Background: Motor outcomes following perinatal and childhood stroke are highly variable and likely reflect complex structural and functional changes within motor-related brain networks. Greater understanding of these network mechanisms is needed to improve patient-specific prognostication and develop targeted therapies to restore motor function. This study explored post-stroke motor-related reorganization patterns through assessment of functional MRI (fMRI) activation and white matter connectivity patterns. Hypothesis: We hypothesized that activation and connectivity patterns would differ between children with and without hemiparesis following stroke. Methods: Twelve children (age 9-19 years) with a history of perinatal or childhood stroke underwent 3T MRI with diffusion-weighted imaging and task-related hand-motor fMRI. The Paediatric Stroke Outcome Measure was used to assess motor outcome and dichotomized into two groups. MRI data were processed and analyzed for whole-brain fMRI activation patterns and white matter track-weighted functional connectivity (TW-FC) profiles, in relation to motor outcomes. Results: Divergent fMRI activation and TW-FC patterns were seen between the two groups. Children in the no hemiparesis group were more likely to retain an ipsilesional fMRI activation pattern while children in the hemiparesis group were more likely to demonstrate bilateral or contralesional patterns. Increased utilization of cortical-subcortical pathways was identified by TW-FC in both groups. Greater TW-FC strength when moving the stroke-affected hand was also seen in the no hemiparesis group compared to the hemiparesis group. Conclusions: We identified distinct patterns of motor network activation and white matter connectivity relating to clinical outcomes after perinatal and childhood stroke. These patterns have potential to improve prognostic ability and aid identification of infants and children who would most benefit from targeted therapy to improve long-term motor outcomes

The authors have declared no competing interest.

Funding for this project was provided by a 2016 grant from the Brain Foundation: ?Brain structural and motor function correlations in childhood arterial ischaemic stroke using multimodal magnetic resonance imaging?. Dr SRC undertook a paid research fellowship funded by the RCH Foundation to carry out this project. Drs JYMY and AW acknowledge position funding support from the Royal Children?s Hospital Foundation (RCHF 2022?1402). The funding sources had no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.

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