Changes in White Matter Late after Severe Traumatic Brain Injury in Childhood

Tasker, Robert C.

doi:10.1159/000094156

Cited by 39 publications

(42 citation statements)

References 102 publications

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“…Reduced integrity of the CC after TBI is believed to result from pathophysiological processes, including demyelination, expansion of extracellular space, possibly attributed to neuronal or glial loss, buildup of cellular debris from breakdown of axonal structure, and disordered microtubule arrangement. [73][74][75][76] Our results are consistent with the building evidence suggesting that DTI of the CC may serve as an effective biomarker for the degree of TAI and potential cognitive dysfunction after traumatic injury to the brain. 44,51,53,[77][78][79] In addition to being a surrogate marker of general injury severity and outcome after TBI, increasing evidence suggests that reduced microstructural integrity of particular callosal subregions differentially predicts particular cognitive deficits.…”

Section: Discussionsupporting

confidence: 89%

Working Memory and Corpus Callosum Microstructural Integrity after Pediatric Traumatic Brain Injury: A Diffusion Tensor Tractography Study

Treble

Hasan

Iftikhar

et al. 2013

Journal of Neurotrauma

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Deficits in working memory (WM) are a common consequence of pediatric traumatic brain injury (TBI) and are believed to contribute to difficulties in a range of cognitive and academic domains. Reduced integrity of the corpus callosum (CC) after TBI may disrupt the connectivity between bilateral frontoparietal neural networks underlying WM. In the present investigation, diffusion tensor imaging (DTI) tractography of eight callosal subregions (CC1-CC8) was examined in relation to measures of verbal and visuospatial WM in 74 children sustaining TBI and 49 typically developing comparison children. Relative to the comparison group, children with TBI demonstrated poorer visuospatial WM, but comparable verbal WM. Microstructure of the CC was significantly compromised in brain-injured children, with lower fractional anisotropy (FA) and higher axial and radial diffusivity metrics in all callosal subregions. In both groups of children, lower FA and/or higher radial diffusivity in callosal subregions connecting anterior and posterior parietal cortical regions predicted poorer verbal WM, whereas higher radial diffusivity in callosal subregions connecting anterior and posterior parietal, as well as temporal, cortical regions predicted poorer visuospatial WM. DTI metrics, especially radial diffusivity, in predictive callosal subregions accounted for significant variance in WM over and above remaining callosal subregions. Reduced microstructural integrity of the CC, particularly in subregions connecting parietal and temporal cortices, may act as a neuropathological mechanism contributing to long-term WM deficits. The future clinical use of neuroanatomical biomarkers may allow for the early identification of children at highest risk for WM deficits and earlier provision of interventions for these children.

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Section: Discussionsupporting

confidence: 89%

Working Memory and Corpus Callosum Microstructural Integrity after Pediatric Traumatic Brain Injury: A Diffusion Tensor Tractography Study

Treble

Hasan

Iftikhar

et al. 2013

Journal of Neurotrauma

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“…Cerebral white matter has a particular vulnerability in traumatic brain injury (TBI) [1]. In the chronic phase of TBI, abnormal white matter integrity reflects the severity of initial injury.…”

Section: Introductionmentioning

confidence: 99%

“…To date, there have been a number of reports of CC vulnerability in paediatric TBI [1]. CC atrophy may be due to (1) the direct effect of the primary injury, (2) the effect of impaired cerebral perfusion at the time of critical illness, (3) impaired development during subsequent recovery, or (4) any combination of these mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Corpus Callosum and Inferior Forebrain White Matter Microstructure Are Related to Functional Outcome from Raised Intracranial Pressure in Child Traumatic Brain Injury

Tasker¹,

Westland²,

White

et al. 2010

Dev Neurosci

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In severe paediatric traumatic brain injury (TBI), a common focus of treatment is raised intracranial pressure (ICP). We have previously reported frontal cerebral vulnerability with executive deficits from raised ICP in paediatric TBI. Now, using diffusion tensor imaging (DTI) in a different population, we have examined fractional anisotropy (FA), and mean, axial and radial diffusivity (MD, AD, RD) in 4 regions of the corpus callosum (CC) and in both inferior frontal regions. Our aim was to examine during the chronic phase of TBI whether the CC cross-sectional area correlated with regional DTI metrics of white matter microstructure, with global outcome ratings of function (Functional Independence Measure and Multiattribute Health Status Classification) and with performance in the Rey-Osterrieth Complex Figure (ROCF) test. We examined 33 paediatric TBI cases who were followed, on average, 4.9 years after severe injury. All cases had received mechanical ventilation during their acute treatment and, a priori, they were assigned to a non-ICP or a raised ICP group. Twenty-two participants had mainly right-sided injury at the time of acute ictus. The findings confirm that severe TBI in childhood, complicated by intracranial hypertension, results in CC vulnerability. In the chronic phase of recovery, it is reduced in the cross-sectional area, it is more compact and thinned, and the anterior region is disproportionately small. Late after raised ICP, we have also found that individuals exhibit regional microstructural abnormality with combined reduced FA and increased MD, AD and RD. Smaller size and such microstructural changes in the anterior CC were associated with similar right-sided (rather than left-sided) frontal microstructural changes in the ICP group. Taken together, this evidence points to an interaction between raised ICP-related brain tissue perturbation and focal frontal extracallosal injury, leading to anterior CC regional vulnerability, most likely wallerian degeneration. At long-term follow-up, this lack of white matter integrity in the anterior CC is correlated with functional outcome, particularly in aspects of social interaction and the copy component of the ROCF test, which suggests that the CC-to-forebrain function warrants further study in chronic TBI.

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“…Traumatic brain injury (TBI) is a major cause of death and disability in children 2,3 and can have devastating consequences on a wide range of cognitive domains. 4 Focal as well as diffuse brain changes have been observed after TBI, including long-term white matter alterations 5,6 that can be now be revealed using diffusion-weighted imaging (DWI). [7][8][9][10][11] Among children with moderate and severe TBI, approximately 20% may have chronic dysarthria, 12 which can affect speech across articulation, respiration, phonation, prosody, and resonance.…”

mentioning

confidence: 99%

Corticobulbar tract changes as predictors of dysarthria in childhood brain injury

et al. 2013

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Objectives: To identify corticobulbar tract changes that may predict chronic dysarthria in young people who have sustained a traumatic brain injury (TBI) in childhood using diffusion MRI tractography. Methods:We collected diffusion-weighted MRI data from 49 participants. We compared 17 young people (mean age 17 years, 10 months; on average 8 years postinjury) with chronic dysarthria who sustained a TBI in childhood (range 3-16 years) with 2 control groups matched for age and sex: 1 group of young people who sustained a traumatic injury but had no subsequent dysarthria (n 5 15), and 1 group of typically developing individuals (n 5 17). We performed tractography from spherical seed regions within the precentral gyrus white matter to track: 1) the hand-related corticospinal tract; 2) the dorsal corticobulbar tract, thought to correspond to the lips/larynx motor representation; and 3) the ventral corticobulbar tract, corresponding to the tongue representation.Results: Despite widespread white matter damage, radial (perpendicular) diffusivity within the left dorsal corticobulbar tract was the best predictor of the presence of dysarthria after TBI. Diffusion metrics in this tract also predicted speech and oromotor performance across the whole group of TBI participants, with additional significant contributions from ventral speech tract volume in the right hemisphere.Conclusion: An intact left dorsal corticobulbar tract seems crucial to the normal execution of speech long term after acquired injury. Examining the speech-related motor pathways using diffusion-weighted MRI tractography offers a promising prognostic tool for people with acquired, developmental, or degenerative neurologic conditions likely to affect speech. Recent advances in diffusion-weighted MRI analyses now allow the in vivo reconstruction of white matter pathways in the human brain using tractography.1 Although speech is vulnerable to numerous neurologic conditions, the association between speech disorders and integrity of the corticobulbar tracts is rarely examined. Traumatic brain injury (TBI) is a major cause of death and disability in children 2,3 and can have devastating consequences on a wide range of cognitive domains. 4 Focal as well as diffuse brain changes have been observed after TBI, including long-term white matter alterations 5,6 that can be now be revealed using diffusion-weighted imaging (DWI).7-11 Among children with moderate and severe TBI, approximately 20% may have chronic dysarthria, 12 which can affect speech across articulation, respiration, phonation, prosody, and resonance. Given the potential for functional reorganization seen in the immature brain, 6,13,14 studies in the chronic stage are crucial to unravel the neural basis of those deficits that do persist long term after TBI in childhood. Because a recent review indicated that damage along the corticobulbar/corticospinal tracts was a common feature in children with dysarthria, 15 we used tractography to test the

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Changes in White Matter Late after Severe Traumatic Brain Injury in Childhood

Cited by 39 publications

References 102 publications

Working Memory and Corpus Callosum Microstructural Integrity after Pediatric Traumatic Brain Injury: A Diffusion Tensor Tractography Study

Working Memory and Corpus Callosum Microstructural Integrity after Pediatric Traumatic Brain Injury: A Diffusion Tensor Tractography Study

Corpus Callosum and Inferior Forebrain White Matter Microstructure Are Related to Functional Outcome from Raised Intracranial Pressure in Child Traumatic Brain Injury

Corticobulbar tract changes as predictors of dysarthria in childhood brain injury

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