Diffusion tensor imaging of incentive effects in prospective memory after pediatric traumatic brain injury.

Few studies exist investigating the brain-behavior relations of event-based prospective memory (EB-PM) impairments following traumatic brain injury (TBI). To address this, children with moderate-to-severe TBI performed an EB-PM test with two motivational enhancement conditions and underwent concurrent diffusion tensor imaging (DTI) at 3 months post-injury. Children with orthopedic injuries (OI; n=37) or moderate-to-severe TBI (n=40) were contrasted. Significant group differences were found for fractional anisotropy (FA) and apparent diffusion coefficient for orbitofrontal white matter (WM), cingulum bundles, and uncinate fasciculi. The FA of these WM structures in children with TBI significantly correlated with EB-PM performance in the high, but not the low motivation condition. Regression analyses within the TBI group indicated that the FA of the left cingulum bundle (p=0.003), left orbitofrontal WM (p<0.02), and left (p<0.02) and right (p<0.008) uncinate fasciculi significantly predicted EB-PM performance in the high motivation condition. We infer that the cingulum bundles, orbitofrontal WM, and uncinate fasciculi are important WM structures mediating motivation-based EB-PM responses following moderate-to-severe TBI in children.

Diffusion tensor imaging analysis of frontal lobes in pediatric traumatic brain injury.

This study examined the use of diffusion tensor imaging in detecting white matter changes in the frontal lobes following pediatric traumatic brain injury. A total of 46 children (ages 8-16 years) with moderate to severe traumatic brain injury and 47 children with orthopedic injury underwent 1.5 Tesla magnetic resonance imaging (MRI) at 3 months postinjury. Conventional MRI studies were obtained along with diffusion tensor imaging. Diffusion tensor imaging metrics, including fractional anisotropy, apparent diffusion coefficient, and radial diffusivity, were compared between the groups. Significant group differences were identified, implicating frontal white matter alterations in the injury group that were predictive of later Glasgow Outcome Scale ratings; however, focal lesions were not related to the Glasgow Outcome Scale ratings. Injury severity was also significantly associated with diffusion tensor imaging metrics. Diffusion tensor imaging holds great promise as an index of white matter integrity in traumatic brain injury and as a potential biomarker reflective of outcome.