Journal of neurotrauma
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Journal of neurotrauma · Apr 2017
Cognitive Deficits Post Traumatic Brain Injury and Their Association with Injury Severity and Gray Matter Volumes.
Traumatic brain injury (TBI) is known to have a substantial though highly variable impact on cognitive abilities. Due to the wide range of cognitive abilities among healthy individuals, an objective assessment of TBI-related cognitive loss requires an accurate measurement of pre-morbid cognitive performance. To address this problem, we recruited 50 adults who sustained a TBI and had performed a cognitive baseline assessment in adolescence as part of the aptitude tests mandated by the Israeli Defense Forces. ⋯ Mathematical reasoning was not affected by TBI. In the TBI patients, non-verbal abstract reasoning post-pre-injury change scores were negatively correlated with the volume of the insula. We conclude that access to pre-morbid neuropsychological data may have facilitated the discovery of the effects of mild TBI on abstract reasoning, as well as a significant correlation between TBI-related decline in this cognitive domain and the volume of the bilateral insula, both of which had not been appreciated in the past.
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Journal of neurotrauma · Apr 2017
Repetitive Model of Mild Traumatic Brain Injury Produces Cortical Abnormalities Detectable by Magnetic Resonance Diffusion Imaging (DTI/DKI), Histopathology, and Behavior.
Noninvasive detection of mild traumatic brain injury (mTBI) is important for evaluating acute through chronic effects of head injuries, particularly after repetitive impacts. To better detect abnormalities from mTBI, we performed longitudinal studies (baseline, 3, 6, and 42 days) using magnetic resonance diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) in adult mice after repetitive mTBI (r-mTBI; daily × 5) or sham procedure. This r-mTBI produced righting reflex delay and was first characterized in the corpus callosum to demonstrate low levels of axon damage, astrogliosis, and microglial activation, without microhemorrhages. ⋯ Using Thy1-YFP-16 mice to fluorescently label neuronal cell bodies and processes revealed low levels of axon damage in the cortex after r-mTBI. Finally, r-mTBI produced social deficits consistent with the function of this anterior cingulate region of cortex. Overall, vulnerability of cortical regions is demonstrated after mild repetitive injury, with underlying differences of DTI and DKI, microglial activation, and behavioral deficits.
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Journal of neurotrauma · Apr 2017
A clinically relevant closed-head model of single and repeat concussive injury in the adult rat using a controlled cortical impact device.
Repeat concussions (RC) can result in significant long-term neurological consequences and increased risk for neurodegenerative disease compared with single concussion (SC). Mechanisms underlying this difference are poorly understood and best elucidated using an animal model. To the best of our knowledge, there is no closed-head model in the adult rat using a commercially available device. ⋯ No obvious gross pathology was observed on the cortical surface or in coronal sections. Further examination showed thinning of the cortex and corpus callosum in RC animals compared with shams and increased axonal pathology in the corpus callosum of both SC and RC animals. Our data present a model of CHI that results in clinically relevant markers of concussion and an early differentiation between SC and RC.
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Journal of neurotrauma · Apr 2017
Social and behavioral outcomes following traumatic brain injury: What predicts outcome at 12 months post-insult?
This study sought to investigate social and behavioral outcomes 12 months following childhood traumatic brain injury (TBI) and to identify predictors of these outcomes. The study also compared rates of impairment in social and behavioral outcomes at 12 months post-injury between children with TBI and a typically developing (TD) control group. The study comprised 114 children ages 5.5 to 16.0 years, 79 with mild, moderate, or severe TBI and 35 TD children, group-matched for age, sex and socio-economic status. ⋯ Analysis of covariance models identified a significant mean difference between the mild and moderate groups for social problems only, but the moderate and severe TBI groups showed a higher rate of impairment, particularly in externalizing problems. Pre-injury function, injury severity, parent mental health, and child self-esteem all contributed significantly to predicting social and behavioral outcomes. Both injury and non-injury factors should be considered when identifying children at risk for long-term difficulties in social and behavioral domains.
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Journal of neurotrauma · Apr 2017
Structural and Functional Integrity of the Intraparietal Sulcus in Moderate and Severe Traumatic Brain Injury.
Severe and moderate traumatic brain injury (sTBI) often results in long-term cognitive deficits such as reduced processing speed and attention. The intraparietal sulcus (IPS) is a neocortical structure that plays a crucial role in the deeply interrelated processes of multi-sensory processing and top down attention. Therefore, we hypothesized that disruptions in the functional and structural connections of the IPS may play a role in the development of such deficits. ⋯ The patients also showed reduced structural integrity of the superior longitudinal fasciculus (SLF), a key white matter tract connecting the IPS to anterior frontal areas, as measured by reduced mean kurtosis (MK) and fractional anisotropy (FA) and increased mean diffusivity (MD). Further, this reduced structural integrity of the SLF was associated with a reduction in overall cognitive performance. These findings suggest that disruptions in the structural and functional connectivity of the IPS may contribute to chronic cognitive deficits experienced by these patients.