The Impact of Traumatic Brain Injury on Neurocognitive Outcomes in Children: a Systematic Review and Meta-Analysis

Objective To assess the burden of paediatric traumatic brain injury (TBI) on neurocognition via a systematic review and meta-analysis. Methods Studies 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. Results Of 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; I-2=0.00%), -0.18 (95% CI -0.29 to -0.06; I-2=26.1%) and -0.95 (95% CI -1.12 to -0.77; I-2=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. Conclusion A 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.