Epidemiology of sports concussion in the United States

Associations Between Brain Metabolites Measured With MR Spectroscopy and Head Impacts in High School American Football Athletes

BACKGROUND

While changes in brain metabolites after injury have been reported, relationships between metabolite changes and head impacts are less characterized.

PURPOSE

To investigate alterations in neurochemistry in high school athletes as a function of head impacts, concussion, and the use of a jugular vein compression (JVC) collar.

STUDY TYPE

Prospective controlled trial.

SUBJECTS

A total of 284 male American football players, divided into JVC collar and noncollar groups; 215 included in final analysis (age = 15.9 ± 1.0 years; 114 in collar group).

FIELD STRENGTH/SEQUENCE

3 Tesla/T1-weighted gradient echo, 1H point resolved spectroscopy, acquired between August and November 2018.

ASSESSMENT

Head impacts were quantified using accelerometers. Concussion was diagnosed by medical professionals for each team. Pre- to postseason differences in total N-acetylaspartate (tNAA), total choline (tCho), myo-inositol (myoI), and glutamate + glutamine (Glx), in primary motor cortex (M1) and anterior cingulate cortex (ACC), relative to total creatine (tCr), were determined.

STATISTICAL TESTS

Group-wise comparisons were performed using Wilcoxon signed-rank, Friedman's, and Mann-Whitney U tests. Relationships between ∆metabolite/tCr and mean g-force were analyzed using linear regressions accounting for concussion and JVC collar. Significance was set at P ≤ 0.05.

RESULTS

In participants without concussion, a significant decrease in tCho/tCr (0.233 ± 1.40 × 10-3 to 0.227 ± 1.47 × 10-7) and increase in Glx/tCr (1.60 ± 8.75 × 10-3 to 1.63 ± 1.08 × 10-2) in ACC were observed pre- to postseason. The relationship between ∆tCho/tCr in M1 and ACC and mean g-force from >80 g to >140 g differed significantly between participants with and without concussion (M1 β ranged from 3.9 × 10-3 to 2.1 × 10-3; ACC β ranged from 2.7 × 10-3 to 2.1 × 10-3). Posthoc analyses revealed increased tCho/tCr in M1 was positively associated with mean g-force >100 g (β = 3.6 × 10-3) and >110 g (β = 2.9 × 10-3) in participants with concussion. Significant associations between ∆ myoI / tCr in ACC and mean g-force >110 g (β = -1.1 × 10-3) and >120 g (β = -1.1 × 10-3) were observed in the collar group only.

DATA CONCLUSION

Diagnosed concussion and the use of a JVC collar result in distinct neurochemical trends after repeated head impacts.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 3.

The influence of sport-related concussion history on standing balance during upper limb movements under varying attentional demands

Sport-related concussions can influence athletic performance and everyday function. We implemented a dual-task paradigm whereby perturbed reaching while standing was combined with a simple reaction-time task. The purpose was to explore how concussion history influences balance control with and without external arm perturbations under varying attentional demands. Male athletes with no previous concussions (Hx0; n = 16; 19.3 ± 1.6 years) or history of two or more concussions (Hx2+; n = 16; 19.5 ± 1.8 years) participated. Participants reached to visual targets with their dominant hand and received randomly interspersed perturbations, performed either in isolation or simultaneously with a button press task with the non-dominant hand. Assessments included center of pressure (COP) parameters, hand movement reaction time and kinematics, and button-press reaction time. Participants with multiple concussions exhibited larger peak COP displacements and velocities than those with none. Compared to single task, the dual task increased cognitive processing and divided attention for both groups, demonstrated by slower button press and reaching reaction times, reduced anteroposterior hand velocity, and increased mediolateral hand displacement and velocity. Athletes with a concussion history likely have worse balance control, possibly owing to sensorimotor processing deficits or increased neural time delays leading to a subsequent reduction in motor activation. Because COP responses were overall maintained during the dual task, attentional resources were likely allocated towards maintaining balance control at the expense of upper limb performance.

Comparing Time to Recovery Between Initial and Repeat Concussion in Athletes

OBJECTIVE

Compare time to recovery between initial and repeat concussions.

DESIGN

Retrospective review of electronic medical record.

SETTING

An interdisciplinary concussion clinic.

PATIENTS

Fifty patients (14.4 years old [±2.5]; 24 [48%] female) who sustained >1 concussion between 2016 and 2020 and were evaluated within 30 days of their concussion.

INTERVENTION

Injuries were divided into first, second, and/or last concussions.

MAIN OUTCOME MEASURES

The primary outcome was time to recovery, as defined by clearance for return to sport. This was compared between first versus second concussion (primary analysis) and first versus last concussion (secondary analysis) using Cox regression. Multivariable models accounted for time from concussion to initial clinic visit and Sport Concussion Assessment Tool symptom severity score at initial encounter. Sensitivity analyses explored potential influences of initial encounter timing and interval between concussions.

RESULTS

Time to recovery did not differ between initial and repeat concussion in univariate or multivariable models (HR = 1.02, 95% CI, 0.65-1.62, P = 0.92; HR = 1.01, 95% CI, 0.64-1.62, P = 0.91 for multivariable models comparing first (ref) versus second and first (ref) versus last concussion, respectively). Similar results were obtained in sensitivity analyses stratifying by time to initial visit (≤7 days vs >7 days) or time between injuries (≤1 year vs >1 year).

CONCLUSIONS

There were no differences in time to recovery between initial and repeat concussions sustained by the same athlete. A nonsignificant trend of shorter recovery after repeat concussions was observed for patients presenting within 1 week of injury and when repeat injuries occurred within 1 year.

Maintaining Cognitive Performance at the Expense of Gait Speed for Asymptomatic Concussed Athletes: A Novel Dual-Task and Post-Exercise Assessment

Our goal was to evaluate persisting deficits in gait and executive functioning in asymptomatic athletes with a history of concussion using a novel approach combining a dual-task paradigm and post-exercise exertion. Thirty-eight athletes aged 17 to 25 years old participated in the study, including 18 with a history of concussion. The dual-task paradigm required walking continuously at a predetermined self-paced target speed of 6.5 km/h while executing a complex switch task. Athletes completed two conditions, each on separate days: (1) dual task alone and (2) dual task following 20 min of running on a non-motorized treadmill. The statistical analyses revealed a significant reduction in gait speed exclusively for athletes with a history of concussion and only following the post-exercise condition (p = 0.008). These findings suggest that although asymptomatic concussed athletes maintain a cognitive performance comparable to non-concussed athletes, this appears to be achieved at the expense of gait speed. Our results underscore the importance of incorporating gait assessments and post-exercise exertion into concussion evaluation protocols in both research and clinical settings.

Traumatic brain injuries in paediatric patients: individual vs. team sports-related hospitalizations

Paediatric sport participation continues to increase in the United States, with a corresponding increase in sports-related concussions or traumatic brain injuries (TBIs). It is important to recognize which sports are at elevated risk and identify risk factors for hospital admission and length of stay (LOS). Paediatric patients (ages 5-18) from 2008 to 2014 were identified from the Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample (NIS). Eight hundred and ninety-four patients included those who were hospitalized with a TBI resulting from participation in an individual (451 patients) or team (443 patients) sport. We evaluated the differences in LOS and total charges between individual and team sports and found that compared to team sports, TBI patients in individual sports had significantly longer hospital stays compared to team sports (1.75 days versus 1.34 days, p < 0.001) and costlier ($27,333 versus $19,069, p < 0.001) hospital stays. This may be due to reduced awareness and reduced compliance with return-to-play protocols in individual sports. Safety education information at a young age, increased awareness of TBIs, and additional medical support for individual sports as well as team sports may help mitigate these findings.

Optimizing Concussion Care Seeking: Using Machine Learning to Predict Delayed Concussion Reporting

BACKGROUND

Early medical attention after concussion may minimize symptom duration and burden; however, many concussions are undiagnosed or have a delay in diagnosis after injury. Many concussion symptoms (eg, headache, dizziness) are not visible, meaning that early identification is often contingent on individuals reporting their injury to medical staff. A fundamental understanding of the types and levels of factors that explain when concussions are reported can help identify promising directions for intervention.

PURPOSE

To identify individual and institutional factors that predict immediate (vs delayed) injury reporting.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

This study was a secondary analysis of data from the Concussion Assessment, Research and Education (CARE) Consortium study. The sample included 3213 collegiate athletes and military service academy cadets who were diagnosed with a concussion during the study period. Participants were from 27 civilian institutions and 3 military institutions in the United States. Machine learning techniques were used to build models predicting who would report an injury immediately after a concussive event (measured by an athletic trainer denoting the injury as being reported "immediately" or "at a delay"), including both individual athlete/cadet and institutional characteristics.

RESULTS

In the sample as a whole, combining individual factors enabled prediction of reporting immediacy, with mean accuracies between 55.8% and 62.6%, depending on classifier type and sample subset; adding institutional factors improved reporting prediction accuracies by 1 to 6 percentage points. At the individual level, injury-related altered mental status and loss of consciousness were most predictive of immediate reporting, which may be the result of observable signs leading to the injury report being externally mediated. At the institutional level, important attributes included athletic department annual revenue and ratio of athletes to athletic trainers.

CONCLUSION

Further study is needed on the pathways through which institutional decisions about resource allocation, including decisions about sports medicine staffing, may contribute to reporting immediacy. More broadly, the relatively low accuracy of the machine learning models tested suggests the importance of continued expansion in how reporting is understood and facilitated.

Comparison of different definitions of traumatic brain injury: implications for cohort characteristics and survival in women, Philadelphia, USA

BACKGROUND

Traumatic brain injury (TBI) is an acute injury that is understudied in civilian cohorts, especially among women, as TBI has historically been considered to be largely a condition of athletes and military service people. Both the Centres for Disease Control and Prevention (CDC) and Department of Defense (DOD)/Veterans Affairs (VA) have developed case definitions to identify patients with TBI from medical records; however, their definitions differ. We sought to re-examine these definitions to construct an expansive and more inclusive definition among a cohort of women with TBI.

METHODS

In this study, we use electronic health records (EHR) from a single healthcare system to study the impact of using different case definitions to identify patients with TBI. Specifically, we identified adult female patients with TBI using the CDC definition, DOD/VA definition and a combined and expanded definition herein called the Penn definition.

RESULTS

We identified 4446 adult-female TBI patients meeting the CDC definition, 3619 meeting the DOD/VA definition, and together, 6432 meeting our expanded Penn definition that includes the CDC ad DOD/VA definitions.

CONCLUSIONS

Using the expanded definition identified almost two times as many patients, enabling investigations to more fully characterise these patients and related outcomes. Our expanded TBI case definition is available to other researchers interested in employing EHRs to investigate TBI.

The Postconcussion Syndrome and Posttraumatic Headaches in Civilians, Soldiers, and Athletes

Posttraumatic headaches are one of the most common and controversial secondary headache types. After a mild traumatic brain, an estimated 11% to 82% of people develop a postconcussion syndrome, which has been controversial for more than 160 years. Headache is estimated as present in 30% to 90% of patients after a mild head injury. Most headaches are tension-type-like or migraine-like. Headaches in civilians, soldiers, athletes, and postcraniotomy are reviewed. The treatments are the same as for the primary headaches. Persistent posttraumatic headaches can continue for many years.

Inflammation, brain connectivity, and neuromodulation in post-traumatic headache

Post-traumatic headache (PTH) is a debilitating condition that affects individuals with different levels of traumatic brain injury (TBI) severity. The difficulties in developing an effective treatment are related to a lack of understanding the complicated mechanisms and neurobiological changes in brain function after a brain injury. Preclinical studies have indicated that peripheral and central sensitization of the trigeminal nociceptive pathways contributes to PTH. While recent brain imaging studies have uncovered widespread changes in brain functional connectivity following trauma, understanding exactly how these networks contribute to PTH after injury remains unknown. Stimulation of peripheral (trigeminal or vagus) nerves show promising efficacies in PTH experimental animals, likely mediated by influencing TBI-induced pathological plasticity by decreasing neuroinflammation and neuronal apoptosis. Non-invasive brain stimulations, such as transcranial magnetic or direct current stimulations, show analgesia for multiple chronic pain conditions, including PTH. Better mechanistic understanding of analgesia achieved by neuromodulations can define peripheral and central mechanisms involved in the development, the resolution, and the management of PTH.

Neurophysiological Markers to Guide Return to Sport After Sport-Related Concussion

SUMMARY

Sport-related concussion (SRC) has been defined as a subset of mild traumatic brain injury (mTBI), without structural abnormalities, reflecting a functional disturbance. Over the past decade, SRC has gained increasing awareness and attention, which coincides with an increase in incidence rates. Because this injury has been considered one of the most challenging encounters for clinicians, there is a need for objective biomarkers to aid in diagnosis (i.e., presence/severity) and management (i.e., return to sport) of SRC/mTBI.The primary aim of this article was to present state-of-the-art neurophysiologic methods (e.g., electroencephalography, magnetoencephalography, transcranial magnetic stimulation, and autonomic nervous system) that are appropriate to investigate the complex pathophysiological process of a concussion. A secondary aim was to explore the potential for evidence-based markers to be used in clinical practice for SRC management. The article concludes with a discussion of future directions for SRC research with specific focus on clinical neurophysiology.

Multicentre evaluation of anxiety and mood among collegiate student athletes with concussion

Objectives

Mental health problems are a premorbid and postinjury concern among college student athletes. Clinical phenotypes of anxiety and mood disruption are prevalent following mild traumatic brain injury, including concussion, a common sports injury. This work examined whether concussed student athletes with a history of mental health problems and higher symptoms of anxiety and mood disruption at baseline were more likely to have higher postinjury reports of mood and anxiety as well as prolonged resolution of postconcussive symptoms to near-baseline measures.

Methods

This was a retrospective cohort study of a multi-institutional database of standardised baseline and postinjury assessments among college student athletes. Anxiety/mood evaluation data among varsity college athletes from four institutions over 1 year were measured and compared at baseline and postconcussion recovery using descriptive statistics and multilevel/mixed-effects analysis.

Results

Data from 2248 student athletes were analysed, with 40.6% reporting at least one symptom of anxiety and/or mood disruption at baseline. Of the 150 distinct concussions, 94.7% reported symptoms of anxiety/mood disruption during recovery (recovery time=0-96 days). Higher anxiety/mood scores at baseline were significantly associated with higher scores following concussion (p<0.001). Recovery trajectories of anxiety/mood scores showed different patterns by sex and prolonged recovery.

Conclusion

Symptoms of anxiety and mood disruption are common at baseline among college student athletes. These students are at higher risk for symptomatology following injury, representing a screening cohort that may benefit from early counselling. Almost all student athletes will experience symptoms of anxiety and/or mood disruption following concussion.

Concussions in young adult athletes: No effect on cerebral white matter

Introduction

The media's recent focus on possible negative health outcomes following sports- related concussion has increased awareness as well as anxiety among parents and athletes. However, the literature on concussion outcomes is equivocal and limited by a variety of diagnostic approaches.

Methods

The current study used a rigorous, open- access concussion identification method-the Ohio State University Traumatic Brain Injury Identification method (OSU TBI-ID) to identify concussion and periods of repeated, subclinical head trauma in 108 young adult athletes who also underwent a comprehensive protocol of cognitive tests, mood/anxiety questionnaires, and high-angular-resolution diffusion-weighted brain imaging to evaluate potential changes in white matter microstructure.

Results

Analyses showed that athletes with a history of repetitive, subclinical impacts to the head performed slightly worse on a measure of inhibitory impulse control and had more anxiety symptoms compared to those who never sustained any type of head injury but were otherwise the same as athletes with no history of concussion. Importantly, there were no group differences in cerebral white matter as measured by tract- based spatial statistics (TBSS), nor were there any associations between OSU TBI-ID measures and whole-brain principal scalars and free-water corrected scalars.

Discussion

Our results provide support for the hypothesis that it is not concussion per se, but repetitive head impacts that beget worse outcomes.

Head Injuries in Rock Climbing: A Scoping Review

Rock climbing was recognized as a sport at the 2020 Tokyo Olympics. Despite its increasing participation, there is no knowledge synthesis of head injuries (HIs), defined as any injury to the head, associated with climbing, making it challenging for clinicians to provide evidence-based care. Our aim was to synthesize HI literature within rock climbing and identify knowledge gaps. Six databases (Medline, Embase, Sports Medicine & Education Index, SPORTDiscus, CINAHL, and Cochrane) were searched. Two reviewers screened 345 studies and 31 studies were selected for data abstraction. We found the quality of individual studies mainly "fair" to "good." Both HI and traumatic brain injury (TBI) had inconsistent definitions and categorization. The HIs represented between 0 to 36% of reported climbing injuries. Between 11 to 100% of HIs were TBIs, defined as an HI with permanent or temporary neurological sequelae. The most common causes of HIs were outdoor falls and falling objects. Climbing-specific factors associated with the causes were infrequently examined in the literature. Data sources of safety practices were incomplete. Overall, there was a lack of literature examining HIs, mechanisms of injury, and safety practices associated with climbing. To improve the tracking of HIs in climbing, we suggest the use of consistent reporting standards and the creation of a climbing injury surveillance system.

Repetitive bout of controlled soccer heading does not alter heart rate variability metrics: A preliminary investigation

Objectives

There is elevated unease regarding how repetitive head impacts, such as those associated with soccer heading, contribute to alterations in brain function. This study examined the extent heart rate variability (HRV) and cardiac baroreceptor sensitivity (BRS) metrics are altered immediately following an acute bout of soccer heading.

Methods

Seven male elite soccer players (24.1 ± 1.5 years) completed 40 successful soccer headers in 20-min. The headers were performed under controlled circumstances using a soccer ball launcher located 25 meters away and using an initial ball velocity of 77.5 ± 3.7 km/h (heading condition). An accelerometer (xPatch) on the right mastoid process quantified linear/rotational head accelerations. Participants also completed sham (body contact) and control (non-contact) sessions. A three-lead ECG and finger photoplethysmography characterized short-term spontaneous HRV/cardiac BRS, before and after each condition. The SCAT3 indexed symptom scores pre-post exposures to all three conditions.

Results

During the heading condition, cumulative linear and rotational accelerations experienced were 1,574 ± 97.9 g and 313,761 ± 23,966 rad/s², respectively. Heart rate trended toward an increase from pre- to post-heading (p = 0.063), however HRV metrics in the time-domain (ps > 0.260) and frequency-domain (ps > 0.327) as well as cardiac BRS (ps > 0.144) were not significantly changed following all three conditions. Following the heading condition, SCAT3 symptom severity increased (p = 0.030) with a trend for symptom score augmentation (p = 0.078) compared to control and sham.

Conclusion

Whereas, symptoms as measured by the SCAT3 were induced following an acute bout of controlled soccer heading, these preliminary findings indicate they were not accompanied by alterations to autonomic function. Ultimately, this demonstrates further research is needed to understand the physiological underpinnings of alterations in brain function occurring immediately after a bout of soccer heading and how these may, over time, contribute to long-term neurological impairments.

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.

Trends in Traumatic Brain Injury Related to Consumer Products Among U.S. School-aged Children Between 2000 and 2019

INTRODUCTION

Consumer product‒related traumatic brain injury in children is common, but long-term trends have not been well characterized. Understanding the long-term trends in consumer product‒related traumatic brain injury may inform prevention efforts. The study objective is to examine the trends in consumer product‒related traumatic brain injury in school-aged children.

METHODS

Data were extracted from the National Electronic Injury Surveillance System-All Injury Program for initial emergency department visits for consumer product‒related traumatic brain injury (2000-2019) in school-aged children and analyzed in 2021.

RESULTS

Approximately 6.2 million children presented to emergency department with consumer product‒related traumatic brain injury during 2000-2019. Consumer product‒related traumatic brain injury increased from 4.5% of overall consumer product‒emergency department visits in 2000 to 12.3% in 2019, and its incidence rate (cases per 100,000 population) was higher in males (681.2; 95% CI=611.2, 751.2) than in females (375.8; 95% CI=324.1, 427.6). The annual percentage change in consumer product‒related traumatic brain injury was 3.6% from 2000 to 2008, 13.3% from 2008 to 2012, and ‒2.0% through 2019. Average annual percentage change was higher in females (5.1%; 95% CI=3.4, 6.8) than in males (2.8%; 95% CI=1.6, 3.9). Consumer product‒related traumatic brain injury increased from 2000 to 2012 in females and then remained stable. In males, annual percentage change increased from 2008 to 2012 and then declined through 2019.

CONCLUSIONS

Traumatic brain injury incidence rate in school-aged children increased from 2000 to 2019, peaked in 2012, and then declined in males but not in females. Percentage increases were highest in females. Prevention strategies should continue, with a specific focus on reducing consumer product‒related traumatic brain injury in female children.

Effect of Sleep-Related Symptoms on Recovery From a Sport-Related Concussion

Background

Sleep issues are commonly reported in athletes after a sport-related concussion (SRC). Further studies are needed to evaluate screening methods for sleep disturbances and the risk of persisting symptoms after an SRC.

Purpose

To evaluate the association between the Sport Concussion Assessment Tool 5 (SCAT5) symptoms of trouble falling asleep, fatigue (or low energy), and drowsiness and the risk of persisting symptoms (≥28 days to recovery) in adolescent athletes.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 519 athletes aged 13 to 18 years reported any sleep-related symptoms with an SRC, scored as none (0), mild (1-2), moderate (3-4), or severe (5-6), at their initial office visit (median, 5.4 days after an SRC). Scores were correlated with the risk of persisting symptoms. A composite "sleep cluster" score (range, 0-18) was calculated by summing the SCAT5 component items for trouble falling asleep, fatigue, and drowsiness.

Results

The results indicated that, compared with athletes who reported that they did not have each symptom, (1) athletes who reported mild, moderate, or severe trouble falling asleep were 3.0, 4.6, and 6.7 times more likely to have persisting symptoms, respectively; (2) athletes reporting mild, moderate, or severe fatigue (or low energy) were 2.6, 4.8, and 7.6 times more likely to have persisting symptoms, respectively; and (3) athletes reporting mild, moderate, or severe drowsiness were 1.9, 4.6, and 6.8 times more likely to have persisting symptoms, respectively (P < .001 for all). For every 1-point increase in the sleep cluster score, there was a 1.2-fold increased risk of persisting symptoms and an additional 2.4 days of recovery required (P < .001 for both).

Conclusion

Athletes who reported mild, moderate, or severe sleep-related symptoms on the SCAT5 were at a proportionally increased risk of persisting symptoms at the initial office visit.

Repeated Mild TBI in Adolescent Rats Reveals Sex Differences in Acute and Chronic Behavioral Deficits

High school students who participate in contact sports are vulnerable to sustaining multiple concussions and exhibit deficits in cognitive function in both the acute and chronic phases and in emotional behavior in the chronic phase. Further, boys are more likely to suffer cognitive problems whereas girls tend to report depression and anxiety. The effects of repetitive mild TBI in adolescent (35-40-day old) male and female Sprague-Dawley rats on object location and spatial working memory (hippocampal-dependent) and object recognition memory (hippocampal-independent) at 1-and-4-weeks post-injury along with trait-dependent anxiety- and depressive-like behaviors at 5 weeks were examined. Compared to sham-injured rats, male brain-injured rats demonstrated significant impairment in both hippocampal-dependent and -independent memory tasks at both time points, whereas female brain-injured rats only exhibited impairment in these tests at the 4-week time point. In contrast, depressive-like behaviors were present in the forced swim test in only the female brain-injured animals at 5 weeks post-injury; anxiety-like behaviors were not evident in either male or female brain-injured animals. Histological analysis at 6 weeks after injury revealed that repeated mild TBI in male and female adolescent rats resulted in increased reactivity of astrocytes and microglia within the corpus callosum below the impact site and in the stratum oriens and stratum pyramidale of the CA2 region of the dorsal hippocampus. Together, these data are indicative of the differences in the temporal pattern of post-traumatic behavioral deficits between male and female animals and that female animals may be more likely to develop deficits in the chronic post-traumatic period.

Epidemiology of racket and paddle sports-related injuries treated in the United States emergency departments, 2007-2016

OBJECTIVE

Racket and paddle sports are popular worldwide. Although there are several epidemiologic studies on tennis, there are limited epidemiologic studies on injuries in badminton, squash, racquetball, table tennis, pickleball and other racket and paddle sports. We aimed to analyze acute racket and paddle sports injuries that presented to emergency departments.

DESIGN

Descriptive epidemiologic study; level of evidence 3.

SETTING

United States emergency departments (USEDs).

METHODS

Data from National Electronic Injury Surveillance System (NEISS) were queried to characterize racket and paddle sports-related (RPSR) injuries that presented to USEDs over a 10-year period.

RESULTS

From 2007 to 2016, there were 7,723 cases of racket and paddle sports-related (RPSR) injuries that presented to USEDs. This data provides a weighted estimate of 301,038 RPSR injuries in USEDs over the 10-year study period. The majority (60.3) of these injuries were in men. Men had a higher percentage of injuries of most body parts except the lower arm, wrist, and ankle. The mean age at the time of injury was 37 years. The highest percentage of sprains, strains, and lower extremity injuries occurred in athletes between ages 18-40 years. Between sports, table tennis had highest percentage of skin and internal organ injuries while badminton had the highest percentage of sprains, strains, fractures, and dislocations.

CONCLUSION

This study is the largest nationally representative study of RPSR injuries to date. RPSR injuries are varied in their presentation based on age, sex, body location, and type of injury.

CLINICAL RELEVANCE

This study determined common RPSR injuries presenting to USEDs, their patterns, and severity over a 10-year period. Researchers and clinicians can begin to use this data for future research studies and may consider this early data in management decisions.

Brain Injury Effects on Neuronal Activation and Synaptic Transmission in the Basolateral Amygdala of Adult Male and Female Wistar Rats

Traumatic brain injury (TBI) is defined as brain damage produced by an external mechanical force that leads to behavioral, cognitive, and psychiatric sequelae. The basolateral amygdala (BLA) is involved in emotional regulation, and its function and morphology are altered following TBI. Little is known about potential sex-specific effects of TBI on BLA neuronal function, but it is critical for the field to identify potential sex differences in TBI effects on brain and behavior. Here, we hypothesized that TBI would produce sex-specific acute (1 h) effects on BLA neuronal activation, excitability, and synaptic transmission in adult male and female rats. Forty-nine Wistar rats (n = 23 males and 26 females) were randomized to TBI (using lateral fluid percussion) or Sham groups in two separate studies. Study 1 used in situ hybridization (i.e., RNAscope) to measure BLA expression of c-fos (a marker of cell activation), vGlut, and vGat (markers of glutamatergic and GABAergic neurons, respectively) messenger RNA (mRNA). Study 2 used slice electrophysiology to measure intrinsic excitability and excitatory/inhibitory synaptic transmission in putative pyramidal neurons in the BLA. Physiological measures of injury severity were collected from all animals. Our results show that females exhibit increased apnea duration and reduced respiratory rate post-TBI relative to males. In male and female rats, TBI increased c-fos expression in BLA glutamatergic cells but not in BLA GABAergic cells, and TBI increased firing rate in BLA pyramidal neurons. Further, TBI increased spontaneous excitatory and inhibitory postsynaptic current (sEPSC and sIPSC) amplitude in BLA neurons of females relative to all other groups. TBI increased sEPSC frequency in BLA neurons of females relative to males but did not alter sIPSC frequency. In summary, lateral fluid percussion produced different physiological responses in male and female rats, as well as sex-specific alterations in BLA neuronal activation, excitability, and synaptic transmission 1 h after injury.

An acute bout of controlled subconcussive impacts can alter dynamic cerebral autoregulation indices: a preliminary investigation

OBJECTIVES

There is growing concern repetitive head contacts sustained by soccer players may lead to long-term health ramifications. Therefore, this preliminary investigation examined the impact an acute soccer heading bout has on dynamic cerebral autoregulation (dCA) metrics.

METHODS

In this preliminary investigation, 40 successful soccer headers were performed in 20 min by 7 male elite soccer players (24.1 ± 1.5 years). Soccer balls were launched at 77.5 ± 3.7 km/h from JUGS soccer machine, located 35 m away from participants. Linear and rotational head accelerations impacts were measured using an accelerometer (xPatch). The SCAT3 indexed concussion symptom score and severity before and after: soccer headers, sham (body contact only), and control conditions. Squat-stand maneuvers were performed at 0.05 Hz and 0.10 Hz to quantity dCA through measures of coherence, phase, and gain.

RESULTS

Cumulative linear and rotational accelerations during soccer headers were 1574 ± 97.9 g and 313,761 ± 23,966 rads/s², respectively. SCAT3 symptom severity was elevated after the soccer heading bout (pre 3.7 ± 3.6, post 9.4 ± 7.6: p = 0.030) and five of the seven participants reported an increase in concussion-like symptoms (pre: 2.6 ± 3.0, post: 6.7 ± 6.2; p = 0.078). Phase at 0.10 Hz was elevated following soccer heading (p = 0.008). No other dCA metric differed following the three conditions.

CONCLUSION

These preliminary results indicate an acute bout of soccer heading resulted in alterations to dCA metrics. Therefore, future research with larger sample sizes is warranted to fully comprehend short- and long-term physiological changes related to soccer heading.

Systematic review and meta-analysis of sex-based differences for concussion incidence in soccer

OBJECTIVE

To compare concussion incidence in male and female soccer players due to the specific concussion-causing activity.

METHODS/DATA SOURCES

PubMed, EMBASE, and Cochrane Library were searched for studies published between January 2000 and February 2020. Search terms included 'sex,' 'gender,' 'sex differences,' 'brain injury,' 'sports,' 'athletes,' 'incidence,' 'epidemiology,' 'symptoms,' and 'injury rate.' Studies that contained data on concussion incidence in soccer and featured comparisons by sex and soccer activity were included. Studies that were not written in English, contained data on non-sports-related concussions, or were conference abstracts were excluded.

RESULTS

Six studies were included in this meta-analysis, each of which contributed the number of concussions in males and females for a specific soccer activity. Concussion incidence rates were calculated using athlete-exposures as the denominator and a rate ratio was measured by dividing the concussion rate among female soccer players by the rate among male soccer players. Female soccer players were shown to have a greater rate of concussions from heading [1.65 (95% CI: 1.35, 2.03, p < 0.001)] and goalkeeping [1.63 (95% CI: 1.22, 2.17, p = 0.001)]. There were 3 studies comparing sex differences for general play. While the pooled rate ratio was statistically significant [1.51 (95% CI: 1.12, 2.04), p = 0.007], this result was largely driven by 1 study.

CONCLUSION

Concussion incidence rates were significantly higher in female soccer players compared to male players while heading. There is also some evidence to suggest that the incidence is higher for female goalkeepers. Soccer coaches and health care providers need to recognize this sex difference when coaching or treating players.

Acute Cycling Injuries

The overall activity of cycling, although profoundly heterogenous, often occurs with mechanisms consistent with motor vehicle collisions. Advanced trauma life support is the standard of care. Traumatic brain injury is the leading cause of death, and concussions are common in cyclists. Road rash is the most common injury, and management should be synonymous with other kinds of burns. A unique aspect of cycling medicine is that it often is done on public roadways in close proximity to the athletes during competition. Clinicians who care for cyclists in the field setting should be prepared to manage a broad spectrum of traumatic injuries.

Mild Traumatic Brain Injury and Postconcussive Symptom Endorsement: A Parallel Comparison Between Two Nonclinical Cohorts

INTRODUCTION

The prevalence of mild traumatic brain injury (mTBI) is commonly estimated based on indirect metrics such as emergency department visits and self-reporting tools. The study of postconcussive symptoms faces similar challenges because of their unspecific character and indistinct causality. In this article, we compare two nonclinical, epidemiological studies that addressed these two elements and were performed within a relatively narrow period in the state of Colorado.

MATERIALS AND METHODS

De-identified datasets were obtained from a random digit-dialed survey study conducted by the Craig Hospital and a study surveying soldiers returning from deployment by Defense and Veteran Traumatic Brain Injury Center. Information pertinent to participants' demographics, a history of mTBI, and symptom endorsement was extracted and homogenized in order to establish a parallel comparison between the populations of the two studies.

RESULTS

From the 1,558 (Warrior Strong, 679; Craig Hospital, 879) records selected for analysis, 43% reported a history of at least one mTBI. The prevalence was significantly higher among individuals from the Defense and Veteran Traumatic Brain Injury Center study independent of gender or race. Repetitive injuries were reported by 15% of the total combined cohort and were more prevalent among males. Symptom endorsement was significantly higher in individuals with a positive history of mTBI, but over 80% of those with a negative history of mTBI endorsed at least one of the symptoms interrogated. Significant differences were observed between the military and the civilian populations in terms of the types and frequencies of the symptoms endorsed.

CONCLUSIONS

The prevalence of mTBI and associated symptoms identified in the two study populations is higher than that of previously reported. This suggests that not all individuals sustaining concussion seek medical care and highlights the limitations of using clinical reports to assess such estimates. The lack of appropriate mechanisms to determine symptom presence and causality remains a challenge. However, the differences observed in symptom reporting between cohorts raise questions about the nature of the symptoms, the impact on the quality of life for different individuals, and the effects on military health and force readiness.

Cerebrolysin restores balance between excitatory and inhibitory amino acids in brain following concussive head injury. Superior neuroprotective effects of TiO2 nanowired drug delivery

Concussive head injury (CHI) often associated with military personnel, soccer players and related sports personnel leads to serious clinical situation causing lifetime disabilities. About 3-4k head injury per 100k populations are recorded in the United States since 2000-2014. The annual incidence of concussion has now reached to 1.2% of population in recent years. Thus, CHI inflicts a huge financial burden on the society for rehabilitation. Thus, new efforts are needed to explore novel therapeutic strategies to treat CHI cases to enhance quality of life of the victims. CHI is well known to alter endogenous balance of excitatory and inhibitory amino acid neurotransmitters in the central nervous system (CNS) leading to brain pathology. Thus, a possibility exists that restoring the balance of amino acids in the CNS following CHI using therapeutic measures may benefit the victims in improving their quality of life. In this investigation, we used a multimodal drug Cerebrolysin (Ever NeuroPharma, Austria) that is a well-balanced composition of several neurotrophic factors and active peptide fragments in exploring its effects on CHI induced alterations in key excitatory (Glutamate, Aspartate) and inhibitory (GABA, Glycine) amino acids in the CNS in relation brain pathology in dose and time-dependent manner. CHI was produced in anesthetized rats by dropping a weight of 114.6g over the right exposed parietal skull from a distance of 20cm height (0.224N impact) and blood-brain barrier (BBB), brain edema, neuronal injuries and behavioral dysfunctions were measured 8, 24, 48 and 72h after injury. Cerebrolysin (CBL) was administered (2.5, 5 or 10mL/kg, i.v.) after 4-72h following injury. Our observations show that repeated CBL induced a dose-dependent neuroprotection in CHI (5-10mL/kg) and also improved behavioral functions. Interestingly when CBL is delivered through TiO₂ nanowires superior neuroprotective effects were observed in CHI even at a lower doses (2.5-5mL/kg). These observations are the first to demonstrate that CBL is effectively capable to attenuate CHI induced brain pathology and behavioral disturbances in a dose dependent manner, not reported earlier.

Do physical interventions improve outcomes following concussion: a systematic review and meta-analysis?

OBJECTIVE

To investigate the effect of physical interventions (subthreshold aerobic exercise, cervical, vestibular and/or oculomotor therapies) on days to recovery and symptom scores in the management of concussion.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

Medline, CINAHL, Embase, SportDiscus, Cochrane library, Scopus and PEDro.

ELIGIBILITY CRITERIA

Randomised controlled trials of participants with concussion that evaluated the effect of subthreshold aerobic exercise, cervical, vestibular and/or oculomotor therapies on days to recovery/return to activity, symptom scores, balance, gait and/or exercise capacity.

RESULTS

Twelve trials met the inclusion criteria: 7 on subthreshold aerobic exercise, 1 on vestibular therapy, 1 on cervical therapy and 3 on individually tailored multimodal interventions. The trials were of fair to excellent quality on the PEDro scale. Eight trials were included in the quantitative analysis. Subthreshold aerobic exercise had a significant small to moderate effect in improving symptom scores (standardised mean difference (SMD)=0.43, 95% CI 0.18 to 0.67, p=0.001, I²=0%) but not in reducing days to symptom recovery in both acutely concussed individuals and those with persistent symptoms (SMD=0.19, 95% CI -0.54 to 0.93, p=0.61, I²=52%). There was limited evidence for stand-alone cervical, vestibular and oculomotor therapies. Concussed individuals with persistent symptoms (>2 weeks) were approximately 3 times more likely to have returned to sport by 8 weeks (relative risk=3.29, 95% CI 0.30 to 35.69, p=0.33, I²=83%) if they received individually tailored, presentation-specific multimodal interventions (cervical, vestibular and oculo-motor therapy). In addition, the multimodal interventions had a moderate effect in improving symptom scores (SMD=0.63, 95% CI 0.11 to 1.15, p=0.02, I²=0%) when compared with control.

CONCLUSIONS

Subthreshold aerobic exercise appears to lower symptom scores but not time to recovery in concussed individuals. Individually tailored multimodal interventions have a worthwhile effect in providing faster return to sport and clinical improvement, specifically in those with persistent symptoms.

PROSPERO REGISTRATION NUMBER

CRD42020108117.

Sex Differences in Neurophysiological Changes Following Voluntary Exercise in Adolescent Rats

Background: Adolescence is a period of time characterized by the onset of puberty and is marked by cognitive and social developments and gross physical changes that can play a role in athletic performance. Sex differences are present with differences in body size, height, physiology and behavior which contribute to differences in athletic performance as well. Pre-clinical studies representing this active group are lacking.

Methods: Acute and chronic effects of exercise were evaluated. Male and female adolescent rats were given voluntary access to a running wheel for 10 consecutive days. Running behavior (males and females) and estrous cycling (females only) were analyzed daily. A second group was given 10 days of voluntary access to a running wheel, then rested for 10 days to determine the long-term effects of exercise on the adolescent brain. Brain and muscle tissue were harvested at 10 and 20 day time points to understand exercise-dependent changes in mitochondrial activity and neuroplasticity. Animal cohorts were carried out at two different sites: University of California Los Angeles and Pepperdine University.

Results: On average, running distance, intensity of run, and length of running bout increased for both male and female rats across the 10 days measured. Females ran significantly further and for longer intervals compared to males. Cortical and muscle expression of PGC1α showed similar levels at 10 days regardless of sex and exercise. There was a significant increase in expression at 20 days in all groups correlating with body size (p's < 0.05). Cortical and hippocampal levels of BDNF were similar across all groups, however, BDNF was significantly higher in exercised females at the acute compared to long-term time point.

Discussion: Adolescent rats allowed 10 days of exercise show changes in physiologic function. There are sex differences in running behavior not impacted by sex hormones. These results are important to further our understanding of how exercise impacts the adolescent brain.

Sports-related concussions in high school females: an epidemiologic analysis of twenty-year national trends

The epidemiology of sports-related concussions (SRCs) and closed head injuries (CHIs) in high school females remains undefined at the national level, especially for unorganized sports and recreational activities. This study examines 1,176,092 national weighted estimates of SRCs or CHIs in female patients 14-18 years of age presenting to United States (US) emergency departments (EDs) between 2000 and 2019 in the National Electronic Injury Surveillance System (NEISS). The national weighted estimate of female patients in our study increased significantly (p < 0.001) between 2000 (9,835; 95% Confidence Interval [CI] 7,105-12,566) and 2019 (31,751; CI 26,392-37,110). The top five ranked sports and recreational activities most commonly associated with concussions and CHIs in female patients 14-18 years of age were: soccer (20.6%; CI 17.6%-23.6%); basketball (18.5%; CI 16.9%-20.1%); cheerleading (10.4%; CI 8.9%-11.9%); softball (10.1%; CI 9.0%-11.3%); volleyball (6.5%; CI 5.7%-7.2%). Simple univariate regression models showed that an increase of 10,000 annual female participants across all high school sports and recreational activities was associated with 308.7 (SE = 20.8, p < 0.001, R2 = 0.92) additional annual SRCs and CHIs presenting to US EDs. The promotion of concussion awareness and educational programs may help minimize SRCs and CHIs.

A Novel Neuropsychological Tool for Immersive Assessment of Concussion and Correlation with Subclinical Head Impacts

Mild traumatic brain injury (mTBI) remains a diagnostic challenge and therefore strategies for objective assessment of neurological function are key to limiting long-term sequelae. Current assessment methods are not optimal in austere environments such as athletic fields; therefore, we developed an immersive tool, the Display Enhanced Testing for Cognitive Impairment and mTBI (DETECT) platform, for rapid objective neuropsychological (NP) testing. The objectives of this study were to assess the ability of DETECT to accurately identify neurocognitive deficits associated with concussion and evaluate the relationship between neurocognitive measures and subconcussive head impacts. DETECT was used over a single season of two high school and two college football teams. Study participants were instrumented with Riddell Head Impact Telemetry (HIT) sensors and a subset tested with DETECT immediately after confirmed impacts for different combinations of linear and rotational acceleration. A total of 123 athletes were enrolled and completed baseline testing. Twenty-one players were pulled from play for suspected concussion and tested with DETECT. DETECT was 86.7% sensitive (95% confidence interval [CI]: 59.5%, 98.3%) and 66.7% specific (95% CI: 22.3%, 95.7%) in correctly identifying athletes with concussions (15 of 21). Weak but significant correlations were found between complex choice response time (processing speed and divided attention) and both linear (Spearman rank correlation coefficient 0.262, p = 0.02) and rotational (Spearman coefficient 0.254, p = 0.03) acceleration on a subset of 76 players (113 DETECT tests) with no concussion symptoms. This study demonstrates that DETECT confers moderate to high sensitivity in identifying acute cognitive impairment and suggests that football impacts that do not result in concussion may negatively affect cognitive performance immediately following an impact. Specificity, however, was not optimal and points to the need for additional studies across multiple neurological domains. Given the need for more objective concussion screening in triage situations, DETECT may provide a solution for mTBI assessment.

A Latent Profile Analysis to Categorize and Describe Athletes Based on Factors Related to Concussion Disclosure

CONTEXT

Collegiate student-athletes continue competing after experiencing symptoms of a concussion. Self-report of concussion symptoms is a critical element of the recovery process. Identifying factors related to concussion disclosure can aid in encouraging self-reporting.

OBJECTIVE

To use latent profile analysis to categorize and describe athletes based on factors related to concussion disclosure.

DESIGN

Cross-sectional study.

SETTING

Web-based survey.

PATIENTS OR OTHER PARTICIPANTS

A total of 2 881 (52.4% female; 65.3% in-season; 40% collision sport) student-athletes from 16 National Collegiate Athletic Association member institutions.

MAIN OUTCOME MEASURE(S)

Student-athlete concussion expectations, attitudes, and norms were the profile variables and reporting intentions served as the distal outcome variable. We conducted latent profile analysis using select profile variables to determine the optimal number of classes. Differences in concussion-reporting intentions by profile assignment were then examined. Lastly, the extent to which a student-athlete's sex, season status, and level of contact predicted his or her intentions to report a concussion within each profile was investigated.

RESULTS

Five unique student-athlete profiles emerged, including 1 profile that was most risky and another that was least risky. Females had significantly higher odds of being in the least risky profile. Those participating in collision sports had significantly higher odds of being in the top 2 most risky profiles. Contact-sport and in-season athletes were less likely to be in the least risky profile.

CONCLUSIONS

With a better understanding of student-athlete profiles, athletic trainers have an opportunity to encourage concussion disclosure. Prompt disclosure would allow student-athletes to begin the return-to-play protocol in a more timely manner.

A Genome-wide Association Study for Concussion Risk

PURPOSE

This study aimed to screen the entire genome for genetic markers associated with risk for concussion.

METHODS

A genome-wide association analyses was performed using data from the Kaiser Permanente Research Bank and the UK Biobank. Concussion cases were identified based on electronic health records from the Kaiser Permanente Research Bank and the UK Biobank from individuals of European ancestry. Genome-wide association analyses from both cohorts were tested for concussion using a logistic regression model adjusting for sex, height, weight, and race/ethnicity using allele counts for single nucleotide polymorphisms. Previously identified genes within the literature were also tested for association with concussion.

RESULTS

There were a total of 4064 cases of concussion and 291,472 controls within the databases, with two single nucleotide polymorphisms demonstrating a genome-wide significant association with concussion. The first polymorphism, rs144663795 (P = 9.7 × 10-11; OR = 2.91 per allele copy), is located within the intron of SPATA5. Strong, deleterious mutations in SPATA5 cause intellectual disability, hearing loss, and vision loss. The second polymorphism, rs117985931 (P = 3.97 × 10-9; OR = 3.59 per allele copy), is located within PLXNA4. PLXNA4 plays a key role is axon outgrowth during neural development, and DNA variants in PLXNA4 are associated with risk for Alzheimer's disease. Previous investigations have identified five candidate genes that may be associated with concussion, but none showed a significant association in the current model (P < 0.05).

CONCLUSION

Two genetic markers were identified as potential risk factors for concussion and deserve further validation and investigation of molecular mechanisms.

A Role for the Amygdala in Impairments of Affective Behaviors Following Mild Traumatic Brain Injury

Mild traumatic brain injury (TBI) results in chronic affective disorders such as depression, anxiety, and fear that persist up to years following injury and significantly impair the quality of life for patients. Although a great deal of research has contributed to defining symptoms of mild TBI, there are no adequate drug therapies for brain-injured individuals. Preclinical studies have modeled these deficits in affective behaviors post-injury to understand the underlying mechanisms with a view to developing appropriate treatment strategies. These studies have also unveiled sex differences that contribute to the varying phenotypes associated with each behavior. Although clinical and preclinical studies have viewed these behavioral deficits as separate entities with unique neurobiological mechanisms, mechanistic similarities suggest that a novel approach is needed to advance research on drug therapy. This review will discuss the circuitry involved in the expression of deficits in affective behaviors following mild TBI in humans and animals and provide evidence that the manifestation of impairment in these behaviors stems from an amygdala-dependent emotional processing deficit. It will highlight mechanistic similarities between these different types of affective behaviors that can potentially advance mild TBI drug therapy by investigating treatments for the deficits in affective behaviors as one entity, requiring the same treatment.

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.

Mild traumatic brain injury exacerbates Parkinson's disease induced hemeoxygenase-2 expression and brain pathology: Neuroprotective effects of co-administration of TiO2 nanowired mesenchymal stem cells and cerebrolysin

Mild traumatic brain injury (mTBI) is one of the leading predisposing factors in the development of Parkinson's disease (PD). Mild or moderate TBI induces rapid production of tau protein and alpha synuclein (ASNC) in the cerebrospinal fluid (CSF) and in several brain areas. Enhanced tau-phosphorylation and ASNC alters the molecular machinery of the brain leading to PD pathology. Recent evidences show upregulation of constitutive isoform of hemeoxygenase (HO-2) in PD patients that correlates well with the brain pathology. mTBI alone induces profound upregulation of HO-2 immunoreactivity. Thus, it would be interesting to explore whether mTBI exacerbates PD pathology in relation to tau, ASNC and HO-2 expression. In addition, whether neurotrophic factors and stem cells known to reduce brain pathology in TBI could induce neuroprotection in PD following mTBI. In this review role of mesenchymal stem cells (MSCs) and cerebrolysin (CBL), a well-balanced composition of several neurotrophic factors and active peptide fragments using nanowired delivery in PD following mTBI is discussed based on our own investigation. Our results show that mTBI induces concussion exacerbates PD pathology and nanowired delivery of MSCs and CBL induces superior neuroprotection. This could be due to reduction in tau, ASNC and HO-2 expression in PD following mTBI, not reported earlier. The functional significance of our findings in relation to clinical strategies is discussed.

Post-concussion states: How do we improve our patients’ outcomes? An Australian perspective

There is limited data surrounding incidence and prevalence of concussion and the resulting post-concussion states. This creates difficulty when investigating ways to optimise patient management. It is proposed that a registry of patients presenting with symptoms and signs after a concussion, as part of a large scale TBI registry across Australia, would provide a starting point for future research with a view to improving the outcomes of patients experiencing symptoms and signs after concussion.

Late contributions of repetitive head impacts and TBI to depression symptoms and cognition

OBJECTIVE

To test the hypothesis that repetitive head impacts (RHIs), like those from contact sport play and traumatic brain injury (TBI) have long-term neuropsychiatric and cognitive consequences, we compared middle-age and older adult participants who reported a history of RHI and/or TBI with those without this history on measures of depression and cognition.

METHODS

This cross-sectional study included 13,323 individuals (mean age, 61.95; 72.5% female) from the Brain Health Registry who completed online assessments, including the Ohio State University TBI Identification Method, the Geriatric Depression Scale (GDS-15), and the CogState Brief Battery and Lumos Labs NeuroCognitive Performance Tests. Inverse propensity-weighted linear regressions accounting for age, sex, race/ethnicity, and education tested the effects of RHI and TBI compared to a non-RHI/TBI group.

RESULTS

A total of 725 participants reported RHI exposure (mostly contact sport play and abuse) and 7,277 reported TBI (n = 2,604 with loss of consciousness [LOC]). RHI (β, 1.24; 95% CI, 0.36-2.12), TBI without LOC (β, 0.43; 95% CI, 0.31-0.54), and TBI with LOC (β, 0.75; 95% CI, 0.59-0.91) corresponded to higher GDS-15 scores. While TBI with LOC had the most neuropsychological associations, TBI without LOC had a negative effect on CogState Identification (β, 0.004; 95% CI, 0.001-0.01) and CogState One Back Test (β, 0.004; 95% CI, 0.0002-0.01). RHI predicted worse CogState One Back Test scores (β, 0.02; 95% CI, -0.01 to 0.05). There were RHI × TBI interaction effects on several neuropsychological subtests, and participants who had a history of both RHI and TBI with LOC had the greatest depression symptoms and worse cognition.

CONCLUSIONS

RHI and TBI independently contributed to worse mid- to later-life neuropsychiatric and cognitive functioning.

Association of artificial turf and concussion in competitive contact sports: a systematic review and meta-analysis

Objective

To determine the incidence of head injuries and concussion in contact sports, comparing natural grass with artificial turf surfaces.

Design

Systematic review and meta-analysis via the RevMan V.5.3 software.

Eligibility criteria for selecting studies

All studies describing competitive contact sports played on both natural grass and artificial turf. The primary outcome measured was occurrence of head injury and concussion.

Data sources

The databases include PubMed, Embase, Cochrane, Medline and Sport Discus. The last search took place on 23 May 2019. The Newcastle-Ottawa Quality Assessment Scale evaluated the methodological quality of the selected studies with a funnel plot designed to determine publication bias. Study screening and data extraction were performed by two independent reviewers.

Results

Initial screening generated 42 publications, with 12 meeting criteria for inclusion. Eight studies described concussion only. The rate ratio (RR) of head injury and concussion was less on artificial turf compared with natural grass (RR=0.89, 95% CI 0.77 to 1.04) as was the rate ratio of concussion only (RR=0.72, 95% CI 0.58 to 0.89).

Conclusion

Analysis of published data demonstrates a decreased incidence of head injury and concussion when contact sports are played on artificial turf. This difference was most marked for sports such as rugby and American football. However, artificial turf has no association with the incidence of head injury or concussion while playing soccer.

Multiple Concussions Increase Odds and Rate of Lower Extremity Injury in National Collegiate Athletic Association Athletes After Return to Play

BACKGROUND

Concussion in collegiate athletics is one of the most prevalent sport-related injuries in the United States, with recent studies suggesting persistent deficits in neuromuscular control after a concussion and an associated increase in risk of lower extremity injury.

PURPOSE

To expand on the relationship between concussion and lower extremity injury by examining the effect of multiple concussions (MC) on rate and odds of future lower extremity injury in collegiate athletes after return to play (RTP) compared with matched controls.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

From 2001 to 2016, 48 National Collegiate Athletic Association Division I athletes sustaining multiple concussions at a single institution were identified. Athletes with multiple concussions (MC) were matched directly to athletes with a single concussion (SC) and to athletes with no concussion history (NC) by sex, sport, position, and games played. Incidence of, time to, and location of lower extremity injury were recorded for each group after RTP from their first reported concussion until completion of their collegiate career. Logistic regression was used to analyze odds ratios (ORs) for sustaining lower extremity injury, whereas time to injury was summarized by use of Kaplan-Meier curves and log rank test analysis.

RESULTS

The incidence of lower extremity injury after RTP was significantly greater (P = .049) in the MC cohort (36/48, 75%) than in SC athletes (25/48 = 52%) and NC athletes (27/48 = 56%). Similarly, odds of lower extremity injury were significantly greater in the MC cohort than in SC athletes (OR, 3.00; 95% CI, 1.26-7.12; P = .01) and NC athletes (OR, 1.66; 95% CI, 1.07-2.56; P = .02). Time to lower extremity injury was significantly shorter in the MC group compared with matched controls (P = .01). No difference was found in odds of lower extremity injury or time to lower extremity injury between SC and NC athletes.

CONCLUSION

Collegiate athletes with MC were more likely to sustain a lower extremity injury after RTP in a shorter time frame than were the matched SC and NC athletes. This may suggest the presence of a cohort more susceptible to neuromuscular deficits after concussion or more injury prone due to player behavior, and it may imply the need for more stringent RTP protocols for athletes experiencing MC.

Expansion of a fly TBI model to four levels of injury severity reveals synergistic effects of repetitive injury for moderate injury conditions

Several million traumatic brain injury (TBI) events are reported in the United States annually. However, mild TBI events often go unreported, and mild and repetitive mild TBI conditions are challenging to model. Fruit flies (Drosophila melanogaster) have gained traction for the study of TBI. The best-characterized fly TBI model is the high-impact trauma (HIT) method. We replicated the HIT method and confirmed several previous findings at the standard level of injury severity. We then expanded upon the HIT model by characterizing mortality across three reduced levels of injury severity. Importantly, we found reduced mortality with reduced injury severity and synergistic effects on mortality in response to repetitive TBI by our moderate injury conditions. Last, we compared moderate, repetitive TBI to a single severe TBI via assessment of the pattern of mortality and geotaxis performance in the 24 h following TBI. We found the number and severity of injuries could result in different patterns of death, while all TBI conditions led to impaired geotaxis compared to uninjured flies at 0.5 h and 6 h post-TBI. Thus, we have extended a well-characterized model of TBI in flies, and shown the utility of this model for making unique insights into TBI across various severities, injury numbers, and time-points post-injury.