Journal of neurotrauma
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Journal of neurotrauma · Jul 2017
Inter-Subject Variability of Axonal Injury in Diffuse Traumatic Brain Injury.
Traumatic brain injury (TBI) is a leading cause of cognitive morbidity worldwide for which reliable biomarkers are needed. Diffusion tensor imaging (DTI) is a promising biomarker of traumatic axonal injury (TAI); however, existing studies have been limited by a primary reliance on group-level analytic methods not well suited to account for inter-subject variability. In this study, 42 adults with TBI of at least moderate severity were examined 3 months following injury and compared with 35 healthy controls. ⋯ In moderate-to-severe TBI, there is substantial inter-subject variation in TAI, with extent strongly correlated to post-traumatic deficits in processing speed. Significant group-level effects do not necessarily represent consistent effects at the individual level. Better accounting for inter-subject variability in neurobiological manifestations of TBI may substantially improve the ability to detect and classify patterns of injury.
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Journal of neurotrauma · Jul 2017
HYPERTENSION-INDUCED ENHANCED MYOGENIC CONSTRICTION OF CEREBRAL ARTERIES IS PRESERVED AFTER TRAUMATIC BRAIN INJURY.
Traumatic brain injury (TBI) was shown to impair pressure-induced myogenic response of cerebral arteries, which is associated with vascular and neural dysfunction and increased mortality of TBI patients. Hypertension was shown to enhance myogenic tone of cerebral arteries via increased vascular production of 20-hydroxyeicosatrienoic acid (HETE). This adaptive mechanism protects brain tissue from pressure/volume overload; however, it can also lead to increased susceptibility to cerebral ischemia. ⋯ Therefore, we investigated the myogenic responses of isolated middle cerebral arteries (MCA) of normotensive and spontaneously hypertensive rats (SHR) after severe impact acceleration diffuse brain injury. TBI diminished myogenic constriction of MCAs isolated from normotensive rats, whereas the 20-HETE-mediated enhanced myogenic response of MCAs isolated from SHRs was not affected by TBI. These results suggest that the optimal cerebral perfusion pressure values and vascular signaling pathways can be different and, therefore, should be targeted differently in normotensive and hypertensive patients following TBI.
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Journal of neurotrauma · Jul 2017
Social competence at 2 years following child traumatic brain injury.
Children with traumatic brain injury (TBI) are at risk for social impairment, but research has yet to document the trajectory of these skills post-injury and factors that may predict social problems. This study addressed these gaps in knowledge, reporting on findings from a prospective, longitudinal follow-up study that investigated social outcomes post-injury and explored factors contributing to these outcomes at two years post-injury. The sample included 113 children, 74 with TBI and 39 typically developing (TD) controls. ⋯ Within the TBI group, 23% of children exhibited social impairments. Younger age at injury, greater pre-injury, and current behavior problems and family dysfunction, and poorer intelligence quotient (IQ), processing speed, and empathy were linked to impairment. Further follow-up is required to track social recovery and the influences of cognition, brain, and environment over time.
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Hippocampal-dependent deficits in learning and memory formation are a prominent feature of traumatic brain injury (TBI); however, the role of the hippocampus in cognitive dysfunction after concussion (mild TBI) is unknown. We therefore investigated functional and structural changes in the swine hippocampus following TBI using a model of head rotational acceleration that closely replicates the biomechanics and neuropathology of closed-head TBI in humans. We examined neurophysiological changes using a novel ex vivo hippocampal slice paradigm with extracellular stimulation and recording in the dentate gyrus and CA1 occurring at 7 days following non-impact inertial TBI in swine. ⋯ Input-output curves demonstrated an elevated excitatory post-synaptic potential (EPSP) output for a given fiber volley input in injured versus sham animals, suggesting a form of homeostatic plasticity that manifested as a compensatory response to decreased axonal function in post-synaptic regions. These data indicate that closed-head rotational acceleration-induced TBI, the common cause of concussion in humans, may induce significant alterations in hippocampal circuitry function that have not resolved at 7 days post-injury. This circuitry dysfunction may underlie some of the post-concussion symptomatology associated with the hippocampus, such as post-traumatic amnesia and ongoing cognitive deficits.
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Journal of neurotrauma · Jul 2017
Directions for use of intracranial pressure monitoring in treatment of severe traumatic brain injury using data from the Japan Neurotrauma Data Bank.
Neuromonitoring can be used to observe intracranial pathological conditions in neurointensive care; however, use of intracranial pressure (ICP) monitoring is low in Japan. In this study, we retrospectively investigated the effects of ICP monitoring in the treatment of severe traumatic brain injury (TBI), using data from the Japan Neurotrauma Data Bank (JNTDB). The study was conducted in 1091 subjects enrolled in the JNTDB (Project 2009) from July 2009 to June 2011. ⋯ In multivariate analysis, age, GCS, pupillary abnormalities, perimesencephalic cistern disappearance or compression, and ICP were associated with a favorable outcome, but the therapeutic method did not affect outcome. We conclude that ICP monitoring and management of ICP are both important for management and care of severe TBI. However, current therapies do not control ICP sufficiently, and more effective therapies are needed.