Mild traumatic brain injury

Correlation of clinical features with neuroimaging in children with mild head injury

Objectives

Mild head injury is defined as a pediatric Glasgow Coma Scale (GCS) score of 13-15 at admission following head trauma. There are no clear indications for neuroimaging in such children. The aim of our study was to analyze the correlation of symptoms commonly encountered following mild head injury with any abnormality on the computed tomography (CT) scan.

Materials and Methods

This is a retrospective and observational study done in a tertiary care hospital. Records of all the children fulfilling the inclusion criteria were retrieved. Demographic details such as age, gender, and type of injury (hit by a blunt object, fall from height, and road traffic accident), symptoms such as presence and number of episodes of vomiting, presence and duration of loss of consciousness (LOC), presence of drowsiness, headache, giddiness, seizures, focal deficits and the GCS score, and CT scan findings were noted in a predesigned proforma. A CT scan with any of the following abnormalities such as skull fracture, cerebral edema, intracranial bleed (epidural hematoma, subdural hematoma, intracerebral hematoma, and subarachnoid hemorrhage), and cerebral contusion was considered as abnormal. Any neurosurgical intervention done was also noted.

Results

A total of 134 children in the age group of 1 month to 18 years with mild head injury were included in this study. The median (interquartile range) age of the children was 5 (2, 8) years, with majority being males. Road traffic accidents (34.3%) were the most common cause of injury, followed by fall from lesser than 3 feet height (31.3%). The most common symptoms were vomiting (43.6%), scalp/facial abrasions (37.2%), and LOC (31.9%). CT scan was abnormal in 53.7% of the cases, with skull fracture (35.1%) being the most common finding, followed by cerebral edema (13.4%). Among all the symptoms, ear/nosebleed or cerebrospinal fluid (CSF) otorrhea/rhinorrhea had a statistically significant association with a positive CT scan with P = 0.05 and an odds ratio of 1.4 (95% confidence interval, 1-1.9).

Conclusion

Children with mild head injury presenting with clinical features such as bleeding from the ear or nose and CSF otorrhea/rhinorrhea are more likely to have an abnormal CT scan. Hence, such children require close neurological observation and prompt intervention if necessary. However, abnormality on CT scan cannot be reliably ruled out based on the symptoms alone.

Automatically Diagnosing Skull Fractures Using an Object Detection Method and Deep Learning Algorithm in Plain Radiography Images

OBJECTIVE

Deep learning is a machine learning approach based on artificial neural network training, and object detection algorithm using deep learning is used as the most powerful tool in image analysis. We analyzed and evaluated the diagnostic performance of a deep learning algorithm to identify skull fractures in plain radiographic images and investigated its clinical applicability.

METHODS

A total of 2026 plain radiographic images of the skull (fracture, 991; normal, 1035) were obtained from 741 patients. The RetinaNet architecture was used as a deep learning model. Precision, recall, and average precision were measured to evaluate the deep learning algorithm's diagnostic performance.

RESULTS

In ResNet-152, the average precision for intersection over union (IOU) 0.1, 0.3, and 0.5, were 0.7240, 0.6698, and 0.3687, respectively. When the intersection over union (IOU) and confidence threshold were 0.1, the precision was 0.7292, and the recall was 0.7650. When the IOU threshold was 0.1, and the confidence threshold was 0.6, the true and false rates were 82.9% and 17.1%, respectively. There were significant differences in the true/false and false-positive/false-negative ratios between the anteriorposterior, towne, and both lateral views (p=0.032 and p=0.003). Objects detected in false positives had vascular grooves and suture lines. In false negatives, the detection performance of the diastatic fractures, fractures crossing the suture line, and fractures around the vascular grooves and orbit was poor.

CONCLUSION

The object detection algorithm applied with deep learning is expected to be a valuable tool in diagnosing skull fractures.

ACR Appropriateness Criteria® Head Trauma: 2021 Update

Head trauma (ie, head injury) is a significant public health concern and is a leading cause of morbidity and mortality in children and young adults. Neuroimaging plays an important role in the management of head and brain injury, which can be separated into acute (0-7 days), subacute (<3 months), then chronic (>3 months) phases. Over 75% of acute head trauma is classified as mild, of which over 75% have a normal Glasgow Coma Scale score of 15, therefore clinical practice guidelines universally recommend selective CT scanning in this patient population, which is often based on clinical decision rules. While CT is considered the first-line imaging modality for suspected intracranial injury, MRI is useful when there are persistent neurologic deficits that remain unexplained after CT, especially in the subacute or chronic phase. Regardless of time frame, head trauma with suspected vascular injury or suspected cerebrospinal fluid leak should also be evaluated with CT angiography or thin-section CT imaging of the skull base, respectively. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The Association of Perioperative Serum Lactate Levels with Postoperative Delirium in Elderly Trauma Patients

Background

Several studies have shown the utility of lactate level as a predictor of early outcomes in trauma patients. We conducted this study to evaluate the association of perioperative serum lactate levels with postoperative delirium (POD) in elderly trauma patients.

Materials and Methods

This study included 466 elderly trauma patients with measurements of serum lactate levels on admission and 1 h after surgery. The associations of POD with serum lactate levels (on admission and 1 h after surgery) and lactate clearance were analyzed using Kendall's correlation. Perioperative serum lactate levels and lactate clearance as predictors of POD were evaluated using univariate and multivariable analyses.

Results

The incidence of POD in the present study was 38.1%. Serum lactate levels on admission and at 1 h after surgery were significantly higher in major trauma than in minor trauma. In univariate analysis of perioperative serum lactate levels and lactate clearance as predictors of POD, the odds ratio (OR) for serum lactate level on admission was 4.19 (P < 0.01, 2.91 < 95% confidence interval (CI) < 6.02) and that 1 h after surgery was 3.83 (P < 0.01, 2.79 < 95% CI < 5.25); however, the OR for serum change of lactate level was 0.99 ((P < 0.09, 0.99 < 95% CI < 1.00). In multivariable analysis for predictors of POD, the OR for serum lactate level on admission was 2.40 (P < 0.09, 0.87 < 95% CI < 6.7), that for serum lactate 1 h after surgery was 2.83 (P=0.01, 1.28 < 95% CI < 6.24), that for ICU admission was 3.01 (P=0.01, 2.09 < 95% CI < 6.03), and that for ISS was 1.47 (P < 0.01, 1.27 < 95% CI < 3.70).

Conclusions

Taking together the results of univariate and multivariable analyses, serum lactate level 1 h after surgery may be used as a prediction model of POD development in elderly trauma patients.

Clinical predictors of abnormal head computed tomography scan in patients who are conscious after head injury

Background:

Indication of a head computed tomography (CT) scan in a patient who remains conscious after head injury is controversial. We aimed to determine the clinical features that are most likely to be associated with abnormal CT scan in patients with a history of head injury, and who are conscious at the time of presentation to casualty.

Materials and Methods:

This is a prospective observation study of patients presented to casualty with history of head injury, and who were conscious, i.e., Glasgow Coma Scale (GCS) 15 at the time of evaluation. All patients underwent head CT scan. The CT scan was reported as abnormal if it showed any pathology ascribed to trauma. The following variables were used: age, gender, mode of injury (road traffic accident, fall, assault, and others), duration since injury, and history of transient loss of consciousness, headache, vomiting, ear/nose bleeding, and seizures. Logistic regression analysis was used to identify the clinical features that predicted an abnormal CT scan.

Results:

During the observation period, a total of 1629 patients with head injury were evaluated, out of which 453 were in GCS 15. Abnormal CT scan was present in 195 (43%) patients. Among all the variables, the following were found significantly associated with abnormal CT scan: duration since injury (>12 h) P < 0.001; vomiting odds, ratio (OR) 1.89 (1.23, 2.80), P < 0.001; and presence of any symptom, OR 2.36 (1.52, 3.71), P < 0.001.

Conclusion:

A patient with GCS 15 presenting after 12 hours of injury with vomiting or combination of symptoms has a significant risk of abnormal head CT scan.

Clinical significance of posttraumatic intracranial hemorrhage in clinically mild brain injury: a retrospective cohort study

BACKGROUND

Much attention has been focused on management of severe traumatic brain injury (TBI); however, comparatively little is known about management of traumatic hemorrhage in clinically mild TBI. We aimed to clarify the role of clinical observation and repeat radiography for patients with mild TBI and abnormal findings on initial computed tomography (CT) of the head.

METHODS

We queried the neurotrauma database of the Ontario Trauma Registry and the Sunnybrook institutional database to identify patients with CT findings of a traumatic hemorrhage or calvarial fracture between November 2014 and December 2016. Exclusionary criteria were age less than 16 years, Glasgow Coma Scale (GCS) score less than 13, anticoagulant use, bleeding diathesis and midline shift greater than 5 mm. The primary outcome was the need for neurosurgical intervention.

RESULTS

A total of 607 patients were included. Most (374 [61.6%]) had a GCS score of 15; 185 (30.5%) and 48 (7.9%) had a GCS score of 14 and 13, respectively. Five patients (0.8%) required surgical intervention, all within the first 72 hours, owing to clinical deterioration with subsequently demonstrated radiographic evidence of expanding hemorrhage. Most patients (506 [83.4%]) had routine repeat imaging, without documented change in their neurologic status.

INTERPRETATION

The majority of patients in our cohort had repeat imaging, which did not influence surgical management, at substantial cost to the health care system. The findings suggest the need to reevaluate repeat imaging protocols for this subset of patients with TBI.

Postconcussion symptom reporting is not associated with diffusion tensor imaging findings in the subacute to chronic phase of recovery in military service members following mild traumatic brain injury

INTRODUCTION

The purpose of this study was to examine the relation between white matter integrity of the brain and postconcussion symptom reporting following mild traumatic brain injury (MTBI).

METHOD

Participants were 109 U.S. military service members (91.7% male) who had sustained a MTBI (n = 88) or orthopedic injury without TBI (trauma controls, TC, n = 21), enrolled from the Walter Reed National Military Medical Center, Bethesda, Maryland. Participants completed a battery of neurobehavioral symptom measures and underwent diffusion tensor imaging (DTI; General Electric 3T) of the whole brain, on average 44.9 months post injury (SD = 42.3). Measures of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were generated for 18 regions of interest (ROIs). Participants in the MTBI group were divided into two subgroups based on International Classification of Diseases-10th Revision (ICD-10) Category C criteria for postconcussion syndrome (PCS): PCS-present (n = 41) and PCS-absent (n = 47).

RESULTS

The PCS-present group had significantly worse scores on all 13 neurobehavioral measures than the PCS-absent group (p < .001, d = 0.87-2.50) and TC group (p < .003, d = 0.84-2.06). For all ROIs, there were no significant main effects across the three groups for FA, MD, AD, and RD (all ps >.03). Pairwise comparisons revealed no significant differences for all ROIs when using FA and RD, and only two significant pairwise differences were found between PCS-present and PCS-absent groups when using MD and AD [i.e., anterior thalamic radiation and cingulate gyrus (supracallosal) bundle].

CONCLUSIONS

Consistent with past research, but not all studies, postconcussion symptom reporting was not associated with white matter integrity in the subacute to chronic phase of recovery following MTBI.

Protein Network Analysis of the Serum and Their Functional Implication in Patients Subjected to Traumatic Brain Injury

Traumatic brain injury (TBI) often leads to severe neurobehavioral impairment, but the underlying molecular mechanism remains to be elucidated. Here, we collected the sera from 23 patients (aged from 19 to 81 years old, third day after TBI as TBI-third group) subjected to TBI from The First Hospital of Kunming City, and the sera from 22 healthy donors (aged from 18 to 81 years old and as control group). Then, three samples from TBI-third group and three samples from control group were subjected to the protein microarray detection, and bioinformatics analysis. Then, enzyme-linked immunosorbent assay (ELISA) was used to verify significantly altered protein levels. Results showed that, when compared with the control group, all significantly differentially expressed proteins [DEPs, P < 0.05, FDR < 0.05, fold change (FC) > 2] contained 172 molecules in the TBI-third group, in which 65 proteins were upregulated, while 107 proteins were downregulated. The biological processes of these DEPs, mostly happened in the extracellular region and the extracellular region parts, are mainly involved in the regulation of cellular process, signaling and signal transduction, cell communication, response to stimuli, the immune system process and multicellular organismal development. Moreover, the essential molecular functions of them are cytokine activity, growth factor activity and morphogen activity. Additionally, the most significant pathways are enriched in cytokine–cytokine receptor interaction and PI3K-Akt signaling pathways among downregulated proteins, and pathways in cancer and cytokine–cytokine receptor interaction among upregulated proteins. Of these, we focused on the NGF, NT-3, IGF-2, HGF, NPY, CRP, MMP-9, and ICAM-2 with a high number of interactors in Protein–Protein Interaction (PPI) Network indicated by bioinformatics report. Furthermore, using ELISA test, we confirmed that all increase in the levels of NGF, NT-3, IGF-2, HGF, NPY, CRP, MMP-9, and ICAM-2 in the serum from TBI patients. Together, we determined the screened protein expressional profiles in serum for TBI patients, in which the cross-network between inflammatory factors and growth factors may play a crucial role in TBI damage and repair. Our findings could contribute to indication for the diagnosis and treatment of TBI in future translational medicine and clinical practice.

Delirium in Trauma Patients: Prevalence and Predictors

BACKGROUND

Delirium is associated with increased mortality, morbidity, hospital costs, and postdischarge cognitive dysfunction. Most research focuses on nontrauma patients receiving mechanical ventilation in the intensive care unit.

OBJECTIVES

To determine the prevalence and predictors of delirium in trauma patients residing in intensive and intermediate care units of an academic medical center.

METHODS

Trauma patients were screened for delirium by using the Confusion Assessment Method for the Intensive Care Unit. Exclusion criteria included documented brain injury, history of psychosis or cognitive impairment, not speaking English, and hearing or vision loss.

RESULTS

Of the 215 study patients, 24% were positive for delirium; 36% of patients in the intensive care unit and 11% of patients in the intermediate care unit. Delirium-positive patients were older (mean age, 53.4 years) than patients who were not (mean age, 44 years; P = .004). Although mechanical ventilation (odds ratio, 4.73, P = .004) was the strongest independent risk factor for delirium, 12% of delirium-positive patients were not receiving mechanical ventilation. Other predictors of delirium were use of antipsychotic medications, higher scores on the Acute Physiology and Chronic Health Evaluation III, and lower scores on the Richmond Agitation-Sedation Scale.

CONCLUSIONS

Patients in both the intermediate and intensive care units, whether mechanical ventilation was used or not, were positive for delirium. Delirium prevention protocols may benefit trauma patients regardless of their inpatient location.

Strides Toward Better Understanding of Post-Traumatic Headache Pathophysiology Using Animal Models

PURPOSE OF REVIEW

In recent years, the awareness of the detrimental impact of concussion and mild traumatic brain injuries (mTBI) is becoming more apparent. Concussive head trauma results in a constellation of cognitive and somatic symptoms of which post-traumatic headache is the most common. Our understanding of post-traumatic headache is limited by the paucity of well validated, characterized, and clinically relevant animal models with strong predictive validity. In this review, we aim to summarize and discuss current animal models of concussion/mTBI and related data that start to shed light on the pathophysiology of post-traumatic headache.

RECENT FINDINGS

Each of the models will be discussed in terms of their face, construct, and predictive validity as well as overall translational relevance to concussion, mTBI, and post-traumatic headache. Significant contributions to the pathophysiology of PTH garnered from these models are discussed as well as potential contributors to the development of chronic post-traumatic headache. Although post-traumatic headache is one of the most common symptoms following mild head trauma, there remains a disconnect between the study of mild traumatic brain injury and headache in the pre-clinical literature. A greater understanding of the relationship between these phenomena is currently needed to provide more insight into the increasing frequency of this debilitating condition in both military and civilian populations.

Comparisons of the accuracy of radiation diagnostic modalities in brain tumor: A nonrandomized, nonexperimental, cross-sectional trial

Tumor morphology improved sensitivity, accuracy, and specificity of the diagnosis, but all diagnostic techniques have attenuation correction issues.To compare computed tomographic (CT), positron emission tomographic (PET), and magnetic resonance imaging (MRI) characteristics of patients with brain tumor in a Chinese setting.A nonrandomized, nonexperimental, cross-sectional trial.Jining No. 1 People's Hospital, China.In total, 127 patients who had clinically confirmed a brain tumor were included in the cross-sectional study. Patients were subjected to brain CT, MRI, and PET. The tumors resected after brain surgery were subjected to morphological diagnosis. Statistical analysis of data of surgically removed tumor and that of different methods of diagnosis was performed using Wilcoxon test following Tukey-Kramer test. Spearmen correlation was performed between diagnostic modalities and in vivo morphology. Results were considered significant at 99% of confidence level.The data of diameter and volume of tumor derived from CT (Spearman r = 0.9845 and 0.9706), and MRI (Spearman r = 0.955 and 0.2378) were failed to correlate with that of that of the surgically removed tumor. However, prediction of diameter and volume of the tumor by PET (Spearman r = 0.9922 and 0.9921) were correlated with that of the surgically removed tumor. CT and MRI were failed to quantified pituitary adenomas.The study was recommended PET for assessment of brain tumor.

Staying in the game: a pilot study examining the efficacy of protective headgear in an animal model of mild traumatic brain injury (mTBI)

PRIMARY OBJECTIVE

Rugby is one of the few contact sports that do not mandate protective headgear, possibly because studies have shown poor efficacy for protection related to concussion pathology with existing headguards.

RESEARCH DESIGN

Following innovative material technology utilization to produce headgear believed to have protective capabilities, this study examined the effects of a soft-shell headgear constructed from a novel viscoelastic material, on both behaviour and serum biomarkers after high and average impact force mild traumatic brain injuries (mTBI).

METHODS AND PROCEDURES

Seventy-five male Sprague Dawley rats were divided into five groups: control, average - 37G impact, with and without headgear, and high - 106G impact, with and without headgear. Rats were sacrificed at 3 or 48 hours and serum samples were analyzed for levels of TNF-α, NEF-L, and GFAP. Animals sacrificed at 48 hours also underwent testing for balance and motor coordination, and exploratory/locomotor behaviour.

MAIN OUTCOMES AND RESULTS

The novel headgear offered significant protection against mTBI symptomology and biomarkers in the group that experienced an average impact force, but only moderated protection for the animals in the high impact group.

CONCLUSIONS

This innovative headgear may prevent some of the negative sequel associated with concussion pathology.

Discharge Instructions for Concussion: Are We Meeting the Patient Needs?

Education to improve symptom management is an agreed-upon strategy to reduce the impact of symptoms on the quality of life for persons with mild traumatic brain injury. The purpose of this study was to investigate whether current discharge education practices are deemed adequate by persons treated and released from the emergency department with concussion. A review of current literature identified a need for patient education improvements in emergency departments. Strategies for improving information retention in the mild traumatic brain injury patient population for effective symptom management are identified. A concussion symptom management booklet was created using current scientific information. The concussion education booklet along with standardized postconcussion education was provided to patients with mild traumatic brain injuries who were discharged from a level I trauma center emergency department. A prospective small-scale study was performed to establish the ease of use and usefulness of the newly created concussion education booklet and determine whether patients preferred the booklet of information over the standard discharge instructions.

Female gonadal hormone effects on microglial activation and functional outcomes in a mouse model of moderate traumatic brain injury

AIM

To address the hypothesis that young, gonad-intact female mice have improved long-term recovery associated with decreased neuroinflammation compared to male mice.

METHODS

Eight to ten week-old male, female, and ovariectomized (OVX) mice underwent closed cranial impact. Gonad-intact female mice were injured only in estrus state. After injury, between group differences were assessed using complementary immunohistochemical staining for microglial cells at 1 h, mRNA polymerase chain reaction for inflammatory markers at 1 h after injury, Rotarod over days 1-7, and water maze on days 28-31 after injury.

RESULTS

Male mice had a greater area of injury (P = 0.0063), F4/80-positive cells (P = 0.032), and up regulation of inflammatory genes compared to female mice. Male and OVX mice had higher mortality after injury when compared to female mice (P = 0.043). No group differences were demonstrated in Rotarod latencies (P = 0.62). OVX mice demonstrated decreased water maze latencies compared to other groups (P = 0.049).

CONCLUSION

Differences in mortality, long-term neurological recovery, and markers of neuroinflammation exist between female and male mice after moderate traumatic brain injury (MTBI). Unexpectedly, OVX mice have decreased long term neurological function after MTBI when compared to gonad intact male and female mice. As such, it can be concluded that the presence of female gonadal hormones may influence behavioural outcomes after MTBI, though mechanisms involved are unclear.

Development of CGRP-dependent pain and headache related behaviours in a rat model of concussion: Implications for mechanisms of post-traumatic headache

Background and objective Posttraumatic headache (PTH) is one of the most common, debilitating and difficult symptoms to manage after a mild traumatic brain injury, or concussion. However, the mechanisms underlying PTH remain elusive, in part due to the lack of a clinically relevant animal model. Here, we characterized for the first time, headache and pain-related behaviours in a rat model of concussion evoked by a mild closed head injury (mCHI) - the major type of military and civilian related trauma associated with PTH - and tested responses to current and novel headache therapies. Methods Concussion was induced in adult male rats using a weight-drop device. Characterization of headache and pain related behaviours included assessment of cutaneous tactile pain sensitivity, using von Frey monofilaments, and ongoing pain using the conditioned place preference or aversion (CPP/CPA) paradigms. Sensitivity to headache/migraine triggers was tested by exposing rats to low-dose glyceryl trinitrate (GTN). Treatments included acute systemic administration of sumatriptan and chronic systemic administration of a mouse anti-CGRP monoclonal antibody. Results Concussed rats developed cephalic tactile pain hypersensitivity that was resolved by two weeks post-injury and was ameliorated by treatment with sumatriptan or anti-CGRP monoclonal antibody. Sumatriptan also produced CPP seven days post mCHI, but not in sham animals. Following the resolution of the concussion-evoked cephalic hypersensitivity, administration of GTN produced a renewed and pronounced cephalic pain hypersensitivity that was inhibited by sumatriptan or anti-CGRP antibody treatment as well as a CGRP-dependent CPA. GTN had no effect in sham animals. Conclusions Concussion leads to the development of headache and pain-related behaviours, in particular sustained enhanced responses to GTN, that are mediated through a CGRP-dependent mechanism. Treatment with anti-CGRP antibodies may be a useful approach to treat PTH.

The Effectiveness of Early Educational Interventions in the Emergency Department to Reduce Incidence or Severity of Postconcussion Syndrome Following a Concussion: A Systematic Review

OBJECTIVES

Concussions or mild traumatic brain injury are a major public health concern accounting for 85% of all brain injuries. Postconcussion syndrome (PCS) has been found to affect between 15 and 25% of patients with concussion 1 year after the initial injury. The goal of this review is to assess the effectiveness of early educational information or interventions provided in the emergency department on the onset and/or severity of PCS.

METHODS

A comprehensive literature search strategy involving seven electronic databases was developed. A grey literature search of Google Scholar, recent conference proceedings in emergency medicine, bibliographies of included studies, and clinical trial registries was also performed. The citation list was reviewed independently by two reviewers; no restrictions on publication status or language of publication were applied. The Cochrane risk-of-bias tool and the Newcastle-Ottawa scale were used to assess quality.

RESULTS

From 1,325 citations retrieved, four RCTs and one controlled clinical trial met inclusion criteria. Interventions identified in these studies included: educational information sheets, with or without telephone or in-person follow-up, and one study on bed rest. While rarely requested, one study offered referrals and additional treatment, if needed. None of the studies were deemed to be high quality. Heterogeneity among outcome reporting, follow-up dates and interventions used precluded a pooled analysis. Overall, only two of the five included studies involving adult patients receiving early educational interventions reported a significant improvement in PCS symptoms. No reduction in PCS symptoms was found in the study on bed rest interventions.

CONCLUSION

Limited evidence exists regarding the effectiveness of early educational interventions following concussion. Standardization of the interventions, outcome measures, and follow-up periods would make quantitative comparisons more valid. Moreover, higher-quality research in the field of early interventions for patients in the acute care setting is urgently required.

Current status of fluid biomarkers in mild traumatic brain injury

Mild traumatic brain injury (mTBI) affects millions of people annually and is difficult to diagnose. Mild injury is insensitive to conventional imaging techniques and diagnoses are often made using subjective criteria such as self-reported symptoms. Many people who sustain a mTBI develop persistent post-concussive symptoms. Athletes and military personnel are at great risk for repeat injury which can result in second impact syndrome or chronic traumatic encephalopathy. An objective and quantifiable measure, such as a serum biomarker, is needed to aid in mTBI diagnosis, prognosis, return to play/duty assessments, and would further elucidate mTBI pathophysiology. The majority of TBI biomarker research focuses on severe TBI with few studies specific to mild injury. Most studies use a hypothesis-driven approach, screening biofluids for markers known to be associated with TBI pathophysiology. This approach has yielded limited success in identifying markers that can be used clinically, additional candidate biomarkers are needed. Innovative and unbiased methods such as proteomics, microRNA arrays, urinary screens, autoantibody identification and phage display would complement more traditional approaches to aid in the discovery of novel mTBI biomarkers.

Compensation through Functional Hyperconnectivity: A Longitudinal Connectome Assessment of Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is a major public health concern. Functional MRI has reported alterations in several brain networks following mTBI. However, the connectome-scale brain network changes are still unknown. In this study, sixteen mTBI patients were prospectively recruited from an emergency department and followed up at 4-6 weeks after injury. Twenty-four healthy controls were also scanned twice with the same time interval. Three hundred fifty-eight brain landmarks that preserve structural and functional correspondence of brain networks across individuals were used to investigate longitudinal brain connectivity. Network-based statistic (NBS) analysis did not find significant difference in the group-by-time interaction and time effects. However, 258 functional pairs show group differences in which mTBI patients have higher functional connectivity. Meta-analysis showed that "Action" and "Cognition" are the most affected functional domains. Categorization of connectomic signatures using multiview group-wise cluster analysis identified two patterns of functional hyperconnectivity among mTBI patients: (I) between the posterior cingulate cortex and the association areas of the brain and (II) between the occipital and the frontal lobes of the brain. Our results demonstrate that brain concussion renders connectome-scale brain network connectivity changes, and the brain tends to be hyperactivated to compensate the pathophysiological disturbances.

Diffusion tensor imaging findings and postconcussion symptom reporting six weeks following mild traumatic brain injury

The purpose of this study is to examine the relation between the microstructural architecture of white matter, as measured by diffusion tensor imaging (DTI), and postconcussion symptom reporting 6-8 weeks following mild traumatic brain injury (MTBI). Participants were 108 patients prospectively recruited from a Level 1 Trauma Center (Vancouver, BC, Canada) following an orthopedic injury [i.e., 36 trauma controls (TCs)] or MTBI (n = 72). DTI of the whole brain was undertaken using a Phillips 3T scanner at 6-8 weeks postinjury. Participants also completed a 5 h neurocognitive test battery and a brief battery of self-report measures (e.g., depression, anxiety, and postconcussion symptoms). The MTBI sample was divided into two groups based on ICD-10 criteria for postconcussional syndrome (PCS): first, PCS-present (n = 20) and second, PCS-absent (n = 52). There were no significant differences across the three groups (i.e., TC, PCS-present, and PCS-absent) for any of the neurocognitive measures (p = .138-.810). For the self-report measures, the PCS-present group reported significantly more anxiety and depression symptoms compared with the PCS-absent and TC groups (p < .001, d = 1.63-1.89, very large effect sizes). For the DTI measures, there were no significant differences in fractional anisotropy, axial diffusivity, radial diffusivity, or mean diffusivity when comparing the PCS-present and PCS-absent groups. However, there were significant differences (p < .05) in MD and RD when comparing the PCS-present and TC groups. There were significant differences in white matter between TC subjects and the PCS-present MTBI group, but not the PCS-absent MTBI group. Within the MTBI group, white-matter changes were not a significant predictor of ICD-10 PCS.

Alteration of default mode network in high school football athletes due to repetitive subconcussive mild traumatic brain injury: a resting-state functional magnetic resonance imaging study

Long-term neurological damage as a result of head trauma while playing sports is a major concern for football athletes today. Repetitive concussions have been linked to many neurological disorders. Recently, it has been reported that repetitive subconcussive events can be a significant source of accrued damage. Since football athletes can experience hundreds of subconcussive hits during a single season, it is of utmost importance to understand their effect on brain health in the short and long term. In this study, resting-state functional magnetic resonance imaging (rs-fMRI) was used to study changes in the default mode network (DMN) after repetitive subconcussive mild traumatic brain injury. Twenty-two high school American football athletes, clinically asymptomatic, were scanned using the rs-fMRI for a single season. Baseline scans were acquired before the start of the season, and follow-up scans were obtained during and after the season to track the potential changes in the DMN as a result of experienced trauma. Ten noncollision-sport athletes were scanned over two sessions as controls. Overall, football athletes had significantly different functional connectivity measures than controls for most of the year. The presence of this deviation of football athletes from their healthy peers even before the start of the season suggests a neurological change that has accumulated over the years of playing the sport. Football athletes also demonstrate short-term changes relative to their own baseline at the start of the season. Football athletes exhibited hyperconnectivity in the DMN compared to controls for most of the sessions, which indicates that, despite the absence of symptoms typically associated with concussion, the repetitive trauma accrued produced long-term brain changes compared to their healthy peers.

Traumatic brain injury - modeling neuropsychiatric symptoms in rodents

Each year in the US, ∼1.5 million people sustain a traumatic brain injury (TBI). Victims of TBI can suffer from chronic post-TBI symptoms, such as sensory and motor deficits, cognitive impairments including problems with memory, learning, and attention, and neuropsychiatric symptoms such as depression, anxiety, irritability, aggression, and suicidal rumination. Although partially associated with the site and severity of injury, the biological mechanisms associated with many of these symptoms - and why some patients experience differing assortments of persistent maladies - are largely unknown. The use of animal models is a promising strategy for elucidation of the mechanisms of impairment and treatment, and learning, memory, sensory, and motor tests have widespread utility in rodent models of TBI and psychopharmacology. Comparatively, behavioral tests for the evaluation of neuropsychiatric symptomatology are rarely employed in animal models of TBI and, as determined in this review, the results have been inconsistent. Animal behavioral studies contribute to the understanding of the biological mechanisms by which TBI is associated with neurobehavioral symptoms and offer a powerful means for pre-clinical treatment validation. Therefore, further exploration of the utility of animal behavioral tests for the study of injury mechanisms and therapeutic strategies for the alleviation of emotional symptoms are relevant and essential.

Minor traumatic brain injury: a primer for the orthopaedic surgeon

Minor traumatic brain injury (mTBI) is a major public health problem. The Centers for Disease Control and Prevention and the National Center for Injury Prevention and Control label it a "silent epidemic." Subtle signs and symptoms of mTBI, including headache, fatigue, and memory loss, are often seen in conjunction with musculoskeletal trauma. Although sometimes evident immediately, mTBI may not manifest until patients return to work and their personal lives. In the patient with acute concurrent mTBI, skeletal management must be based on either a period of observation to rule out evolving neurologic symptoms or, when warranted, the recommendations of a neurosurgeon. Such input is particularly important when mTBI is associated with a prolonged loss of consciousness or posttraumatic amnesia. In the outpatient setting, when concern for mTBI exists weeks after an injury, familiarity with and referral to locally available mTBI specialists and programs can facilitate proper care. Armed with this knowledge, the orthopaedic surgeon has an opportunity to positively influence outcomes and help provide crucial care that extends beyond the management of musculoskeletal injuries.

Postconcussion syndrome and mild head injury: the role of early diagnosis using neuropsychological tests and functional magnetic resonance/spectroscopy

OBJECTIVE

Postconcussion syndrome (PCS) is usually underestimated in cases of mild head injury (MHI). It is one of the most common causes of physical, cognitive, and psychomotor disturbances that affect the quality of life, work, and social reintegration of individuals. Until now, we did not have evidence of structural abnormalities shown by traditional imaging methods. We describe a series of instruments that confirm PCS with satisfactory evidence.

METHODS

We conducted a clinical prospective study of 19 adult patients selected from a pool of 320 adults who had MHI. The cognitive, executive, and memory functions of subjects were examined within the first 72 hours using neuropsychological tests. These results were analyzed with neurological examination and functional MR/spectroscopy.

RESULTS

Neurobehavioral alterations were found in 47% of cases, with posttraumatic amnesia. Around 55% of subjects experienced physical disturbances such as headache and postural vertigo due to PCS. The spectroscopy reports revealed neurometabolite disturbances in 54% of cases, particularly N-acetylaspartate (Naa) and the Naa/lactate ratio in the frontal lobe. We observed a relationship between metabolite disturbances in spectroscopy and the digit span backward test (P = .045).

CONCLUSIONS

This first diagnostic strategy supports with scientific evidence the presence of PCS in MHI. We identified physical and neuropsychological abnormalities from this group, affecting the areas of memory and learning. Evidence of neurometabolite disturbances were found specifically in the frontal lobe. It is necessary to complete comparative follow-up for an extended period of time. The neuropsychological and spectroscopy tests allow us to confirm the diagnosis of a syndrome that is usually neglected.

Application of blood-based biomarkers in human mild traumatic brain injury

Traumatic Brain Injury (TBI) is a global health concern. The majority of TBI's are mild, yet our ability to diagnose and treat mild traumatic brain injury (mTBI) is lacking. This deficiency results from a variety of issues including the difficulty in interpreting ambiguous clinically presented symptoms, and ineffective imaging techniques. Thus, researchers have begun to explore cellular and molecular based approaches to improve both diagnosis and prognosis. This has been met with a variety of challenges, including difficulty in relating biological markers to current clinical symptoms, and overcoming our lack of fundamental understanding of the pathophysiology of mTBI. However, recent adoption of high throughput technologies and a change in focus from the identification of single to multiple markers has given just optimism to mTBI research. The purpose of this review is to highlight a number of current experimental peripheral blood biomarkers of mTBI, as well as comment on the issues surrounding their clinical application and utility.

Biomarkers in traumatic brain injury

Traumatic brain injury (TBI) is a common cause of neurological morbidity globally, and neurologic sequelae may occur even in the setting of mild injury. At present, the tools that guide diagnostic and prognostic evaluation of patients who suffer from TBI remain limited, especially for prehospital evaluation. Biomarkers of brain injury hold promise in facilitating early management and triage decisions in the civilian and military settings. The identification of biomarkers of brain injury may also be helpful in guiding end-of-life decision making and may facilitate the design of neuroprotective trials.

Effects of brain contusion on mild traumatic brain-injured patients

Traumatic brain injury (TBI) is an important health issue with high prevalence. The most common type of TBI is mild TBI (MTBI). MTBI is known as a condition with self-limited symptoms; however, it could cause some structural abnormalities of brain and become complicated. Visible structural brain damage could have an important effect on recovery after MTBI, but the outcome is not fully understood. This study investigated the clinical course of MTBI patients with the existence of contusion in computed tomography (CT) imaging. Fifty patients with MTBI and simultaneous brain contusion in CT scan were enrolled according to specific exclusion criteria in 14 month. Patients were followed up for two weeks after their first arrival for neurosurgical interventions, decreased level of consciousness, and other neurological complications. Presence of neurological symptoms increased duration of hospital stay and number of CT scans. Forty-two percent of MTBI patients with contusion did not have any objective neurological signs. Fifty percent returned to the hospital with neurologic symptoms and signs. Leading causes were headache followed by seizure and dizziness. Rehospitalization was increased in the patients with altered level of consciousness. The size of brain contusion increased in two patients without further need for neurosurgical intervention. Contusion alone did not worsen the prognosis of patients in short-term follow-up and did not cause neurosurgical interventions.

Diffusion tensor imaging findings are not strongly associated with postconcussional disorder 2 months following mild traumatic brain injury

OBJECTIVE

To examine the relation between diffusion tensor imaging (DTI) of the corpus callosum and postconcussion symptom reporting following mild traumatic brain injury (MTBI).

PARTICIPANTS

Sixty patients with MTBI and 34 patients with orthopedic/soft-tissue injuries (Trauma Controls) prospectively enrolled from consecutive admissions to a level 1 trauma center.

PROCEDURE

Diffusion tensor imaging of the corpus callosum was undertaken using a Phillips 3T scanner at 6 to 8 weeks postinjury. Participants also completed a postconcussion symptom checklist. The MTBI group was divided into 2 subgroups based on the International Classification of Diseases, Tenth Revision symptom criteria for postconcussion disorder (PCD): PCD Present (n = 21), PCD Absent (n = 39).

MAIN OUTCOME MEASURES

Measures of fractional anisotropy and mean diffusivity for the genu, body, and splenium of the corpus callosum. Participants also completed the British Columbia Post-Concussion Symptom Inventory.

RESULTS

The MTBI group reported more postconcussion symptoms than the trauma controls. There were no significant differences between MTBI and trauma control groups on all DTI measures. In the MTBI sample, there were no significant differences on all DTI measures between those who did and did not meet the International Classification of Diseases, Tenth Revision research criteria for postconcussion disorder.

CONCLUSIONS

These data do not support an association between white matter integrity in the corpus callosum and self-reported postconcussion syndrome 6 to 8 weeks post-MTBI.

Improving the care of people with traumatic brain injury through the Neurotrauma Evidence Translation (NET) program: protocol for a program of research

The Neurotrauma Evidence Translation (NET) program was funded in 2009 to increase the uptake of research evidence in the clinical care of patients who have sustained traumatic brain injury. This paper reports the rationale and plan for this five-year knowledge translation research program. The overarching aims of the program are threefold: to improve outcomes for people with traumatic brain injury; to create a network of neurotrauma clinicians and researchers with expertise in knowledge translation and evidence-based practice; and to contribute knowledge to the field of knowledge translation research. The program comprises a series of interlinked projects spanning varying clinical environments and disciplines relevant to neurotrauma, anchored within four themes representing core knowledge translation activities: reviewing research evidence; understanding practice; developing and testing interventions for practice change; and building capacity for knowledge translation in neurotrauma. The program uses a range of different methods and study designs, including: an evidence fellowship program; conduct of and training in systematic reviews; mixed method study designs to describe and understand factors that influence current practices (e.g., semi-structured interviews and surveys); theory-based methods to develop targeted interventions aiming to change practice; a cluster randomised trial to test the effectiveness of a targeted theory-informed intervention; stakeholder involvement activities; and knowledge translation events such as consensus conferences.

A review of magnetic resonance imaging and diffusion tensor imaging findings in mild traumatic brain injury

Mild traumatic brain injury (mTBI), also referred to as concussion, remains a controversial diagnosis because the brain often appears quite normal on conventional computed tomography (CT) and magnetic resonance imaging (MRI) scans. Such conventional tools, however, do not adequately depict brain injury in mTBI because they are not sensitive to detecting diffuse axonal injuries (DAI), also described as traumatic axonal injuries (TAI), the major brain injuries in mTBI. Furthermore, for the 15 to 30 % of those diagnosed with mTBI on the basis of cognitive and clinical symptoms, i.e., the "miserable minority," the cognitive and physical symptoms do not resolve following the first 3 months post-injury. Instead, they persist, and in some cases lead to long-term disability. The explanation given for these chronic symptoms, i.e., postconcussive syndrome, particularly in cases where there is no discernible radiological evidence for brain injury, has led some to posit a psychogenic origin. Such attributions are made all the easier since both posttraumatic stress disorder (PTSD) and depression are frequently co-morbid with mTBI. The challenge is thus to use neuroimaging tools that are sensitive to DAI/TAI, such as diffusion tensor imaging (DTI), in order to detect brain injuries in mTBI. Of note here, recent advances in neuroimaging techniques, such as DTI, make it possible to characterize better extant brain abnormalities in mTBI. These advances may lead to the development of biomarkers of injury, as well as to staging of reorganization and reversal of white matter changes following injury, and to the ability to track and to characterize changes in brain injury over time. Such tools will likely be used in future research to evaluate treatment efficacy, given their enhanced sensitivity to alterations in the brain. In this article we review the incidence of mTBI and the importance of characterizing this patient population using objective radiological measures. Evidence is presented for detecting brain abnormalities in mTBI based on studies that use advanced neuroimaging techniques. Taken together, these findings suggest that more sensitive neuroimaging tools improve the detection of brain abnormalities (i.e., diagnosis) in mTBI. These tools will likely also provide important information relevant to outcome (prognosis), as well as play an important role in longitudinal studies that are needed to understand the dynamic nature of brain injury in mTBI. Additionally, summary tables of MRI and DTI findings are included. We believe that the enhanced sensitivity of newer and more advanced neuroimaging techniques for identifying areas of brain damage in mTBI will be important for documenting the biological basis of postconcussive symptoms, which are likely associated with subtle brain alterations, alterations that have heretofore gone undetected due to the lack of sensitivity of earlier neuroimaging techniques. Nonetheless, it is noteworthy to point out that detecting brain abnormalities in mTBI does not mean that other disorders of a more psychogenic origin are not co-morbid with mTBI and equally important to treat. They arguably are. The controversy of psychogenic versus physiogenic, however, is not productive because the psychogenic view does not carefully consider the limitations of conventional neuroimaging techniques in detecting subtle brain injuries in mTBI, and the physiogenic view does not carefully consider the fact that PTSD and depression, and other co-morbid conditions, may be present in those suffering from mTBI. Finally, we end with a discussion of future directions in research that will lead to the improved care of patients diagnosed with mTBI.

MicroRNA let-7i is a promising serum biomarker for blast-induced traumatic brain injury

Blast-induced traumatic brain injury (TBI) is of significant concern in soldiers returning from the current conflicts in Iraq and Afghanistan. Incidents of TBI have increased significantly in the current conflicts compared to previous wars, and a majority of these injuries are caused by improvised explosive devices. Currently, no specific technique or biomarker is available for diagnosing TBI when no obvious clinical symptoms are present. Micro-RNAs are small RNA (~ 22nts) molecules that are expressed endogenously and play an important role in regulating gene expression. MicroRNAs have emerged as novel serum diagnostic biomarkers for various diseases. In this study, we studied the effect of blast overpressure injury on the microRNA signatures in the serum of rats. Rats were exposed to three serial 120-kPa blast overpressure exposures through a shockwave tube. Blood and cerebrospinal fluid were collected at various time points after injury, and microRNA modulation was analyzed using real-time PCR. Five microRNAs were significantly modulated in the serum samples of these animals at three time points post-injury. Further, we also found that the levels of microRNA let-7i are also elevated in cerebrospinal fluid post-blast wave exposure. The presence of microRNA in both serum and cerebrospinal fluid immediately after injury makes microRNA let-7i an ideal candidate for further studies of biomarkers in TBI.

Long-term cognitive and emotional consequences of mild traumatic brain injury

BACKGROUND

The objective of this study was to investigate long-term cognitive and emotional sequelae of mild traumatic brain injury (mTBI), as previous research has remained inconclusive with respect to their prevalence and extent.

METHOD

Thirty-three individuals who had sustained mTBI on average 6 years prior to the study and 33 healthy control subjects were matched according to age, gender and education. Structural brain damage at time of testing was excluded by magnetic resonance imaging (MRI). A comprehensive neuropsychological test battery was conducted to assess learning, recall, working memory, attention and executive function. Psychiatric symptoms were assessed by the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and the Beck Depression Inventory (BDI). Possible negative response bias was ruled out by implementing the Word Memory Test (WMT).

RESULTS

The mTBI individuals had significant impairments in all cognitive domains compared to the healthy control subjects. Effect sizes of cognitive deficits were medium to large, and could not be accounted for by self-perceived deficits, depression, compensation claims or negative response bias. BDI scores were significantly higher in the patient group, and three patients fulfilled DSM-IV criteria for a mild episode of major depression.

CONCLUSIONS

Primarily, well-recovered individuals who had sustained a minor trauma more than half a decade ago continue to have long-term cognitive and emotional sequelae relevant for everyday social and professional life. mTBI may lead to a lasting disruption of neurofunctional circuits not detectable by standard structural MRI and needs to be taken seriously in clinical and forensic evaluations.

Mild traumatic brain injury results in extensive neuronal degeneration in the cerebral cortex

Mild traumatic brain injury (mTBI) leads to long-term cognitive and emotional difficulties and behavioral disturbances, but the diagnosis and treatment of mTBI have historically been hampered by a lack of evidence-based correlates of these clinical manifestations. Unlike moderate and severe TBI, mTBI does not show significant tissue lesions or cavities in the cortex. Moreover, neuroimaging by magnetic resonance imaging or computed tomography is usually negative, suggesting that the damage is beyond the resolution of current structure-based scanning technologies. Therefore, we investigated the morphologies of spared neurons in the mouse cortex after mTBI in a controlled cortical impact injury model. Our results indicate that, although mTBI caused only a mild extent of cell death, it led to extensive dendrite degeneration and synapse reduction in the cortex in this model. This study sheds light on the neuropathologic consequences of mTBI in humans and suggests that neurodegeneration may be a novel target for developing diagnostic methods and therapeutic approaches for mTBI.

Neuropsychiatric complications of traumatic brain injury

Traumatic brain injury (TBI) may be defined as any extracranial mechanical force to the brain that results in any period of loss of consciousness, any loss of memory for events immediately before or after the event, or any alteration in mental status at the time of the event. The major causes are automobile accidents, falls, sporting injuries, and assaults. Many soldiers returning from combat in Afghanistan and Iraq have also experienced TBI. This article provides an overview of the neuropsychiatric complications of TBI, including impairment of consciousness, posttraumatic amnesia, cognitive disorders and dementia, posttraumatic epilepsy, aphasia, depression, mania, psychosis, anxiety disorders, personality changes, aggression, behavioral dyscontrol, fatigue/apathy, and increased risk of suicide. Discussion will focus primarily on issues affecting mental health clinicians. Because mental health providers are more involved in care of chronic issues related to TBI, these issues will be discussed in more detail, although acute neuropsychiatric complications of TBI will be briefly explained.

Increase in blood-brain barrier permeability, oxidative stress, and activated microglia in a rat model of blast-induced traumatic brain injury

Traumatic brain injury (TBI) as a consequence of exposure to blast is increasingly prevalent in military populations, with the underlying pathophysiological mechanisms mostly unknown. In the present study, we utilized an air-driven shock tube to investigate the effects of blast exposure (120 kPa) on rat brains. Immediately following exposure to blast, neurological function was reduced. BBB permeability was measured using IgG antibody and evaluating its immunoreactivity in the brain. At 3 and 24 hr postexposure, there was a transient significant increase in IgG staining in the cortex. At 3 days postexposure, IgG immunoreactivity returned to control levels. Quantitative immunostaining was employed to determine the temporal course of brain oxidative stress following exposure to blast. Levels of 4-hydroxynonenal (4-HNE) and 3-nitrotyrosine (3-NT) were significantly increased at 3 hr postexposure and returned to control levels at 24 hr postexposure. The response of microglia to blast exposure was determined by autoradiographic localization of (3) H-PK11195 binding. At 5 days postexposure, increased binding was observed in the contralateral and ipsilateral dentate gyrus. These regions also displayed increased binding at 10 days postexposure; in addition to these regions there was increased binding in the contralateral ventral hippocampus and substantia nigra at this time point. By using antibodies against CD11b/c, microglia morphology characteristic of activated microglia was observed in the hippocampus and substantia nigra of animals exposed to blast. These results indicate that BBB breakdown, oxidative stress, and microglia activation likely play a role in the neuropathology associated with TBI as a result of blast exposure.