Journal of neurotrauma
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Journal of neurotrauma · Aug 2017
Evaluation of Head and Brain Injury Risk Functions using Sub-Injurious Human Volunteer Data.
Risk assessment models are developed to estimate the probability of brain injury during head impact using mechanical response variables such as head kinematics and brain tissue deformation. Existing injury risk functions have been developed using different datasets based on human volunteer and scaled animal injury responses to impact. However, many of these functions have not been independently evaluated with respect to laboratory-controlled human response data. ⋯ Kinematic-based head and brain injury risk probabilities were calculated directly from the kinematic data, while strain-based risks were determined through finite element model simulation of the 335 tests. Several injury risk functions substantially over predict the likelihood of concussion and diffuse axonal injury; proposed maximum principal strain-based injury risk functions predicted nearly 80 concussions and 14 cases of severe diffuse axonal injury out of the 335 non-injurious cases. This work is an important first step in assessing the efficacy of existing brain risk functions and highlights the need for more predictive injury assessment models.
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Journal of neurotrauma · Aug 2017
Randomized Controlled TrialNeck collar with mild jugular vein compression ameliorates brain activation changes during a working memory task after a season of high school football.
Emerging evidence indicates that repetitive head impacts, even at a sub-concussive level, may result in exacerbated or prolonged neurological deficits in athletes. This study aimed to: 1) quantify the effect of repetitive head impacts on the alteration of neuronal activity based on functional magnetic resonance imaging (fMRI) of working memory after a high school football season; and 2) determine whether a neck collar that applies mild jugular vein compression designed to reduce brain energy absorption in head impact through "slosh" mitigation can ameliorate the altered fMRI activation during a working memory task. Participants were recruited from local high school football teams with 27 and 25 athletes assigned to the non-collar and collar group, respectively. ⋯ Areas displaying less activation change in the collar group (corrected p < 0.05) included the precuneus, inferior parietal cortex, and dorsal lateral prefrontal cortex. Additionally, BOLD response in the non-collar group increased significantly in direct association with the total number of impacts and total g-force (p < 0.05). Our data provide initial neuroimaging evidence for the effect of repetitive head impacts on the working memory related brain activity, as well as a potential protective effect that resulted from the use of the purported brain slosh reducing neck collar in contact sports.
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Journal of neurotrauma · Aug 2017
Observational StudyImpaired Cognitive Performance in Youth Athletes Exposed to Repetitive Head Impacts.
Worldwide, more than 22 million children and adolescents are exposed to repetitive head impacts (RHI) in soccer. Evidence indicates cumulative effects on brain structure, but it is not known whether exposure to RHI affects cognitive improvement in adolescents. The aim of the study was to determine whether exposure to RHI while heading the ball in soccer affects improvement in cognitive performance in adolescents over time. ⋯ Further, the more long headers performed, the slower the improvement in RT over the season. Youth athletes experience an immediate cognitive improvement after training most likely because of physical exercise. Results of this study also suggest an association between exposure to specific RHI (long headers) and lack of improvement in cognitive performance in youth athletes over time.
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Journal of neurotrauma · Aug 2017
ReviewDNA methylation: Basic biology and application to traumatic brain injury.
This article reviews the literature pertinent to epigenetic changes, and in particular, DNA methylation following traumatic brain injury (TBI). TBI is a heterogeneous disease that is a major cause of death and long-term disability. The links between TBI and epigenetics, the process by which environmental factors alter gene expression without changing the underlying DNA sequence, is an expanding area of research that may have profound consequences for understanding the disease, and for clinical care. ⋯ Here, we briefly describe the interaction of DNA methylation with the two other key epigenetic changes, and highlight key work being performed to understand the functional relevance of those mechanisms. The field of epigenetics is rapidly advancing as a result of the advent of less invasive and more versatile methods for measuring epigenetic proteins and their functional impact on cells; however, the evidence specific to TBI is limited. This review identifies several important outstanding questions that remain from the work already conducted, and highlights directions for the future.
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Journal of neurotrauma · Aug 2017
Mild and mild to moderate traumatic brain injury (TBI)-induced significant progressive and enduring multiple comorbidities.
Traumatic brain injury (TBI) can produce life-long disabilities, including anxiety, cognitive, balance, and motor deficits. The experimental model of closed head TBI (cTBI) induced by weight drop/impact acceleration is known to produce hallmark TBI injuries. However, comprehensive long-term characterization of comorbidities induced by graded mild-to- mild/moderate intensities using this experimental cTBI model has not been reported. ⋯ A natural hypothesis would pose that all disabilities would increase incrementally relative to injury severity. Surprisingly, anxiety disability progressed over time to be greater in the mildest injury. Collectively, translational implications of these observations suggest that patients with mild TBI should be evaluated longitudinally at multiple time points, and that anxiety disorder could potentially have a particularly low threshold for appearance and progressively worsen post-injury.