Epidemiology of Isolated Versus Nonisolated Mild Traumatic Brain Injury Treated in Emergency Departments in the United States, 2006-2012: Sociodemographic Characteristics

Mechanisms of Injury for Traumatic Brain Injury Among U.S. Military Service Members Before and During the COVID-19 Pandemic

OBJECTIVE

To understand the mechanisms of injury and demographic risk factors associated with traumatic brain injury (TBI) patients among active and reserve service members in the U.S. Military before and during the COVID-10 pandemic.

METHODS

Active and reserve service members diagnosed with an incident TBI from January 2019 through September 2021 were selected. Traumatic brain injury patients diagnosed before March 1, 2020 were categorized as pre-COVID (PC), and patients diagnosed on or after March 1, 2020 were categorized as the intra-COVID (IC) group, aligning closely with the date when the World Health Organization officially proclaimed the pandemic. We determined the frequency of causes of injuries associated with TBI separate by sex, age, occupation, and TBI severity. In addition, we conducted multivariate logistic regression analyses to assess the demographic risk factors associated with TBI severity during the PC and IC eras.

RESULTS

Our cohort included 48,562 TBI patients: 22,819 (47.0%) diagnosed during the PC era and 25,743 (53.0%) diagnosed during the IC era. The major mechanisms of injury within our TBI cohort were being struck by/against objects, falls/slips/trips, and motor vehicle traffic accidents before and during the pandemic. The most common causes of TBI were not impacted by COVID, but motor vehicle accidents did increase during the IC era. The mechanisms of injury associated with TBI differed by TBI severity: being struck by or against an object caused more mild and moderate TBI; motor vehicle accidents caused more severe TBI; and firearms was a major cause of penetrating TBI. In addition, the percentage of severe TBI because of firearms rose sharply during the IC era. Further, women were more likely to be diagnosed with mild TBI compared to men.

CONCLUSION

Military leaders should consider how different causes of injury are associated with differing TBI severities and how certain demographic groups were vulnerable to specific TBI severities when developing injury prevention programs.

Cavitation in blunt impact traumatic brain injury

Traumatic brain injury (TBI) poses a major public health challenge. No proven therapies for the condition exist so protective equipment that prevents or mitigates these injuries plays a critical role in minimizing the societal burden of this condition. Our ability to optimize protective equipment depends on our capacity to relate the mechanics of head impact events to morbidity and mortality. This capacity, in turn, depends on correctly identifying the mechanisms of injury. For several decades, a controversial theory of TBI biomechanics has attributed important classes of injury to cavitation inside the cranial vault during blunt impact. This theory explains counter-intuitive clinical observations, including the coup-contre-coup pattern of injury. However, it is also difficult to validate experimentally in living subjects. Also, blunt impact TBI is a broad term that covers a range of different head impact events, some of which may be better described by cavitation theory than others. This review surveys what has been learned about cavitation through mathematical modeling, physical modeling, and experimentation with living tissues and places it in context with competing theories of blunt injury biomechanics and recent research activity in the field in an attempt to understand what the theory has to offer the next generation of innovators in TBI biomechanics.

Diagnostic potential of IL6 and other blood-based inflammatory biomarkers in mild traumatic brain injury among children

Objectives

Inflammatory biomarkers, as indicators of biological states, provide a valuable approach for accurate and reproducible measurements, crucial for the effective management of mild traumatic brain injury (mTBI) in pediatric patients. This study aims to assess the diagnostic utility of blood-based inflammatory markers IL6, IL8, and IL10 in children with mTBI, including those who did not undergo computed tomography (CT) scans.

Methods

A prospective multicentric cohort study involving 285 pediatric mTBI patients was conducted, stratified into CT-scanned and non-CT-scanned groups within 24 h post-trauma, alongside 74 control subjects. Biomarker levels were quantitatively analyzed using ELISA. Sensitivity and specificity metrics were calculated to determine the diagnostic efficacy of each biomarker.

Results

A total of 223 mTBI patients (78%) did not undergo CT scan examination but were kept in observation for symptoms monitoring at the emergency department (ED) for more than 6 h (in-hospital-observation patients). Among CT-scanned patients (n = 62), 14 (23%) were positive (CT+). Elevated levels of IL6 and IL10 were found in mTBI children compared to controls. Within mTBI patients, IL6 was significantly increased in CT+ patients compared to both CT- and in-hospital-observation patients. No significant differences were observed for IL8 among the compared groups. IL6 yielded a specificity of 48% in identifying CT- and in-hospital-observation patients, with 100% sensitivity in excluding all CT+ cases. These performances were maintained whether IL6 was measured within 6 h or within 24 h after the trauma.

Conclusion

The inflammatory marker IL6 emerges as a robust biomarker, showing promising stratification value for pediatric mTBI patients undergoing CT scans or staying in observation in a pediatric ED.

Analyzing Dual-Task Paradigms to Improve Postconcussion Assessment and Management

CONTEXT

Dual-task (simultaneous cognitive-motor activities) assessments have been adapted into reliable and valid clinical concussion measures. However, abundant motor and cognitive variations leave researchers and clinicians uncertain about which combinations elicit the intended dual-task effect. Our objective was to examine differences between commonly employed dual-task motor and cognitive combinations among healthy, college-aged individuals.

DESIGN

Cross-sectional laboratory study.

METHODS

Twenty participants (age: 21.3 [2.4] y; height: 176.0 [9.1] cm; mass: 76.0 [16.4] kg; 20% with concussion history) completed 4 motor tasks (gait, tandem gait, single-leg balance, and tandem balance) under 5 cognitive conditions (single task, subtraction, month reversal, spelling backward, and visual Stroop) in a research laboratory. The motor performance outcomes were spatiotemporal variables for gait and tandem gait and center of pressure path length (in centimeters) for single-leg and tandem balance. Cognitive outcomes were response rate (responses/second) and cognitive accuracy. We used separate repeated-measures analyses of variance for each motor and cognitive outcome with post hoc Tukey t tests.

RESULTS

Gait velocity, gait stride length, and tandem gait velocity demonstrated significant cognitive-motor interactions (P's < .001) such that all dual-task conditions resulted in varyingly slower or shorter movement than single task. Conversely, single-leg balance (P = .627) and tandem balance (P = .434) center of pressure path length did not significantly differ among the dual-task cognitive conditions or relative to single task. Statistically significant cognitive-motor interactions were observed only for spelling backward accuracy (P = .004) and response rates for spelling backward, month reversal, and visual Stroop (P's < .001) such that worse accuracy, but faster response rates, occurred during motor tasks.

CONCLUSIONS

Gait and tandem gait motor tasks accompanied with spelling backward or subtraction cognitive tasks demonstrated consistently strong dual-task effects and, therefore, may be the best suited for clinical and research use following concussion.

A strike to the head: Parallels between the pediatric and adult human and the rodent in traumatic brain injury

Traumatic brain injury (TBI) is a condition that occurs commonly in children from infancy through adolescence and is a global health concern. Pediatric TBI presents with a bimodal age distribution, with very young children (0-4 years) and adolescents (15-19 years) more commonly injured. Because children's brains are still developing, there is increased vulnerability to the effects of head trauma, which results in entirely different patterns of injury than in adults. Pediatric TBI has a profound and lasting impact on a child's development and quality of life, resulting in long-lasting consequences to physical, cognitive, and emotional development. Chronic issues like learning disabilities, behavioral problems, and emotional disturbances can develop. Early intervention and ongoing support are critical for minimizing these long-term deficits. Many animal models of TBI exist, and each varies significantly, displaying different characteristics of clinical TBI. The neurodevelopment differs in the rodent from the human in timing and effect, so TBI outcomes in the juvenile rodent can thus vary from the human child. The current review compares findings from preclinical TBI work in juvenile and adult rodents to clinical TBI research in pediatric and adult humans. We focus on the four brain regions most affected by TBI: the prefrontal cortex, corpus callosum, hippocampus, and hypothalamus. Each has its unique developmental projections and thus is impacted by TBI differently. This review aims to compare the healthy neurodevelopment of these four brain regions in humans to the developmental processes in rodents.

Factors Associated With Head and Neck Polytrauma Presentation and Admissions at Emergency Departments of Varying Sizes

Timely diagnosis of acute head and neck polytrauma presenting to emergency departments (EDs) optimizes outcomes. Since ED capacity influences triage and admission, the authors utilized the National Electronic Injury Surveillance System database to understand how ED size and trauma characteristics affect head and neck polytrauma presentation and admissions. Demographics and injury characteristics from the National Electronic Injury Surveillance System database from 2018 to 2021 were analyzed to delineate factors contributing to polytrauma presence and admission through multivariable logistic regressions. The authors' 207,951-patient cohort was primarily females (48.6%), non-Hispanic (62.4%), and white (51.4%) people who averaged 57.2 years old. Nonspecific head injuries were predominant (59.7%), followed by facial trauma (22.6%) with rare substance involvement (alcohol, 6.3%; drugs, 4.1%) presenting to high-volume EDs (48.5%). Of the patients, 20% were admitted, whereas 31.1% sustained polytrauma. Substance use [alcohol, odds ratio (OR) = 4.44; drugs, OR = 2.90] increased polytrauma likelihood; neck (OR = 1.35), face (OR = 1.14), and eye (OR = 1.26) associated with polytrauma more than head injuries. Burns (OR = 1.38) increased polytrauma likelihood more than internal organ injuries. Black patients sustained higher polytrauma when presented to non-small EDs (OR = 1.41-1.90) than white patients showed to small EDs. Admissions were higher for males (OR = 1.51). Relative to small EDs, large EDs demonstrated a higher increase in admissions (OR = 2.42). Neck traumas were more likely admitted than head traumas (OR = 1.71). Fractures (OR = 2.21) and burns (OR = 2.71) demonstrated an increased admission likelihood than internal organ injuries. Polytrauma presence and admissions likelihood are site, injury, and substance dependent. Understanding the impact of factors influencing polytrauma presence or admission will enhance triage to optimize outcomes.

Geographic characteristics of sport- and non-sport-related concussions presenting to emergency departments in the United States

BACKGROUND

Concussion is a type of traumatic brain injury (TBI) that can be sustained through sport-related and non-sport-related (e.g., motor vehicle accidents, falls, assaults) mechanisms of injury (MOI). Variations in concussion incidence and MOI may be present throughout the four geographic regions (Midwest, Northeast, South, West) of the United States. However, there is limited evidence exploring concussion cause and diagnosis patterns based on geographic region and MOI. These factors have implications for better understanding the burden of concussion and necessary efforts that can translate to the mitigation of safety concerns.

PURPOSE

The purpose of this study was to identify patterns of sport-related concussion (SRC) and non-sport-related concussion (NSRC) across the four geographic regions of the United States.

METHODS

A descriptive epidemiology study of patient visits to the emergency department (ED) for concussion between 2010 and 2018, using publicly available data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) was conducted. The exposure of interest was geographic region while the main outcome measures were concussion diagnosis and MOI. Descriptive statistics were calculated using population-weighted frequencies and percentages. The association between geographic region and MOI (SRC vs. NSRC) was analyzed using logistic regression models. Odds ratios (OR) presented with 95% confidence intervals (CI) were included. Univariate analyses were conducted followed by multivariable analyses adjusting for sex, age, race/ethnicity, and primary source of payment. Statistical significance was set a priori at p < 0.05 for all analyses.

RESULTS

From 2010 to 2018, 1,161 visits resulted in a concussion diagnosis, representing an estimated 7,111,856 visits nationwide. A greater proportion of concussion diagnoses occurred within EDs in the South (38.2%) followed by the West (25.8%), Midwest (21.4%), and Northeast (14.6%). Compared to the West region, patients visiting the ED in the Midwest (OR = 0.75, 95% CI = 0.57-0.98) and Northeast (OR = 0.71, 95% CI = 0.51-0.98) had a lower odds of being diagnosed with a concussion. More patients sustained a NSRC MOI (94.3%) compared to SRC MOI (5.7%). For both mechanisms, the South region had the highest population-weighted frequency of SRC (n = 219,994) and NSRC diagnoses (n = 2,495,753). Univariate and multivariable logistic regression analyses did not reveal statistically significant associations for geographic region and MOI (p > 0.05).

CONCLUSION

Our findings showed that the Midwest and Northeast regions had a lower odds of concussion diagnoses in EDs. Overall, the vast majority of concussions were not sport-related, which has public health implications. These findings improve our understanding of how concussion injuries are being sustained geographically nationwide and help to explain care-seeking patterns for concussion in the ED setting.

Patient-centered mild traumatic brain injury interventions in the emergency department

INTRODUCTION

Traumatic brain injury (TBI) results in 2.5 million emergency department (ED) visits per year in the US, with mild traumatic brain injury (mTBI) accounting for 90% of cases. There is considerable evidence that many experience chronic symptoms months to years later. This population is rarely represented in interventional studies. Management of adult mTBI in the ED has remained unchanged, without consensus of therapeutic options. The aim of this review was to synthesize existing literature of patient-centered ED treatments for adults who sustain an mTBI, and to identify practices that may offer promise.

METHODS

A systematic review was conducted using the PubMed and Cochrane databases, while following PRISMA guidelines. Studies describing pediatric patients, moderate to severe TBI, or interventions outside the ED were excluded. Two reviewers independently performed title and abstract screening. A third blinded reviewer resolved discrepancies. The Mixed Methods Appraisal Tool (MMAT) was employed to assess the methodological quality of the studies.

RESULTS

Our search strategy generated 1002 unique titles. 95 articles were selected for full-text screening. The 26 articles chosen for full analysis were grouped into one of the following intervention categories: (1) predictive models for Post-Concussion Syndrome (PCS), (2) discharge instructions, (3) pharmaceutical treatment, (4) clinical protocols, and (5) functional assessment. Studies that implemented a predictive PCS model successfully identified patients at highest risk for PCS. Trials implementing discharge related interventions found the use of video discharge instructions, encouragement of daily light exercise or bed rest, and text messaging did not significantly reduce mTBI symptoms. The use of electronic clinical practice guidelines (eCPG) and longer leaves of absence from work following injury reduced symptoms. Ondansetron was shown to reduce nausea in mTBI patients. Studies implementing ED Observation Units found significant declines in inpatient admissions and length of hospital stay. The use of tablet-based tasks was found to be superior to many standard cognitive assessments.

CONCLUSION

Validated instruments are available to aid clinicians in identifying patients at risk for PCS or serious cognitive impairment. EDOU management and evidence-based modifications to discharge instructions may improve mTBI outcomes. Additional research is needed to establish the therapeutic value of medications and lifestyle changes for the treatment of mTBI in the ED.

Occupational therapy scope of practice in the rehabilitation of adults experiencing persistent post-concussion symptoms following traumatic brain injury: a scoping review protocol

OBJECTIVE

The objective of the review is to identify, categorize, and examine literature describing occupational therapy scope of practice in the rehabilitation of adults experiencing persistent post-concussion symptoms (PPCS).

INTRODUCTION

PPCS are symptoms experienced by adults a minimum of 2 to 4 weeks after a traumatic brain injury (TBI), and include vestibular, neuropsychiatric, visual, and cognitive issues. Enduring PPCS may result in disability, affecting a person's independence and/or participation in daily activities. Despite growing recognition of the role occupational therapy can offer in TBI rehabilitation, evidence is limited regarding the scope of practice occupational therapists have in the rehabilitation of adults experiencing PPCS.

INCLUSION CRITERIA

Literature that includes adults (aged 18 to 65 years) experiencing PPCS that describes the occupational therapy scope of practice in concussion programs will be considered for inclusion in this review. Sources reporting on participants aged under 18 years, classified with non-persistent symptoms, and receiving care in acute health care settings will be excluded. Non-English publications or gray literature from civil society or disabled persons organizations or other representative bodies in the field of brain injury will also be excluded.

METHODS

The scoping review will follow the JBI methodology for scoping reviews. Five electronic databases will be searched for literature published between 2013 and the present: MEDLINE, Embase, Emcare, PsycINFO, and CINAHL. Two reviewers will independently conduct title and abstract screening of the results and, upon consensus, independently screen full texts to confirm final sources for inclusion. Any disagreements will be resolved by discussion with a third reviewer. Data will be extracted from included sources and we will then map occupational therapy scope of practice (inclusive of assessments and interventions) against the World Health Organization's International Classification of Functioning One-Level Classification. Results will be presented in tabular or narrative format.

REVIEW REGISTRATION

Open Science Framework osf.io/qxgzj.

Characteristics, Outcomes, and Its Associated Factors Among Patients Hospitalized With Mild Traumatic Brain Injuries

OBJECTIVE

The aim of the study is to investigate the characteristics and hospital outcomes of patients with mild traumatic brain injuries.

DESIGN

A total of 1940 patients with mild traumatic brain injuries from seven community hospitals between 2017 and 2019 were identified using International Classification of Disease codes and an documented initial Glasgow Coma Scale score of 13-15. A stepwise logistic regression was used to identify demographics and clinical characteristics associated with in-hospital mortality and home discharge.

RESULTS

The median age was 69 yrs old with 66.6% associated with falls at admission. Subdural hemorrhage was the most common brain lesion and more common in the group with falls. Increased age, male sex, epidural hemorrhage, presence of hemiplegia, paraplegia, renal disease, cancer, hospital-acquired sepsis, anemia, and use of direct vasodilator were associated with increased odds of in-hospital mortality. Increased age, medical coverage by Medicare, cerebral edema, lower initial Glasgow Coma Scale, length of stay, comorbidity of acute myocardiac infarction, and use of thiamine and opioids were associated with decreased likelihood of discharge to home.

CONCLUSIONS

Recognizing characteristics of hospitalized patients with mild traumatic brain injuries and their association with increased in-hospital mortality and nonhome discharge can be useful for improving care of this vulnerable population.

Research Letter: Rate of BPPV in Patients Diagnosed With Concussion

OBJECTIVE

The purpose of this study was to investigate the incidence of benign paroxysmal positional vertigo (BPPV) specifically among patients with dizziness in the rehabilitation phase of concussion recovery and to provide evidence regarding the importance of BPPV assessment in physical therapy concussion evaluations.

SETTING

Outpatient neurologic rehabilitation center at a suburban comprehensive rehabilitation hospital.

PARTICIPANTS

Fifty patients diagnosed with concussion and referred to vestibular physical therapy with complaints of dizziness were tested for BPPV within their first 3 visits.

DESIGN

In this prospective cohort study, a positive Dix-Hallpike test or Horizontal Roll test indicated the presence of BPPV.

MAIN MEASURES

The primary outcome measure was the presence of BPPV. Additional demographic and injury-specific variables were also considered. Among secondary outcomes, patient characteristics and Dizziness Handicap Inventory scores were compared on the basis of presence or absence of BPPV.

RESULTS

Eleven participants, 22%, tested positive for BPPV. Only fall, as the mechanism of injury, was statistically significant ( P < .05), with 72.7% of those who tested positive for BPPV reporting having been injured in a fall compared with 30.8% in the negative group. Nearly half, 45%, of the participants who were positive for BPPV had resolution of their BPPV within 1 visit.

CONCLUSION

This study is unique in its focus on mild traumatic brain injury in the rehabilitation phase of recovery. The results provide evidence regarding the importance of BPPV assessment in physical therapy concussion evaluations.

Early Exercise is Associated with Faster Concussion Recovery Among Collegiate Athletes: Findings from the NCAA-DoD CARE Consortium

BACKGROUND

Growing evidence indicates early exercise may improve symptoms and reduce clinical recovery time after concussion, but research examining collegiate student-athletes is scarce.

OBJECTIVE

The aim of this study was to compare symptom recovery time, clinical recovery time, and persisting post-concussion symptom (i.e., symptoms ≥ 28 days) prevalence by the timing of light exercise initiation before the graded return to play (RTP) protocol among concussed participants.

METHODS

Collegiate student-athletes (n = 1228; age 18.4 ± 0.9 years; 56.5% male, 76.3% division I; 33.7% ≥ 1 prior concussion) across 30 institutions enrolled in the CARE Consortium completed post-concussion assessments and were monitored over time. Symptom recovery (days from injury to symptom resolution) and clinical recovery (days from injury to return to play protocol completion) was determined by the student-athletes' clinicians. Student-athletes were categorized by timing of light exercise initiation. Early (< 2 days post-concussion; n = 161), typical (3-7 days post-concussion; n = 281), and late exercise (≥ 8 days post-concussion; n = 169) groups were compared with the no-exercise group (n = 617; i.e., did not exercise prior to beginning the RTP protocol) for all analyses. Multivariable Cox regression models with hazard ratios (HR) and survival curves and a multivariable binomial regression model with prevalence ratios (PR) compared recovery outcomes between exercise groups while accounting for covariates.

RESULTS

Compared to the no-exercise group, the early exercise group was 92% more probable to experience symptom recovery (HR 1.92; 95% CI 1.57-2.36), 88% more probable to reach clinical recovery (HR 1.88; 95% CI 1.55-2.28) and took a median of 2.4 and 3.2 days less to recover, respectively. The late exercise group relative to the no-exercise group was 57% less probable to reach symptom recovery (HR 0.43; 95% CI 0.35-0.53), 46% less probable to achieve clinical recovery (HR 0.54; 95% CI 0.45-0.66) and took 5.3 days and 5.7 days more to recover, respectively. The typical exercise group did not differ in hazard for symptom or clinical recovery (p ≥ 0.329) compared with the no-exercise group. The prevalence of persisting post-concussion symptoms in the combined sample was 6.6%. Early exercise had 4% lower prevalence (PR 0.96, 95% CI 0.94-0.99) and typical exercise had 3% lower prevalence (PR 0.97, 95% CI 0.94-0.99) of persisting post-concussion symptoms, while the late exercise group had an elevated prevalence (PR 1.11, 95% CI 1.04-1.18) compared with the no-exercise group.

CONCLUSION

Exercise < 2 days post-concussion was associated with more probable and faster symptom and clinical recovery, and lower persisting post-concussion symptom prevalence. When considering our findings and existing literature, qualified clinicians may implement early exercise into their clinical practice to provide therapeutic treatment and improve student-athlete recovery.

Concussion Exposure and Suicidal Ideation, Planning, and Attempts Among US High School Students

CONTEXT

Interest is growing in the association between repetitive concussions and mental health. However, studies on the relationship between concussion frequency and adverse mental health outcomes among female and male youth are lacking.

OBJECTIVES

To examine the association between self-reported concussion frequency and nonfatal suicidal behaviors among youth and to explore the possible interaction of biological sex.

DESIGN

Retrospective cross-sectional survey.

SETTING

National Youth Risk Behavior Surveillance System.

PATIENTS OR OTHER PARTICIPANTS

United States secondary school students (N = 28 442).

MAIN OUTCOME MEASURE(S)

Exposure variables were the frequency of self-reported sport- or recreation-related concussion in the previous 12 months (0, 1, ≥2). Outcome variables were feelings of self-reported sadness or hopelessness and suicidal ideation, planning, and attempts. Covariates were age, sex, race and ethnicity, bullying victimization, sexual orientation, and physical activity.

RESULTS

Students who reported ≥2 concussions were at significantly greater odds of reporting suicidal attempts (adjusted odds ratio = 2.03; 95% CI = 1.43, 2.88) when compared with students reporting a single concussive event during the past 12 months. However, sex interactions revealed that this finding may have been driven by males; the strength of associations did not increase from single to multiple concussions among females.

CONCLUSIONS

Our findings suggest that adolescents who reported concussion were at increased odds of reporting poor mental health and suicidal behaviors. Moreover, an increased number of concussive events may be associated with significantly greater odds of reporting suicidal attempts, particularly among males. Irrespective of sex, health care professionals should closely monitor mental health behaviors in adolescents with repetitive concussions, especially those that occur in close temporal proximity.

Longitudinal Assessment of Postconcussion Driving: Evidence of Acute Driving Impairment

BACKGROUND

Current medical practices and recommendations largely ignore the safety of postconcussion driving, even though commonly used measures of neurocognition, balance, and vestibulo-ocular function show impairment.

PURPOSE

To compare simulated driving between patients with concussion and controls throughout concussion recovery using a case-control design.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 26 concussed and 23 control Division I collegiate athletes completed a driving simulation assessment at 3 time points (within 72 hours, asymptomatic, and return to sport). Cumulative driving simulation outcome variables included total number of collisions, speed exceedances, stop signs missed, lane excursions, total drive time, percentage of time over the speed limit, and percentage of time out of the lane. The mean speed, standard deviation of speed (SDS), lateral lane position, and standard deviation of lateral lane position (SDLP) were examined for each of the 11 drive segments. Outcomes were compared using generalized linear mixed models with random intercepts by participant with Poisson or normal distributions.

RESULTS

Within 72 hours of injury, the concussion group committed more lane excursions (median difference, 2; P = .003), exhibited greater SDS while avoiding a child pedestrian crossing the road (Cohen d = 0.73; P = .011), drove ~7 inches (~18 cm) closer to the centerline during a residential left curve (d = 0.90; P = .015), and had greater SDLP while navigating around a car crash compared with controls (d = 0.72; P = .016). When asymptomatic, the concussion group committed fewer speed exceedances (median difference, 2; P = .002) and had lower SDLP while navigating through a traffic light compared with controls (d = 0.60; P = .045). No differences were evident at return to sport. Groups did not differ in total collisions at any time point.

CONCLUSION

The concussion group showed more impaired driving patterns within 72 hours of injury, drove more conservatively once asymptomatic, and had similar driving performance at the time they returned fully to sport. Clinicians should consider these findings when discussing driving with patients acutely after concussion. Further research is needed to determine whether on-road collision risk is elevated after concussion.

Repetitive Transcranial Magnetic Stimulation for Depression and Posttraumatic Stress Disorder in Veterans With Mild Traumatic Brain Injury

OBJECTIVES

Mild traumatic brain injury (mTBI) is a signature injury of military conflicts and is prevalent in veterans with major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). Although therapeutic transcranial magnetic stimulation (TMS) can reduce symptoms of depression and PTSD, whether traumatic brain injury (TBI) affects TMS responsiveness is not yet known. We hypothesized mTBI would be associated with higher pretreatment symptom burden and poorer TMS response.

MATERIALS AND METHODS

We investigated a registry of veterans (N = 770) who received TMS for depression across the US Veterans Affairs system. Of these, 665 (86.4%) had data on TBI and lifetime number of head injuries while 658 had complete data related to depression outcomes. Depression symptoms were assessed using the nine-item Patient Health Questionnaire and PTSD symptoms using the PTSD Checklist for DSM-5. Linear mixed effects models and t-tests evaluated whether head injuries predicted symptom severity before treatment, and how TBI status affected clinical TMS outcomes.

RESULTS

Of the 658 veterans included, 337 (50.7%) reported previous mTBI, with a mean of three head injuries (range 1-20). TBI status did not predict depressive symptom severity or TMS-associated changes in depression (all p's > 0.1). TBI status was associated with a modest attenuation of TMS-associated improvement in PTSD (in patients with PTSD Checklist for DSM-5 scores > 33). There was no correlation between the number of head injuries and TMS response (p > 0.1).

CONCLUSIONS

Contrary to our hypothesis, presence of mTBI did not meaningfully change TMS outcomes. Veterans with mTBI had greater PTSD symptoms, yet neither TBI status nor cumulative head injuries reduced TMS effectiveness. Limitations include those inherent to retrospective registry studies and self-reporting. Although these findings are contrary to our hypotheses, they support the safety and effectiveness of TMS for MDD and PTSD in patients who have comorbid mTBI.

Reliability and Minimal Detectable Change of the Standardized Assessment of Reaction Time

CONTEXT

Postconcussion reaction time deficits are common, but existing assessments lack sport-related applicability. We developed the Standardized Assessment of Reaction Time (StART) tool to emulate the simultaneous cognitive and motor function demands in sport, but its reliability is unestablished.

OBJECTIVES

To determine the intrarater, interrater, and test-retest reliability of StART and to examine the dual-task effect, time effect, and relationships between StART and computerized and laboratory-based functional reaction time assessments.

DESIGN

Prospective cohort study.

SETTING

Clinical laboratory.

PATIENTS OR OTHER PARTICIPANTS

Twenty healthy, physically active individuals (age = 20.3 ± 1.8 years, females = 12, no concussion history = 75%).

MAIN OUTCOME MEASURE(S)

Participants completed the StART, computerized reaction time (Stroop task via CNS Vital Signs), and laboratory-based jump landing and cutting reaction time under single-task and dual-task (subtracting by 6s or 7s) cognitive conditions at 2 testing sessions a median of 7 days apart. We used intraclass correlation coefficients (ICCs), repeated-measure analysis of variance, and Pearson r correlations to address our aims.

RESULTS

Overall, good to strong interrater (ICC [2,k] range = 0.83-0.97), intrarater (ICC [3,k] range = 0.91-0.98), and test-retest (ICC [3,k] range = 0.69-0.89) reliability were observed. A significant reaction time assessment-by-cognitive condition interaction was present (P = .018, ηp2 = 0.14), with StART having the largest dual-task effect. Main time effects for dual-task conditions were seen across all reaction time assessments (mean difference = -25 milliseconds, P = .026, ηp2 = 0.08) with improved performance at the second testing session. No StART outcomes correlated with computerized reaction time (P > .05), although some correlated with single-task (r range = 0.42-0.65) and dual-task (r range = 0.19-0.50) laboratory cutting reaction time.

CONCLUSIONS

The StART demonstrated overall reliable performance relative to other reaction time measures. Reliability coupled with a strong dual-task effect indicates that StART is a valid measure for examining functional reaction time and may have future utility for sport-related concussion return-to-play decision-making.

Motor vehicle crash concussion mechanism displays a greater total number of symptoms and greater affective symptom severity but no neurocognitive differences compared with sport-related concussion mechanism

Previous research among adolescents has shown differences in symptoms and neurocognitive performance between sport-related (SRC) and motor vehicle crash (MVC) concussion mechanisms. Limited research has focused on young adults. The purpose of our study was to compare symptoms, balance, and neurocognitive performance between SRC and MVC mechanisms in young adults. Forty-three (58.1% female, age = 25.5 ± 3.2 years, days since concussion = 12.8 ± 12.7) and 26 (76.9% female, age = 24.1 ± 5.6 years, days since concussion = 12.6 ± 8.3) individuals with an SRC and MVC mechanism, respectively, participated. Primary outcome measures included the total number, severity, cluster (disorientation, migraine, lethargy, and affective) of post-concussion symptoms endorsed, Balance Error Scoring System (BESS), and CNS Vital Signs scores. Clusters are subgroups of symptoms used for targeted rehabilitation. We used independent t-tests and Mann-Whitney U tests to compare symptoms, BESS, and neurocognitive performance. Cliff's Delta effect size was interpreted as negligible (<0.15), small (0.15-0.33), medium (0.34-0.47), and large (≥0.48). There were no group differences for any demographic factors or preexisting conditions (p-range = 0.112-0.991). Participants with an MVC mechanism reported a greater number of total post-concussion symptoms (p = 0.025, Cliff's Delta = 0.32) and a more severe affective symptom cluster (p = 0.010, Cliff's Delta = 0.37). There were no group differences for BESS or neurocognitive performance after correcting for multiple comparisons. The MVC mechanism resulted in a greater total symptom burden relative to the SRC mechanism. Medical practitioners and individuals experiencing a concussion should know that concussions are heterogeneous within and across various mechanisms.

Lower Extremity Somatosensory Function Throughout Concussion Recovery: A Prospective Cohort Study

OBJECTIVE

Balance impairments may suggest somatosensory disruption beyond concussion clinical recovery, but somatosensory subsystems have never been directly assessed. Our objective was to examine somatosensory function between individuals with a concussion and healthy matched-controls at acute (<7 days) and asymptomatic (<72 hours of being symptom-free) time points.

SETTING

Laboratory.

PARTICIPANTS

Participants with a concussion and matched controls ( n = 24; 58% male, age: 19.3 ± 1.1 years, mass: 70.3 ± 16.4 kg, height: 177.3 ± 12.7 cm).

DESIGN

Prospective cohort.

MAIN MEASURES

Somatosensory assessments on the dominant limb at both time points included: (1) plantar touch sensation threshold via Semmes-Weinstein monofilaments, (2) plantar pressure pain threshold via algometry, and (3) knee absolute passive joint repositioning (PJR) error via Biodex across 3 arcs (105°-75°, 30°-60°, 90°-45° knee-flexion). We used mixed-model analyses of variance, post hoc Tukey honestly significant difference t tests with mean difference, 95% CI, and Hedges' g effect sizes to examine outcomes.

RESULTS

Touch sensation had a group effect with the concussion cohort needing 0.95 grams of force (gf) more relative to controls (95% CI: 0.03 to 1.87; P = .043). No touch sensation interaction was present, but medium and large effects were observed for greater gf needed among the concussed cohort at the acute (1.11 gf; 95% CI: 0.17 to 2.05; g = 0.96) and asymptomatic time points (0.79 gf; 95% CI: -0.15 to 1.73; g = 0.73). No plantar pressure pain threshold effects were observed ( P ≥ .311), with negligible pressure difference magnitudes at the acute (0.26 pound force [lbf]/cm 2 ; 95% CI: -1.54 to 2.06; g = 0.13) and medium magnitudes at the asymptomatic time points (0.99 lbf/cm 2 ; 95% CI: -0.81 to 2.80; g = 0.42) for the concussed cohort needing more pressure to detect pain. The 30° to 60° PJR had a time effect, with asymptomatic time point having 3.12° better accuracy (95% CI: 1.23° to 5.02; P = .002). The concussed cohort had small-to-medium magnitude differences relative to controls at the acute time point for PJR during 105° to 75° (0.89°; g = 0.30) and 90° to 45° (0.62°; g = 0.17), but not 30° to 60° (-1.75°; g = -0.40).

CONCLUSIONS

Individuals with a concussion exhibited large effects for diminished plantar touch sensation and small to medium effects for inhibited plantar pressure pain sensation compared with controls, which may indicate altered somatosensory function. Negligible PJR differences suggest knee joint position sense is not altered post-concussion. Pre- and postconcussion examination is warranted to understand causal somatosensory mechanisms.

Influential Factors and Preliminary Reference Data for a Clinically Feasible, Functional Reaction Time Assessment: The Standardized Assessment of Reaction Time

CONTEXT

Clinical reaction-time (RT) measures are frequently used when examining patients with concussion but do not correlate with functional movement RT. We developed the Standardized Assessment of RT (StART) to emulate the rapid cognitive demands and whole-body movement needed in sport.

OBJECTIVE

To assess StART differences across 6 cognitive-motor combinations, examine potential demographic and health history confounders, and provide preliminary reference data for healthy collegiate student-athletes.

DESIGN

Prospective, cross-sectional study.

SETTING

Clinical medicine facilities.

PATIENTS OR OTHER PARTICIPANTS

A total of 89 student-athletes (56 [62.9%] men, 33 [37.1%] women; age = 19.5 ± 0.9 years, height = 178.2 ± 21.7 cm, mass = 80.4 ± 24 kg; no concussion history = 64 [71.9%]).

MAIN OUTCOME MEASURE(S)

Student-athletes completed health history questionnaires and StART during preseason testing. The StART consisted of 3 movements (standing, single-legged balance, and cutting) under 2 cognitive states (single task and dual task [subtracting by 6's or 7's]) for 3 trials under each condition. The StART trials were calculated as milliseconds between penlight illumination and initial movement. We used a 3 × 2 repeated-measures analysis of variance with post hoc t tests and 95% CIs to assess StART cognitive and movement differences, conducted univariable linear regressions to examine StART performance associations, and reported StART performance as percentiles.

RESULTS

All StART conditions differed (P ≤ .03), except single-task standing versus single-task single-legged balance (P = .36). Every 1-year age increase was associated with an 18-millisecond (95% CI = 8, 27 milliseconds) slower single-task cutting RT (P < .001). Female athletes had slower single-task (15 milliseconds; 95% CI = 2, 28 milliseconds; P = .02) and dual-task (28 milliseconds; 95% CI = 2, 55 milliseconds; P = .03) standing RT than male athletes. No other demographic or health history factors were associated with any StART condition (P ≥ .056).

CONCLUSIONS

The StART outcomes were unique across each cognitive-motor combination, suggesting minimal subtest redundancy. Only age and sex were associated with select outcomes. The StART composite scores may minimize confounding factors, but future researchers should consider age and sex when providing normative data.

Single-Leg Hop Stabilization Throughout Concussion Recovery: A Preliminary Biomechanical Assessment

CONTEXT

Aberrant movement patterns among individuals with concussion history have been reported during sport-related movement. However, the acute postconcussion kinematic and kinetic biomechanical movement patterns during a rapid acceleration-deceleration task have not been profiled and leaves their progressive trajectory unknown. Our study aimed to examine single-leg hop stabilization kinematics and kinetics between concussed and healthy-matched controls acutely (≤7 d) and when asymptomatic (≤72 h of symptom resolution).

DESIGN

Prospective, cohort laboratory study.

METHODS

Ten concussed (60% male; 19.2 [0.9] y; 178.7 [14.0] cm; 71.3 [18.0] kg) and 10 matched controls (60% male; 19.5 [1.2] y; 176.1 [12.6] cm; 71.0 [17.0] kg) completed the single-leg hop stabilization task under single and dual task (subtracting by 6's or 7's) at both time points. Participants stood on a 30-cm tall box set 50% of their height behind force plates while in an athletic stance. A synchronized light was illuminated randomly, queuing participants to initiate the movement as rapidly as possible. Participants then jumped forward, landed on their nondominant leg, and were instructed to reach and maintain stabilization as fast as possible upon ground contact. We used 2 (group) × 2 (time) mixed-model analyses of variance to compare single-leg hop stabilization outcomes separately during single and dual task.

RESULTS

We observed a significant main group effect for single-task ankle plantarflexion moment, with greater normalized torque (mean difference = 0.03 N·m/body weight; P = .048, g = 1.18) for concussed individuals across time points. A significant interaction effect for single-task reaction time indicated that concussed individuals had slower performance acutely relative to asymptomatic (mean difference = 0.09 s; P = .015, g = 0.64), while control group performance was stable. No other main or interaction effects for single-leg hop stabilization task metrics were present during single and dual task (P ≥ .051).

CONCLUSIONS

Greater ankle plantarflexion torque coupled with slower reaction time may indicate stiff, conservative single-leg hop stabilization performance acutely following concussion. Our findings shed preliminary light on the recovery trajectories of biomechanical alterations following concussion and provide specific kinematic and kinetic focal points for future research.

Lower-Extremity Neuromuscular Function Following Concussion: A Preliminary Examination

CONTEXT

Neuromuscular function is altered acutely following concussion and theoretically linked to the subsequent postconcussion musculoskeletal injury risk. Existing research has only examined voluntary muscle activation, limiting mechanistic understanding. Therefore, our study aimed to examine voluntary and involuntary muscle activation between college-aged, concussed individuals when symptom-free and healthy matched controls.

DESIGN

Prospective, cross-sectional cohort laboratory study.

METHODS

Concussed and healthy participants (n = 24; 58% male, age: 19.3 [1.1] y, mass: 70.3 [16.4] kg, height: 177.3 [12.7] cm) completed the superimposed burst (SB) neuromuscular assessment on their dominant limb within 72 hours after self-reporting asymptomatic (22.4 [20.2] d postinjury). Unnormalized and bodyweight-normalized quadriceps maximal voluntary isometric contraction torque (in newton meters), unnormalized and bodyweight-normalized electrically stimulated SB torque, pain (numeric 1-10) during SB, and the central activation ratio (in percentage) were assessed via the SB. Parametric and nonparametric analyses, 95% confidence intervals (95% CIs), and Hedges g (parametric) and Spearman ρ (nonparametric) effect sizes were used to examine group differences (α = .05).

RESULTS

The maximal voluntary isometric contraction torque (concussed: 635.60 N·m [300.93] vs control: 556.27 N·m [182.46]; 95% CI, -131.36 to 290.02; P = .443; d = 0.33), SB torque (concussed: 203.22 N·m [97.17], control: 262.85 N·m [159.07]; 95% CI, -171.22 to 51.97; P = .280; d = -0.47), and central activation ratio (concussed: 72.16% [17.16], control: 70.09% [12.63]; 95% CI, -10.68 to 14.83; P = .740; d = 0.14) did not differ between the concussed and control groups regardless of bodyweight normalization (P ≥ .344). Pain during the SB was significantly higher with a medium effect for participants with a concussion versus healthy controls (concussed: median = 7, control: median = 5; P = .046; ρ = -0.42).

DISCUSSION

These findings suggest concussed participants do not have statistically altered voluntary or involuntary quadricep neuromuscular function once asymptomatic compared with controls. Therefore, the elevated postconcussion musculoskeletal injury risk may not be attributed to lower-extremity muscle activation. Concussed participants displayed greater pain perception during the SB, which suggests somatosensory or perception changes requiring further examination.

Validity of algorithms for identifying mild traumatic brain injury in the French national emergency department database OSCOUR: a retrospective multicentre validation study protocol

INTRODUCTION

The French emergency department (ED) surveillance network OSCOUR transmits data on ED visits to Santé publique France (the national public health agency). As these data are collected daily and are almost exhaustive at a national level, it would seem relevant to use them for national epidemiological surveillance of mild traumatic brain injury (mTBI). This article presents the protocol of a planned study to validate algorithms for identifying mTBI in the OSCOUR database. Algorithms to be tested will be based on International Classification of Diseases (ICD)-10 codes.

METHODS AND ANALYSIS

We will perform a multicentre validation study of algorithms for identifying mTBI in OSCOUR. Different combinations of ICD-10 codes will be used to identify cases of mTBI in the OSCOUR database. A random sample of mTBI cases and non-cases will be selected from four EDs. Medical charts will serve as the reference standard to validate the algorithms. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the different algorithms, as well as their 95% CIs, will be calculated and compared.

ETHICS AND DISSEMINATION

The ethics committee of the French National Data Protection Authority (CNIL) approved this study (n° 921152, 1 August 2021). Results will be submitted to national and international peer-reviewed journals and presented at conferences dedicated to trauma and to methodologies for the construction and validation of algorithms.

Plasticity impairment alters community structure but permits successful pattern separation in a hippocampal network model

Patients who suffer from traumatic brain injury (TBI) often complain of learning and memory problems. Their symptoms are principally mediated by the hippocampus and the ability to adapt to stimulus, also known as neural plasticity. Therefore, one plausible injury mechanism is plasticity impairment, which currently lacks comprehensive investigation across TBI research. For these studies, we used a computational network model of the hippocampus that includes the dentate gyrus, CA3, and CA1 with neuron-scale resolution. We simulated mild injury through weakened spike-timing-dependent plasticity (STDP), which modulates synaptic weights according to causal spike timing. In preliminary work, we found functional deficits consisting of decreased firing rate and broadband power in areas CA3 and CA1 after STDP impairment. To address structural changes with these studies, we applied modularity analysis to evaluate how STDP impairment modifies community structure in the hippocampal network. We also studied the emergent function of network-based learning and found that impaired networks could acquire conditioned responses after training, but the magnitude of the response was significantly lower. Furthermore, we examined pattern separation, a prerequisite of learning, by entraining two overlapping patterns. Contrary to our initial hypothesis, impaired networks did not exhibit deficits in pattern separation with either population- or rate-based coding. Collectively, these results demonstrate how a mechanism of injury that operates at the synapse regulates circuit function.

Relationship and Latent Factors Between Clinical Concussion Assessments and the Functional Standardized Assessment of Reaction Time (StART)

OBJECTIVE

To examine the relationships and latent factors within the Standardized Assessment of Reaction Time (StART), and between StART and current clinical assessments.

DESIGN

Cross-sectional study.

SETTING

Clinical medicine facility.

PARTICIPANTS

Eighty-nine healthy collegiate student-athletes (63% male, age: 19.5 ± 0.9 years, 28% ≥1 concussion history).

ASSESSMENT OF RISK FACTORS

Student-athletes completed StART and clinical assessments during preinjury testing.

MAIN OUTCOME MEASURES

Standardized Assessment of Reaction Time consisted of 3 conditions (standing, single-leg balance, cutting) under 2 cognitive states (single task and dual task) for 3 trials each condition. Clinical assessments were the Sport Concussion Assessment Tool (SCAT) symptom checklist, Standardized Assessment of Concussion (SAC), tandem gait (single task and dual task), and Immediate PostConcussion Assessment and Cognitive Testing (ImPACT). We used Pearson- r correlation coefficients and exploratory factor analysis (EFA) to examine relationships and latent factors between StART and clinical assessments.

RESULTS

Null to moderate correlations presented among the StART outcomes (r range: 0.06-0.70), and null to small correlations between StART and clinical assessments (r range: -0.16 to 0.34). The three-factor EFA for solely StART explained 70.6% total variance: functional movement (cutting), static dual-task (standing and single-leg balance), and static single task (standing and single-leg balance). The five-factor EFA for StART and clinical assessments explained 65.8% total variance: gait (single-task and dual-task tandem gait), functional movement (StART single-task and dual-task cutting), static dual-task (StART standing, single-leg balance), neurocognitive (ImPACT verbal memory, visual memory, visual-motor speed), and static single task (StART standing, single-leg balance). No other outcomes met the factor loading threshold.

CONCLUSIONS

StART displayed 3 distinct categories and had minimal redundancy within its subtests. StART did not meaningfully correlate with clinical assessments, suggesting that StART provides unique information by examining more functional, reactive movement.

Optimizing VOMS for identifying acute concussion in collegiate athletes: Findings from the NCAA-DoD CARE consortium

The Vestibular/Ocular-Motor Screening (VOMS), an important component in acute (<72 h) sport-related concussion (SRC) assessment, is increasingly used alongside the Sport Concussion Assessment Tool (SCAT) and as part of the Military Acute Concussion Evaluation 2 (MACE2). VOMS demonstrates clinically useful diagnostic accuracy for acute SRC and improves the overall utility when added to the SCAT3. However, potential overlap among VOMS's vestibular and oculomotor items suggests the possibility of a more efficient version. VOMS and SCAT3 scores were analyzed for 3,958 preseason (47.8% female) and 496 acute-SRC (37.5% female) NCAA-DoD Concussion Assessment, Research, and Education (CARE) consortium collegiate athlete evaluations. Analyses revealed very large effect sizes (d = 2.39-2.45) and high correlations (rho = 0.95-0.99) among all VOMS items except near point of convergence distance (d = 0.79, rho ≤ 0.341). Receiver operating characteristic (ROC) curve analyses showed clinically useful discriminative utility for VOMS Total (AUC = 0.85) and the VOMS Total change score, where pretest symptoms were incorporated (AUC = 0.81). A modified VOMS (mVOMS) consisting of four items (smooth pursuits, horizontal saccades, horizontal vestibulo-ocular reflex, visual motion sensitivity) yielded identical AUCs to VOMS Total. Integer cutoff analyses suggest a score of ≥4 for VOMS Total and ≥4 for mVOMS Total optimizes concussion identification. Incorporating VOMS or mVOMS into SCAT3 (AUC = 0.79) significantly improved the combined tool's acute utility for acute concussion identification by a maximum of 4% (SCAT3+VOMS AUC = 0.84, SCAT3+mVOMS AUC = 0.83). Future versions of SCAT or MACE may want to consider incorporating a more parsimonious VOMS for the purpose of identifying acute concussion.

Understanding Acquired Brain Injury: A Review

Any type of brain injury that transpires post-birth is referred to as Acquired Brain Injury (ABI). In general, ABI does not result from congenital disorders, degenerative diseases, or by brain trauma at birth. Although the human brain is protected from the external world by layers of tissues and bone, floating in nutrient-rich cerebrospinal fluid (CSF); it remains susceptible to harm and impairment. Brain damage resulting from ABI leads to changes in the normal neuronal tissue activity and/or structure in one or multiple areas of the brain, which can often affect normal brain functions. Impairment sustained from an ABI can last anywhere from days to a lifetime depending on the severity of the injury; however, many patients face trouble integrating themselves back into the community due to possible psychological and physiological outcomes. In this review, we discuss ABI pathologies, their types, and cellular mechanisms and summarize the therapeutic approaches for a better understanding of the subject and to create awareness among the public.

Challenging the Vestibular System Affects Gait Speed and Cognitive Workload in Chronic Mild Traumatic Brain Injury and Healthy Adults

People with persistent symptoms after mild traumatic brain injury (mTBI) report imbalance during walking with head movements. The purpose of this study was (1) to compare usual walk gait speed to walking with head turns (HT) between people with mTBI and controls, (2) to compare the cognitive workload from usual walk to HT walk between groups, and (3) to examine if gaze stability deficits and mTBI symptoms influence gait speed. Twenty-three individuals (mean age 55.7 ± 9.3 years) with persistent symptoms after mTBI (between 3 months to 2 years post-injury) were compared with 23 age and sex-matched controls. Participants walked a 12-inch wide, 60-foot walkway when looking ahead and when walking with HT to identify letters and their colors. Gait speed during usual walk and HT walk were calculated. Pupillary responses during both walks were converted to the Index of Cognitive Activity (ICA) as a measure of cognitive workload. Gaze stability was examined by the dynamic visual acuity (DVA) test in the yaw plane. The post-concussion symptom scale (PCSS) was used to collect symptom severity. Within group analysis showed that gait speed was lower during HT walk compared to usual walk in the people with mTBI (p < 0.001) as well as in controls (p < 0.001). ICA was higher with HT compared to usual walk in the mTBI group in the right eye (p = 0.01) and left eye (p = 0.001), and in controls in the right eye (p = 0.01) and left eye (p = 0.01). Participants in the mTBI group had slower usual (p < 0.001), and HT gait speed (p < 0.001) compared to controls. No differences were noted in ICA in the right or left eye during usual walk and HT walk between groups (p > 0.05). DVA loss in the yaw plane to the right and left was not different between groups (p > 0.05) and were not correlated with gait speed. PCSS scores were correlated with usual walk (r = −0.50, p < 0.001) and HT gait speed (r = −0.44, p = 0.002). Slower gait speed, poorer stability, and higher cognitive workload during walking with head turns may reduce community participation in people with mTBI and persistent symptoms.

Plasticity impairment exposes CA3 vulnerability in a hippocampal network model of mild traumatic brain injury

Proper function of the hippocampus is critical for executing cognitive tasks such as learning and memory. Traumatic brain injury (TBI) and other neurological disorders are commonly associated with cognitive deficits and hippocampal dysfunction. Although there are many existing models of individual subregions of the hippocampus, few models attempt to integrate the primary areas into one system. In this work, we developed a computational model of the hippocampus, including the dentate gyrus, CA3, and CA1. The subregions are represented as an interconnected neuronal network, incorporating well-characterized ex vivo slice electrophysiology into the functional neuron models and well-documented anatomical connections into the network structure. In addition, since plasticity is foundational to the role of the hippocampus in learning and memory as well as necessary for studying adaptation to injury, we implemented spike-timing-dependent plasticity among the synaptic connections. Our model mimics key features of hippocampal activity, including signal frequencies in the theta and gamma bands and phase-amplitude coupling in area CA1. We also studied the effects of spike-timing-dependent plasticity impairment, a potential consequence of TBI, in our model and found that impairment decreases broadband power in CA3 and CA1 and reduces phase coherence between these two subregions, yet phase-amplitude coupling in CA1 remains intact. Altogether, our work demonstrates characteristic hippocampal activity with a scaled network model of spiking neurons and reveals the sensitive balance of plasticity mechanisms in the circuit through one manifestation of mild traumatic injury.

Alterations of microRNAs expression profiles in small extracellular vesicle after traumatic brain injury in mice

Traumatic brain injury (TBI) is one of the leading causes of mortality and morbidity worldwide. Tools available for diagnosis and therapy are limited. Small extracellular vesicle (sEV) microRNAs (miRNAs) play an important role in TBI disease progression. This study aimed to investigate the alterations in sEV miRNAs expression in the mouse brain extracellular space after TBI. Twenty-four C57BL/6J mice were randomly divided into two groups (12/group). The TBI group was subjected to all surgical procedures and fluid percussion injury (FPI). The sham group only underwent surgery. Brain specimens were collected 3 h after TBI/sham. The brain sEV were isolated. Differentially expressed miRNAs were identified. A total of 50 miRNAs were observed to be differentially expressed (fold change ≥1.5 and P<0.05) after TBI, including 5 upregulated and 45 downregulated. The major enriched Gene Ontology terms were metabolic processes, cell, intracellular, organelle, cytoplasm, axon, binding, protein kinase activity, protein binding, and protein dimerization activity. The KEGG pathway analysis predicted that the pathways affected by the variation of miRNAs in sEVs after TBI included the Wnt signaling pathway and NF-κB signaling pathway. The changes in five miRNAs were confirmed by qRT-PCR. In conclusion, this study demonstrated the differential expression of a series of miRNAs in brain sEV after TBI, which might be correlated with post-TBI physiological and pathological processes. The findings might also provide novel targets for further investigating the molecular mechanisms underlying TBI and potential therapeutic interventions.

Examining racial and ethnic disparities in adult emergency department patient visits for concussion in the United States

Background

Racial and ethnic differences in emergency department (ED) visits have been reported among adolescent patients but are unsubstantiated among adults. Therefore, our purpose in this study was to examine the relationship between race/ethnicity and adult ED visits for concussions, their injury mechanisms, and computed tomography (CT) scan use among a nationally representative sample.

Methods

We used the National Hospital Ambulatory Medical Care Survey database from 2010-2015 to examine 63,725 adult (20-45 years old) patient visits, representing an estimated 310.6 million visits presented to EDs. Of these visits, 884 (4.5 million national estimate) were diagnosed with a concussion. Visit records detailed patient information (age, sex, race/ethnicity, geographic region, primary payment type), ED visit diagnoses, injury mechanism (sport, motor vehicle, fall, struck by or against, "other"), and head CT scan use. The primary independent variable was race/ethnicity (non-Hispanic Asian, non-Hispanic Black or African American, Hispanic/Latinx, non-Hispanic multiracial or another, and non-Hispanic White). We used multivariable logistic and multinomial regression models with complex survey sampling design weighting to examine the relationship between concussion ED visits, injury mechanisms, and CT scan use separately by race/ethnicity while accounting for covariates.

Results

There were no associations between race/ethnicity and concussion diagnosis among adult ED visits after accounting for covariates. Relative to sports-related injuries, non-Hispanic Black or African American patient visits were associated with a motor vehicle (OR = 2.69, 95% CI: 1.06-6.86) and "other" injury mechanism (OR = 4.58, 95% CI: 1.34-15.69) compared to non-Hispanic White patients. Relative to sports-related injuries, non-Hispanic Asian, multiracial, or patients of another race had decreased odds of falls (OR = 0.20, 95% CI: 0.04-0.91) and "other" injuries (OR = 0.09, 95% CI: 0.01-0.55) compared to non-Hispanic White patients. The odds of a CT scan being performed were significantly lower among Hispanic/Latinx patient visits relative to non-Hispanic White patients (OR = 0.52, 95% CI: 0.30-0.91), while no other race/ethnicity comparisons differed.

Conclusion

Our findings indicate that the overarching concussion ED visit likelihood may not differ by race/ethnicity in adults, but the underlying mechanism causing the concussion and receiving a CT scan demonstrates considerable differences. Prospective future research is warranted to comprehensively understand and intervene in the complex, multi-level race/ethnicity relationships related to concussion health care to ensure equitable patient treatment.

Comprehensive analysis of circRNA expression profiles in rat cerebral cortex after moderate traumatic brain injury

Traumatic brain injury is a medical event of global concern, and a growing body of research suggests that circular RNAs can play very important roles in traumatic brain injury. To explore the functions of more novel and valuable circular RNA in traumatic brain injury response, a moderate traumatic brain injury in rats was established and comprehensive analysis of circular RNA expression profiles in rat cerebral cortex was done. As a result, 301 up-regulated and 284 down-regulated circular RNAs were obtained in moderate traumatic brain injury rats, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed based on the circular RNA's host genes, and a circRNA-miRNA interaction network based on differentially expressed circular RNAs was constructed. Also, four circular RNAs were validated by RT-qPCR and Sanger sequencing. This study showed that differentially expressed circular RNAs existed between rat cerebral cortex after moderate traumatic brain injury and control. And this will provide valuable information for circular RNA research in the field of traumatic brain injury.

Biofidelic dynamic compression of human cortical spheroids reproduces neurotrauma phenotypes

Fundamental questions about patient heterogeneity and human-specific pathophysiology currently obstruct progress towards a therapy for traumatic brain injury (TBI). Human in vitro models have the potential to address these questions. 3D spheroidal cell culture protocols for human-origin neural cells have several important advantages over their 2D monolayer counterparts. Three dimensional spheroidal cultures may mature more quickly, develop more biofidelic electrophysiological activity and/or reproduce some aspects of brain architecture. Here, we present the first human in vitro model of non-penetrating TBI employing 3D spheroidal cultures. We used a custom-built device to traumatize these spheroids in a quantifiable, repeatable and biofidelic manner and correlated the heterogeneous, mechanical strain field with the injury phenotype. Trauma reduced cell viability, mitochondrial membrane potential and spontaneous, synchronous, electrophysiological activity in the spheroids. Electrophysiological deficits emerged at lower injury severities than changes in cell viability. Also, traumatized spheroids secreted lactate dehydrogenase, a marker of cell damage, and neurofilament light chain, a promising clinical biomarker of neurotrauma. These results demonstrate that 3D human in vitro models can reproduce important phenotypes of neurotrauma in vitro.

Concussion Characteristics and Early Postinjury Outcomes Between College Students and Intercollegiate Athletes

OBJECTIVE

To describe concussion characteristics among general college students and compare postinjury outcomes to intercollegiate student athletes.

DESIGN

Retrospective cohort.

SETTING

Large university in the Southeast region of the United States.

PARTICIPANTS

A total of 179 (N=179) college students' (female=120; 67.0%; 23.9±3.9 years) and 49 athletes' (female=28, 57.1%;19.3±1.3 years) medical records were examined. Participants self-reported injury mechanism, health history information, and completed clinical assessments acutely (<7 days postinjury).

MAIN OUTCOME MEASURES

Descriptive statistics were calculated for each group. Concussion outcomes between students with and without certain health history diagnoses were assessed using separate t tests. We conducted univariate regression analyses to determine if sex, age, and time from concussion to first clinical assessment were significant predictors of clinical outcomes. Statistically significant variables were included as covariates in a series of 1-way analyses of covariance to identify differences in balance, symptom severity, total symptom presence, and neurocognitive domain performance between students and athletes. Fisher exact tests were used to compare health history information between groups (α<0.05).

RESULTS

Among students, 24% reported sustaining a concussion while participating in recreational sports, and 27% of impacts occurred to the back of the head. Students had higher proportions of headache, migraine, anxiety, and depression (P<.05). Students reported greater total symptom presence (P=.006) and performed worse on the computerized neurocognitive test domain score for complex attention (P=.015) relative to athletes.

CONCLUSIONS

These findings highlight the need for better access to medical care for non- National Collegiate Athletic Association sanctioned athletes because of a large proportion of concussions in the student sample being sustained during sports participation. Identifying common injury mechanisms can provide clinicians with powerful information to improve evaluation and treatment models.

A Prognostic Model for Predicting One-Month Outcomes among Emergency Department Patients with Mild Traumatic Brain Injury and a Presenting Glasgow Coma Scale of Fifteen

The lack of well-performing prognostic models for early prognostication of outcomes remains a major barrier to improving the clinical care of patients with mild traumatic brain injury (mTBI). We aimed to derive a prognostic model for predicting incomplete recovery at 1-month in emergency department (ED) patients with mTBI and a presenting Glasgow Coma Scale (GCS) score of 15 who were enrolled in the HeadSMART (Head Injury Serum Markers for Assessing Response to Trauma) study. The derivation cohort included 355 participants with complete baseline (day-of-injury) and follow-up data. The primary outcome measure was the Glasgow Outcome Scale Extended (GOSE) at 1-month and incomplete recovery was defined as a GOSE <8. At 1-month post-injury, incomplete recovery was present in 58% (n = 205) of participants. The final multi-variable logistic regression model included six variables: age in years (odds ratio [OR] = 0.98; 95% confidence interval [CI]: 0.97-1.00), positive head CT (OR = 4.42; 95% CI: 2.21-9.33), history of depression (OR = 2.59; 95% CI: 1.47-4.69), and self-report of moderate or severe headache (OR = 2.49; 95% CI: 1.49-4.18), difficulty concentrating (OR = 3.17; 95% CI: 1.53-7.04), and photophobia (OR = 4.17; 95% CI: 2.08-8.92) on the day-of-injury. The model was validated internally using bootstrap resampling (1000 resamples), which revealed a mean over-optimism value of 0.01 and an optimism-corrected area under the curve (AUC) of 0.79 (95% CI: 0.75-0.85). A prognostic model for predicting incomplete recovery among ED patients with mTBI and a presenting GCS of 15 using easily obtainable clinical and demographic variables has acceptable discriminative accuracy. External validation of this model is warranted.

Oculomotor Deficits and Symptom Severity Are Associated With Poorer Dynamic Mobility in Chronic Mild Traumatic Brain Injury

Oculomotor deficits, vestibular impairments, and persistent symptoms are common after a mild traumatic brain injury (mTBI); however, the relationship between visual-vestibular deficits, symptom severity, and dynamic mobility tasks is unclear. Twenty-three individuals (mean age 55.7 ± 9.3 years) with persistent symptoms after mTBI, who were between 3 months to 2 years post-injury were compared with 23 age and sex-matched controls. Oculomotor deficits [depth perception, near-point convergence, baseline visual acuity (BLVA), perception time], vestibular deficits (dynamic visual acuity in the pitch and yaw planes), dynamic mobility measured by the Functional Gait Assessment (FGA), and symptoms measured by the Post-Concussion Symptom Scale (PCSS) and Dizziness Handicap Inventory (DHI) were compared between groups. Participants with mTBI had poorer performance on the FGA (p < 0.001), higher symptom severity on the PCSS (p < 0.001), and higher DHI scores (p < 0.001) compared to controls. Significant differences were seen on specific items of the FGA between individuals with mTBI and controls during walking with horizontal head turns (p = 0.002), walking with vertical head tilts (p < 0.001), walking with eyes closed (p = 0.003), and stair climbing (p = 0.001). FGA performance was correlated with weeks since concussion (r = −0.67, p < 0.001), depth perception (r = −0.5348, p < 0.001), near point convergence (r = −0.4717, p = 0.001), baseline visual acuity (r = −0.4435, p = 0.002); as well as with symptoms on the PCSS (r = −0.668, p < 0.001), and DHI (r = −0.811, p < 0.001). Dynamic balance deficits persist in chronic mTBI and may be addressed using multifaceted rehabilitation strategies to address oculomotor dysfunction, post-concussion symptoms, and perception of handicap due to dizziness.

Slowed driving-reaction time following concussion-symptom resolution

BACKGROUND

Concussed patients have impaired reaction time (RT) and cognition following injury that may linger and impair driving performance. Limited research has used direct methods to assess driving-RT post-concussion. Our study compared driving RT during simulated scenarios between concussed and control individuals and examined driving-RT's relationship with traditional computerized neurocognitive testing (CNT) domains.

METHODS

We employed a cross-sectional study among 14 concussed (15.9 ± 9.8 days post-concussion, mean ± SD) individuals and 14 healthy controls matched for age, sex, and driving experience. Participants completed a driving simulator and CNT (CNS Vital Signs) assessment within 48 h of symptom resolution. A driving-RT composite (ms) was derived from 3 simulated driving scenarios: stoplight (green to yellow), evasion (avoiding approaching vehicle), and pedestrian (person running in front of vehicle). The CNT domains included verbal and visual memory; CNT-RT (simple-, complex-, Stroop-RT individually); simple and complex attention; motor, psychomotor, and processing speed; executive function; and cognitive flexibility. Independent t tests and Hedge d effect sizes assessed driving-RT differences between groups, Pearson correlations (r) examined driving RT and CNT domain relationships among cohorts separately, and p values were controlled for false discovery rate via Benjamini-Hochberg procedures (α = 0.05).

RESULTS

Concussed participants demonstrated slower driving-RT composite scores than controls (mean difference = 292.86 ms; 95% confidence interval (95%CI): 70.18-515.54; p = 0.023; d = 0.992). Evasion-RT (p = 0.054; d = 0.806), pedestrian-RT (p = 0.258; d = 0.312), and stoplight-RT (p = 0.292; d = 0.585) outcomes were not statistically significant after false-discovery rate corrections but demonstrated medium to large effect sizes for concussed deficits. Among concussed individuals, driving-RT outcomes did not significantly correlate with CNT domains (r-range: -0.51 to 0.55; p > 0.05). No correlations existed between driving-RT outcomes and CNT domains among control participants either (r-range: -0.52 to 0.72; p > 0.05).

CONCLUSION

Slowed driving-RT composite scores and large effect sizes among concussed individuals when asymptomatic signify lingering impairment and raise driving-safety concerns. Driving-RT and CNT-RT measures correlated moderately but not statistically, which indicates that CNT-RT is not an optimal surrogate for driving RT.

Examination of Reaction Time Deficits Following Concussion: A Systematic Review and Meta-analysis

BACKGROUND

Reaction time (RT) deficits are reported following concussion, but it is unknown when these deficits normalize to pre-injury status. It is also unclear how factors such as RT measurement technique and participant characteristics influence post-concussion RT.

OBJECTIVE

The purpose of this systematic review and meta-analysis was to (1) characterize acute post-concussion (0-3 days) RT impairments, (2) examine RT recovery over time, and (3) explore moderating factors related to acute RT impairment following concussion.

METHODS

Database searches (PubMed, CINAHL, EBSCOhost) were conducted according to PRISMA guidelines for articles published in English from January 2002 to March 2019. Studies compared baseline-to-post-injury RT within individuals (within-subject) and/or RT in concussed individuals to non-concussed controls (between-subject). Sixty studies met inclusion criteria, reporting on a total of 9688 participants with 214 discrete RT effects (Hedges' d; between-subject: N = 29, k = 129; within-subject: N = 42, k = 85). Of the 214 effects, 93 occurred in the acute (0-3 days) post-injury timeframe (k = 47 between-subject). Numerous demographic [sex, age, concussion history, population type (athlete, military, and general population), athlete level (high school, college), and sport], and method-based (RT test and measure type, computerized neurocognitive testing platform, concussion definition, and time post-injury) moderators were examined for mean effect influence. Mixed-effects multi-level modeling with restricted-maximum-likelihood estimation was used to account for nested effects and high heterogeneity for the pooled effect size (D+).

RESULTS

Significant medium-magnitude RT deficits were observed acutely for between- (D+ = - 0.7279, 95% CI - 0.9919, - 0.4639, I² = 88.66, p < 0.0001) and within-subject (D+ = - 0.7472, 95% CI - 0.9089, - 0.5855, I² = 89.21, p < 0.0001) effect models. RT deficits were present at the sub-acute and intermediate-term timeframes for between-subject effects (sub-acute: D+ = - 0.5655, 95% CI - 0.6958, - 0.4352, p < 0.0001; intermediate-term: D+ = - 0.3219, 95% CI - 0.5988, - 0.0450, p = 0.0245). No significant RT mean effect was observed for the between-subject model at the long-term timeframe, indicating RT recovery among concussed participants relative to controls (D+ = 0.3505, 95% CI - 0.4787, 1.1797, p = 0.3639). Sex was a significant moderator for between-subject effects, with every 1% male sample size increase demonstrating - 0.0171 (95% CI - 0.0312, - 0.0029, p = 0.0193) larger RT deficits. Within-subject effect models resulted in RT measure type (simple: [D+ = - 0.9826] vs. mixed: [D+ = - 0.6557], p = 0.0438) and computerized neurocognitive testing platforms (ANAM: [D+ = - 0.3735] vs. HeadMinder CRI: [D+ = - 1.4799] vs. ImPACT: [D+ = - 0.6749], p = 0.0004) having significantly different RT-deficit magnitudes. No other moderators produced significantly different RT-deficit magnitudes (between-subject: [p ≥ 0.0763], within-subject: [p ≥ 0.1723]).

CONCLUSIONS

Robust RT deficits were observed acutely following concussion. Minimal magnitude differences were noted when comparing between- and within-subject effects, suggesting that pre-injury baselines may not add clinical value in determining post-injury RT impairment. RT deficits persisted up till the intermediate-term (21-59 days post-injury) timeframe and indicate lingering deficits exist. Mean effect size differences were observed between RT measure types and computerized neurocognitive testing platforms; however, all categories displayed negative effects consistent with impaired RT following concussion. Clinical interpretation suggests that measuring RT post-concussion is more important than considering the RT method employed so long as reliable and valid tools are used. PROSPERO Registration #CRD42019119323.

A Systematic Review of the Incidence, Prevalence, Costs, and Activity and Work Limitations of Amputation, Osteoarthritis, Rheumatoid Arthritis, Back Pain, Multiple Sclerosis, Spinal Cord Injury, Stroke, and Traumatic Brain Injury in the United States: A 2019 Update

OBJECTIVES

To present recent evidence on the prevalence, incidence, costs, activity limitations, and work limitations of common conditions requiring rehabilitation.

DATA SOURCES

Medline (PubMed), SCOPUS, Web of Science, and the gray literature were searched for relevant articles about amputation, osteoarthritis, rheumatoid arthritis, back pain, multiple sclerosis, spinal cord injury, stroke, and traumatic brain injury.

STUDY SELECTION

Relevant articles (N=106) were included.

DATA EXTRACTION

Two investigators independently reviewed articles and selected relevant articles for inclusion. Quality grading was performed using the Methodological Evaluation of Observational Research Checklist and Newcastle-Ottawa Quality Assessment Form.

DATA SYNTHESIS

The prevalence of back pain in the past 3 months was 33.9% among community-dwelling adults, and patients with back pain contribute $365 billion in all-cause medical costs. Osteoarthritis is the next most prevalent condition (approximately 10.4%), and patients with this condition contribute $460 billion in all-cause medical costs. These 2 conditions are the most prevalent and costly (medically) of the illnesses explored in this study. Stroke follows these conditions in both prevalence (2.5%-3.7%) and medical costs ($28 billion). Other conditions may have a lower prevalence but are associated with relatively higher per capita effects.

CONCLUSIONS

Consistent with previous findings, back pain and osteoarthritis are the most prevalent conditions with high aggregate medical costs. By contrast, other conditions have a lower prevalence or cost but relatively higher per capita costs and effects on activity and work. The data are extremely heterogeneous, which makes anything beyond broad comparisons challenging. Additional information is needed to determine the relative impact of each condition.

Traumatic Brain Injury: Does Admission Service Matter?

BACKGROUND

Traumatic brain injury (TBI) is common, and significant institutional variation exists with regards to structure and processes of care. Affected patients may be admitted to one of several different services, and this may drive differential care and outcomes. We sought to evaluate differential care and outcomes for patients with isolated mild-to-moderate traumatic brain injury based on admission service.

MATERIALS AND METHODS

This is a single-institution retrospective study of all adult (≥18 y old) patients admitted with isolated TBI (AIS ≤1 in all other body regions) over a 3-year period (6/2015-6/2018). Patients who underwent neurosurgical intervention (craniectomy/craniotomy) and those with a head AIS ≥4 were excluded. Patients were assigned to one of three groups based upon admission service: Trauma Surgery, Neurology/Medicine or Neurosurgery. Outcomes evaluated included in-hospital mortality and markers of differential care. We performed multivariate analyses adjusting for patient demographics and clinical characteristics.

RESULTS

A total of 401 isolated mild-to-moderate TBI patients were identified. Overall mortality was 1.7%. Adjusted multivariate logistic regression analysis demonstrated no difference in mortality. Patients admitted to Neurosurgery underwent more repeat head CTs and were more likely to receive antiseizure medication in the absence of seizure activity, and those admitted to Neurology/Medicine were less likely to receive venous thromboembolism chemoprophylaxis compared to those admitted to Trauma Surgery.

CONCLUSIONS

We identify several important metrics of variation in care received by patients with an isolated mild-to-moderate TBI based upon admission service. These findings deserve further study, and this study may lay the foundation for future efforts at protocolizing care in an evidence-based fashion for this patient cohort.

NMDA Receptor Alterations After Mild Traumatic Brain Injury Induce Deficits in Memory Acquisition and Recall

Mild traumatic brain injury (mTBI) presents a significant health concern with potential persisting deficits that can last decades. Although a growing body of literature improves our understanding of the brain network response and corresponding underlying cellular alterations after injury, the effects of cellular disruptions on local circuitry after mTBI are poorly understood. Our group recently reported how mTBI in neuronal networks affects the functional wiring of neural circuits and how neuronal inactivation influences the synchrony of coupled microcircuits. Here, we utilized a computational neural network model to investigate the circuit-level effects of N-methyl D-aspartate receptor dysfunction. The initial increase in activity in injured neurons spreads to downstream neurons, but this increase was partially reduced by restructuring the network with spike-timing-dependent plasticity. As a model of network-based learning, we also investigated how injury alters pattern acquisition, recall, and maintenance of a conditioned response to stimulus. Although pattern acquisition and maintenance were impaired in injured networks, the greatest deficits arose in recall of previously trained patterns. These results demonstrate how one specific mechanism of cellular-level damage in mTBI affects the overall function of a neural network and point to the importance of reversing cellular-level changes to recover important properties of learning and memory in a microcircuit.

Factors Influencing Primary Care Follow-Up After Pediatric Mild Traumatic Brain Injury

OBJECTIVE

To identify socioeconomic, demographic, and caregiver factors associated with children attending primary care provider (PCP) follow-up after emergency department (ED) evaluation for mild traumatic brain injury (mTBI).

SETTING

Pediatric trauma center ED.

PARTICIPANTS

Children 8 to 18 years of age sustaining mTBI less than 48 hours prior to an ED visit. Mean age of the 183 participants was 12 years with no significant differences between those who attended follow-up and those who did not in race, ethnicity, insurance provider, or PCP office setting.

DESIGN

Thirty-day longitudinal cohort study.

MAIN MEASURES

Insurance type, PCP practice setting, and a caregiver attitudes survey regarding mTBI recovery and management (5 questions each scored on a 5-point Likert scale). The primary outcome was attending a PCP follow-up visit within 1 month of injury.

RESULTS

Females were more likely than males to attend PCP follow-up (adjusted odds ratio: 2.27 [95% confidence interval: 1.00-5.18]). Increasing scores on the caregiver attitudes survey indicating greater concerns about recovery were significantly associated with attending PCP follow-up (adjusted odds ratio: 1.12 per unit increase in composite score [95% confidence interval: 1.02-1.23]). No other socioeconomic, demographic, or injury characteristics were associated with attending PCP follow-up.

CONCLUSIONS

The ED counseling regarding PCP follow-up of mTBI should stress the importance of follow-up care to monitor recovery and identify presence of lingering symptoms.

Neurodegeneration exposes firing rate dependent effects on oscillation dynamics in computational neural networks

Traumatic brain injury (TBI) can lead to neurodegeneration in the injured circuitry, either through primary structural damage to the neuron or secondary effects that disrupt key cellular processes. Moreover, traumatic injuries can preferentially impact subpopulations of neurons, but the functional network effects of these targeted degeneration profiles remain unclear. Although isolating the consequences of complex injury dynamics and long-term recovery of the circuit can be difficult to control experimentally, computational networks can be a powerful tool to analyze the consequences of injury. Here, we use the Izhikevich spiking neuron model to create networks representative of cortical tissue. After an initial settling period with spike-timing-dependent plasticity (STDP), networks developed rhythmic oscillations similar to those seen in vivo. As neurons were sequentially removed from the network, population activity rate and oscillation dynamics were significantly reduced. In a successive period of network restructuring with STDP, network activity levels returned to baseline for some injury levels and oscillation dynamics significantly improved. We next explored the role that specific neurons have in the creation and termination of oscillation dynamics. We determined that oscillations initiate from activation of low firing rate neurons with limited structural inputs. To terminate oscillations, high activity excitatory neurons with strong input connectivity activate downstream inhibitory circuitry. Finally, we confirm the excitatory neuron population role through targeted neurodegeneration. These results suggest targeted neurodegeneration can play a key role in the oscillation dynamics after injury.

Post Traumatic Headache: Clinical care of athletes vs non athletes with Persistent Post Traumatic Headache after Concussion: Sports Neurologist and Headache Specialist Perspective

PURPOSE

The purpose of this paper is to review and outline the similarities and differences in the treatment of athletes compared with that of other populations with a persistent post-traumatic headache after a concussion.

RECENT FINDINGS

After an extensive review of the literature and despite well over 2 million Americans experiencing post-traumatic headache (PTH) each year, a number of which will continue to experience persistent post-traumatic headache (PPTH). There is little evidence on the management of the disorder and essentially no evidence-based research when it comes to the management of athletes. With little evidence available for the treatment of individuals with PPTH, be it athletes or non-athletes, the clinician will need to rely on their experience and the application of existing treatments for migraine and chronic migraine. Clearly, more research is needed, especially with respect to the management of athletes versus non-athletes.

A Multibody Model for Predicting Spatial Distribution of Human Brain Deformation Following Impact Loading

With an increasing focus on long-term consequences of concussive brain injuries, there is a new emphasis on developing tools that can accurately predict the mechanical response of the brain to impact loading. Although finite element models (FEM) estimate the brain response under dynamic loading, these models are not capable of delivering rapid (∼seconds) estimates of the brain's mechanical response. In this study, we develop a multibody spring-mass-damper model that estimates the regional motion of the brain to rotational accelerations delivered either about one anatomic axis or across three orthogonal axes simultaneously. In total, we estimated the deformation across 120 locations within a 50th percentile human brain. We found the multibody model (MBM) correlated, but did not precisely predict, the computed finite element response (average relative error: 18.4 ± 13.1%). We used machine learning (ML) to combine the prediction from the MBM and the loading kinematics (peak rotational acceleration, peak rotational velocity) and significantly reduced the discrepancy between the MBM and FEM (average relative error: 9.8 ± 7.7%). Using an independent sports injury testing set, we found the hybrid ML model also correlated well with predictions from a FEM (average relative error: 16.4 ± 10.2%). Finally, we used this hybrid MBM-ML approach to predict strains appearing in different locations throughout the brain, with average relative error estimates ranging from 8.6% to 25.2% for complex, multi-axial acceleration loading. Together, these results show a rapid and reasonably accurate method for predicting the mechanical response of the brain for single and multiplanar inputs, and provide a new tool for quickly assessing the consequences of impact loading throughout the brain.

Definition and epidemiology of mild traumatic brain injury

BACKGROUND/OBJECTIVES

The definition of mild traumatic brain injury (mTBI), also known as concussion, has been a matter of controversy, which makes comparison between studies difficult. Incidence varies greatly from one country to another. The present article reviews definitions and epidemiology.

METHODS

Literature review.

RESULTS

According to the Mild TBI Committee of the American Congress of Rehabilitation Medicine, revised by the World Health Organization (WHO), mTBI is defined by a Glasgow Coma Scale score between 13 and 15 at 30minutes post-injury, and one or more of the following symptoms: <30min loss of consciousness; <24hours post-traumatic amnesia (PTA); impaired mental state at time of accident (confusion, disorientation, etc.); and/or transient neurological deficit. If a focal lesion is found on computed tomography (CT) or magnetic resonance imaging (MRI), the term "complicated mild TBI" has been proposed. Incidence of mTBI is 200-300/100,000 persons per year for hospitalized patients and probably twice as high if non-hospitalized patients are included. However, a few recent population-based studies reported a much higher rate (>700/100,000). A changing pattern of epidemiology has been found in high-income countries, related to a decrease in road-accident injuries in young adults, while conversely the proportion of falls has increased with population aging.

CONCLUSION

Mild TBI is a major public health concern, the epidemiology of which has greatly changed in the last twenty years.

Clinical Predictors of 3- and 6-Month Outcome for Mild Traumatic Brain Injury Patients with a Negative Head CT Scan in the Emergency Department: A TRACK-TBI Pilot Study

A considerable subset of mild traumatic brain injury (mTBI) patients fail to return to baseline functional status at or beyond 3 months postinjury. Identifying at-risk patients for poor outcome in the emergency department (ED) may improve surveillance strategies and referral to care. Subjects with mTBI (Glasgow Coma Scale 13–15) and negative ED initial head CT < 24 h of injury, completing 3- or 6-month functional outcome (Glasgow Outcome Scale-Extended; GOSE), were extracted from the prospective, multicenter Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) Pilot study. Outcomes were dichotomized to full recovery (GOSE = 8) vs. functional deficits (GOSE < 8). Univariate predictors with p < 0.10 were considered for multivariable regression. Adjusted odds ratios (AOR) were reported for outcome predictors. Significance was assessed at p < 0.05. Subjects who completed GOSE at 3- and 6-month were 211 (GOSE < 8: 60%) and 185 (GOSE < 8: 65%). Risk factors for 6-month GOSE < 8 included less education (AOR = 0.85 per-year increase, 95% CI: (0.74–0.98)), prior psychiatric history (AOR = 3.75 (1.73–8.12)), Asian/minority race (American Indian/Alaskan/Hawaiian/Pacific Islander) (AOR = 23.99 (2.93–196.84)), and Hispanic ethnicity (AOR = 3.48 (1.29–9.37)). Risk factors for 3-month GOSE < 8 were similar with the addition of injury by assault predicting poorer outcome (AOR = 3.53 (1.17–10.63)). In mTBI patients seen in urban trauma center EDs with negative CT, education, injury by assault, Asian/minority race, and prior psychiatric history emerged as risk factors for prolonged disability.

Physical Therapy Evaluation and Treatment After Concussion/Mild Traumatic Brain Injury

Over the last decade, numerous concussion evidence-based clinical practice guidelines (CPGs), consensus statements, and clinical guidance documents have been published. These documents have typically focused on the diagnosis of concussion and medical management of individuals post concussion, but provide little specific guidance for physical therapy management of concussion and its associated impairments. Further, many of these guidance documents have targeted specific populations in specific care contexts. The primary purpose of this CPG is to provide a set of evidence-based recommendations for physical therapist management of the wide spectrum of patients who have experienced a concussive event. J Orthop Sports Phys Ther 2020;50(4):CPG1-CPG73. doi:10.2519/jospt.2020.0301.

Concussion and Mild-Traumatic Brain Injury in Rural Settings: Epidemiology and Specific Health Care Considerations

Background  Mild-traumatic brain injury (mTBI) and concussions cause significant morbidity. To date, synthesis of specific health care disparities and gaps in care for rural mTBI/concussion patients remains needed. Methods  A comprehensive literature search was performed using PubMed database for English articles with keywords "rural" and ("concussion" or "mild traumatic brain injury") from 1991 to 2019. Eighteen articles focusing on rural epidemiology ( n = 5), management/cost ( n = 5), military ( n = 2), and concussion prevention/return to play ( n = 6) were included. Results  mTBI/concussion incidence was higher in rural compared with urban areas. Compared with urban patients, rural patients were at increased risk for vehicular injuries, lifetime number of concussions, admissions for observation without neuroimaging, and injury-related costs. Rural patients were less likely to utilize ambulatory and mental health services following mTBI/concussion. Rural secondary schools had decreased access to certified personnel for concussion evaluation, and decreased use of standardized assessment instruments/neurocognitive testing. While school coaches were aware of return-to-play laws, mTBI/concussion education rates for athletes and parents were suboptimal in both settings. Rural veterans were at increased risk for postconcussive symptoms and posttraumatic stress. Telemedicine in rural/low-resource areas is an emerging tool for rapid evaluation, triage, and follow-up. Conclusions  Rural patients are at unique risk for mTBI/concussions and health care costs. Barriers to care include lower socioeconomic status, longer distances to regional medical center, and decreased availability of neuroimaging and consultants. Due to socioeconomic and distance barriers, rural schools are less able to recruit personnel certified for concussion evaluation. Telemedicine is an emerging tool for remote triage and evaluation.

The Role of Circular RNAs in Brain Injury

Circular RNAs are an increasingly important topic in non-coding RNA biology, drawing considerable attention in recent years. Accumulating evidence suggests a critical role for circular RNAs in both early and latent stages of disease pathogenesis. Circular RNAs are abundantly expressed in brain tissue, with significant implications for neural development and disease progression. Disruption of these processes, including those seen in response to brain injury, can have serious consequences such as hemiplegia, aphasia, coma, and death. In this review, we describe the role of circular RNAs in the context of brain injury and explore the potential connection between circular RNAs, brain hypoxic ischemic injury, ischemia-reperfusion injury, and traumatic injury.

Surveillance of concussion-related injuries using electronic medical records from the Canadian Primary Care Sentinel Surveillance Network (CPCSSN): a proof-of-concept

INTRODUCTION

Previous studies on traumatic brain injury trends in Canada have been restricted to hospitalization and emergency department visit data. However, many concussion patients may present first, or only, to family physicians. Therefore, the true burden of concussion in Canada is likely underestimated. The Canadian Primary Care Sentinel Surveillance Network (CPCSSN) collects information electronically from family physicians across Canada and can potentially be used for concussion surveillance. The objective of this study is to explore the feasibility of using data collated from CPCSSN for concussion surveillance purposes and examine trends over time.

METHODS

Electronic medical records housed by CPCSSN from 2010 to 2016 were analyzed. Case ascertainment was determined through a combination of International Classification of Diseases, Ninth Revision codes. Binomial regression models were used to calculate the prevalence ratio (PR) of concussion by age, sex, deprivation indices, body mass index, and comorbid conditions.

RESULTS

Concussion prevalence rates increased from 2010 to 2016 (p < 0.001). Based on 2016 data, males had a higher prevalence of concussion compared with females (PR = 1.09; 95% CI 1.02, 1.18), and those aged 10-14 (PR = 8.52; 95% confidence interval [CI] 6.34, 11.44) and 15-19 (PR = 7.75; 95% CI 5.84, 10.28) had higher prevalence of concussion compared with those aged 0-4 years.

CONCLUSION

This pilot study demonstrates the feasibility of using the CPCSSN system for surveillance of concussion in the Canadian population. The initial findings on prevalence are in agreement with previous studies that have used hospitalization or emergency department data.