Journal of neurotrauma
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Journal of neurotrauma · May 2019
A Data-driven Approach to Unlikely, Possible, Probable, and Definite Acute Concussion Assessment.
Kutcher and Giza suggested incorporating levels of certainty in concussion diagnosis decisions. These guidelines were based on clinical experience rather than objective data. Therefore, we combined data-driven optimization with predictive modeling to identify which athletes are unlikely to have concussion and to classify remaining athletes as having possible, probable, or definite concussion with diagnostic certainty. ⋯ Baseline to post-injury change scores for the SAC, SCAT symptoms, and BESS were significantly different between acute possible and probable concussions and normal performances (p < 0.05). There were no consistent patterns in demographics across risk categories, although a greater proportion of concussions classified as unlikely were reported immediately compared with definite concussions (p < 0.05). Although clinical interpretation is still needed, our data-driven approach to concussion risk stratification provides a promising step toward evidence-based concussion assessment.
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Journal of neurotrauma · May 2019
Rapid Repeat Exposure to Subthreshold Trauma Causes Synergistic Axonal Damage and Functional Deficits in the Visual Pathway in a Mouse Model.
We examined the effect of repeat exposure to a non-damaging insult on central nervous system axons using the optic projection as a model. The optic projection is attractive because its axons are spatially separated from the cell bodies, it is easily accessible, it is composed of long axons, and its function can be measured. We performed closed-system ocular neurotrauma in C57Bl/6 mice using bursts of 15 or 26-psi (pounds per square inch) overpressure air that caused no gross damage. ⋯ Therefore, repeat mild trauma within an interinjury interval of 1 min or less causes synergistic axon damage, whereas mild trauma repeated at a longer interinjury interval causes additive, cumulative damage. The synergistic damage may underlie the high incidence of traumatic brain injury and traumatic optic neuropathy in blast-injured service members given that explosive blasts are multiple injury events that occur in a very short time span. This study also supports the use of the VEP as a biomarker for traumatic optic neuropathy.
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Journal of neurotrauma · May 2019
Matrix Metalloproteinase 9 and Osteopontin Interact to Support Synaptogenesis in the Olfactory Bulb after Mild Traumatic Brain Injury.
Olfactory receptor axons reinnervate the olfactory bulb (OB) after chemical or transection lesion. Diffuse brain injury damages the same axons, but the time course and regulators of OB reinnervation are unknown. Gelatinases (matrix metalloproteinase [MMP]2, MMP9) and their substrate osteopontin (OPN) are candidate mediators of synaptogenesis after central nervous system (CNS) insult, including olfactory axon damage. ⋯ Olfactory marker protein (OMP), used to identify injured olfactory axons, revealed persistent axon damage in the absence of MMP9. MMP9 KO ultrastructure at 21 days post-injury indicated that persistent OMP reduction was paired with delayed removal of degenerated axons. These results provide evidence that diffuse, concussive brain trauma induces a post-injury interaction between MMP9, OPN, and CD44, which mediates synaptic plasticity and reinnervation within the OB.
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Journal of neurotrauma · May 2019
Autonomic Dysfunction and Associations with Functional and Neurophysiological Outcome in Moderate/Severe Traumatic Brain Injury: A Scoping Review.
The quantification and objective documentation of autonomic dysfunction in traumatic brain injury (TBI) is neither well studied nor extensively validated. Most of the descriptions of autonomic dysfunction in the literature are in the form of vague non-specific clinical manifestations. Few studies propose the use of objective measures of assessing the extent of autonomic dysfunction to link them to the outcome of TBI. ⋯ A total of 2714 adult patients were studied. Although the nature of association between autonomic dysfunction and outcome is unclear, the objective quantification of autonomic dysfunction seems to be associated with global patient outcome and other neurophysiological measures. Further studies are needed to validate its use and explore the underlying molecular mechanisms of the described associations.
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Journal of neurotrauma · May 2019
Headache trigger sensitivity and avoidance after mild traumatic brain injury.
Most patients with primary headache disorders identify environmental stimuli (e.g., visual glare), situational factors (e.g., stress), physiological states (e.g., hormones), or activities (e.g., exercise) as triggers that elicit or worsen headache episodes. Headache triggers have not been previously studied in post-traumatic headache (PTH). The present study explored the frequency of headache triggers and their avoidance in PTH. ⋯ Headache severity was more associated with trigger sensitivity [F(2,49) = 13.45, p < 0.001] than trigger avoidance [F(2,47) = 2.97, p = 0.062]. In summary, the pattern of headache triggers in persistent PTH after mild TBI appears somewhat different from that in primary headache disorders, with mental exertion emerging as uniquely important. Pervasive avoidance of mental exertion to prevent headaches (cogniphobia) might be a worthwhile behavioral intervention target after mild TBI.