Developmental Alterations in Cortical Organization and Socialization in Adolescents Who Sustained a Traumatic Brain Injury in Early Childhood.

This study investigated patterns of cortical organization in adolescents who had sustained a traumatic brain injury (TBI) during early childhood to determine ways in which early head injury may alter typical brain development. Increased gyrification in other patient populations is associated with polymicrogyria and aberrant development, but this has not been investigated in TBI. Seventeen adolescents (mean age = 14.1 ± 2.4) who sustained a TBI between 1-8 years of age, and 17 demographically-matched typically developing children (TDC) underwent a high-resolution, T1-weighted 3-Tesla magnetic resonance imaging (MRI) at 6-15 years post-injury. Cortical white matter volume and organization was measured using FreeSurfer's Local Gyrification Index (LGI). Despite a lack of significant difference in white matter volume, participants with TBI demonstrated significantly increased LGI in several cortical regions that are among those latest to mature in normal development, including left parietal association areas, bilateral dorsolateral and medial frontal areas, and the right posterior temporal gyrus, relative to the TDC group. Additionally, there was no evidence of increased surface area in the regions that demonstrated increased LGI. Higher Vineland-II Socialization scores were associated with decreased LGI in right frontal and temporal regions. The present results suggest an altered pattern of expected development in cortical gyrification in the TBI group, with changes in late-developing frontal and parietal association areas. Such changes in brain structure may underlie cognitive and behavioral deficits associated with pediatric TBI. Alternatively, increased gyrification following TBI may represent a compensatory mechanism that allows for typical development of cortical surface area, despite reduced brain volume.

Acute pediatric traumatic brain injury severity predicts long-term verbal memory performance through suppression by white matter integrity on diffusion tensor imaging.

Mediation analysis was used to investigate the role of white matter integrity in the relationship between injury severity and verbal memory performance in participants with chronic pediatric traumatic brain injury (TBI). DTI tractography was used to measure fractional anisotropy (FA) within the corpus callosum, fornix, cingulum bundles, perforant pathways, and uncinate fasciculi. Injury severity was indexed using Glasgow Coma Scale (GCS) scores obtained at the time of the injury. Verbal memory was measured by performance on the long-delay free recall (LDFR) trial of the California Verbal Learning Test-Children's version. Participants were between the ages of 10-18 and included 21 children with TBI (injured before age 9) and 19 typically-developing children (TDC). Children with TBI showed lower FA across all pathways and poorer LDFR performance relative to TDC. Within the TBI group, mediation analysis revealed neither a significant total effect of GCS on LDFR nor significant direct effects of GCS on LDFR across pathways; however, the indirect effects of GCS on LDFR through FA of the corpus callosum, left perforant pathway, and left uncinate fasciculus were significant and opposite in sign to their respective direct effects. These results suggests that the predictive validity of GCS for LDFR is initially suppressed by the substantial variance accounted for by FA, which is uncorrelated with GCS, and the predictive validity of GCS increases only when FA is considered, and the opposing path is controlled. These findings illustrate the complex associations between acute injury severity, white matter pathways, and verbal memory several years following pediatric TBI.

Neurological outcome scale for traumatic brain injury: III. Criterion-related validity and sensitivity to change in the NABIS hypothermia-II clinical trial.

The neurological outcome scale for traumatic brain injury (NOS-TBI) is a measure assessing neurological functioning in patients with TBI. We hypothesized that the NOS-TBI would exhibit adequate concurrent and predictive validity and demonstrate more sensitivity to change, compared with other well-established outcome measures. We analyzed data from the National Acute Brain Injury Study: Hypothermia-II clinical trial. Participants were 16-45 years of age with severe TBI assessed at 1, 3, 6, and 12 months postinjury. For analysis of criterion-related validity (concurrent and predictive), Spearman's rank-order correlations were calculated between the NOS-TBI and the glasgow outcome scale (GOS), GOS-extended (GOS-E), disability rating scale (DRS), and neurobehavioral rating scale-revised (NRS-R). Concurrent validity was demonstrated through significant correlations between the NOS-TBI and GOS, GOS-E, DRS, and NRS-R measured contemporaneously at 3, 6, and 12 months postinjury (all p<0.0013). For prediction analyses, the multiplicity-adjusted p value using the false discovery rate was <0.015. The 1-month NOS-TBI score was a significant predictor of outcome in the GOS, GOS-E, and DRS at 3 and 6 months postinjury (all p<0.015). The 3-month NOS-TBI significantly predicted GOS, GOS-E, DRS, and NRS-R outcomes at 6 and 12 months postinjury (all p<0.0015). Sensitivity to change was analyzed using Wilcoxon's signed rank-sum test of subsamples demonstrating no change in the GOS or GOS-E between 3 and 6 months. The NOS-TBI demonstrated higher sensitivity to change, compared with the GOS (p<0.038) and GOS-E (p<0.016). In summary, the NOS-TBI demonstrated adequate concurrent and predictive validity as well as sensitivity to change, compared with gold-standard outcome measures. The NOS-TBI may enhance prediction of outcome in clinical practice and measurement of outcome in TBI research.