Journal of neurotrauma
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Journal of neurotrauma · Jan 2019
In-Season Variations in Head Impact Exposure among Youth Football Players.
Head impact exposure (HIE) is often summarized by the total exposure measured during the season and does not indicate how the exposure was accumulated, or how it varied during the season. Therefore, the objective of this study was to compare HIE during pre-season, the first and second halves of the regular season, and playoffs in a sample of youth football players (n = 119, aged 9-13 years). Athletes were divided into one of four exposure groups based on quartiles computed from the distribution of risk-weighted cumulative exposure (RWECP). ⋯ Time of season had a significant relationship with mean 95th percentile linear and rotational acceleration in games (both, p = 0.01) but not with practice accelerations or impacts per session. The in-practice mean levels of 95th percentile linear and rotational acceleration remained fairly constant across the four time frames, but in games these changed over time depending on exposure group (interactions, p ≤ 0.05). The results of this study improve our understanding of in-season variations in HIE in youth football and may inform important opportunities for future interventions.
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Journal of neurotrauma · Jan 2019
Orthopedic Injured versus Uninjured Comparison Groups for Neuroimaging Research in Mild Traumatic Brain Injury.
To address controversy surrounding the most appropriate comparison group for mild traumatic brain injury (mTBI) research, mTBI patients 12-30 years of age were compared with an extracranial orthopedic injury (OI) patient group and an uninjured, typically developing (TD) participant group with comparable demographic backgrounds. Injured participants underwent subacute (within 96 h) and late (3 months) diffusion tensor imaging (DTI); TD controls underwent DTI once. Group differences in fractional anisotropy (FA) and mean diffusivity (MD) of commonly studied white matter tracts were assessed. ⋯ The mTBI and OI groups had generally similar longitudinal results. Findings suggest that different conclusions about group-level DTI analyses could be drawn, depending on the selected comparison group, highlighting the need for additional research in this area. Where possible, mTBI studies may benefit from the inclusion of both OI and TD controls.
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Journal of neurotrauma · Jan 2019
Neurostimulant prescribing patterns in children admitted to the ICU after traumatic brain injury.
Neurostimulant medications are commonly prescribed following traumatic brain injury (TBI) in adults; little is known about their use in children with TBI. Our objective was to analyze neurostimulant prescribing practices from 2005 to 2015 in children admitted to the intensive care unit (ICU) with TBI. We hypothesized that neurostimulant prescriptions have increased over time and are associated with older age and injury severity. ⋯ In a multi-variable analysis, variables most strongly associated with receipt of a neurostimulant were age 14-18 years (odds ratio 5.8, 95% confidence interval [4.3,7.8]), motor vehicle collision (3.1, [2.4,4.2]), intracranial pressure (ICP) monitor (3.8, [3.1,4.5]), and mechanical ventilation (3.4, [2.7,4.3]). Use of neurostimulants following pediatric TBI is uncommon, has increased over time, and is associated with indicators of higher severity of illness. Knowledge of prescribing practices may assist in optimizing the design of efficacy and outcome studies that will inform clinical guidelines.
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Journal of neurotrauma · Jan 2019
White Matter Anisotropy for Impact Simulation and Response Sampling in Traumatic Brain Injury.
Advanced neuroimaging provides new opportunities to enhance head injury models, including the incorporation of white matter (WM) structural anisotropy. Information from high-resolution neuroimaging, however, usually has to be "down-sampled" to match a typically coarse brain mesh. To understand how this mesh-image resolution mismatch affects impact simulation and subsequent response sampling, we compared three competing anisotropy implementations (using either voxels, tractography, or a multiscale submodeling) and two response sampling strategies (element-wise or tractography-based, using brain mesh or neuroimaging for region segmentation, respectively). ⋯ Brain strain responses were also parametrically found to be closer to that from minimum fiber reinforcement, consistent with the fact that the majority of WM had a rather high degree of fiber dispersion. Finally, the upgraded Worcester Head Injury Model incorporating WM anisotropy was successfully re-validated against cadaveric impacts and an in vivo head rotation ("good" to "excellent" validation with an average Correlation Analysis score of 0.437 and 0.509, respectively). These investigations may facilitate further continual development of head injury models to better study traumatic brain injury.
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Journal of neurotrauma · Jan 2019
Acute Inflammatory Biomarker Responses to Diffuse Traumatic Brain Injury in the Rat Monitored by a Novel Microdialysis Technique.
Neuroinflammation is a major contributor to the progressive brain injury process induced by traumatic brain injury (TBI), and may play an important role in the pathophysiology of axonal injury. The immediate neuroinflammatory cascade cannot be characterized in the human setting. Therefore, we used the midline fluid percussion injury model of diffuse TBI in rats and a novel microdialysis (MD) method providing stable diffusion-driven biomarker sampling. ⋯ Therefore, diffuse TBI was associated with an increased level of 18 of the 27 inflammatory biomarkers at one through six time points, during the observation period whereas the remaining 9 biomarkers were unaltered. The study shows that diffuse TBI induces an acute increase in a number of inflammatory biomarkers. The novel MD technique provides stable MD sampling suitable for further studies on the early neuroinflammatory cascade in TBI.