Annals of biomedical engineering
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One football season of sub-concussive head blows has been shown to be associated with subclinical white matter (WM) changes on diffusion tensor imaging (DTI). Prior research analyses of helmet-based impact metrics using mean and peak linear and rotational acceleration showed relatively weak correlations to these WM changes; however, these analyses failed to account for the emerging concept that neuronal vulnerability to successive hits is inversely related to the time between hits (TBH). To develop a novel method for quantifying the cumulative effects of sub-concussive head blows during a single season of collegiate football by weighting helmet-based impact measures for time between helmet impacts. ⋯ A novel method for weighting cumulative helmet-based impact measures summed over the course of a football season resulted in a marked improvement in the correlation to brain WM changes observed after a single football season of sub-concussive head blows. Our results lend support to the emerging concept that sub-concussive head blows can result in sub-clinical brain injury, and this may be influenced by the time between hits. If confirmed in an independent data set, our novel method for quantifying the cumulative effects of sub-concussive head blows could be used to develop threshold-based countermeasures to prevent the accumulation of WM changes with multiple seasons of play.
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Numerous injury criteria have been developed to predict brain injury using the kinematic response of the head during impact. Each criterion utilizes a metric that is some mathematical combination of the velocity and/or acceleration components of translational and/or rotational head motion. Early metrics were based on linear acceleration of the head, but recent injury criteria have shifted towards rotational-based metrics. ⋯ Correlations between brain strain and metrics based on angular velocity were highest among those evaluated, while metrics based on linear acceleration were least correlative. BrIC and RVCI were the kinematic metrics with the highest overall correlation; however, each metric had limitations in certain impact conditions. The results of this study suggest that rotational head kinematics are the most important parameters for brain injury criteria.
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Subarachnoid hemorrhage (SAH) mostly occurs following the rupture of cerebral aneurysm causing blood to leak into the cranial subarachnoid space (SAS). Hemorrhage volume has been linked to the development of secondary vasospasm. Therefore, eliminating blood contaminants from the cerebrospinal fluid (CSF) space after the initial hemorrhage could improve patient outcomes and prevent the development of vasospasm. ⋯ Bench-top experiments and CFD simulations identify body position and drainage rates as key parameters for effective blood clearance. The study findings suggest the importance of treatment in upright position to maximize contaminant diversion from the cranial CSF compartment. The bench-top CNS model together with the validated CFD predictions of lumbar drainage systems can serve to optimize subject-specific treatment options for SAH patients.