Kim Annink

127 The papez circuit and school-age outcome in HIE Brain volumes versus neurodevelopmental outcome Forty-one children (82%) had a 3D-T1-weighted sequence at 10 years of age of sufficient quality for segmentation. In the univariate linear regressions with the brain structure as independent variable and the neuropsychological test score as dependent variable, MB and relative hippocampal volume were significantly associated with multiple neuropsychological tests after correcting for multiple comparisons. The parahippocampal white matter and caudal anterior cingulate cortex were, after correcting for multiple comparisons significantly, associated with processing speed. All structures that showed an association (uncorrected p-value <0.05) with one of the outcome measures are reported in supplemental Table 1. For all variables that were significant in the univariate linear regression, multivariable linear regression was performed to test the association between the therapeutic hypothermia group and outcome measures. Therapeutic hypothermia was not associated with dependent variable for almost all models, except for verbal long-term memory (immediate recall). A significant regression equation was found for relative hippocampal volume and therapeutic hypothermia (F(2.37) = 10.2, p<0.001, R 2 =0.36. A 1% decrease in the relative hippocampal volume resulted in 14.1 points lower verbal long-term memory, whereas therapeutic hypothermia decreased verbal long-term memory with 1.7 points. For the models including the MB score, a significant model was also found for verbal long-term memory (immediate recall): (F(2,41) =11.2, p<0.001, R 2 =0.35). Verbal long-term memory was 1.4 points lower in the presence of atrophic MB, and 1.4 points lower following therapeutic hypothermia. Mammillary bodies and neurodevelopmental outcome Table 4 shows the differences in outcome measures between infants with normal and abnormal MB. Mammillary bodies and brain volumes All volumes assessed by Freesurfer were compared between infants with and without MB atrophy. After correction for multiple comparisons, children with MB atrophy had smaller relative hippocampal volumes (p<0.001) and smaller relative parahippocampal white matter (p=0.001) (Figure 1). The other relative subcortical, white matter and cortical relative volumes did not differ between the groups. 6