Predicting behavioral deficits in pediatric traumatic brain injury through uncinate fasciculus integrity

Abstract

Behavioral dysregulation is a common and detrimental consequence of traumatic brain injury (TBI) in children that contributes to poor academic achievement and deficits in social development. Unfortunately, behavioral dysregulation is difficult to predict from either injury severity or early neuropsychological evaluation. The uncinate fasciculus (UF) connects orbitofrontal and anterior temporal lobes, which are commonly implicated in emotional and behavioral regulation. Using probabilistic diffusion tensor tractography (DTT), we examined the relationship between the integrity of the UF 3 months post-injury and ratings of executive functions 12 months post-injury in children with moderate to severe TBI and a comparison group with orthopedic injuries. As expected, fractional anisotropy of the UF was lower in the TBI group relative to the orthopedic injury group. DTT metrics from the UF served as a biomarker and predicted ratings of emotional and behavior regulation, but not metacognition. In contrast, the Glasgow Coma Scale score was not related to either UF integrity or to executive function outcomes. Neuroanatomical biomarkers like the uncinate fasciculus may allow for early identification of behavioral problems and allow for investigation into the relationship of frontotemporal networks to brain-behavior relationships.

Fig. 1

Sagittal images demonstrating the gray matter masks for the orbitofrontal cortex (green), anterior temporal pole (red), and the resulting uncinate fasciculus (blue).

Fig. 2

Three-dimensional reconstructions of the uncinate fasciculus in three 15-year-old participants (clockwise from top left): (a) orthopedic control participant with good outcome on the Behavioral Regulation Index (T score = 43); (b) traumatic brain injury participant with good outcome on the Behavioral Regulation Index (T = 52), and (c) traumatic brain injury participant with poor outcome on the Behavioral Regulation Index (T = 63).