Diffusion Tensor Imaging of Incentive Effects in Prospective Memory after Pediatric Traumatic Brain Injury

Abstract

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.

Emerging Imaging Tools for Use with Traumatic Brain Injury Research

“…Significant differences in the FA, ADC, or MD, or other DTIderived diffusivity metrics have been demonstrated in studies of TBI in both adults (Bigler et al, 2010b;Kraus et al, 2007;Lipton et al, 2008;Perlbarg et al, 2009;Warner et al, 2010a) and children (Ewing-Cobbs et al, 2008;Levin et al, 2008;McCauley et al, 2011;Wilde et al, 2006bWilde et al, , 2010Wozniak et al, 2007;Wu et al, 2010a;Yuan et al, 2007), with decreases in FA and increases in measures of diffusivity often found in chronic post-injury intervals. More importantly, changes in DTIderived measures have shown correlation with injury severity (Arfanakis et al, 2002;Benson et al, 2007;Wilde et al, 2010;Yuan et al, 2007), functional outcome (Huisman et al, 2004;Levin et al, 2008;Salmond et al, 2006;Wozniak et al, 2007), neurologic functioning (Caeyenberghs et al, 2010a,b), and cognitive ability (Bigler et al, 2010b;Ewing-Cobbs et al, 2008;Kraus et al, 2007;Kumar et al, 2009;Levin et al, 2008;McCauley et al, 2011;Niogi et al, 2008;Salmond et al, 2006;Warner et al, 2010a;Wilde et al, 2010). Longitudinal studies have also indicated that DTI might serve as a tool for revealing changes in the neural tissue during recovery from TBI (Bendlin et al, 2008;Sidaros et al, 2008;Wu et al, 2010a).…”

Gray Matter Abnormalities in Pediatric Mild Traumatic Brain Injury

“…5 Thus, the pathophysiology of pmTBI and the subsequent relationship to neurobehavioral sequelae remain actively debated. Diffusion tensor imaging (DTI) has emerged as a potential mechanism for non-invasively measuring traumatic injuries, with the majority of studies focusing on moderate-to-severe [6][7][8][9] or mixed 10,11 pediatric injury cohorts at more chronic (e.g., months to years post-injury) time-points. The majority of these studies report decreased fractional anisotropy (FA) in the white matter of chronic patients.…”

Social importance enhances prospective memory: evidence from an event-based task

“…The main method to manipulate the importance of a prospective memory task is to promise a reward for successful prospective memory performance (e.g., Aberle, Rendell, Rose, McDaniel, & Kliegel, 2010;Guajardo & Best, 2000;Jeong & Cranney, 2009;Krishnan & Shapiro, 1999;McCauley et al, 2011;Meacham & Singer, 1977).…”