Journal of neurotrauma
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Journal of neurotrauma · Feb 2021
Association of Head Impact Exposure with White Matter Macro- and Microstructure Metrics.
Prior studies have reported white matter abnormalities associated with a history of cumulative concussion and/or repetitive head impacts (RHI) in contact sport athletes. Growing evidence suggests these abnormalities may begin as more subtle changes earlier in life in active younger athletes. We investigated the relationship between prior concussion and contact sport exposure with multi-modal white matter microstructure and macrostructure using magnetic resonance imaging. ⋯ Concussion history was not significantly associated with QSM, DTI, DKI, or white matter volume (all, p 0.05). Cumulative contact sport exposure is associated with subtle differences in white matter microstructure, but not gross white matter macrostructure, in young active athletes. Longitudinal follow-up is required to assess the progression of these findings to determine their contribution to potential adverse effects later in life.
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Journal of neurotrauma · Feb 2021
Recovery Profiles Following Concussion Among Male Student-Athletes and Service Cadets with a Family History of Neurodegenerative Disease: Data from the NCAA-DOD CARE Consortium.
Preliminary evidence indicates that genetic factors associated with having a family history of neurodegenerative disease (fhNDD) may predispose an individual to persistent symptoms and poorer cognitive performance after concussion. No previous study, however, longitudinally examined athletes with (+) and without (-) a fhNDD. Therefore, we aimed to compare clinical symptoms and cognitive performance of fhNDD+ and fhNDD- athletes at baseline and at multiple time points after concussion. ⋯ Compared with fhNDD- athletes, fhNDD+ individuals demonstrated greater decrements in impulse control, 24-48 h post-injury, at the return to play, and at six-month assessments (p < 0.01, d = 0.23). These findings suggest that male athletes with a fhNDD may exhibit greater decrements in cognitive performance after concussion. Small, subtle deficits in cognitive performance may still significantly hinder day-to-day function in student-athletes.
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Journal of neurotrauma · Feb 2021
Early life stress preceding mild pediatric traumatic brain injury increases neuroinflammation but does not exacerbate impairment of cognitive flexibility during adolescence.
Early life stress (ELS) followed by pediatric mild traumatic brain injury (mTBI) negatively impacts spatial learning and memory and increases microglial activation in adolescent rats, but whether the same paradigm negatively affects higher order executive function is not known. Hence, we utilized the attentional set-shifting test (AST) to evaluate executive function (cognitive flexibility) and to determine its relationship with neuroinflammation and hypothalamic-pituitary-adrenal (HPA) axis activity after pediatric mTBI in male rats. ELS was induced via maternal separation for 180 min per day (MS180) during the first 21 post-natal (P) days, while controls (CONT) were undisturbed. ⋯ A significant correlation was observed in executive dysfunction and IL-1β expression in the ipsilateral pre-frontal cortex and hippocampus. Although the combination of ELS and pediatric mTBI did not worsen executive function beyond that of mTBI alone (p > 0.05), it did result in increased hippocampal neuroinflammation relative to mTBI (p < 0.05). These findings provide important insight into the susceptibility to incur alterations in cognitive and neuroimmune functioning after stress exposure and TBI during early life.
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Journal of neurotrauma · Feb 2021
Longitudinal characterization of blood-brain barrier permeability after experimental traumatic brain injury by in vivo 2-photon microscopy.
Vasogenic brain edema (VBE) formation remains an important factor determining the fate of patients with traumatic brain injury (TBI). The spatial and temporal development of VBE, however, remains poorly understood because of the lack of sufficiently sensitive measurement techniques. To close this knowledge gap, we directly visualized the full time course of vascular leakage after TBI by in vivo 2-photon microscopy (2-PM). ⋯ The rate of extravasation showed a biphasic pattern, peaking 4 h and 48-72 h after trauma. Taken together, longitudinal quantification of vascular leakage after TBI in vivo demonstrates that VBE formation after TBI develops in a biphasic manner suggestive of acute and delayed mechanisms. Further studies using the currently developed dynamic in vivo imaging modalities are needed to investigate these mechanisms and potential therapeutic strategies in more detail.
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Journal of neurotrauma · Feb 2021
Effects of norepinephrine, propofol and hemoglobin concentration on dynamic measurements of cerebrovascular reactivity in acute brain injury.
Effects of treatment-associated variables on cerebrovascular autoregulation (CA) in acute brain injury patients remain unclear. As deficient CA is associated with worse outcomes and ideas about CA-steered management are emerging, this question is relevant. We investigated effects of norepinephrine and propofol infusion rates and hemoglobin concentration on dynamic measurements of cerebrovascular reactivity as surrogate for CA. ⋯ No significant differences as function of age, gender, cardiovascular risk, brain comorbidity, GCS, pupil reactivity, and type of injury were found. Dynamic intracranial pressure-based measurements of cerebrovascular reactivity in acute brain injured patients are not affected by gradually adjusted norepinephrine or propofol infusion rates or slow changes in hemoglobin concentration within the typical ranges during ICU admission. Future trials on cerebrovascular reactivity-steered management and treatment of CA impairment may not have to take these variables into account.