Traumatic brain injury in the neonate, child and adolescent human: An overview of pathology

Activation of the melanocortin-1 receptor attenuates neuronal apoptosis after traumatic brain injury by upregulating Merlin expression

Traumatic brain injury (TBI) is a common disease worldwide with high mortality and disability rates. Besides the primary mechanical injury, the secondary injury associated with TBI can also induce numerous pathological changes, such as brain edema, nerve apoptosis, and neuroinflammation, which further aggravates neurological dysfunction and even causes the death due to the primary injury. Among them, neuronal apoptosis is a key link in the injury. Melanocortin-1 receptor (MC1R) is a G protein coupled receptor, belonging to the melanocortin receptor family. Studies have shown that activation of MC1R inhibits oxidative stress and apoptosis, and confers neuroprotective effects against various neurological diseases. Merlin is a protein product of the NF2 gene, which is widely expressed in the central nervous system (CNS) of mice, rats, and humans. Studies have indicated that Merlin is associated with MC1R. In this study, we explored the anti-apoptotic effects and potential mechanisms of MC1R. A rat model of TBI was established through controlled cortical impact. The MC1R-specific agonist Nle4-D-Phe7-α-Melanocyte (NDP-MSH) and the inhibitor MSG-606 were employed to explore the effects of MC1R and Merlin following TBI and investigated the associated mechanisms. The results showed that the expression levels of MC1R and Merlin were upregulated after TBI, and activation of MC1R promoted Merlin expression. Further, we found that MC1R activation significantly improved neurological dysfunction and reduced brain edema and neuronal apoptosis induced by TBI in rats. Mechanistically, its neuroprotective function and anti-apoptotic were partly associated with MC1R activation. In conclusion, we demonstrated that MC1R activation after TBI may inhibit apoptosis and confer neuroprotection by upregulating the expression of Merlin.

The neuroprotective potential of phytochemicals in traumatic brain injury: mechanistic insights and pharmacological implications

Traumatic brain injury (TBI) leads to brain damage, comprising both immediate primary damage and a subsequent cascade of secondary injury mechanisms. The primary injury results in localized brain damage, while the secondary damage initiates inflammatory responses, followed by the disruption of the blood-brain barrier, infiltration of peripheral blood cells, brain edema, and the release of various immune mediators, including chemotactic factors and interleukins. TBI disrupts molecular signaling, cell structures, and functions. In addition to physical tissue damage, such as axonal injuries, contusions, and haemorrhages, TBI interferes with brain functioning, impacting cognition, decision-making, memory, attention, and speech capabilities. Despite a deep understanding of the pathophysiology of TBI, an intensive effort to evaluate the underlying mechanisms with effective therapeutic interventions is imperative to manage the repercussions of TBI. Studies have commenced to explore the potential of employing natural compounds as therapeutic interventions for TBI. These compounds are characterized by their low toxicity and limited interactions with conventional drugs. Moreover, many natural compounds demonstrate the capacity to target various aspects of the secondary injury process. While our understanding of the pathophysiology of TBI, there is an urgent need for effective therapeutic interventions to mitigate its consequences. Here, we aimed to summarize the mechanism of action and the role of phytochemicals against TBI progression. This review discusses the therapeutic implications of various phytonutrients and addresses primary and secondary consequences of TBI. In addition, we highlighted the roles of emerging phytochemicals as promising candidates for therapeutic intervention of TBI. The review highlights the neuroprotective roles of phytochemicals against TBI and the mechanistic approach. Furthermore, our efforts focused on the underlying mechanisms, providing a better understanding of the therapeutic potential of phytochemicals in TBI therapeutics.

Post-Concussive Symptoms in Preschool Children up to Three Months Post-Injury

BACKGROUND AND AIMS

Post-concussive symptoms (PCS) are central to the assessment and management of mild traumatic brain injury (mTBI); however, this remains poorly understood in children aged ≤5 years. The study aimed to explore individual PCS, pattern of parents' PCS report over time, proportion of symptomatic children, and variables associated with parents' report of PCS in their preschool child after a mTBI.

METHODS

Children aged 2-5 years with either a mTBI (n=13) or limb injury (n=6) were recruited from the emergency department (ED). Parent ratings of child PCS were assessed at ED presentation, at one month, and at three months post-injury. Injury (e.g. injury group, pain), child (e.g. pre-existing behavior, symptoms), and parent (e.g. parental stress, education) characteristics were considered when investigating variables that may be relevant to parent report of PCS.

RESULTS

The number of total, physical, and sleep PCS were significantly higher after mTBI, with a significant decrease in physical and sleep PCS over time. The proportion of symptomatic children was comparable between injury groups at each time point. Acute pain and pre-injury symptoms were significantly associated with parents' acute PCS report in the mTBI group. Further research is needed on variables that may be relevant to parents' PCS report at follow-up.

CONCLUSION

Preliminary findings suggest a general trauma response after a mTBI or limb injury, but acute physical and sleep PCS may help differentiate the injury groups. Injury and premorbid child variables may be relevant to parents' report of acute PCS in their child. Additional research is needed to investigate PCS in preschoolers and variables that may predict parents' PCS report.

Neuroanatomical restoration of salience network links reduced headache impact to cognitive function improvement in mild traumatic brain injury with posttraumatic headache

BACKGROUND

Neuroanatomical alterations have been associated with cognitive deficits in mild traumatic brain injury (MTBI). However, most studies have focused on the abnormal gray matter volume in widespread brain regions using a cross-sectional design in MTBI. This study investigated the neuroanatomical restoration of key regions in salience network and the outcomes in MTBI.

METHODS

Thirty-six MTBI patients with posttraumatic headache (PTH) and 34 matched healthy controls were enrolled in this study. All participants underwent magnetic resonance imaging scans and were assessed with clinical measures during the acute and subacute phases. Surface-based morphometry was conducted to get cortical thickness (CT) and cortical surface area (CSA) of neuroanatomical regions which were defined by the Desikan atlas. Then mixed analysis of variance models were performed to examine CT and CSA restoration in patients from acute to subacute phase related to controls. Finally, mediation effects models were built to explore the relationships between neuroanatomical restoration and symptomatic improvement in patients.

RESULTS

MTBI patients with PTH showed reduced headache impact and improved cognitive function from the acute to subacute phase. Moreover, patients experienced restoration of CT of the left caudal anterior cingulate cortex (ACC) and left insula and cortical surface area of the right superior frontal gyrus from acute to subacute phase. Further mediation analysis found that CT restoration of the ACC and insula mediated the relationship between reduced headache impact and improved cognitive function in patients.

CONCLUSIONS

These results showed that neuroanatomical restoration of key regions in salience network correlated reduced headache impact with cognitive function improvement in MTBI with PTH, which further substantiated the vital role of salience network and provided an alternative clinical target for cognitive improvement in MTBI patients with PTH.

How much paediatric major trauma is truly paediatric? Experience from a level 1 urban Major Trauma Centre

Background

At its inception, there was no formal provision for children within the English major trauma network. There are now combined and stand-alone centres, but the scarcity of paediatric trauma facilities in some regions can result in long patient transfers and impact patient outcomes. The objective of this study was to determine the proportion of paediatric trauma patients who may benefit from input by adult services or may be safely managed within the local adult MTC, either because of patient physiology or injury patterns.

Methods

All trauma presentations to our urban MTC aged ≤16 over a 3-year period were retrospectively identified and grouped, based on age and weight. ‘Young adult’ mechanisms of trauma and patient destinations (whether paediatric or adult wards) were determined.

Results

There were 847 paediatric trauma cases recorded with a mean age of 9 and a male preponderance. Based on age and weight, 10–45% of cases could be considered physiologically adult-like, and 22–28% pubertal. Almost all penetrating trauma occurred in males, increasing with age. 14% of all admissions were managed on adult wards, with frequency increasing with patient age and with mechanism of actions (MOIs) relating to interpersonal violence.

Conclusion

In this dataset, nearly half of paediatric trauma was ‘pubertal’ or ‘adult’ in their physiology and of these most presented with ‘young adult’ MOIs. These children likely benefit from combined paediatric and adult trauma services; where these do not exist, some older patients may be safely managed within local adult MTCs.

Structural-covariance networks identify topology-based cortical-thickness changes in children with persistent executive function impairments after traumatic brain injury

Paediatric traumatic brain injury (pTBI) results in inconsistent changes to regional morphometry of the brain across studies. Structural-covariance networks represent the degree to which the morphology (typically cortical-thickness) of cortical-regions co-varies with other regions, driven by both biological and developmental factors. Understanding how heterogeneous regional changes may influence wider cortical network organization may more appropriately capture prognostic information in terms of long term outcome following a pTBI. The current study aimed to investigate the relationships between cortical organisation as measured by structural-covariance, and long-term cognitive impairment following pTBI. T1-weighted magnetic resonance imaging (MRI) from n = 83 pTBI patients and 33 typically developing controls underwent 3D-tissue segmentation using Freesurfer to estimate cortical-thickness across 68 cortical ROIs. Structural-covariance between regions was estimated using Pearson's correlations between cortical-thickness measures across 68 regions-of-interest (ROIs), generating a group-level 68 × 68 adjacency matrix for patients and controls. We grouped a subset of patients who underwent executive function testing at 2-years post-injury using a neuropsychological impairment (NPI) rule, defining impaired- and non-impaired subgroups. Despite finding no significant reductions in regional cortical-thickness between the control and pTBI groups, we found specific reductions in graph-level strength of the structural covariance graph only between controls and the pTBI group with executive function (EF) impairment. Node-level differences in strength for this group were primarily found in frontal regions. We also investigated whether the top n nodes in terms of effect-size of cortical-thickness reductions were nodes that had significantly greater strength in the typically developing brain than n randomly selected regions. We found that acute cortical-thickness reductions post-pTBI are loaded onto regions typically high in structural covariance. This association was found in those patients with persistent EF impairment at 2-years post-injury, but not in those for whom these abilities were spared. This study posits that the topography of post-injury cortical-thickness reductions in regions that are central to the typical structural-covariance topology of the brain, can explain which patients have poor EF at follow-up.

Pediatric Moderate-Severe Traumatic Brain Injury and Gray Matter Structural Covariance Networks: A Preliminary Longitudinal Investigation

Pediatric traumatic brain injury (TBI) is prevalent and can disrupt ongoing brain maturation. However, the long-term consequences of pediatric TBI on the brain's network architecture are poorly understood. Structural covariance networks (SCN), based on anatomical correlations between brain regions, may provide important insights into brain topology following TBI. Changes in global SCN (default-mode network [DMN], central executive network [CEN], and salience network [SN]) were compared sub-acutely (<90 days) and in the long-term (approximately 12-24 months) after pediatric moderate-severe TBI (n = 16), and compared to typically developing children assessed concurrently (n = 15). Gray matter (GM) volumes from selected seeds (DMN: right angular gyrus [rAG], CEN: right dorsolateral prefrontal cortex [rDLPFC], SN: right anterior insula) were extracted from T1-weighted images at both timepoints. No group differences were found sub-acutely; at the second timepoint, the TBI group showed significantly reduced structural covariance within the DMN seeded from the rAG and the (1) right middle frontal gyrus, (2) left superior frontal gyrus, and (3) left fusiform gyrus. Reduced structural covariance was also found within the CEN, that is, between the rDLPFC and the (1) calcarine sulcus, and (2) right occipital gyrus. In addition, injury severity was positively associated with GM volumes in the identified CEN regions. Over time, there were no significant changes in SCN in either group. The findings, albeit preliminary, suggest for the first time a long-term effect of pediatric TBI on SCN. SCN may be a complementary approach to characterize the global effect of TBI on the developing brain. Future work needs to further examine how disruptions of these networks relate to behavioral and cognitive difficulties.

Traumatic Brain Injury: Mechanistic Insight on Pathophysiology and Potential Therapeutic Targets

Traumatic brain injury (TBI) causes brain damage, which involves primary and secondary injury mechanisms. Primary injury causes local brain damage, while secondary damage begins with inflammatory activity followed by disruption of the blood-brain barrier (BBB), peripheral blood cells infiltration, brain edema, and the discharge of numerous immune mediators including chemotactic factors and interleukins. TBI alters molecular signaling, cell structures, and functions. Besides tissue damage such as axonal damage, contusions, and hemorrhage, TBI in general interrupts brain physiology including cognition, decision-making, memory, attention, and speech capability. Regardless of the deep understanding of the pathophysiology of TBI, the underlying mechanisms still need to be assessed with a desired therapeutic agent to control the consequences of TBI. The current review gives a brief outline of the pathophysiological mechanism of TBI and various biochemical pathways involved in brain injury, pharmacological treatment approaches, and novel targets for therapy.

Biomechanical Comparison of Real World Concussive Impacts in Children, Adolescents, and Adults

Accidental falls occur to people of all ages, with some resulting in concussive injury. At present, it is unknown whether children and adolescents are at a comparable risk of sustaining a concussion compared to adults. This study reconstructed the impact kinematics of concussive falls for children, adolescents, and adults and simulated the associated brain tissue deformations. Patients included in this study were diagnosed with a concussion as defined by the Zurich Consensus guidelines. Eleven child, 10 adolescent, and 11 adult falls were simulated using mathematical dynamic models(MADYMO), with three ellipsoid pedestrian models sized to each age group. Laboratory impact reconstruction was conducted using Hybrid III head forms, with finite element model simulations of the brain tissue response using recorded impact kinematics from the reconstructions. The results of the child group showed lower responses than the adolescent group for impact variables of impact velocity, peak linear acceleration, and peak rotational acceleration but no statistical differences existed for any other groups. Finite element model simulations showed the child group to have lower strain values than both the adolescent and adult groups. There were no statistical differences between the adolescent and adult groups for any variables examined in this study. With the cases included in this study, young children sustained concussive injuries at lower modeled brain strains than adolescents and adults, supporting the theory that children may be more susceptible to concussive impacts than adolescents or adults.

Developmental divergence of structural brain networks as an indicator of future cognitive impairments in childhood brain injury: Executive functions

Brain insults during childhood can perturb the already non-linear trajectory of typical brain maturation. The diffuse effects of injury can be modelled using structural covariance networks (SCN), which change as a function of neurodevelopment. However, SCNs are estimated at the group-level, limiting applicability to predicting individual-subject outcomes. This study aimed to measure the divergence of the brain networks in paediatric traumatic brain injury (pTBI) patients and controls, and investigate relationships with executive functioning (EF) at 24 months post-injury. T1-weighted MRI acquired acutely in 78 child survivors of pTBI and 33 controls underwent 3D-tissue segmentation to estimate cortical thickness (CT) across 68 atlas-based regions-of-interest (ROIs). Using an 'add-one-patient' approach, we estimate a developmental divergence index (DDI). Our approach adopts a novel analytic framework in which age-appropriate reference networks to calculate the DDI were generated from control participants from the ABIDE dataset using a sliding-window approach. Divergence from the age-appropriate SCN was related to reduced EF performance and an increase in behaviours related to executive dysfunctions. The DDI measure showed predictive value with regard to executive functions, highlighting that early imaging can assist in prognosis for cognition.

The Rise of the Concussion Clinic for Diagnosis of Pediatric Mild Traumatic Brain Injury

It was not too long ago that being struck violently in the head or "getting your bell rung" was often brushed off as nothing to worry about. These days the pendulum has swung and there is growing appreciation that this mild traumatic brain injury (mTBI), often called concussion, must be taken seriously and is now on the forefront of public health concerns. As a growing body of research continues to expand our understanding of concussion, the paradigm of diagnosis and treatment is transforming rapidly. The recent rise of specialty concussion clinics across the country has grown out of a need for safe, effective, and efficient evaluation of these injuries by healthcare professionals qualified to implement diagnostic and management strategies that align with the latest evidence-based practice guidelines. Due to the complex nature of each injury, a comprehensive multidisciplinary team can provide a valuable individualized approach to concussion care.

Is diffuse axonal injury on susceptibility weighted imaging a biomarker for executive functioning in adolescents with traumatic brain injury?

Traumatic brain injury (TBI) is a heterogeneous disorder in which diffuse axonal injury (DAI) is an important component contributing to executive dysfunction. During adolescence, developing brain networks are especially vulnerable to acceleration-deceleration forces. We aimed to examine the correlation between DAI (number and localization) and executive functioning in adolescents with TBI. We recruited 18 adolescents with a mean age of 15y8m (SD = 1y7m), averaging 2.5 years after sustaining a moderate-to-severe TBI with documented DAI. Susceptibility Weighted Imaging sequence was administered to localize the DAI lesions. The adolescents performed a neurocognitive test-battery, addressing different aspects of executive functioning (working memory, attention, processing speed, planning ability) and their parents completed the Behavior Rating Inventory of Executive Function (BRIEF) - questionnaire. Executive performance of the TBI-group was compared with an age and gender matched control group of typically developing peers. Based on these results we focused on the Stockings of Cambridge test and the BRIEF to correlate with the total number and location of DAI. Results revealed that the anatomical distribution of DAI, especially in the corpus callosum and the deep brain nuclei, may have more implications for executive functioning than the total amount of DAI in adolescents. Results of this study may help guide targeted rehabilitation to redirect the disturbed development of executive function in adolescents with TBI.

A systematic review of cross-sectional differences and longitudinal changes to the morphometry of the brain following paediatric traumatic brain injury

Paediatric traumatic brain injury (pTBI) is a leading cause of disability for children and young adults. Children are a uniquely vulnerable group with the disease process that occurs following a pTBI interacting with the trajectory of normal brain development. Quantitative MRI post-injury has suggested a long-term, neurodegenerative effect of TBI on the morphometry of the brain, in both adult and childhood TBI. Changes to the brain beyond that of anticipated, age-dependant differences may allow us to estimate the state of the brain post-injury and produce clinically relevant predictions for long-term outcome. The current review synthesises the existing literature to assess whether, following pTBI, the morphology of the brain exhibits either i) longitudinal change and/or ii) differences compared to healthy controls and outcomes. The current literature suggests that morphometric differences from controls are apparent cross-sectionally at both acute and late-chronic timepoints post-injury, thus suggesting a non-transient effect of injury. Developmental trajectories of morphometry are altered in TBI groups compared to patients, and it is unlikely that typical maturation overcomes damage post-injury, or even 'catches up' with that of typically-developing peers. However, there is limited evidence for diverted developmental trajectories being associated with cognitive impairment post-injury. The current review also highlights the apparent challenges to the existing literature and potential methods by which these can be addressed.

Exploration of gray matter correlates of cognitive training benefit in adolescents with chronic traumatic brain injury

Sustaining a traumatic brain injury (TBI) during adolescence has a profound effect on brain development and can result in persistent executive functioning deficits in daily life. Cognitive recovery from pediatric-TBI relies on the potential of neuroplasticity, which can be fostered by restorative training-programs. However the structural mechanisms underlying cognitive recovery in the immature brain are poorly understood. This study investigated gray matter plasticity following 2 months of cognitive training in young patients with TBI. Sixteen adolescents in the chronic stage of moderate-severe-TBI (9 male, mean age = 15y8m ± 1y7m) were enrolled in a cognitive computerized training program for 8 weeks (5 times/week, 40 min/session). Pre-and post-intervention, and 6 months after completion of the training, participants underwent a comprehensive neurocognitive test-battery and anatomical Magnetic Resonance Imaging scans. We selected 9 cortical-subcortical Regions-Of-Interest associated with Executive Functioning (EF-ROIs) and 3 control regions from the Desikan-Killiany atlas. Baseline analyses showed significant decreased gray matter density in the superior frontal gyri p = 0.033, superior parietal gyri p = 0.015 and thalamus p = 0.006 in adolescents with TBI compared to age and gender matched controls. Linear mixed model analyses of longitudinal volumetric data of the EF-ROI revealed no strong evidence of training-related changes in the group with TBI. However, compared to the change over time in the control regions between post-intervention and 6 months follow-up, the change in the EF-ROIs showed a significant difference. Exploratory analyses revealed a negative correlation between the change on the Digit Symbol Substitution test and the change in volume of the putamen (r = −0.596, p = 0.015). This preliminary study contributes to the insights of training-related plasticity mechanisms after pediatric-TBI.

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Longitudinal data on cortical – subcortical volume before and after training.

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Post-training significant difference in change between ROI and control regions.

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Post-training significant correlation Digit Symbol Substitution test and putamen.

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Theory of an impaired capacity of plasticity in an immature traumatized brain.

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Exploring plasticity is essential to provide foundation for rehab interventions.

Psychological and behavioural difficulties following severe TBI in adolescence: a comparison with a sample of peers with brain lesions of other origin and with a control group

OBJECTIVE

To describe behavioural and adjustment problems in a group of 57 adolescents with severe traumatic brain injury (TBI) and compare them with a clinical group of peers with brain lesions of other origin (N = 33) and a control group of healthy adolescents (N = 48).

METHODS

All subjects received an age-appropriate assessment, including the child behaviour checklist (CBCL) 4/18, the strengths and difficulties questionnaire (SDQ) and the vineland adaptive behaviour scales (VABS).

RESULTS

Compared with healthy peers, adolescents with TBI presented with more marked behavioural problems on most CBCL scales (Internalization and Externalization domains were both affected) and on the SDQ Hyperactivity and Peer problems scales. They also showed a more impaired functioning in most VABS domains. Compared with adolescents with brain lesions of other aetiology, patients with TBI showed more conduct problems on the SDQ scale, but no significant differences were found on the CBCL scales. Regarding the VABS, patients with other lesions presented with the worst outcome in the Motor and Daily Living Skills domains.

CONCLUSIONS

Adolescents with TBI are exposed at a very high risk to develop behavioural and psychological disturbances with the potential to severely affect their social re-entry. Further knowledge is needed to plan early and well-timed interventions.

Treating childhood traumatic brain injury with autologous stem cell therapy

INTRODUCTION

Neonatal traumatic brain injury (TBI) is a significant cause of developmental disorders. Autologous stem cell therapy may enhance neonatal brain plasticity towards repair of the injured neonatal brain.

AREAS COVERED

The endogenous neonatal anti-inflammatory response can be enhanced through the delivery of anti-inflammatory agents. Stem cell therapy stands as a robust approach for sequestering the inflammation-induced cell death in the injured brain. Here, we discuss the use of umbilical cord blood cells and bone marrow stromal cells for acute and chronic treatment of experimental neonatal TBI. Autologous stem cell transplantation may dampen neuroinflammation. Clinical translation of this stem cell therapy will require identifying the therapeutic window post-injury and harvesting ample supply of transplantable autologous stem cells. Stem cell banking of cryopreserved cells may allow readily available transplantable cells and circumvent the unpredictable nature of neonatal TBI. Harnessing the anti-inflammatory properties of stem cells is key in combating the progressive neurodegeneration after the initial injury.

EXPERT OPINION

Combination treatments, such as with hypothermia, may enhance the therapeutic effects of stem cells. Stem cell therapy has immense potential as a stand-alone or adjunctive therapy for treating neuroinflammation associated with neonatal TBI acutely and for preventing further progression of the injury.

The Course of Concussion Recovery in Children 6-12 Years of Age: Experience From an Interdisciplinary Rehabilitation Clinic

BACKGROUND

Current concussion evidence is derived largely from teenagers and adults. Concussion in younger children occurs within the context of neuromaturation, with differing age-based pathophysiological responses to injury. Therefore, our current understanding of concussion in older children and adults is unlikely to directly apply to younger children.

OBJECTIVE

To describe patient variables, clinical course, and factors associated with time to discharge from concussion care in children 6-12 years of age with concussion treated in an interdisciplinary rehabilitation-based concussion clinic.

DESIGN

Retrospective chart review.

SETTING

Interdisciplinary concussion clinic at an academically affiliated rehabilitation center.

PATIENTS

Children aged 6-12 years (n = 105; mean 10.8 years of age, 70% male) seen within 60 days of concussive injury.

MAIN OUTCOME MEASUREMENTS

Descriptive statistics explored demographic, injury, and clinical features. The primary outcome measure, time to discharge from concussion care, was estimated with survival-analysis methods based on the date of discharge from the clinic. Multivariate models were used to examine factors associated with longer time to discharge.

RESULTS

Median time to discharge was 34 days postinjury (range 5-192 days); 75% of children were discharged within 60 days of injury. A minority reported persisting symptoms at discharge. Younger age and increased symptom burden at initial evaluation predicted longer time to discharge.

CONCLUSIONS

Although children 6-12 years old treated in a specialty concussion clinic show variability in time to discharge from concussion care, most were discharged within 2 months after injury. Risk factors for prolonged recovery, such as younger age and greater symptom burden at initial visit, can be used when counseling families and planning interventions. There may be varying contributions, including psychosocial stressors, to ongoing symptoms in children who experience persisting symptoms after other concussion-related concerns have resolved. Future work focused on the subset of children who report persisting symptoms will be useful for developing an evidence base related to their care.

LEVEL OF EVIDENCE

II.

Mild cognitive impairment and structural brain abnormalities in a sexagenarian with a history of childhood traumatic brain injury

In this report, we present a case study involving an older, female patient with a history of pediatric traumatic brain injury (TBI). Magnetic resonance imaging and diffusion tensor imaging volumes were acquired from the volunteer in question, her brain volumetrics and morphometrics were extracted, and these were then systematically compared against corresponding metrics obtained from a large sample of older healthy control (HC) subjects as well as from subjects in various stages of mild cognitive impairment (MCI) and Alzheimer disease (AD). Our analyses find the patient's brain morphometry and connectivity most similar to those of patients classified as having early-onset MCI, in contrast to HC, late MCI, and AD samples. Our examination will be of particular interest to those interested in assessing the clinical course in older patients having suffered TBI earlier in life, in contradistinction to those who experience incidents of head injury during aging.

Intracranial Pressure Monitoring in Infants and Young Children With Traumatic Brain Injury

OBJECTIVE

To examine the use of intracranial pressure monitors and treatment for elevated intracranial pressure in children 24 months old or younger with traumatic brain injury in North Carolina between April 2009 and March 2012 and compare this with a similar cohort recruited 2000-2001.

DESIGN

Prospective, observational cohort study.

SETTING

Twelve PICUs in North Carolina.

PATIENTS

All children 24 months old or younger with traumatic brain injury, admitted to an included PICU.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

The use of intracranial pressure monitors and treatments for elevated intracranial pressure were evaluated in 238 children with traumatic brain injury. Intracranial pressure monitoring (risk ratio, 3.7; 95% CI, 1.5-9.3) and intracranial pressure therapies were more common in children with Glasgow Coma Scale less than or equal to 8 compared with Glasgow Coma Scale greater than 8. However, only 17% of children with Glasgow Coma Scale less than or equal to 8 received a monitoring device. Treatments for elevated intracranial pressure were more common in children with monitors; yet, some children without monitors received therapies traditionally used to lower intracranial pressure. Unadjusted predictors of monitoring were Glasgow Coma Scale less than or equal to 8, receipt of cardiopulmonary resuscitation, nonwhite race. Logistic regression showed no strong predictors of intracranial pressure monitor use. Compared with the 2000 cohort, children in the 2010 cohort with Glasgow Coma Scale less than or equal to 8 were less likely to receive monitoring (risk ratio, 0.5; 95% CI, 0.3-1.0), although the estimate was not precise, or intracranial pressure management therapies.

CONCLUSION

Children in the 2010 cohort with a Glasgow Coma Scale less than or equal to 8 were less likely to receive an intracranial pressure monitor or hyperosmolar therapy than children in the 2000 cohort; however, about 10% of children without monitors received therapies to decrease intracranial pressure. This suggests treatment heterogeneity in children 24 months old or younger with traumatic brain injury and a need for better evidence to support treatment recommendations for this group of children.

Nodal versus Total Axonal Strain and the Role of Cholesterol in Traumatic Brain Injury

Traumatic brain injury (TBI) is a health threat that affects every year millions of people involved in motor vehicle and sporting accidents, and thousands of soldiers in battlefields. Diffuse axonal injury (DAI) is one of the most frequent types of TBI leading to death. In DAI, the initial traumatic event is followed by a cascade of biochemical changes that take time to develop in full, so that symptoms may not become apparent until days or weeks after the original injury. Hence, DAI is a dynamic process, and the opportunity exists to prevent its progression provided the initial trauma can be predicted at the molecular level. Here, we present preliminary evidence from micro-finite element (FE) simulations that the mechanical response of central nervous system myelinated fibers is dependent on the axonal diameter, the ratio between axon diameter and fiber diameter (g-ratio), the microtubules density, and the cholesterol concentration in the axolemma and myelin. A key outcome of the simulations is that there is a significant difference between the overall level of strain in a given axonal segment and the level of local strain in the Ranvier nodes contained in that segment, with the nodal strain being much larger than the total strain. We suggest that the acquisition of this geometric and biochemical information by means of already available high resolution magnetic resonance imaging techniques, and its incorporation in current FE models of the brain will enhance the models capacity to predict the site and magnitude of primary axonal damage upon TBI.

Reversible restricted-diffusion lesion representing transient intramyelinic cytotoxic edema in a patient with traumatic brain injury

We report this case to increase the awareness of magnetic resonance imaging (MRI) features of reversible white matter abnormalities in diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps in a patient with traumatic brain injury (TBI). An eight-year-old girl, who was hit by a truck, was brought to the emergency department by the emergency medical service (EMS). Eleven days later, she experienced cognitive impairment requiring MRI evaluation. DWI and ADC maps showed restricted diffusion in the white matter of the corpus callosum, peri-atrial white matter, and in the right centrum semiovale. There were no significant hemorrhagic foci in these regions, which showed complete resolution on follow up DWI MRI 13 days later. This reported case revealed TBI-related transient reversible intramyelinic cytotoxic edema.

Duration of post-traumatic amnesia as a predictor of functional outcome in school-age children: a systematic review

AIM

In adults, duration of post-traumatic amnesia (PTA) is a powerful early predictor of functional outcomes in traumatic brain injury. The aim of this work was to assess the predictive validity of PTA duration for outcomes in children (6-18y).

METHOD

PsycINFO, MEDLINE, Web of Science, and Embase were searched for papers published to January 2014. Ten studies met inclusion criteria: they used standardized instruments to assess PTA and functional outcomes, and examined relationships between the two. Outcomes were classified according to (1) the International Classification of Functioning, Disability and Health (ICF) core sets for neurological conditions for post-acute care and (2) global functioning and quality of life. Methodological quality was rated for each study.

RESULTS

The search identified 10 studies of moderate mean quality (M=11.8 out of 18). Longer PTA duration related to worse functional outcomes: global functioning and in the two ICF categories ('body function', 'activities and participation'). Relationships between PTA duration and quality of life and the ICF category of 'body structure' were not examined. PTA duration was, in 46 out of 60 (76.67%) instances, a stronger predictor of outcomes than other indices of injury severity.

CONCLUSION

Longer PTA duration is a valid predictor of worse outcomes in school-age children. Thus, PTA should be routinely assessed in children after traumatic brain injury.

Repetitive mild traumatic brain injury induces ventriculomegaly and cortical thinning in juvenile rats

Traumatic brain injury (TBI) most frequently occurs in pediatric patients and remains a leading cause of childhood death and disability. Mild TBI (mTBI) accounts for nearly 75% of all TBI cases, yet its neuropathophysiology is still poorly understood. While even a single mTBI injury can lead to persistent deficits, repeat injuries increase the severity and duration of both acute symptoms and long-term deficits. In this study, to model pediatric repetitive mTBI (rmTBI) we subjected unrestrained juvenile animals (postnatal day 20) to repeat weight-drop impacts. Animals were anesthetized and subjected to sham injury or rmTBI once per day for 5 days. Magnetic resonance imaging (MRI) performed 14 days after injury revealed marked cortical atrophy and ventriculomegaly in rmTBI animals. Specifically, beneath the impact zone the thickness of the cortex was reduced by up to 46% and the area of the ventricles increased by up to 970%. Immunostaining with the neuron-specific marker NeuN revealed an overall loss of neurons within the motor cortex but no change in neuronal density. Examination of intrinsic and synaptic properties of layer II/III pyramidal neurons revealed no significant difference between sham-injured and rmTBI animals at rest or under convulsant challenge with the potassium channel blocker 4-aminopyridine. Overall, our findings indicate that the neuropathological changes reported after pediatric rmTBI can be effectively modeled by repeat weight drop in juvenile animals. Developing a better understanding of how rmTBI alters the pediatric brain may help improve patient care and direct "return to game" decision making in adolescents.

Suppressed cytokine expression immediatey following traumatic brain injury in neonatal rats indicates an expeditious endogenous anti-inflammatory response

The timing of therapeutic intervention in traumatic brain injury (TBI) is critical. Although immediate cell death cascades have become established in adult TBI, the pathophysiology underlying neonatal TBI is poorly understood. The objective of the present study was to determine the role of cytokine regulation following TBI in neonatal rats. Seven-day-old Sprague-Dawley rats were subjected to TBI using the controlled cortical impact (CCI) injury model. Age-matched littermates that did not receive TBI served as the controls. Immediately following TBI, rats were euthanized, and the brains were divided into the ipsilateral and contralateral hemispheres then flash frozen. A BioRad 23-Plex panel was used to measure cytokine levels. Surprisingly, the data revealed that 18 of the 23 cytokines analyzed were significantly downregulated in the hemisphere contralateral to the TBI impacted hemisphere. IL-5, IL-6 and MIP-3a were significantly suppressed in both ipsilateral and contralateral hemispheres of neonatal TBI rats compared to the control rats. A parallel study processing the plasma of the same cohort of neonatal rats revealed no difference in the same cytokines analyzed in the brain tissue, suggesting highly localized cytokine suppression in the brain during early injury. In stark contrast to the reported early pro-inflammatory response exhibited in adult TBI, the present neonatal TBI study demonstrated a reversed cytokine profile of downregulation. These results suggest a robust, immediate anti-inflammatory response mounted by the contralateral hemisphere of the young brain.

Low brain DHA content worsens sensorimotor outcomes after TBI and decreases TBI-induced Timp1 expression in juvenile rats

The effects of dietary modulation of brain DHA content on outcomes after TBI were examined in a juvenile rat model. Long-Evans rats with normal or diet-induced decreases in brain DHA were subjected to a controlled cortical impact or sham surgery on postnatal day 17. Rats with the greatest decreases in brain DHA had the poorest sensorimotor outcomes after TBI. Ccl2, Gfap, and Mmp 9 mRNA levels, and MMP-2 and -9 enzymatic activities were increased after TBI regardless of brain DHA level. Lesion volume was not affected by brain DHA level. In contrast, TBI-induced Timp1 expression was lower in rats on the Deficient diet and correlated with brain DHA level. These data suggest that decreased brain DHA content contributes to poorer sensorimotor outcomes after TBI through a mechanism involving modulation of Timp1 expression.