scholarly journals Age, Sex and Cerebral Microbleed Effects On White Matter Degradation After Traumatic Brain Injury

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 886-887
Author(s):  
Andrei Irimia ◽  
Ammar Dharani ◽  
Van Ngo ◽  
David Robles ◽  
Kenneth Rostowsky
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Diffusion Tensor ◽  
Diffuse Axonal Injury ◽  
Principal Component ◽  
Older Age ◽  
Analysis Of Covariance ◽  
Future Research ◽  
Cerebral Microbleed

Abstract Mild traumatic brain injury (mTBI) affects white matter (WM) integrity and accelerates neurodegeneration. This study assesses the effects of age, sex, and cerebral microbleed (CMB) load as predictors of WM integrity in 70 subjects aged 18-77 imaged acutely and ~6 months after mTBI using diffusion tensor imaging (DTI). Two-tensor unscented Kalman tractography was used to segment and cluster 73 WM structures and to map changes in their mean fractional anisotropy (FA), a surrogate measure of WM integrity. Dimensionality reduction of mean FA feature vectors was implemented using principal component (PC) analysis, and two prominent PCs were used as responses in a multivariate analysis of covariance. Acutely and chronically, older age was significantly associated with lower FA (F2,65 = 8.7, p < .001, η2 = 0.2; F2,65 = 12.3, p < .001, η2 = 0.3, respectively), notably in the corpus callosum and in dorsolateral temporal structures, confirming older adults’ WM vulnerability to mTBI. Chronically, sex was associated with mean FA (F2,65 = 5.0, p = 0.01, η2 = 0.1), indicating males’ greater susceptibility to WM degradation. Acutely, a significant association was observed between CMB load and mean FA (F2,65 = 5.1, p = 0.009, η2 = 0.1), suggesting that CMBs reflect the acute severity of diffuse axonal injury. Together, these findings indicate that older age, male sex, and CMB load are risk factors for WM degeneration. Future research should examine how sex- and age-mediated WM degradation lead to cognitive decline and connectome degeneration after mTBI.

281 Predicting neurodegeneration after traumatic brain injury

2018 ◽  
Vol 89 (10) ◽  
pp. A42.1-A42
Author(s):  
Graham Neil SN ◽  
Jolly Amy E ◽  
Bourke Niall J ◽  
Scott Gregory ◽  
Cole James H ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Brain Atrophy ◽  
Diffusion Tensor ◽  
Chronic Traumatic Encephalopathy ◽  
Axonal Injury ◽  
Diffuse Axonal Injury ◽  
Jacobian Determinant ◽  
Post Injury

BackgroundDementia rates are elevated after traumatic brain injury (TBI) and a subgroup develops chronic traumatic encephalopathy. Post-traumatic neurodegeneration can be measured by brain atrophy rates derived from neuroimaging, but it is unclear how atrophy relates to the initial pattern of injury.ObjectivesTo investigate the relationship between baseline TBI patterns and subsequent neurodegeneration measured by progressive brain atrophy.Methods55 patients after moderate-severe TBI (mean 3 years post-injury) and 20 controls underwent longitudinal MRI. Brain atrophy was quantified using the Jacobian determinant defined from volumetric T1 scans approximately one year apart. Diffuse axonal injury was measured using diffusion tensor imaging and focal injuries defined from T1 and FLAIR. Neuropsychological assessment was performed.ResultsAbnormal progressive brain atrophy was seen after TBI (~1.8%/year in white matter). This was accompanied by widespread reductions in fractional anisotropy, in keeping with the presence of diffuse axonal injury. There was a strong negative correlation between FA and brain atrophy, whereby areas of greater white matter damage showed greater atrophy over time.ConclusionsThe results show a strong relationship between the location of diffuse axonal injury and subsequent neurodegeneration. This suggests that TBI triggers progressive neurodegeneration through the long-lasting effects of diffuse axonal injury.

scholarly journals GERIATRIC TRAUMATIC BRAIN INJURY AND ALZHEIMER’S DISEASE SHARE SIMILAR PATTERNS OF WHITE MATTER DEGRADATION

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S96-S96
Author(s):  
Andrei Irimia ◽  
Kenneth Rostowsky ◽  
Nikhil Chaudhari ◽  
Maria Calvillo ◽  
Sean Lee
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Corpus Callosum ◽  
Diffusion Tensor ◽  
Future Research ◽  
Post Injury ◽  
Significant Difference

Abstract Although mild traumatic brain injury (mTBI) and Alzheimer’s disease (AD) are associated with white matter (WM) degradation, the nature of these alterations and the outcomes of their comparison have not been elucidated. Diffusion tensor imaging (DTI) has been utilized in both conditions, and has uncovered decreases in the fractional anisotropy (FA) of the corpus callosum and cingulum bundle, compared to healthy control (HC) volunteers [1, 2]. Despite mTBI being a potential risk factor for AD, no systematic quantitative comparison has been drawn between their WM degradation patterns. Here we investigated WM FA differences using DTI and tract-based spatial statistics (TBSS) between age- and sex-matched adults: 33 chronic mTBI patients, 67 AD patients and 81 HC participants. T1-weighted magnetic resonance imaging (MRI) and DTI were acquired at 3T. mTBI patients were scanned acutely and ~6 months post-injury. FSL software was used for artefact correction, FA computation and TBSS implementation. Statistical comparison of WM FA patterns between mTBI and AD patients was achieved by two one-sided t tests (TOSTs) of statistical equivalence, with equivalence bounds defined where Cohen’s d < 0.3. A significant difference was found between the FA means of mTBI vs. HC groups, and the AD vs. HC groups (p < 0.01, corrected). Mean FA differences between mTBI and AD were statistically equivalent in the corpus callosum and in the inferior longitudinal fasciculus (p < 0.05, corrected). Future research should focus on clarifying the similarities between mTBI and AD, potentially leading to novel hypotheses and improved AD diagnosis.

scholarly journals White matter and neurocognitive changes in adults with chronic traumatic brain injury

2009 ◽  
Vol 15 (1) ◽  
pp. 130-136 ◽  
Author(s):  
MARY R.T. KENNEDY ◽  
JEFFREY R. WOZNIAK ◽  
RYAN L. MUETZEL ◽  
BRYON A. MUELLER ◽  
HSIN-HUEI CHIOU ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Cognitive Impairment ◽  
Brain Injury ◽  
White Matter ◽  
Diffusion Tensor ◽  
Mean Diffusivity ◽  
Analysis Of Covariance ◽  
Severely Injured ◽  
Motor Speed ◽  
Time Since Injury

AbstractDiffusion tensor imaging was used to investigate white matter (WM) integrity in adults with traumatic brain injury (TBI) and healthy adults as controls. Adults with TBI had sustained severe vehicular injuries on the average of 7 years earlier. A multivariate analysis of covariance with verbal IQ as the covariate revealed that adults with TBI had lower fractional anisotropy and higher mean diffusivity than controls, specifically in the three regions of interest (ROIs), the centrum semiovale (CS), the superior frontal (SPF), and the inferior frontal (INF). Adults with TBI averaged in the normal range in motor speed and two of three executive functions and were below average in delayed verbal recall and inhibition, whereas controls were above average. Time since injury, but not age, was associated with WM changes in the SPF ROI, whereas age, but not time since injury, was associated with WM changes in the INF ROI, suggesting that the effects of WM on time since injury may interact with age. To understand the utility of WM changes in chronic recovery, larger sample sizes are needed to investigate associations between cognition and WM integrity of severely injured individuals who have substantial cognitive impairment compared to severely injured individuals with little cognitive impairment. (JINS, 2009, 15, 130–136.)

scholarly journals The evolution of white matter microstructural changes after mild traumatic brain injury: A longitudinal DTI and NODDI study

2020 ◽  
Vol 6 (32) ◽  
pp. eaaz6892 ◽  
Author(s):  
E. M. Palacios ◽  
J. P. Owen ◽  
E. L. Yuh ◽  
M. B. Wang ◽  
M. J. Vassar ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Mild Traumatic Brain Injury ◽  
Diffusion Tensor ◽  
Diffuse Axonal Injury ◽  
Mean Diffusivity ◽  
Free Water ◽  
Long Term Outcome ◽  
Microstructural Changes

Neuroimaging biomarkers that can detect white matter (WM) pathology after mild traumatic brain injury (mTBI) and predict long-term outcome are needed to improve care and develop therapies. We used diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) to investigate WM microstructure cross-sectionally and longitudinally after mTBI and correlate these with neuropsychological performance. Cross-sectionally, early decreases of fractional anisotropy and increases of mean diffusivity corresponded to WM regions with elevated free water fraction on NODDI. This elevated free water was more extensive in the patient subgroup reporting more early postconcussive symptoms. The longer-term longitudinal WM changes consisted of declining neurite density on NODDI, suggesting axonal degeneration from diffuse axonal injury for which NODDI is more sensitive than DTI. Therefore, NODDI is a more sensitive and specific biomarker than DTI for WM microstructural changes due to mTBI that merits further study for mTBI diagnosis, prognosis, and treatment monitoring.

scholarly journals Neuropsychological Recovery Trajectories in Moderate to Severe Traumatic Brain Injury: Influence of Patient Characteristics and Diffuse Axonal Injury

2017 ◽  
Vol 24 (3) ◽  
pp. 237-246 ◽  
Author(s):  
Amanda R. Rabinowitz ◽  
Tessa Hart ◽  
John Whyte ◽  
Junghoon Kim
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Severe Traumatic Brain Injury ◽  
Diffusion Tensor ◽  
Verbal Learning ◽  
Axonal Injury ◽  
Diffuse Axonal Injury ◽  
Cognitive Change ◽  
Future Research ◽  
Cognitive Domains

AbstractObjectives: The goal of the present study was to elucidate the influence of demographic and neuropathological moderators on the longitudinal trajectory neuropsychological functions during the first year after moderate to severe traumatic brain injury (TBI). In addition to examining demographic moderators such as age and education, we included a measure of whole-brain diffuse axonal injury (DAI), and examined measures of processing speed (PS), executive function (EF), and verbal learning (VL) separately. Methods: Forty-six adults with moderate to severe TBI were examined at 3, 6, and 12 months post-injury. Participants underwent neuropsychological evaluation and neuroimaging including diffusion tensor imaging. Using linear mixed effects modeling, we examined longitudinal trajectories and moderating factors of cognitive outcomes separately for three domains: PS, VL, and EF. Results: VL and EF showed linear improvements, whereas PS exhibited a curvilinear trend characterized by initial improvements that plateaued or declined, depending on age. Age moderated the recovery trajectories of EF and PS. Education and DAI did not influence trajectory but were related to initial level of functioning for PS and EF in the case of DAI, and all three cognitive domains in the case of education. Conclusions: We found disparate recovery trajectories across cognitive domains. Younger age was associated with more favorable recovery of EF and PS. These findings have both clinical and theoretical implications. Future research with a larger sample followed over a longer time period is needed to further elucidate the factors that may influence cognitive change over the acute to chronic period after TBI. (JINS, 2018, 24, 237–246)

scholarly journals Acute mild traumatic brain injury is not associated with white matter change on diffusion tensor imaging

Brain ◽  
2014 ◽  
Vol 137 (7) ◽  
pp. 1876-1882 ◽  
Author(s):  
Tero Ilvesmäki ◽  
Teemu M. Luoto ◽  
Ullamari Hakulinen ◽  
Antti Brander ◽  
Pertti Ryymin ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Diffusion Tensor Imaging ◽  
Brain Injury ◽  
White Matter ◽  
Mild Traumatic Brain Injury ◽  
Diffusion Tensor ◽  
White Matter Change

The Use of a Cellular Strain Injury Criterion and Diffusion Tensor Imaging in a Computational Model of Traumatic Brain Injury

2010 ◽  
Author(s):  
Rika M. Wright ◽  
K. T. Ramesh
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Mechanical Loading ◽  
Computational Models ◽  
Diffusion Tensor ◽  
Diffuse Axonal Injury ◽  
Element Model ◽  
Cellular Level ◽  
Cellular Injury ◽  
Injury Mechanisms

With the increase in the number of soldiers sustaining traumatic brain injury from military incidents and the recent attention on sports related traumatic brain injury, there has been a focused effort to develop preventative and treatment methods for traumatic brain injury (TBI). Traumatic brain injury is caused by mechanical loading to the head, such as from impacts, sudden accelerations, or blast loading, and the pathology can range from focal damage in the brain to widespread diffuse injury [1]. In this study, we investigate the injury mechanisms of diffuse axonal injury (DAI), which accounts for the second largest percentage of deaths due to brain trauma [2]. DAI is caused by sudden inertial loads to the head, and it is characterized by damage to neural axons. Despite the extensive research on DAI, the coupling between the mechanical loading to the head and the damage at the cellular level is still poorly understood. Unlike previous computational models that use macroscopic stress and strain measures to determine injury, a cellular injury criterion is used in this work as numerous studies have shown that cellular strain can be related to the functional damage of neurons. The effectiveness of using this cellular injury criterion to predict damage in a finite element model of DAI is investigated.

scholarly journals Diffusion Tensor Imaging of the Evolving Response to Mild Traumatic Brain Injury in Rats

2019 ◽  
Vol 13 ◽  
pp. 117906951985862 ◽  
Author(s):  
Wouter S Hoogenboom ◽  
Todd G Rubin ◽  
Kenny Ye ◽  
Min-Hui Cui ◽  
Kelsey C Branch ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Diffusion Tensor Imaging ◽  
Brain Injury ◽  
White Matter ◽  
Mild Traumatic Brain Injury ◽  
Diffusion Tensor ◽  
Axonal Injury ◽  
Mean Diffusivity ◽  
Multiple Time ◽  
Post Injury

Mild traumatic brain injury (mTBI), also known as concussion, is a serious public health challenge. Although most patients recover, a substantial minority suffers chronic disability. The mechanisms underlying mTBI-related detrimental effects remain poorly understood. Although animal models contribute valuable preclinical information and improve our understanding of the underlying mechanisms following mTBI, only few studies have used diffusion tensor imaging (DTI) to study the evolution of axonal injury following mTBI in rodents. It is known that DTI shows changes after human concussion and the role of delineating imaging findings in animals is therefore to facilitate understanding of related mechanisms. In this work, we used a rodent model of mTBI to investigate longitudinal indices of axonal injury. We present the results of 45 animals that received magnetic resonance imaging (MRI) at multiple time points over a 2-week period following concussive or sham injury yielding 109 serial observations. Overall, the evolution of DTI metrics following concussive or sham injury differed by group. Diffusion tensor imaging changes within the white matter were most noticeable 1 week following injury and returned to baseline values after 2 weeks. More specifically, we observed increased fractional anisotropy in combination with decreased radial diffusivity and mean diffusivity, in the absence of changes in axial diffusivity, within the white matter of the genu corpus callosum at 1 week post-injury. Our study shows that DTI can detect microstructural white matter changes in the absence of gross abnormalities as indicated by visual screening of anatomical MRI and hematoxylin and eosin (H&E)-stained sections in a clinically relevant animal model of mTBI. Whereas additional histopathologic characterization is required to better understand the neurobiological correlates of DTI measures, our findings highlight the evolving nature of the brain’s response to injury following concussion.

scholarly journals Elevated Intraindividual Variability in Executive Functions and Associations with White Matter Microstructure in Veterans with Mild Traumatic Brain Injury

2020 ◽  
pp. 1-10
Author(s):  
Scott F. Sorg ◽  
Victoria C. Merritt ◽  
Alexandra L. Clark ◽  
Madeleine L. Werhane ◽  
Kelsey A. Holiday ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
White Matter ◽  
Executive Functions ◽  
Mild Traumatic Brain Injury ◽  
Diffusion Tensor ◽  
Intraindividual Variability ◽  
Ptsd Symptoms ◽  
White Matter Microstructure ◽  
History Of

Abstract Objective: We examined whether intraindividual variability (IIV) across tests of executive functions (EF-IIV) is elevated in Veterans with a history of mild traumatic brain injury (mTBI) relative to military controls (MCs) without a history of mTBI. We also explored relationships among EF-IIV, white matter microstructure, and posttraumatic stress disorder (PTSD) symptoms. Method: A total of 77 Veterans (mTBI = 43, MCs = 34) completed neuropsychological testing, diffusion tensor imaging (DTI), and PTSD symptom ratings. EF-IIV was calculated as the standard deviation across six tests of EF, along with an EF-Mean composite. DSI Studio connectometry analysis identified white matter tracts significantly associated with EF-IIV according to generalized fractional anisotropy (GFA). Results: After adjusting for EF-Mean and PTSD symptoms, the mTBI group showed significantly higher EF-IIV than MCs. Groups did not differ on EF-Mean after adjusting for PTSD symptoms. Across groups, PTSD symptoms significantly negatively correlated with EF-Mean, but not with EF-IIV. EF-IIV significantly negatively correlated with GFA in multiple white matter pathways connecting frontal and more posterior regions. Conclusions: Veterans with mTBI demonstrated significantly greater IIV across EF tests compared to MCs, even after adjusting for mean group differences on those measures as well as PTSD severity. Findings suggest that, in contrast to analyses that explore effects of mean performance across tests, discrepancy analyses may capture unique variance in neuropsychological performance and more sensitively capture cognitive disruption in Veterans with mTBI histories. Importantly, findings show that EF-IIV is negatively associated with the microstructure of white matter pathways interconnecting cortical regions that mediate executive function and attentional processes.

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