Cortical morphometry and IQ in VLBW children without cerebral palsy born in 2003–2007

Abstract

Children born prematurely with very low birth weight (VLBW: bw ≤ 1500 g) have an increased risk of preterm perinatal brain injury, which may subsequently alter the maturation of the brain, including the cerebral cortex. The aim of study was to assess cortical thickness and surface area in VLBW children compared with term-born controls, and to investigate possible relationships between cortical morphology and Full IQ. In this cross-sectional study, 37 VLBW and 104 term children born between the years 2003–2007 were assessed cognitively at 5–10 years of age, using age appropriate Wechsler tests. The FreeSurfer software was used to obtain estimates of cortical thickness and surface area based on T1-weighted MRI images at 1.5 Tesla. The VLBW children had smaller cortical surface area bilaterally in the frontal, temporal, and parietal lobes. A thicker cortex in the frontal and occipital regions and a thinner cortex in posterior parietal areas were observed in the VLBW group. There were significant differences in Full IQ between groups (VLBW M = 98, SD = 9.71; controls M = 108, SD = 13.57; p < 0.001). There was a positive relationship between IQ and surface area in both groups, albeit significant only in the larger control group. In the VLBW group, reduced IQ was associated with frontal cortical thickening and temporo-parietal thinning.We conclude that cortical deviations are evident in childhood even in VLBW children born in 2003–2007 who have received state of the art medical treatment in the perinatal period and who did not present with focal brain injuries on neonatal ultrasonography. The cortical deviations were associated with reduced cognitive functioning.

Mapping the neuroanatomical impact of very preterm birth across childhood

“…Unlike studies with smaller samples but within the same age range (Grunewaldt et al, 2014;Kesler et al, 2008;Lax et al, 2013;Peterson et al, 2000;Sølsnes et al, 2015), we did not find smaller subcortical volumes in the VPT group. An exception was the striatal percentage volume that was larger in VPT, likely due to the age-related decreases, and the VPT being less mature.…”

“…Here we report increases across both groups that extended to 12 years of age in frontal, orbital-frontal and temporal areas; these are late maturing brain regions, and thus increases in surface area may continue longer than the average in other brain areas. The only region to show decreasing surface area with age was in the occipital lobe-one of the earliest Unlike studies with smaller samples but within the same age range (Grunewaldt et al, 2014;Kesler et al, 2008;Lax et al, 2013;Peterson et al, 2000;Sølsnes et al, 2015), we did not find smaller subcortical volumes in the VPT group. The only region to show decreasing surface area with age was in the occipital lobe-one of the earliest Unlike studies with smaller samples but within the same age range (Grunewaldt et al, 2014;Kesler et al, 2008;Lax et al, 2013;Peterson et al, 2000;Sølsnes et al, 2015), we did not find smaller subcortical volumes in the VPT group.…”

“…Total surface area and cortical thickness have been reported to be reduced in VPT children (Lax et al, 2013), while local decreases in surface area have been reported in the bilateral temporal and left preand post-central cortices in VPT compared to FT children (Zhang et al, 2015), yet other brain areas, including the right parietal and frontal regions, the bilateral cingulate cortices and precuneus showed increased surface area (Zhang et al, 2015). Similarly, studies have found both regional cortical thickness decreases (Lax et al, 2013;Sølsnes et al, 2015;Zubiaurre-Elorza et al, 2012) and increases (Sølsnes et al, 2015) in VPT compared to FT children. There is some evidence to suggest delayed maturation in cortical thinning in VPT children in the earlier years with some catch-up in later childhood, with local increases in cortical thickness in VPT children only emerging when children less than 10 years old were considered (Mürner-Lavanchy et al, 2014).…”

Joint analysis of area and thickness as a replacement for the analysis of cortical volume

“…The sample used for this analysis is particularly suitable as neurodevel-opmental brain disorders associated with preterm birth are known to have a divergent effect on cortical area and cortical thickness, including both cortical thinning and thickening (Rimol et al, 2016), hence a joint analysis being potentially more informative in lieu of simple cortical volume. Here, the reduced cortical surface area observed in VLBW subjects compared to controls replicates previous findings from the same cohort at 20 years of age (Skranes et al, 2013), and is consistent with findings from a younger cohort of VLBW subjects (Sølsnes et al, 2015) and teenagers born with extremely low birth weight (⩽ 1000g) (Grunewaldt et al, 2014). The combined evidence from these studies suggests that surface area reductions in the preterm brain are present from early childhood and remain until adulthood (Rimol et al, 2016), and various mechanisms have been proposed (Volpe, 2009, 2011; Eikenes et al, 2011; Hagberg et al, 2015).…”

Brain structure mediates the association between height and cognitive ability

“…CSA undergoes remarkable growth from 0 to 2 years with an average 1.8-fold expansion in the first year of life (Li et al 2013). Very low birth weight children have smaller CSA and lower GCA compared to those with normal birth weight (Solsnes et al 2015). Birth weight within the normal range is positively associated with CSA (Walhovd et al 2016).…”