Objectives: To determine: (1) the magnitude of neurobehavioral deficits following severe traumatic brain injury (TBI) in children, 3 weeks and 1 year after resolution of post-traumatic amnesia (PTA); (2) the relationship between deficits and injury severity; (3) the performance of cases compared to population norms versus individually matched controls.
Design: Prospective cohort study.
Setting: Two regional university medical centers.
Participants: Cases were 30 children 6 to 15 years old with severe TBI, measured by initial Glasgow Coma Scale (GCS) score and days to reach a GCS score of 15. Controls were individually matched for age, gender, and premorbid academic achievement.
Main outcome measures: Subjects received the same neurobehavioral tests three weeks and one year after resolution of PTA. Outcomes included individual test scores and variables summarizing results in eight domains. Correlations were calculated between deficits, expressed as case-control differences, and injury severity.
Results: Cases showed substantial deficits and performed significantly more poorly than controls at both initial and 1-year testing. At initial testing, cases had an overall score two standard deviations below controls. At 1-year testing their overall score was one standard deviation below controls. Greater impairment was found in those who reached a GCS score of 15 after 1 month or who had an initial GCS of 3 to 5. The proportion of cases with deficits and the magnitude of deficits at both testing times was underestimated by using population norms instead of controls.
Conclusions: Severe TBI results in significant, persistent deficits related to the level of severity. Comparisons with population norms instead of controls underestimates deficits.