ObjectiveTo assess the burden of paediatric traumatic brain injury (TBI) on neurocognition via a systematic review and meta-analysis.MethodsStudies that compared neurocognitive outcomes of paediatric patients with TBI and controls were searched using Medline, Embase, PsycINFO and Cochrane Central Register of Controlled Trials, between January 1988 and August 2019. We presented a random-effects model, stratified by TBI severity, time of assessment post injury and age.ResultsOf 5919 studies, 41 (patients=3717) and 33 (patients=3118) studies were included for the systematic review and meta-analysis, respectively. Studies mostly measured mild TBI (n=26, patients=2888) at 0–3 months postinjury (n=17, patients=2502). At 0–3 months postinjury, standardised mean differences between TBI and controls for executive function were −0.04 (95% CI −0.14 to 0.07; I2=0.00%), −0.18 (95% CI −0.29 to –0.06; I2=26.1%) and −0.95 (95% CI −1.12 to –0.77; I2=10.1%) for mild, moderate and severe TBI, respectively; a similar effect was demonstrated for learning and memory. Severe TBI had the worst outcomes across all domains and persisted >24 months postinjury. Commonly used domains differed largely from workgroup recommendations. Risk of bias was acceptable for all included studies.ConclusionA dose-dependent relationship between TBI severity and neurocognitive outcomes was evident in executive function and in learning and memory. Cognitive deficits were present for TBIs of all severity but persisted among children with severe TBI. The heterogeneity of neurocognitive scales makes direct comparison between studies difficult. Future research into lesser explored domains and a more detailed assessment of neurocognitive deficits in young children are required to better understand the true burden of paediatric TBI.

IntroductionChildren who suffer from traumatic brain injury (TBI) are at risk of permanent brain damage and developmental deficits. Reports on neurodevelopmental outcomes in paediatric TBI suffer from small sample size and varying outcome definitions in the neurocognitive domains tested. This protocol describes a systematic review and meta-analysis of paediatric TBI in the following key neurocognitive domains: executive function, perceptual–motor function, language, learning and memory, social cognition and complex attention.MethodsA comprehensive search comprising studies from Medline, Cochrane, Embase and PsycINFO published from 1988 to 2019 will be conducted. We will include studies on children ≤18 years old who suffer from mild, moderate and severe TBI as determined by the Glasgow Coma Scale that report neurocognitive outcomes in domains predetermined by the Diagnostic and Statistical Manual of Mental Disorders fifth edition criteria. Systematic reviews, meta-analyses, randomised controlled trials, case–control, cohort and cross-sectional studies will be included. References from systematic reviews and meta-analyses will be hand-searched for relevant articles. A meta-analysis will be performed and effect sizes will be calculated to summarise the magnitude of change in each neurocognitive domain compared at different timepoints and stratified by severity of TBI. Included studies will be pooled using pooled standardised mean differences with a random effects model to determine an overall effect. In the scenario that we are unable to pool the studies, we will perform a narrative analysis.Ethics and disseminationEthics approval is not required for this study.The authors of this study will publish and present the findings in a peer-reviewed journal as well as national and international conferences. The results of this study will provide understanding into the association between different severities of paediatric TBI and long-term neurocognitive outcomes.PROSPERO registration numberCRD42020152680.