Diffusion tensor imaging detects white matter abnormalities and associated cognitive deficits in chronic adolescent TBI
Developmental Imaging, Murdoch Childrens Research Institute , Parkville, Australia. Brain Injury
(Impact Factor: 1.81).
03/2013; 27(4). DOI: 10.3109/02699052.2012.750756
Primary objective: This study examined long-term alterations in white matter microstructure following TBI in adolescence using diffusion tensor imaging (DTI). It was hypothesized that white matter integrity would be compromised in adolescents with TBI and would correlate with measures of executive functioning and cognitive abilities. Research design: This study employed whole-brain, voxel-wise, statistical comparison of DTI indices in youth of 12-17 years old (mean = 15.06) with TBI vs an age- and gender-matched cohort (mean age = 15.37). Methods and procedures: This study scanned 17 adolescents with complicated-mild-to-severe TBI, 1-3 years after injury, and 13 healthy adolescents. Tract-Based Spatial Statistics (TBSS) was employed for DTI analysis. Main outcomes and results: Overall diffusivity elevations were found in the TBI group with increases in axial diffusivity in the right hemisphere. White matter integrity was associated with word reading, planning and processing times in the TBI group, but not healthy controls. Conclusions: The detected abnormalities in axial diffusivity may reflect neuronal regeneration and cerebral reorganization after injury. These findings provide tentative evidence of persistent white matter alteration following TBI in adolescence. Associations of DTI indices with cognitive performance following TBI provide tentative support for links between white matter integrity and performance post-TBI.
Available from: Charles S Cox
- "Recent meta-analysis of educational outcomes has also demonstrated that reading deficits persist with little evidence of recovery among those with severe injuries between the 5 months post-injury and 24 months, whereas other academic skills, such as math ability, show some recovery of during this period (Vu et al., 2011). White matter in the frontal lobes has been associated with performance on tasks of reading and executive functioning in the TBI population (Adamson et al., 2013). In addition, the integrity of the cingulum bundle has been implicated in speeded task performance and working memory in TBI, though not with performance in word-reading (Wilde et al., 2010). "
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ABSTRACT: Pediatric traumatic brain injury often results in significant long-term deficits in mastery of reading ability. This study aimed to identify white matter pathways that, when damaged, predicted reading deficits in children. Based on the dual-route model of word reading, we predicted that integrity of the inferior fronto-occipital fasciculus would be related to performance in sight word identification while integrity of the superior longitudinal fasciculus would be related to performance in phonemic decoding. Reading fluency and comprehension were hypothesized to relate to the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and cingulum bundle. The connectivity of white matter pathways was used to predict reading deficits in children aged 6 to 16years with traumatic brain injury (n=29) and those with orthopedic injury (n=27) using tract-based spatial statistics. Results showed that children with traumatic brain injury and reduced microstructural integrity of the superior longitudinal fasciculus demonstrated reduced word-reading ability on sight word and phonemic decoding tasks. Additionally, children with traumatic brain injury and microstructural changes involving the cingulum bundle demonstrated reduced reading fluency. Results support the association of a dorsal pathway via the superior longitudinal fasciculus with both sight word reading and phonemic decoding. No association was identified between the inferior fronto-occipital fasciculus and sight word reading or phonemic decoding. Reading fluency was associated with the integrity of the cingulum bundle. These findings support dissociable pathways predicting word reading and fluency using Diffusion Tensor Imaging and provide additional information for developing models of acquired reading deficits by specifying areas of brain damage which may predict reading deficits following recovery from the acute phase of TBI.
Available from: Laszlo A Erdodi
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ABSTRACT: The Behavior Rating Inventory of Executive Function (BRIEF) is a rating scale designed to assess executive functions in everyday life that is widely used in school and clinical settings and in research studies. It has been recently suggested, however, that the limited geographic stratification of the standardization sample renders the measure overly sensitive. We evaluated this hypothesis by examining BRIEF scores across studies of typically developing children and adolescents. Thirty-nine studies were identified that included at least one of three possible index scores. Mean scores across studies were (a) within one to two T-score units from the standardization sample mean of 50, (b) tended to be slightly lower than 50, and (c) were unrelated to geographic location (US Census regions or internationally). These findings refute recent claims that the BRIEF is overly sensitive and further add to the large body of literature supporting the validity of the measure.
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To investigate structural brain changes in inflammatory bowel disease (IBD).
Brain magnetic resonance imaging (MRI) was performed on 18 IBD patients (aged 45.16 ± 14.71 years) and 20 aged-matched control subjects. The imaging protocol consisted of a sagittal-FLAIR, a T1-weighted high-resolution three-dimensional spoiled gradient-echo sequence, and a multisession spin-echo echo-planar diffusion-weighted sequence. Differences between patients and controls in brain volume and diffusion indices were evaluated using the voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) methods, respectively. The presence of white-matter hyperintensities (WMHIs) was evaluated on FLAIR images.
VBM revealed decreased grey matter (GM) volume in patients in the fusiform and the inferior temporal gyrus bilaterally, the right precentral gyrus, the right supplementary motor area, the right middle frontal gyrus and the left superior parietal gyrus (p
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