Alterations in neural connectivity in preterm children at school age

Abstract

Converging data suggest recovery from injury in the preterm brain. We used functional magnetic resonance imaging (fMRI) to test the hypothesis that cerebral connectivity involving Wernicke's area and other important cortical language regions would differ between preterm (PT) and term (T) control school age children during performance of an auditory language task. Fifty-four PT children (600-1250 g birth weight) and 24 T controls were evaluated using an fMRI passive language task and neurodevelopmental assessments including: the Wechsler Intelligence Scale for Children - III (WISC-III), the Peabody Individual Achievement Test - Revised (PIAT-R) and the Peabody Picture Vocabulary Test - Revised (PPVT-R) at 8 years of age. Neural activity was assessed for language processing and the data were evaluated for connectivity and correlations to cognitive outcomes. We found that PT subjects scored significantly lower on all components of the WISC-III (p<0.009), the PIAT-R Reading Comprehension test (p=0.013), and the PPVT-R (p=0.001) compared to term subjects. Connectivity analyses revealed significantly stronger neural circuits in PT children between Wernicke's area and the right inferior frontal gyrus (R IFG, Broca's area homologue) and both the left and the right supramarginal gyri (SMG) components of the inferior parietal lobules (p</=0.02 for all). We conclude that PT subjects employ neural systems for auditory language function at school age differently than T controls; these alterations may represent a delay in maturation of neural networks or the engagement of alternate circuits for language processing.

Figures

Figure 1

Anatomic ROIs interrogated for connectivity with Wernicke’s area, L BA 22 (red). ROIs examined for connectivity to Wernicke’s in preterms and terms include bilateral BA 21 (dark green), BA 39 (lilac), BA 40 (brown), BA 47 (light green), BA 44–45 (light blue) and R BA 22 (navy).

Figure 2

Increased connectivity to Wernicke’s region in PT children. Light blue circles represent regions with significantly increased connectivity to Wernicke’s region (red). Red lines represent connectivity between Wernicke’s region and bilateral BA 40 and R BA 44–45.