Executive Function After Severe Childhood Traumatic Brain Injury - Age-at-injury Vulnerability Periods: The TGE Prospective Longitudinal Study

Background: Executive function (EF) impairment is a major predictor of overall outcome after traumatic brain injury (TBI). TBI severity is a factor of poor outcome, but most studies include a majority of children with mild and moderate TBI. The aims of this study were to estimate EF impairment after severe childhood TBI and to explore factors predicting EF outcome. The secondary aim was to compare recovery trajectories by age-at-injury groups.

Methods: This was a prospective longitudinal study of children with severe TBI who were tested for EFs by performance-based tests and questionnaires at 3, 12 and 24 months.

Results: Children with TBI (n=65) showed significant impairment in working memory, inhibition, attention and global EF, with little or no recovery at 24 months. For flexibility and performance-based EF score, children were impaired at 3 months only and showed normal scores by 12 months. No impairment was found in planning. At 3 and 24 months, Glasgow Coma Scale score and parental education predicted global EF. Coma length was not a significant predictor of outcome. Age at injury predicted progress in EF, but the relationship was not linear; children 10-12 years old at injury showed better outcome than older and younger children.

Conclusions: EFs are impaired after severe TBI in childhood. The relationship between age at injury and outcome is not linear. Relying on only performance-based EF tests can underestimate EF impairment.