Journal of neurotrauma
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Journal of neurotrauma · Aug 2017
Cerebral perfusion pressure insults and associations with outcome in adult traumatic brain injury.
The definition of cerebral perfusion pressure (CPP) secondary insults in severe traumatic brain injury remains unclear. The purpose of the present study is to visualize the association of intensity and duration of episodes below or above CPP thresholds and outcome. The analysis was based on prospectively collected minute-by-minute intracranial pressure (ICP) and blood pressure data and outcome from 259 adult patients. ⋯ In the present study, the CPP pressure-time burden associated with poor outcome was visualized. A safe zone between 60 and 70 mm Hg could be identified for adults ≤65 years, provided AR was active and ICP was ≤25 mm Hg. Deficient AR reduces the tolerability for low CPP.
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Journal of neurotrauma · Aug 2017
Prolonged cerebrospinal fluid neurofilament light chain increase in patients with post-traumatic disorders of consciousness.
The mechanisms involved in secondary brain injury after the acute phase of severe traumatic brain injury (TBI) are largely unknown. Ongoing axonal degeneration, consequent to the initial trauma, may lead to secondary brain injury. To test this hypothesis, we evaluated the cerebrospinal fluid (CSF) level of neurofilament light chain (NF-L), a proposed marker of axonal degeneration, in 10 patients who developed a severe disorder of consciousness after a TBI, including 7 in a minimally conscious state and 3 with unresponsive wakefulness syndrome (time since brain injury, 309 ± 169 days). ⋯ Moreover, NF-L level was significantly higher after a severe TBI than in a reference group of 9 patients with probable Alzheimer's disease, a population with elevated levels of CSF NF-L attributed to neuronal degeneration (median value, 1173 pg/mL; range, 670-3643; p < 0.01). CSF NF-L level was correlated with time post-TBI (p = 0.04). These results demonstrate prolonged secondary brain injury, suggesting that patients exhibit ongoing axonal degeneration up to 19 months after a severe TBI.
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Journal of neurotrauma · Aug 2017
Development of a Prediction Model for Post-Concussive Symptoms following Mild Traumatic Brain Injury: A TRACK-TBI Pilot Study.
Post-concussive symptoms occur frequently after mild traumatic brain injury (mTBI) and may be categorized as cognitive, somatic, or emotional. We aimed to: 1) assess whether patient demographics and clinical variables predict development of each of these three symptom categories, and 2) develop a prediction model for 6-month post-concussive symptoms. Patients with mTBI (Glasgow Coma Scale score 13-15) from the prospective multi-center Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) Pilot study (2010-2012) who completed the Rivermead Post Concussion Symptoms Questionnaire (RPQ) at 6 months post-injury were included. ⋯ The total set of predictors explained 21% of the variance, which decreased to 14% after bootstrap validation. Demographic and clinical variables at baseline are predictive of 6-month post-concussive symptoms following mTBI; however, these variables explain less than one-fifth of the total variance in outcome. Model refinement with larger datasets, more granular variables, and objective biomarkers are needed before implementation in clinical practice.
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Journal of neurotrauma · Aug 2017
Evaluation of Head and Brain Injury Risk Functions using Sub-Injurious Human Volunteer Data.
Risk assessment models are developed to estimate the probability of brain injury during head impact using mechanical response variables such as head kinematics and brain tissue deformation. Existing injury risk functions have been developed using different datasets based on human volunteer and scaled animal injury responses to impact. However, many of these functions have not been independently evaluated with respect to laboratory-controlled human response data. ⋯ Kinematic-based head and brain injury risk probabilities were calculated directly from the kinematic data, while strain-based risks were determined through finite element model simulation of the 335 tests. Several injury risk functions substantially over predict the likelihood of concussion and diffuse axonal injury; proposed maximum principal strain-based injury risk functions predicted nearly 80 concussions and 14 cases of severe diffuse axonal injury out of the 335 non-injurious cases. This work is an important first step in assessing the efficacy of existing brain risk functions and highlights the need for more predictive injury assessment models.
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Journal of neurotrauma · Aug 2017
Environmental Enrichment Mitigates Deficits after Repetitive Mild TBI.
Although environmental enrichment has been shown to improve functional and histologic outcomes in pre-clinical moderate-to-severe traumatic brain injury (TBI), there are a paucity of pre-clinical data regarding enrichment strategies in the setting of repetitive mild traumatic brain injury (rmTBI). Given the vast numbers of athletes and those in the military who sustain rmTBI, the mounting evidence of the long-term and progressive sequelae of rmTBI, and the lack of targeted therapies to mitigate these sequelae, successful enrichment interventions in rmTBI could have large public health significance. Here, we evaluated enrichment strategies in an established pre-clinical rmTBI model. ⋯ Treatment with enrichment also corresponded to normal NMDAR subunit expression, decreased GluR1 phosphorylation, decreased phosphorylated CaMKII, and normal calpain expression post-rmTBI. These data suggest that enrichment strategies may improve functional outcomes and mitigate synaptic changes post-rmTBI. Given that enrichment strategies are feasible in the clinical setting, particularly for athletes and soldiers for whom the risk of repetitive injury is greatest, these data suggest that clinical trials may be warranted.