Cortical thickness and cognition in very-low-birth-weight late teenagers

Abstract

Background: Preterm born children with very low birth weight (VLBW: bw ≤ 1500 g) have an increased risk of perinatal brain injury which may influence the subsequent maturation of grey and white matter. Aberrant cortical development may have implications for future cognitive functioning.

Aims: The aim of this study was to measure deviations in cortical thickness and to investigate the relationship between cortical thickness, perinatal variables and IQ measurements in VLBW late teenagers compared with term-born controls.

Study design: Prospective follow-up study of three year cohorts of children from birth to early adulthood.

Subject: Forty-seven VLBW and 61 term born controls were examined at ages 18-21.

Outcome measures: Cognitive function was assessed with the WAIS-III, measuring full IQ and IQ indices. We applied an automated method to reconstruct the cortical surface based on T1-weighted MRI images using the FreeSurfer software.

Results: We found widespread areas of thinner cerebral cortex in the left parietal and temporal lobes and thicker cortex in frontal areas bilaterally in the VLBW group compared to controls. There were positive correlations between IQ and cortical thickness in areas in ventro-lateral frontal, parietal and temporal lobes in the VLBW group. The most pronounced cortical changes were seen in the VLBW subjects with the lowest birth weight and gestational age, and in those with IQ below 89.

Conclusion: Persistent cortical deviations seen in VLBW late teenagers are associated with immaturity at birth and level of cognitive functioning.