Neonatal critical illness and development: white matter and hippocampus alterations in school-age neonatal extracorporeal membrane oxygenation survivors

Abstract

Aim: To examine the neurobiology of long-term neuropsychological deficits after neonatal extracorporeal membrane oxygenation (ECMO). Method: This cross-sectional study assessed white matter integrity and hippocampal volume of ECMO survivors (8–15y) and healthy children (8–17y) using diffusion tensor imaging (DTI) and structural magnetic resonance imaging (MRI) respectively. Neuropsychological outcome was evaluated in ECMO survivors. Included clinical predictors of white matter integrity: age start ECMO, ECMO duration, highest oxygenation index before ECMO, highest mean airway pressure, and mechanical ventilation duration. Results: ECMO survivors (n=23) had lower global fractional anisotropy than healthy children (n=54) (patients=0.368; comparison group=0.381; p=0.018), but similar global mean diffusivity (p=0.410). ECMO survivors had lower fractional anisotropy in the left cingulum bundle (ECMO survivors=0.345; comparison group=0.399; p<0.001) and higher mean diffusivity in a region of the left parahippocampal cingulum (patients=0.916; comparison group=0.871; p<0.001). Higher global mean diffusivity predicted worse verbal memory in ECMO survivors (n=17) (β=–0.74, p=0.008). ECMO survivors (n=23) had smaller bilateral hippocampal volume than healthy children (n=43) (left, p<0.001; right, p<0.001) and this was related to worse verbal memory (left, β=0.65, p=0.018; right, β=0.71, p=0.006). Interpretation: Neonatal ECMO survivors are at risk for long-term brain alterations, which may partly explain long-term neuropsychological impairments. Neuroimaging may contribute to better risk stratification of long-term impairments.