Neuroimaging and Neurological Outcomes in Perinatal Arterial Ischemic Stroke: A Systematic Review and Meta-Analysis.

BACKGROUND: Prediction of outcomes in perinatal arterial ischemic stroke (PAIS) is challenging. We performed a systematic review and meta-analysis to determine whether infarct characteristics can predict outcomes in PAIS. METHODS: A systematic search was conducted using five databases in January 2023. Studies were included if the sample included children with neonatal or presumed PAIS; if infarct size, location, or laterality was indicated; and if at least one motor, cognitive, or language outcome was reported. The level of evidence and risk of bias were evaluated using the Risk of Bias in Non-Randomized Studies of Interventions tool. Meta-analyses were conducted comparing infarct size or location with neurological outcomes when at least three studies could be analyzed. RESULTS: Eighteen full-text articles were included in a systematic review with nine included in meta-analysis. Meta-analyses revealed that small strokes were associated with a lower risk of cerebral palsy/hemiplegia compared with large strokes (risk ratio [RR] = 0.263, P = 0.001) and a lower risk of epilepsy (RR = 0.182, P < 0.001). Middle cerebral artery (MCA) infarcts were not associated with a significantly different risk of cerebral palsy/hemiplegia compared with non-MCA strokes (RR = 1.220, P = 0.337). Bilateral infarcts were associated with a 48% risk of cerebral palsy/hemiplegia, a 26% risk of epilepsy, and a 58% risk of cognitive impairment. CONCLUSIONS: Larger stroke size was associated with worse outcomes across multiple domains. Widely heterogeneous reporting of infarct characteristics and outcomes limits the comparison of studies and the analysis of outcomes. More consistent reporting of infarct characteristics and outcomes will be important to advance research in this field.

An Initial Psychometric Evaluation of a Novel Upper Extremity Pediatric Stroke Hemiplegic Motor Impairment Scale.

BACKGROUND: Our team designed an innovative, observation-based motor impairment measure-the Pediatric Stroke Hemiplegic Motor Impairment Scale (Pedi HEMIs). Here we present the results of a survey describing common practices in the pediatric stroke community and the initial psychometric properties of the upper extremity subscale of the Pedi HEMIs (Pedi HEMIs-UE). METHODS: This is a cross-sectional study whereby participants completed a battery of assessments including the novel Pedi HEMIs-UE. Internal consistency was measured via Cronbach alpha (α). Intraclass correlation (ICC) was used to assess inter-rater reliability (IRR). Concurrent validity was investigated using Pearson or polychoric correlations and simple linear regressions. RESULTS: The study sample consisted of 18 children aged 1.08 to 15 years. Two participants completed two sets of evaluations, totaling 20 data sets. Cronbach α, a measure of internal consistency, was on average 0.91 (range: 0.89 to 0.92). IRR was excellent with the six raters in almost perfect agreement (ICC = 0.91; 95% confidence interval [CI]: 0.83 to 0.96). Pearson correlation coefficient between the Pedi HEMIs-UE and logit Assisting Hand Assessment (AHA)/mini-AHA was -0.938 (95% CI: -0.979 to -0.827, P < 0.001), indicating excellent concurrent validity. CONCLUSIONS: We found excellent feasibility, reliability, and validity of the Pedi HEMIs-UE in a convenience sample of youth with hemiparesis after stroke.

Perioperative Management of Pediatric Patients with Moyamoya Arteriopathy.

Pediatric patients with moyamoya arteriopathy are at high risk for developing new onset transient or permanent neurologic deficits secondary to cerebral hypoperfusion, particularly in the perioperative period. It is therefore essential to carefully manage these patients in a multidisciplinary, coordinated effort to reduce the risk of new permanent neurologic deficits. However, little has been published on perioperative management of pediatric patients with moyamoya, particularly in the early postoperative period during intensive care unit admission. Our pediatric neurocritical care team sought to create a multidisciplinary periprocedural evidence- and consensus-based care pathway for high-risk pediatric patients with moyamoya arteriopathy undergoing anesthesia for any reason to decrease the incidence of periprocedural stroke or transient ischemic attack (TIA). We reviewed the literature to identify risk factors associated with perioperative stroke or TIA among patients with moyamoya and to gather data supporting specific perioperative management strategies. A multidisciplinary team from pediatric anesthesia, neurocritical care, nursing, child life, neurosurgery, interventional neuroradiology, neurology, and hematology created a care pathway for children with moyamoya undergoing anesthesia, classifying them as either high or standard risk, and applying an individualized perioperative management plan to high-risk patients. The incidence of neurologic sequelae before and after pathway implementation will be compared in future studies.

Consensus-Based Evaluation of Outcome Measures in Pediatric Stroke Care: A Toolkit.

Following a pediatric stroke, outcome measures selected for monitoring functional recovery and development vary widely. We sought to develop a toolkit of outcome measures that are currently available to clinicians, possess strong psychometric properties, and are feasible for use within clinical settings. A multidisciplinary group of clinicians and scientists from the International Pediatric Stroke Organization comprehensively reviewed the quality of measures in multiple domains described in pediatric stroke populations including global performance, motor and cognitive function, language, quality of life, and behavior and adaptive functioning. The quality of each measure was evaluated using guidelines focused on responsiveness and sensitivity, reliability, validity, feasibility, and predictive utility. A total of 48 outcome measures were included and were rated by experts based on the available evidence within the literature supporting the strengths of their psychometric properties and practical use. Only three measures were found to be validated for use in pediatric stroke: the Pediatric Stroke Outcome Measure, the Pediatric Stroke Recurrence and Recovery Questionnaire, and the Pediatric Stroke Quality of Life Measure. However, multiple additional measures were deemed to have good psychometric properties and acceptable utility for assessing pediatric stroke outcomes. Strengths and weaknesses of commonly used measures including feasibility are highlighted to guide evidence-based and practicable outcome measure selection. Improving the coherence of outcome assessment will facilitate comparison of studies and enhance research and clinical care in children with stroke. Further work is urgently needed to close the gap and validate measures across all clinically significant domains in the pediatric stroke population.

Roadmap for the Assessment and Management of Outcomes in Pediatric Stroke.

Neurological morbidity is common after pediatric stroke, with moderate to severe deficits that can significantly impact education and social function. Care and recovery occur in phases distinguished by the time interval after stroke onset. These phases include the hyperacute and acute periods in which the focus is on cerebral reperfusion and prevention of neurological deterioration, followed by the subacute and chronic phases in which the focus is on secondary stroke prevention and mitigation of disability through rehabilitation, adaptation, and reintegration into the community. In this article, a multidisciplinary group of pediatric stroke experts review the stages of recovery after pediatric stroke with an emphasis on critical assessment time points. Our goal is to encourage increased standardization of outcome assessment to facilitate future clinical trials comparing various treatment and intervention options and advance optimized care for children with stroke.

Neuromonitoring During ECMO Support in Children.

Extracorporeal membrane oxygenation is a potentially lifesaving intervention for children with severe cardiac or respiratory failure. It is used with increasing frequency and in increasingly more complex and severe diseases. Neurological injuries are important causes of morbidity and mortality in children treated with extracorporeal membrane oxygenation and include ischemic stroke, intracranial hemorrhage, hypoxic-ischemic injury, and seizures. In this review, we discuss the epidemiology and pathophysiology of neurological injury in patients supported with extracorporeal membrane oxygenation, and we review the current state of knowledge for available modalities of monitoring neurological function in these children. These include structural imaging with computed tomography and ultrasound, cerebral blood flow monitoring with near-infrared spectroscopy and transcranial Doppler ultrasound, and physiological monitoring with electroencephalography and plasma biomarkers. We highlight areas of need and emerging advances that will improve our understanding of neurological injury related to extracorporeal membrane oxygenation and help to reduce the burden of neurological sequelae in these children.

In Vivo Formation and Tracking of π-Peptide Nanostructures.

The photophysics associated with the self-assembly of π-peptide molecules into 1-D nanostructures has been well-established, thus revealing the creation of nanoscale electronic conduits in aqueous media. Such materials have therapeutic potential in many biomedical applications. In this work, we report the in vivo deployment of these π-peptide nanostructures in brain tissue using photothrombotic stroke as a model application. A test peptide was used for brain injections, and the nanostructures formed were visualized with electron microscopy. A new peptide bearing a low-energy fluorescence dye was prepared to facilitate direct visualization of π-peptide localization in the brain cavity by way of fluorescence microscopy. This work demonstrates feasibility for in vivo application of π-peptide nanostructures toward pressing biomedical challenges.

Neurological and Functional Outcomes after Pediatric Stroke.

Pediatric stroke results in life-long morbidity for many patients, but the outcomes can vary depending on factors such as age of injury, or mechanism, size, and location of stroke. In this review, we summarize the current understanding of outcomes in different neurological domains (eg, motor, cognitive, language) for children with stroke of different mechanisms (ie, arterial ischemic stroke, cerebral sinus venous thrombosis, and hemorrhagic stroke), but with a focus on World Health Organization International Classification for Functioning, Disability, and Health (ICF-CY) framework for measuring health and disability for children and youth. We describe outcomes for the population as a whole and certain factors that may further refine prognostication.

Cyclohexanone Exposure in Children on Extracorporeal Membrane Oxygenation Support.

The aim of this study was to determine if plasma cyclohexanone and metabolites are associated with clinical outcomes of children on extracorporeal membrane oxygenation (ECMO) support. We performed a secondary analysis of a prospective observational study of children on ECMO support at two academic centers between July 2010 and June 2015. We measured plasma cyclohexanone and metabolites on the first and last days of ECMO support. Unfavorable outcome was defined as in-hospital death or discharge Pediatric Cerebral Performance Category score > 2 or decline ≥ 1 from baseline. Among 90 children included, 49 (54%) had unfavorable outcome at discharge. Cyclohexanediol, a cyclohexanone metabolite, was detected in all samples and at both time points; concentrations on the first ECMO day were significantly higher in those with unfavorable versus favorable outcome at hospital discharge (median, 5.7 ng/µl; interquartile range [IQR], 3.3-10.6 ng/µl vs. median, 4.2 ng/µl; IQR, 1.7-7.3 ng/µl; p = 0.04). Twofold higher cyclohexanediol concentrations on the first ECMO day were associated with increased risk of unfavorable outcome at hospital discharge (multivariable-adjusted hazard ratio [HR], 1.24 [95% CI, 1.05-1.48]). Higher cyclohexanediol concentrations on the first ECMO day were not significantly associated with new abnormal neuroimaging or 1-year Vineland Adaptive Behavior Scales-II score < 85 or death among survivors.

Pediatric ECMO: unfavorable outcomes are associated with inflammation and endothelial activation.

BACKGROUND: Inflammatory and endothelial activation responses during extracorporeal membrane oxygenation (ECMO) support in children are poorly understood. In this study, we aimed to determine if circulating inflammatory, endothelial activation, and fibrinolytic markers are associated with mortality and with neurologic outcomes in children on ECMO. METHODS: We conducted a secondary analysis of a two-center prospective observational study of 99 neonatal and pediatric ECMO patients. Inflammatory (interferon gamma [IFNγ], interleukin-6 [IL-6], IL-1ß, tumor necrosis factor alpha [TNFα]), endothelial activation (E-selectin, P-selectin, intercellular adhesion molecule-3 [ICAM-3], thrombomodulin [TM]), and fibrinolytic markers (tissue plasminogen activator [tPA], plasminogen activator inhibitor-1 [PAI-1]) were measured in plasma on days 1, 2, 3, 5, 7, and every third day thereafter during the ECMO course. RESULTS: All ECMO day 1 inflammatory biomarkers were significantly elevated in children with abnormal vs. normal neuroimaging. ECMO day 1 and peak levels of IL-6 and PAI-1 were significantly elevated in children who died compared to those who survived to hospital discharge. Tested biomarkers showed no significant association with long-term neurobehavioral outcomes measured using the Vineland Adaptive Behavioral Scales, Second Edition. CONCLUSIONS: High levels of circulating inflammatory, endothelial activation, and fibrinolytic markers are associated with mortality and abnormal neuroimaging in children on ECMO. IMPACT: The inflammatory, endothelial activation, and fibrinolytic profile of children on ECMO differs by primary indication for extracorporeal support. Proinflammatory biomarkers on ECMO day 1 are associated with abnormal neurologic imaging in children on ECMO in univariable but not multivariable models. In multivariable models, a pronounced proinflammatory and prothrombotic biomarker profile on ECMO day 1 and longitudinally was significantly associated with mortality. Further studies are needed to identify inflammatory, endothelial, and fibrinolytic profiles associated with increased risk for neurologic injury and mortality through potential mediation of bleeding and thrombosis.

The Pediatric Neurology 2020 Research Workforce Survey: Optimism in a Time of Challenge.

BACKGROUND: The past decades have seen a transformational shift in the understanding and treatment for neurological diseases affecting infants and children. These advances have been driven in part by the pediatric neurology physician-scientist workforce and its efforts. However, pediatric neurology research faces substantial challenges from internal and external forces including work-life balance demands, COVID-19 pandemic effects, and research funding. Understanding the impact of these challenges on the perceptions, planning, and careers of pediatric neurology physician-scientists is needed to guide the research mission. METHODS: Our objective was to survey the research challenges, goals, and priorities of pediatric neurologists. In 2020 we conducted a cross-sectional, 28-question survey emailed to 1,775 members of the Child Neurology Society. RESULTS: One hundred fifty-one individuals responded to the survey. Most respondents were grant investigators (52%) and conducted clinical research (69%). Research areas included epilepsy (23%), neurodevelopmental and autism (16%), neurocritical care and stroke (11%), neurogenetics and neurometabolics (9%), neonatal neurology (8%), and others. The most common funding source was the National Institutes of Health (37%). Shared major research concerns were funding, utilization of remote technology, overcoming disparities, natural history and multicenter studies, global neurology, and diversification of the research portfolio. Commitment to continuing and increasing research efforts was evident. CONCLUSIONS: Our survey demonstrates obstacles for physician-scientist researchers in pediatric neurology, but it also shows optimism about continued opportunity. Creative approaches to address challenges will benefit the research mission, maximize the current and future pool of researchers, and help improve the lives of children with neurological disorders.

Pediatric Ischemic Stroke: An Infrequent Complication of SARS-CoV-2.

OBJECTIVE: Severe complications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) include arterial ischemic stroke (AIS) in adults and multisystem inflammatory syndrome in children. Whether stroke is a frequent complication of pediatric SARS-CoV-2 is unknown. This study aimed to determine the proportion of pediatric SARS-CoV-2 cases with ischemic stroke and the proportion of incident pediatric strokes with SARS-CoV-2 in the first 3 months of the pandemic in an international cohort. METHODS: We surveyed 61 international sites with pediatric stroke expertise. Survey questions included: numbers of hospitalized pediatric (≤ 18 years) patients with SARS-CoV-2; numbers of incident neonatal and childhood ischemic strokes; frequency of SARS-CoV-2 testing for pediatric patients with stroke; and numbers of stroke cases positive for SARS-CoV-2 from March 1 to May 31, 2020. RESULTS: Of 42 centers with SARS-CoV-2 hospitalization numbers, 8 of 971 (0.82%) pediatric patients with SARS-CoV-2 had ischemic strokes. Proportions of stroke cases positive for SARS-CoV-2 from March to May 2020 were: 1 of 108 with neonatal AIS (0.9%), 0 of 33 with neonatal cerebral sinovenous thrombosis (CSVT; 0%), 6 of 166 with childhood AIS (3.6%), and 1 of 54 with childhood CSVT (1.9%). However, only 30.5% of neonates and 60% of children with strokes were tested for SARS-CoV-2. Therefore, these proportions represent 2.9, 0, 6.1, and 3.0% of stroke cases tested for SARS-CoV-2. Seven of 8 patients with SARS-CoV-2 had additional established stroke risk factors. INTERPRETATION: As in adults, pediatric stroke is an infrequent complication of SARS-CoV-2, and SARS-CoV-2 was detected in only 4.6% of pediatric patients with ischemic stroke tested for the virus. However, < 50% of strokes were tested. To understand the role of SARS-CoV-2 in pediatric stroke better, SARS-CoV-2 testing should be considered in pediatric patients with stroke as the pandemic continues. ANN NEUROL 2021;89:657-665.

Intrathecal chemotherapy-associated cerebral vasospasm in children with hematologic malignancies.

BACKGROUND: Mechanisms of chemotherapy-associated neurotoxicity are poorly understood, and therefore, prevention strategies have not been developed. We hypothesized that a subgroup of children receiving intrathecal cytarabine develops subclinical vasospasm, which may contribute to long-term neurocognitive sequelae of cancer. METHODS: We used transcranial Doppler ultrasound to serially evaluate cerebral blood flow velocities in participants ≤25 years old receiving intrathecal cytarabine for hematologic malignancies. RESULTS: Four of 18 participants (22%) met the criteria for subclinical vasospasm within 4 days of intrathecal cytarabine administration. The distribution of oncologic diagnoses differed between the vasospasm and non-vasospasm groups (p = 0.02). Acute myeloid leukemia was identified as a potential risk factor for vasospasm. Children with vasospasm were more likely to have received intravenous cytarabine (75% versus 0%, p = 0.01) and less likely to have received steroids (25% versus 100%, p = 0.01). CONCLUSIONS: A subpopulation of children with hematologic malignancies develops subclinical vasospasm after intrathecal cytarabine treatment. Future research is needed to determine the long-term clinical consequences of cerebral vasospasm in this population. IMPACT: A subset of children with hematologic malignancies who receive intrathecal cytarabine experience subclinical cerebral vasospasm, as measured by transcranial Doppler ultrasound. Of children receiving intrathecal cytarabine, those who develop cerebral vasospasm are more likely to have diagnosis of acute myeloid leukemia, more likely to receive concurrent intravenous cytarabine, and less likely to receive steroids as part of their chemotherapy regimen, as compared with children without vasospasm. Future research is needed to determine if vasospasm during chemotherapy is associated with higher rates of neurocognitive dysfunction, and if so, to focus on prevention of these long-term sequelae of childhood cancer.

Sex specific correlation between GABAergic disruption in the dorsal hippocampus and flurothyl seizure susceptibility after neonatal hypoxic-ischemic brain injury.

Since neonatal hypoxia-ischemia (HI) disrupts the hippocampal (Hp) GABAergic network in the mouse and Hp injury in this model correlates with flurothyl seizure susceptibility only in male mice, we hypothesized that GABAergic disruption correlates with flurothyl seizure susceptibility in a sex-specific manner. C57BL6 mice were exposed to HI (Vannucci model) versus sham procedures at P10, randomized to normothermia (NT) or therapeutic hypothermia (TH), and subsequently underwent flurothyl seizure testing at P18. Only in male mice, Hp atrophy correlated with seizure susceptibility. The number of Hp parvalbumin positive interneurons (PV+INs) decreased after HI in both sexes, but TH attenuated this deficit only in females. In males only, seizure susceptibility directly correlated with the number of PV+INs, but not somatostatin or calretinin expressing INs. Hp GABAB receptor subunit levels were decreased after HI, but unrelated to later seizure susceptibility. In contrast, Hp GABAA receptor α1 subunit (GABAARα1) levels were increased after HI. Adjusting the number of PV+ INs for their GABAARα1 expression strengthened the correlation with seizure susceptibility in male mice. Thus, we identified a novel Hp sex-specific GABA-mediated mechanism of compensation after HI that correlates with flurothyl seizure susceptibility warranting further study to better understand potential clinical translation.

Mechanical Thrombectomy for Acute Ischemic Stroke: Considerations in Children.

The use of mechanical thrombectomy for the treatment of acute childhood arterial ischemic stroke with large vessel occlusion is increasing, with mounting evidence for its feasibility and safety. Despite this emerging evidence, clear guidelines for patient selection, thrombectomy technique, and postprocedure care do not exist for the pediatric population. Due to unique features of stroke in children, neurologists and interventionalists must consider differences in patient size, anatomy, collateral vessels, imaging parameters, and expected outcomes that may impact appropriate patient selection and timing criteria. In addition, different causes of stroke and comorbidities in children must be considered and may alter the safety and efficacy of thrombectomy. To optimize the success of endovascular intervention in children, a multidisciplinary team should take into account these nuanced considerations when determining patient eligibility, developing a procedural approach, and formulating a postprocedure neurological monitoring and therapeutic plan.

Treatment and outcome of childhood cerebral sinovenous thrombosis.

OBJECTIVE: To test our hypothesis that anticoagulation is associated with better neurologic outcomes in childhood cerebral sinovenous thrombosis (CSVT), we analyzed treatment and outcomes in a population of 410 children from the International Pediatric Stroke Study (IPSS). METHODS: We included patients enrolled in the IPSS registry with a diagnosis of CSVT at age >28 days with radiologic confirmation, in isolation or with concomitant arterial ischemic stroke. The primary outcome was the neurologic status at discharge. We defined unfavorable outcome as severe neurologic impairment or death at discharge. The Pediatric Stroke Outcome Measure was used for long-term outcome in those with follow-up. Predictors of anticoagulation use and outcome were analyzed by logistic regression. RESULTS: Most children (95%) had identifiable risk factors, and 82% received anticoagulation. Shift analysis demonstrated better outcomes at discharge in children who were anticoagulated, and this persisted with longer-term outcomes. In multivariable analysis, anticoagulation was significantly associated with favorable outcomes (adjusted odds ratio [aOR] unfavorable 0.32, p = 0.007) whereas infarct was associated with unfavorable outcome (aOR unfavorable 6.71, p < 0.001). The trauma/intracranial surgery was associated with a lower odds of anticoagulation use (aOR 0.14, p < 0.001). CONCLUSIONS: Within the IPSS registry, children with risk factors of trauma or intracranial surgery were less likely to receive anticoagulation for CSVT. Anticoagulation was associated with a lower odds of severe neurologic impairment or death at hospital discharge, but this finding is limited and needs further confirmation in randomized, controlled, prospective studies.

Performance of a Pediatric Stroke Alert Team Within a Comprehensive Stroke Center.

BACKGROUND: Childhood stroke is rare, and diagnosis is frequently delayed. The use of pediatric stroke teams has the potential to decrease time to neurology evaluation and imaging, hastening appropriate diagnosis and treatment for acute neurologic presentations in children. METHODS: We performed a retrospective analysis of our institutional pediatric stroke or "brain attack" team (pedsBAT) activations from October 2014 to July 2017. Clinical characteristics and timing parameters were compared between pedsBAT activations in the inpatient vs emergency department (ED) / outpatient settings as well as between pediatric and adult BAT activations in the same time period. RESULTS: We identified 120 pedsBAT activations (75% in the ED/outpatient setting) during the study time period. Inpatient pedsBAT activations were more likely than outpatient activations to have heart disease as a risk factor for ischemic stroke and presented more frequently with altered mental status, but there were no differences in the proportion of cerebrovascular diagnoses or timing parameters between the 2 groups. When compared with adult BAT activations, outpatient pedsBAT activations had a longer time from symptom discovery to arrival at the ED, and inpatient pedsBAT activations had longer time from symptom discovery to BAT activation. CONCLUSIONS: Compared with adults, the interval leading up to stroke team activation was longer in children, suggesting delays in symptom recognition. Future interventions should be aimed at reducing these delays in presentation to care and stroke alert activation in pediatric patients.

Predicting Recovery and Outcome after Pediatric Stroke: Results from the International Pediatric Stroke Study.

OBJECTIVE: To characterize predictors of recovery and outcome following pediatric arterial ischemic stroke, hypothesizing that age influences recovery after stroke. METHODS: We studied children enrolled in the International Pediatric Stroke Study between January 1, 2003 and July 31, 2014 with 2-year follow-up after arterial ischemic stroke. Outcomes were defined at discharge by clinician grading and at 2 years by the Pediatric Stroke Outcome Measure. Demographic, clinical, and radiologic outcome predictors were examined. We defined changes in outcome from discharge to 2 years as recovery (improved outcome), emerging deficit (worse outcome), or no change. RESULTS: Our population consisted of 587 patients, including 174 with neonatal stroke and 413 with childhood stroke, with recurrent stroke in 8.2% of childhood patients. Moderate to severe neurological impairment was present in 9.4% of neonates versus 48.8% of children at discharge compared to 8.0% versus 24.7% after 2 years. Predictors of poor outcome included age between 28 days and 1 year (compared to neonates, odds ratio [OR] = 3.58, p < 0.05), underlying chronic disorder (OR = 2.23, p < 0.05), and involvement of both small and large vascular territories (OR = 2.84, p < 0.05). Recovery patterns differed, with emerging deficits more common in children <1 year of age (p < 0.05). INTERPRETATION: Outcomes after pediatric stroke are generally favorable, but moderate to severe neurological impairments are still common. Age between 28 days and 1 year appears to be a particularly vulnerable period. Understanding the timing and predictors of recovery will allow us to better counsel families and target therapies to improve outcomes after pediatric stroke. ANN NEUROL 2020;87:840-852.