Risk of Repeat Concussion Among Patients Diagnosed at a Pediatric Care Network

The beneficial effects of modafinil administration on repeat mild traumatic brain injury (RmTBI) pathology in adolescent male rats are not dependent upon the orexinergic system

The sleep-wake cycle plays an influential role in the development and progression of repeat mild traumatic brain injury (RmTBI)-related pathology. Therefore, we first aimed to manipulate the sleep-wake cycle post-RmTBI using modafinil, a wake-promoting substance used for the treatment of narcolepsy. We hypothesized that modafinil would exacerbate RmTBI-induced deficits. Chronic behavioural analyses were completed along with a 27-plex serum cytokine array, metabolomic and proteomic analyses of cerebrospinal fluid (CSF), as well as immunohistochemical staining in structures important for sleep/wake cycles, to examine orexin, melanin-concentrating hormone, tyrosine hydroxylase, and choline acetyltransferase, in the lateral hypothalamus, locus coeruleus, and basal forebrain, respectively. Contrary to expectation, modafinil administration attenuated behavioural deficits, metabolomic changes, and neuropathological modifications. Therefore, the second aim was to determine if the beneficial effects of modafinil treatment were driven by the orexinergic system. The same experimental protocol was used; however, RmTBI rats received chronic orexin-A administration instead of modafinil. Orexin-A administration produced drastically different outcomes, exacerbating anxiety-related and motor deficits, while also significantly disrupting their metabolomic and neuropathological profiles. These results suggest that the beneficial effects of modafinil administration post-RmTBI, work independently of its wake-promoting properties, as activation of the orexinergic wake-promoting system with orexin-A was detrimental. Overall, these findings highlight the complexity of sleep-wake changes in the injured brain and showcase the potential of the arousal and sleep systems in its treatment.

The Interval Between Concussions Does Not Influence Time to Asymptomatic or Return to Play: A CARE Consortium Study

INTRODUCTION

The purpose of this study was to determine if the time interval between two concussive events influences the number of days to asymptomatic status, days to return to play, or performance on common post-concussion assessments following the second concussion.

METHODS

Data from 448 collegiate athletes and service academy cadets with two concussions (time between concussions: median 295.0 days [interquartile range: 125.0-438.2]), 40.0% female) were analyzed from Concussion Assessment Research and Education (CARE) Consortium institutions between 2014 and 2020. Days between concussions was the primary predictor variable. Primary outcome measures included time to asymptomatic and time to return to play following the second concussion. Secondary outcome measures included total number of symptoms, total symptom severity, Balance Error Scoring System total score, and Standardized Assessment of Concussion total score within 48 h of their second concussion.

RESULTS

Time between concussions did not significantly contribute to the multivariate time to asymptomatic (p = 0.390), time to return to play (p = 0.859), or the secondary outcomes (p-range = 0.165-0.477) models. Time to asymptomatic (p = 0.619) or return to play (p = 0.524) did not differ between same-season and different-season concussions. Sex significantly contributed to the return to play (p = 0.005) multivariate model. Delayed symptom onset and immediate removal from play/competition significantly contributed to the total number of symptoms (p = 0.001, p = 0.014) and symptom severity (p = 0.011, p = 0.022) multivariate models.

CONCLUSION

These results suggest that in a population with a large period between injuries, the time between concussions may not be relevant to clinical recovery.

Microbiome depletion prior to repeat mild TBI differentially alters social deficits and prefrontal cortex plasticity in adolescent and adult rats

Although aging, repeat mild traumatic brain injury (RmTBI), and microbiome modifications independently change social behavior, there has been no investigation into their cumulative effects on social behavior and neuroplasticity within the prefrontal cortex. Therefore, we examined how microbiome depletion prior to RmTBI affected social behavior and neuroplasticity in adolescent and adult rats. Play, temperament analysis, elevated plus maze, and the hot/cold plate assessed socio-emotional function. Analyses of perineuronal nets (PNNs) and parvalbumin (PV) interneurons was completed. Social-emotional deficits were more pronounced in adults, with microbiome depletion attenuating social behavior deficits associated with RmTBI in both age groups. Microbiome depletion increased branch length and PNN arborization within the PFC but decreased the overall number of PNNs. Adults and males were more vulnerable to RmTBI. Interestingly, microbiome depletion may have attenuated the changes to neuroplasticity and subsequent social deficits, suggesting that the microbiome is a viable, but age-specific, target for RmTBI therapeutics.

Risk of Two Sport-Related Concussions in the Same Year: Is the Second Concussion Worse?

OBJECTIVES

1) Evaluate the frequency of same-year, repeat concussions; (2) assess predictors of sustaining a repeat concussion; and (3) compare outcomes of athletes with repeat concussions with athletes with single concussion.

DESIGN

A retrospective, case-control study.

SETTING

Regional sports concussion center.

PATIENTS

Adolescents sustaining a sport-related concussions (SRC) from November 2017 to October 2020.

INDEPENDENT VARIABLES

Participants were dichotomized into 2 groups: (1) athletes with a single concussion; and (2) athletes with repeat concussions.

MAIN OUTCOME MEASURES

Between group and within group analyses were completed to look for differences in demographics, personal and family history, concussion history, and recovery metrics between the 2 groups.

RESULTS

Of 834 athletes with an SRC, 56 (6.7%) sustained a repeat concussion and 778 (93.3%) had a single concussion. Between group: Personal history of migraines (19.6% vs 9.5%, χ 2 = 5.795, P = 0.02), family history of migraines (37.5% vs 24.5%, χ 2 = 4.621, P = 0.03), and family history of psychiatric disorders (25% vs 13.1%, χ 2 = 6.224, P = 0.01) were significant predictors of sustaining a repeat concussion. Within group: Among those with a repeat concussion, initial symptom severity was greater (Z = -2.422; P = 0.02) during the repeat concussion and amnesia was more common (χ 2 = 4.775, P = 0.03) after the initial concussion.

CONCLUSIONS

In a single-center study of 834 athletes, 6.7% suffered a same-year, repeat concussion. Risk factors included personal/family migraine history and family psychiatric history. For athletes with repeat concussions, initial symptom score was higher after the second concussion, yet amnesia was more common after the initial concussion.

Improving outcome after paediatric concussion: challenges and possibilities

The term concussion has permeated mainstream media and household vocabulary mainly due to awareness regarding the risks of concussion in professional contact sports, yet it occurs across a variety of settings and ages. Concussion is prevalent in infants, preschoolers, children, and adolescents, and is a common presentation or reason for referral to primary care providers, emergency departments, and specialised trauma clinics. Its broad range of symptoms and sequelae vary according to multiple individual, environmental, and clinical factors and can lead to health and economic burden. More than 20 years of research into risk factors and consequences of paediatric concussion has revealed as many questions as answers, and scientific work and clinical cases continue to expose its complexity and heterogeneity. In this Review, we present empirical evidence for improving outcome after paediatric concussion. We consider work pertaining to both sports and other injury mechanisms to provide a perspective that should be viewed as complementary to publications focused specifically on sports concussion. Contemporary challenges in prevention, diagnosis, prognosis, and intervention are discussed alongside pathways and future directions for improving outcome.

Sport participation among children with complicated mild traumatic brain injury

BACKGROUND

Complicated mild traumatic brain injury (C-mTBI) represents mTBI with positive trauma-related radiographic findings, such as hematoma. It is estimated that 7.5% of all pediatric mTBIs meet these criteria. There is a paucity of research on return to sports in children with C-mTBI.

OBJECTIVE

To examine children with C-mTBI, mTBI with skull fracture (mTBI-SF) only and mTBI in relation to sport participation and factors associated with repeated injury.

DESIGN

Cross-sectional survey.

SETTING

Level I pediatric trauma center.

PARTICIPANTS

Parents of children who were 5-18 years of age at the time of injury who sustained C-mTBI or mTBI from 2010 to 2013.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Sports participation characteristics before and after injury in children with C-mTBI and mTBI as a function of degree and length of recovery. Repeat mTBI after the index injury was also examined.

RESULTS

Of 247 children who participated in sports preinjury (27.5% with C-mTBI and 9.7% with mTBI-SF), 95.1% returned to sports. There was no significant difference by mTBI type regarding participation in any sports (p = .811) nor with high-risk sports (p = .128). C-mTBI but not mTBI-SF (versus mTBI) was associated with lower odds of sustaining a repeat mTBI (odds ratio = 0.30, p = .045). Waiting longer (>3 months compared to <1 month) to return to contact sports was associated with lower odds of sustaining a repeat mTBI (odds ratio = 0.23, p < .05).

CONCLUSIONS

Children with C-mTBI and mTBI-SF resume similar sports as children with mTBI. Those with C-mTBI and those who take longer to return to play may have lower risk of repeat mTBIs. Prospective research is needed to inform the development of evidence-based guidelines for children with C-mTBI and mTBI-SF.

Sports-Related Concussions and Adverse Health Behaviors Among Middle and High School Students

BACKGROUND

Concussions affect millions of youths in the United States each year, and there is concern about long-term health effects from this injury.

PURPOSE

To examine the association between sports- or physical activity-related concussion and health risk behaviors among middle and high school students in 9 states.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Data from the 2019 middle school and high school Youth Risk Behavior Survey were used for this analysis. Nine states were identified that included the same question on concussion and similar questions on health risk behaviors in their 2019 Youth Risk Behavior Survey. Students were asked to self-report whether they had ≥1 sports- or physical activity-related concussions during the 12 months preceding the survey. Self-reported concussion was the primary outcome of interest. Other variables included sex, race/ethnicity, played on a sports team, were physically active 5 or more days/week, ever tried cigarette smoking, ever used an electronic vapor product, academic grades, drank alcohol, were in a physical fight, seriously considered attempting suicide, made a suicide plan, and attempted suicide.

RESULTS

Among the 9 states, 18.2% of middle school students and 14.3% of high school students self-reported ≥1 sports- or physical activity-related concussions. Among both middle school and high school students, the prevalence of ≥1 sports- or physical activity-related concussions was higher among students who played on a sports team, were physically active 5 or more days per week, had ever tried cigarette smoking, had ever used an electronic vapor product, had seriously considered attempting suicide, had made a suicide plan, and had attempted suicide compared with those who had not engaged in those behaviors. The prevalence of sports- or physical activity-related concussion was consistently higher among middle school students than high school students across sex, race/ethnicity, and adverse health behaviors.

CONCLUSION

Middle school students with a history of concussion warrant attention as an at-risk population for concussions and adverse health behaviors. Health care providers may consider screening students for adverse health behaviors during preparticipation examinations and concussion evaluations.

Repeated mild traumatic brain injuries in mice cause age- and sex-specific alterations in dendritic spine density

Mild traumatic brain injuries (mTBI) plague the human population and their prevalence is increasing annually. More so, repeated mTBIs (RmTBI) are known to manifest and compound neurological deficits in vulnerable populations. Age at injury and sex are two important factors influencing RmTBI pathophysiology, but we continue to know little about the specific effects of RmTBI in youth and females. In this study, we directly quantified the effects of RmTBI on adolescent and adult, male and female mice, with a closed-head lateral impact model. We report age- and sex-specific neurobehavioural deficits in motor function and working memory, microglia responses to injury, and the subsequent changes in dendritic spine density in select brain regions. Specifically, RmTBI caused increased footslips in adult male mice as assessed in a beam walk assay and significantly reduced the time spent with a novel object in adolescent male and female mice. RmTBIs caused a significant reduction in microglia density in male mice in the motor cortex, but not female mice. Finally, RmTBI significantly reduced dendritic spine density in the agranular insular cortex (a region of the prefrontal cortex in mice) and increased dendritic spine density in the adolescent male motor cortex. Together, the data provided in this study sheds new light on the heterogeneity in RmTBI-induced behavioural, glial, and neuronal architecture changes dependent on age and sex.

Pediatric Sports-Related Concussion: An Approach to Care

Sports-related concussion (SRC) is a common sports injury in children and adolescents. With the vast amount of youth sports participation, an increase in awareness of concussion and evidence that the injury can lead to consequences for school, sports and overall quality of life, it has become increasingly important to properly diagnose and manage concussion. SRC in the student athlete is a unique and complex injury, and it is important to highlight the differences in the management of child and adolescent concussion compared with adults. This review focuses on the importance of developing a multimodal systematic approach to diagnosing and managing pediatric sports-related concussion, from the sidelines through recovery.

Beliefs affecting concussion reporting among military cadets: advanced observations through machine learning

BACKGROUND

Untreated concussions are an important health concern. The number of concussions sustained each year is difficult to pinpoint due to diverse reporting routes and many people not reporting. A growing body of literature investigates the motivations for concussion under-reporting, proposing ties with knowledge of concussion outcomes and concussion culture. The present work employs machine learning to identify trends in knowledge and willingness to self-report concussions.

METHODS

2,204 cadets completed a survey addressing athletic and pilot status, concussion symptoms and outcome beliefs, ethical beliefs, demographics, and reporting willingness.

RESULTS

Clustering and non-negative matrix analysis identified connections to self-report willingness within: knowledge of symptoms, ethical beliefs, reporting requirements, and belief of long-term concussion outcomes. Support vector machine classification of cadet reporting likelihood reveals symptom and outcome knowledge may be inversely related to reporting among those rating ethics considerations as low, while heightened ethics may predict higher reporting likeliness overall.

CONCLUSIONS

Machine-learning analysis bolsters prior theories on the importance of concussion culture in reporting and indicate more symptom knowledge may decrease willingness to report. Uniquely, our analysis indicated importance of ethical behavior may be associated with general concussion reporting willingness, inviting further consideration from healthcare practitioners seeking increased reporting.

The Association Between School District-Based Policies Related to Concussions and Concussions Among High School Students

BACKGROUND

Little is known about the effectiveness of school district concussion policies on reducing the concussion prevalence among students.

METHODS

Data from the 2016 School Health Policies and Practices Study and 2017 Youth Risk Behavior Survey for 10 school districts were linked. The outcome variable was having a sports- or physical activity-related concussion during the 12 months before of the survey. Exposure variables were 2 district policies, including district-funded professional development and prioritizing return to the classroom before returning to athletics. Logistic regression models estimated the odds of a concussion among students in districts with one, both, or neither policy (referent).

RESULTS

In districts with district-funded professional development, the odds of students self-reporting ≥2 sports- or physical activity-related concussions were 1.4 times higher than in districts with neither policy. In districts with a policy prioritizing a return to the classroom before returning to athletics, the odds of students self-reporting ≥2 concussions were significantly lower (OR = 0.6) than in districts with neither policy.

CONCLUSION

School district concussion policies may have positive effects by identifying and reducing multiple concussions among students.

Repeated mild traumatic brain injury impairs fracture healing in male mice

Objectives

The goal of this study was to evaluate the long-term impact of repeated (r) mild traumatic brain injury (mTBI) on the healing of fractures in a mouse model. Ten week-old male mice were subjected to r-mTBI once per day for 4 days followed by closed femoral fracture using a three-point bending technique, 1 week post impact and fracture healing phenotype evaluated at 20 weeks of age.

Results

Micro-CT analysis of the fracture callus region at nine weeks post fracture revealed reduced bone volume (30%, p < 0.05) in the r-mTBI fracture group compared to the control-fracture group. The connectivity density of the fracture callus bone was reduced by 40% (p < 0.01) in the r-mTBI fracture group. Finite element analysis of the fracture callus region showed reduced failure load (p = 0.08) in the r-mTBI group compared to control group. There was no residual cartilage in the fracture callus region of either the r-mTBI or control fracture group. The reduced fracture callus bone volume and mechanical strength of fracture callus in r-mTBI mice 9 weeks post fracture are consistent with negative effects of r-mTBI on fracture healing over a long-term resulting in decreased mechanical strength of the fracture callus.

Post-concussive mTBI in Student Athletes: MRI Features and Machine Learning

Purpose: To determine and characterize the radiomics features from structural MRI (MPRAGE) and Diffusion Tensor Imaging (DTI) associated with the presence of mild traumatic brain injuries on student athletes with post-concussive syndrome (PCS).

Material and Methods: 122 student athletes (65 M, 57 F), median (IQR) age 18.8 (15–20) years, with a mixed level of play and sports activities, with a known history of concussion and clinical PCS, and 27 (15 M, 12 F), median (IQR) age 20 (19, 21) years, concussion free athlete subjects were MRI imaged in a clinical MR machine. MPRAGE and DTI-FA and DTI-ADC images were used to extract radiomic features from white and gray matter regions within the entire brain (2 ROI) and the eight main lobes of the brain (16 ROI) for a total of 18 analyzed regions. Radiomic features were divided into five different data sets used to train and cross-validate five different filter-based Support Vector Machines. The top selected features of the top model were described. Furthermore, the test predictions of the top four models were ensembled into a single average prediction. The average prediction was evaluated for the association to the number of concussions and time from injury.

Results: Ninety-one PCS subjects passed inclusion criteria (91 Cases, 27 controls). The average prediction of the top four models had a sensitivity of 0.80, 95% CI: [0.71, 0.88] and specificity of 0.74 95%CI [0.54, 0.89] for distinguishing subjects from controls. The white matter features were strongly associated with mTBI, while the whole-brain analysis of gray matter showed the worst association. The predictive index was significantly associated with the number of concussions (p < 0.0001) and associated with the time from injury (p < 0.01).

Conclusion: MRI Radiomic features are associated with a history of mTBI and they were successfully used to build a predictive machine learning model for mTBI for subjects with PCS associated with a history of one or more concussions.

Influence of insurance type on rate and type of initial concussion-related medical visits among youth

Background

A growing number of studies report increased concussion-related health care utilization in recent years, but factors impacting care-seeking behaviors among youth following a concussion are not well described. This study aimed to evaluate the influence of insurance type on the rate and type of initial concussion visits and the time from injury to the initial visit in youth.

Methods

We extracted and analyzed initial concussion-related medical visits for youth ages 10 to 17 from electronic health records. Patients must have visited Nationwide Children’s Hospital’s (NCH) concussion clinic at least once between 7/1/2012 and 12/31/2017. We evaluated the trends and patterns of initial concussion visits across the study period using regression analyses.

Results

Of 4955 unique concussion visits included, 60.1% were males, 80.5% were white, and 69.5% were paid by private insurance. Patients’ average age was 13.9 years (SD = 3.7). The rate of the initial concussion visits per 10,000 NCH visits was consistently higher in privately insured than publicly insured youth throughout the study period (P < .0001). Privately insured youth had greater odds of initial concussion visits to sports medicine clinics (AOR = 1.45, 95% CI = 1.20, 1.76) but lower odds of initial concussion visits to the ED/urgent care (AOR = 0.74, 95% CI = 0.60, 0.90) than publicly insured youth. Days from injury to initial concussion visit significantly decreased among both insurance types throughout the study (P < .0001), with a greater decrease observed in publicly insured than privately insured youth (P = .011).

Conclusions

Results on the differences in the rate, type, and time of initial concussion-related visits may help inform more efficient care of concussion among youth with different types of insurance.

Recovery From Repeat Mild Traumatic Brain Injury in Adolescent Rats Is Dependent on Pre-injury Activity State

Adolescents and young adults have the highest incidence of mild traumatic brain injury (mTBI); sport-related activities are a major contributor. Roughly a third of these patients diagnosed with mTBI are estimated to have received a subsequent repeat mTBI (rTBI). Previously, animal studies have only modeled mTBI in sedentary animals. This study utilizes physical activity as a dependent variable prior to rTBI in adolescent rats by allowing voluntary exercise in males, establishing the rat athlete (rathlete). Rats were given access to locked or functional running wheels for 10 d prior to sham or rTBI injury. Following rTBI, rathletes were allowed voluntary access to running wheels beginning on different days post-injury: no run (rTBI+no run), immediate run (rTBI+Immed), or 3 day delay (rTBI+3dd). Rats were tested for motor and cognitive-behavioral (anxiety, social, memory) and mechanosensory (allodynia) dysfunction using a novel rat standardized concussion assessment tool on post-injury days 1,3,5,7, and 10. Protein expression of brain derived neurotrophic factor (BDNF) and proliferator-activated gamma coactivator 1-alpha (PGC1α) was measured in the parietal cortex, hippocampus, and gastrocnemius muscle. Sedentary shams displayed lower anxiety-like behaviors compared to rathlete shams on all testing days. BDNF and PGC1α levels increased in the parietal cortex and hippocampus with voluntary exercise. In rTBI rathletes, the rTBI+Immed group showed impaired social behavior, memory impairment in novel object recognition, and increased immobility compared to rathlete shams. All rats showed greater neuropathic mechanosensory sensitivity than previously published uninjured adults, with rTBI+3dd showing greatest sensitivity. These results demonstrate that voluntary exercise changes baseline functioning of the brain, and that among rTBI rathletes, delayed return to activity improved cognitive recovery.

Symptom Burden, School Function, and Physical Activity One Year Following Pediatric Concussion

OBJECTIVES

To characterize symptom burden, school function, and physical activity in youth 1 year following acute concussion and those with subsequent repeat concussion.

STUDY DESIGN

Secondary analysis of Predicting Persistent Postconcussive Problems in Pediatrics prospective, multicenter cohort study conducted in 9 Canadian emergency departments. Participants were children between ages 5 and 18 years who presented consecutively ≤48 hours of concussion and agreed to participate in a post hoc electronic survey 1 year after injury. Outcomes were assessed using a standardized 25-question symptom scale derived from the Post-Concussion Symptom Inventory-Parent; school function and physical activity outcomes were queried. The primary outcome was total symptom score 1 year following concussion, defined as the number of symptoms experienced more than before injury.

RESULTS

Of 3052 youth enrolled in the Predicting Persistent Postconcussive Problems in Pediatrics study, 432 (median [IQR] age, 11.5 [9,14] years; 266 [62%] male) completed the 1-year survey; 34 respondents reported a repeat concussion. Following acute concussion, youth were more likely to be symptom-free than following repeat concussion (75% vs 50%; difference = 25% [95% CI 8-41]; P = .002) and to have recovered fully (90% vs 74%; difference = 17% [95% CI 5-34]; P = .002) after 1 year. Although physical symptoms were less 1 year after initial emergency department presentation for both groups (P < .001), youth with a repeat concussion reported greater headache persistence (26% vs 13%; difference = 13% [95% CI 1,31]; P = .024). Both groups returned to their normal school routine (100% vs 95%; difference = 5% [95% CI -5 to 8; P = .618). Youth without repeat concussion more frequently returned to normal physical activities (98% vs 85%; difference = 13% [95% CI 4-28]; P < .0001) and sport (95% vs 82%; difference = 13% [95% CI 3-29]; P = .009).

CONCLUSIONS

Most youth are symptom-free and fully recovered 1 year following concussion. Some children with repeat concussion have worse outcomes and have delays in returning to normal school routines and sport.

Microglia dynamics in adolescent traumatic brain injury

Repetitive, mild traumatic brain injuries (RmTBIs) are increasingly common in adolescents and encompass one of the largest neurological health concerns in the world. Adolescence is a critical period for brain development where RmTBIs can substantially impact neurodevelopmental trajectories and life-long neurological health. Our current understanding of RmTBI pathophysiology suggests key roles for neuroinflammation in negatively regulating neural health and function. Microglia, the brain’s resident immune population, play important roles in brain development by regulating neuronal number, and synapse formation and elimination. In response to injury, microglia activate to inflammatory phenotypes that may detract from these normal homeostatic, physiological, and developmental roles. To date, however, little is known regarding the impact of RmTBIs on microglia function during adolescent brain development. This review details key concepts surrounding RmTBI pathophysiology, adolescent brain development, and microglia dynamics in the developing brain and in response to injury, in an effort to formulate a hypothesis on how the intersection of these processes may modify long-term trajectories.

Sports- or Physical Activity-Related Concussions and Feelings of Sadness or Hopelessness Among U.S. High School Students: Results From the 2017 Youth Behavior Risk Survey

For this study, we explored the association between high school students' reported history of sport- or physical activity-related concussions and persistent feelings of sadness or hopelessness. Data from the 2017 national Youth Risk Behavior Survey (YRBS; N = 14,765) was used for this analysis. YRBS is administered to high school students throughout the country every 2 years. Findings from this study demonstrate that the prevalence of persistent feelings of sadness or hopelessness was 36.4% among students who reported sustaining one or more concussions. Compared to students who did not report having sustained a concussion, the odds of persistent feelings of sadness or hopelessness were significantly higher among students who had sustained one or more concussions (AOR = 1.41). These findings support the need for continued efforts by school nurses and other health care providers to identify students with a history of concussion and assess their mental health needs.