Presented at the Neonatal Society 2018 Summer Meeting.
Geary G1, Lee-Kelland R1, Jary S1, Tonks J2, Thai J3, Brooks J3, Thoresen M1, Cowan F1, Chakkarapani E1
1 Neonatal Neuroscience, Translational health sciences, St Michael’s Hospital, University of Bristol, Bristol
2 Psychology, University of Exeter, Exeter
3 Clinical Research and Imaging Centre, University of Bristol, Bristol
Background: Infants cooled for neonatal encephalopathy (NE) with normal neurodevelopment scores at 2 years may have cognitive and motor impairments at school-age despite the absence of cerebral palsy (CP).1 The corpus callosum (CC) carries transcallosal fibres connecting different cortical regions and we postulate that its size may be a marker for motor and cognitive function. Our objective was to compare the surface area of the CC between cooled children aged 6-8 years and controls, and determine associations with motor and cognitive scores.
Methods: In a case-control study, 23 cases aged 6-8 years, cooled for NE and without CP, and 20 age, sex and social class matched controls in main stream schools underwent psychometric (WISC-IV), motor (Movement Assessment Battery for Children, MABC-2) and brain MRI assessments. The CC and the cross-sectional supratentorial brain surface area were measured by an assessor blinded to case-control status from the mid-sagittal T1 mprage image. The CC was segmented into 3 equal parts: frontal, mid and occipital. The mid segment was further subdivided into anterior 1/3rd and posterior 2/3rd, as the posterior 2/3rd carries motor fibers.
Results: All cases had a normally appearing CC on neonatal MRI. No focal lesions were seen on the childhood MRI. Cases, compared to controls, had significantly smaller total CC (mean difference (MD):-0.48 (95% CI-0.05,-0.91)), frontal(MD:-0.22 (95%CI:-0.001,-0.436)), occipital(MD:-0.24 (95%CI:-0.045,-0.436)) and anterior 1/3rd of mid CC segment areas (MD:-0.07 (95% CI:-0.018,-0.12)), but a comparable posterior 2/3rds of the mid CC and cross-sectional supra-tentorial brain area. Anterior 1/3rd of mid CC was significantly smaller in cases than controls independent of cross-sectional supratentorial brain area (β=-0.07cm2(95%CI:-0.11,-0.02). In multiple linear regression total CC area was significantly associated with verbal comprehension (β:8.1), processing speed (β:8.05) and full scale-IQ (β:6.46); and occipital CC area with working memory (β:14.4) independent of supra-tentorial brain area and case-control status. CC areas were not associated with motor scores.
Conclusion: In school-aged children cooled for NE who did not have CP, the anterior 1/3rd of the mid CC segment was smaller than in controls. The CC area was associated with cognitive but not motor abilities suggesting that the development of the CC influenced cognitive function.
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1. Lee-Kelland R, et al. Neonatal Society, London, 2017.