippocampal structure-function relationships associated with early brain development related to preterm birth.