Intellectual ability 10 years after traumatic brain injury in infancy and childhood: what predicts outcome?

The long-term consequences of child traumatic brain injury (TBI) are poorly understood, but there are indications of ongoing deterioration in skills with time since injury. This study investigated outcomes up to 10 years post-injury, to determine the influences of injury severity, injury age, and environment. The study design was prospective and longitudinal. Participants included consecutive admissions to the Royal Children's Hospital, Melbourne, Australia. Children sustaining TBI between 2 and 12 years of age (n=76) were recruited on admission and divided according to injury severity (mild, moderate, and severe) and injury age (2-7 years and 8-12 years). Cognitive abilities were evaluated using standard measures of intellectual function (IQ) acutely and at 12 months, 30 months, and 10 years post-injury. At 10 years, mean IQs for survivors fell within the low average to average range. There were no significant effects of injury severity, injury age, or time since injury. In contrast, elevated rates of impairment were identified in association with severe TBI (global deficits), and early injury (non-verbal deficits). Impairments in processing speed were related to injury severity and age at injury. Predictors of 10-year outcome included pre-injury and social factors, injury age, and family function. Child survivors of serious TBI are at elevated risk of cognitive impairment, with recovery continuing into the third year post-injury. However, between 30 months and 10 years post-insult, children appear to make appropriate developmental gains, contrary to the speculation that these children "grow into their deficits."