Children cooled for neonatal encephalopathy without cerebral palsy retain healthy resting-state static and dynamic functional connectivity

Abstract

AbstractTherapeutic hypothermia improves outcomes following neonatal hypoxic-ischaemic encephalopathy (HIE), reducing cases of death and severe disability such as cerebral palsy compared to normothermia management. However, when cooled children reach early school-age they have cognitive and motor impairments which are associated with underlying alterations to brain structure and white matter connectivity. It is unknown whether these differences in structural connectivity cause differences in functional connectivity between cooled children and healthy controls. Resting-state fMRI has been used to characterise static and dynamic functional connectivity in children, both with typical development and those with neurodevelopmental disorders. Previous studies of restingstate brain networks in children with HIE have focussed on the neonatal period. In this study, we used resting-state fMRI to investigate static and dynamic functional connectivity in children aged 6-8 years who were cooled for neonatal HIE without cerebral palsy (n = 22, median age [IQR] 7.08 [6.85-7.52] years), and healthy controls matched for age, sex and socioeconomic status (n = 20, median age [IQR] 6.75 [6.48-7.25] years). Using group independent component analysis, we identified 33 intrinsic connectivity networks consistent with those previously reported in children and adults. There were no case-control differences in the spatial maps of these intrinsic connectivity networks. We constructed subject-specific static functional connectivity networks by measuring pairwise Pearson correlations between component time courses, and found no case-control differences in functional connectivity after FDR correction. To study the time-varying organisation of resting-state networks, we used sliding-window correlations and deep clustering to investigate dynamic functional connectivity characteristics. We found k = 4 repetitively occurring functional connectivity states, which exhibited no case-control differences in dwell time, fractional occupancy, or state functional connectivity matrices. These results show that the spatiotemporal characteristics of resting-state brain networks in cooled children without severe disability are comparable to those in healthy controls at early school-age, despite underlying differences in brain structure and white matter connectivity. To our knowledge, this is the first study to investigate resting-state functional connectivity in children with HIE beyond the neonatal period, and the first to investigate dynamic functional connectivity in any children with HIE.