Sport-Related Concussions: A Review of Epidemiology, Challenges in Diagnosis, and Potential Risk Factors

Comparison of the Buffalo Concussion Treadmill Test With a Physiologically Informed Cycle Test: Calgary Concussion Cycle Test

BACKGROUND

Sport-related concussions are a complex injury requiring multifaceted assessment, including physical exertion. Currently, concussion testing relies primarily on a treadmill-based protocol for assessing exertion-related symptoms in persons after concussion. This study compared a modified cycle protocol (Calgary Concussion Cycle Test [CCCT]) with the clinically adopted standard, the Buffalo Concussion Treadmill Test (BCTT), across multiple physiological parameters.

HYPOTHESIS

Treadmill and cycle matched workload protocols would produce similar results for cerebral blood velocity, mean arterial pressure (MAP), and end-tidal carbon dioxide partial pressure (PETCO2), but heart rate (HR) and oxygen consumption (VO2) would be higher on the treadmill than the cycle modality.

STUDY DESIGN

Crossover study design.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 17 healthy adults (8 men, 9 women; age, 26 ± 3 years; body mass index, 23.8 ± 2.7 kg/m2) completed the BCTT and CCCT protocols, 7 days apart in a randomized order. During both exertional protocols, the physiological parameters measured were middle cerebral artery mean blood velocity (MCAv), MAP, PETCO2, VO2, and HR. Analysis of variance with effect size computations, coefficient of variation, and Bland-Altman plots with 95% limits of agreement were used to compare exercise tests.

RESULTS

The BCTT and CCCT produced comparable results for both male and female participants with no significant differences for average MCAv, MAP, and PETCO2 (all P > 0.05; all generalized eta squared [η2G] < 0.02 [negligible]; P value range, 0.29-0.99) between stages. When accounting for exercise stage and modality, VO2 (P < 0.01) and HR (P < 0.01) were higher on the treadmill compared with the cycle. Aside from the final few stages, all physiology measures displayed good-to-excellent agreeability/variability.

CONCLUSION

The CCCT was physiologically similar to the BCTT in terms of MCAv, PETCO2, and MAP; however, HR and VO2 differed between modalities.

CLINICAL RELEVANCE

Providing a cycle-based modality to exertional testing after injury mayincrease accessibility to determine symptom thresholds in the future.

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.

Clinical evaluation and management of badminton-related eye injuries: a retrospective case series

BACKGROUND

To describe the clinical features, visual outcomes, management, and complications of ocular injury in badminton and investigate risk factors associated with visual impairment.

METHODS

Data on patients injured while playing badminton admitted to Department of Ophthalmology, Eye, Ear, Nose, and Throat Hospital, Fudan University between January 2018 to December 2020.The relationship between visual acuity (VA) and demographic and clinical variables was also analyzed. Patients were managed medically or surgically as per their needs, followed up for at least 18 months. The visual outcomes were predicted using ocular trauma score (OTS), predicted outcomes were compared with actual outcomes using statistical tests.

RESULTS

This study involved 102 patients (78 men, 24 women) with a mean age of 43.8 ± 16.1 years (7-71 years). Of these, 93 patients had closed-globe injuries and 9 had open-globe injuries. Vision-threatening findings included lens subluxation(31.4%),retinal detachment(13.7%),hyphema(12.7%). Open-globe injury had significantly lower presenting VA and final VA (P= 0.0164, 0.0053).Final VA was found to be correlated with presenting VA, maculopathy, retinal detachment, and OTS (P=0.0000, 0.0494, 0.0001, 0.0000 respectively), it was worse in patients who were under 20 years of age and were female. OTS prediction was not significantly different when compared with actual visual outcomes postoperatively in OTS3, OTS4, and OTS5 (P > 0.05),while the prognosis of patients with OTS1 and OTS2 was better than OTS study (P=0.001, 0.007, respectively).

CONCLUSION

Badminton-related closed-globe injuries were more frequent; open-globe injuries were usually more serious. Younger and female patients have poorer visual recovery prognoses. OTS was found to be a reliable tool for predicting visual outcomes.

Update on Pediatric Mild Traumatic Brain Injury in Rural and Underserved Regions: A Global Perspective

BACKGROUND

Mild traumatic brain injury (MTBI) causes morbidity and disability worldwide. Pediatric patients are uniquely vulnerable due to developmental and psychosocial factors. Reduced healthcare access in rural/underserved communities impair management and outcome. A knowledge update relevant to current gaps in care is critically needed to develop targeted solutions.

METHODS

The National Library of Medicine PubMed database was queried using comprehensive search terms (("mild traumatic brain injury" or "concussion") and ("rural" or "low-income" or "underserved") and ("pediatric" or "child/children")) in the title, abstract, and Medical Subject Headings through December 2022. Fifteen articles on rural/underserved pediatric MTBI/concussion not covered in prior reviews were examined and organized into four topical categories: epidemiology, care practices, socioeconomic factors, and telehealth.

RESULTS

Incidences are higher for Individuals in rural regions, minorities, and those aged 0-4 years compared to their counterparts, and are increasing over time. Rural healthcare utilization rates generally exceed urban rates, and favor emergency departments (vs. primary care) for initial injury assessment. Management guidelines require customization to resource-constrained settings for implementation and adoption. Decreased community recognition of the seriousness of injury is a consensus challenge to care provision by clinicians. Low parental education and income were correlated with decreased MTBI knowledge and worse outcome. Telehealth protocols for triage/consultation and rehabilitation were feasible in improving care delivery to rural and remote settings.

CONCLUSIONS

Pediatric MTBI/concussion patients in rural/underserved regions experience increased risks of injury, geographic and financial healthcare barriers, and poorer outcomes. Globally, under-reporting of injury has hindered epidemiological understanding. Ongoing MTBI education should be implemented for rural caregivers, schools, and low-income populations to improve community awareness. Telehealth can improve care delivery across acuity settings, and warrants judicious inclusion in triage and treatment protocols.

Concussion in Women's Flat-Track Roller Derby

Concussions are common among flat-track roller derby players, a unique and under-studied sport, but little has been done to assess how common they are or what players can do to manage injury risk. The purpose of this study is to provide an epidemiological investigation of concussion incidence and experience in a large international sampling of roller derby players. Six hundred sixty-five roller derby players from 25 countries responded to a comprehensive online survey about injury and sport participation. Participants also responded to a battery of psychometric assessment tools targeting risk-factors for poor injury recovery (negative bias, social support, mental toughness) and players' thoughts and feelings in response to injury. Per 1,000 athletes, 790.98 concussions were reported. Current players reported an average of 2.2 concussions, while former players reported 3.1 concussions. However, groups were matched when these figures were corrected for differences in years of play (approximately one concussion every 2 years). Other frequent injuries included fractures in extremities and upper limbs, torn knee ligaments, and sprained ankles. We found no evidence that players' position, full-contact scrimmages, or flooring impacted number of concussions. However, neurological history and uncorrected vision were more influential predictors of an individual's number of concussions during roller derby than years of participation or age, though all four contributed significantly. These findings should assist athletes in making informed decisions about participation in roller derby, though more work is needed to understand the nature of risk.

Head Impact Research Using Inertial Sensors in Sport: A Systematic Review of Methods, Demographics, and Factors Contributing to Exposure

BACKGROUND

The number and magnitude of head impacts have been assessed in-vivo using inertial sensors to characterise the exposure in various sports and to help understand their potential relationship to concussion.

OBJECTIVES

We aimed to provide a comprehensive review of the field of in-vivo sensor acceleration event research in sports via the summary of data collection and processing methods, population demographics and factors contributing to an athlete's exposure to sensor acceleration events.

METHODS

The systematic search resulted in 185 cohort or cross-sectional studies that recorded sensor acceleration events in-vivo during sport participation.

RESULTS

Approximately 5800 participants were studied in 20 sports using 18 devices that included instrumented helmets, headbands, skin patches, mouthguards and earplugs. Female and youth participants were under-represented and ambiguous results were reported for these populations. The number and magnitude of sensor acceleration events were affected by a variety of contributing factors, suggesting sport-specific analyses are needed. For collision sports, being male, being older, and playing in a game (as opposed to a practice), all contributed to being exposed to more sensor acceleration events.

DISCUSSION

Several issues were identified across the various sensor technologies, and efforts should focus on harmonising research methods and improving the accuracy of kinematic measurements and impact classification. While the research is more mature for high-school and collegiate male American football players, it is still in its early stages in many other sports and for female and youth populations. The information reported in the summarised work has improved our understanding of the exposure to sport-related head impacts and has enabled the development of prevention strategies, such as rule changes.

CONCLUSIONS

Head impact research can help improve our understanding of the acute and chronic effects of head impacts on neurological impairments and brain injury. The field is still growing in many sports, but technological improvements and standardisation of processes are needed.

An International Exploration of the Effect of Media Portrayals of Postconcussion Management on Concussion Identification in the General Public

BACKGROUND

Concussion portrayal in media broadcasts of sporting events may contribute to lack of public understanding regarding concussion.

METHODS

In total, 828 participants from Australia, New Zealand, and the United Kingdom completed a questionnaire assessing concussion knowledge. Participants were randomly assigned to either receive sports return-to-play (RTP) guideline information (RTP group) or not (no-RTP group). Participants viewed 12 short clips from televised rugby games and indicated whether they believed the player in each clip had sustained a concussion. Participants were then informed whether the player was removed, returned, or stayed in the game and again asked whether they thought a concussion had occurred.

RESULTS

Probability of reporting a likely concussion over all videos was 65.6%. When told a player's possible concussion was managed by removal from the game, participants were more likely to change their response from "no" (no concussion) to "yes" (concussion) than from "yes" to "no." When told the player stayed or returned to the game, participants were more likely to change their response from "yes" (concussion) to "no" (no concussion) than from "no" to "yes." There was no significant main effect for RTP guideline manipulation or interaction effect with RTP information.

CONCLUSION

Additional player's injury management information influenced participants' judgments of concussion occurrence. Results show that information provided via sports media broadcasts influenced viewers' perceptions of concussion and appropriate concussion management.

Incidence of sports-related concussion in elite para athletes - a 52-week prospective study

Objective: To assess the 52-week incidence proportion and incidence rate of sports-related concussion (SRC) among elite Para athletes, and to analyze the injury mechanisms.Method: In total, 70 male and 37 female Swedish elite Para athletes (median age 29 years) with vision, physical and intellectual impairment, weekly self-reported sports-related injuries including concussion in an eHealth application adapted to Para athletes. Descriptive statistics were used to assess the incidence rate and incidence proportion. Chi-square statistics were used to analyze differences in the proportion of SRC.Results: A total of 13 SRC were reported: three athletes each sustained two SRC. The incidence proportion was 9.3% (95% CI 4.8-16.7), and the incidence rate 0.5 SRC/1000 hours (95% CI 0.3-0.9) of sports exposure. Athletes with vision impairment and female athletes reported a significantly higher proportion of SRC. A majority of the injuries (n = 9; 69%) occurred during sport-specific training. The injury mechanisms were collision with object (n = 7; 54%), collision with person (n = 4; 31%), and poor playing field conditions (n = 2; 16%).Conclusion: The incidence of concussion among elite Paralympic athletes is comparable to sports for able-bodied athletes. Athletes with vision impairment and female athletes reported a significantly higher incidence of SRC, and collisions were the most common injury mechanism. These results can form the basis for future preventive research studies.

A Biomarker for Concussion: The Good, the Bad, and the Unknown

BACKGROUND

Traumatic brain injury (TBI) is a significant cause of morbidity, mortality, and disability in the US, with >2.8 million patients presenting to the emergency department (ED) annually. However, the diagnosis of TBI is challenging and presents a number of difficulties, particularly at the mildest end of the spectrum: concussion. A number of groups have researched biomarkers to aid in the evaluation of TBI, and most recently in 2018 the Food and Drug Administration approved a new blood-based immunoassay biomarker using ubiquitin carboxyl hydrolase L1 and glial fibrillary acidic protein to aid in head computed tomography (CT) triage.

CONTENT

This review clarifies the practical challenges in assessing and implementing a new blood biomarker. It then examines the clinical context and need, as well as the evidence used to validate this new immunoassay.

SUMMARY

Concussion is a multifaceted diagnosis with a need for biomarkers to assist in diagnostic and prognostic assessment. Recent articles in the lay press have revealed misunderstanding about the function of this new test, expressing hopes that this biomarker serves patients at the mildest end of the spectrum and is useful for athletes and children. None of these assumptions are correct, as this biomarker has been evaluated in patients only at the moderate end of the spectrum and has been validated only in adults presenting to the ED who have already been triaged to receive head CT, not in athletes or children. The next steps for this assay should consider clinical work flow and clarifying its intended use, including integration with existing triage methods, and validating the assay for a broader population.

White Matter Tract-Oriented Deformation Is Dependent on Real-Time Axonal Fiber Orientation

Traumatic axonal injury (TAI) is a critical public health issue with its pathogenesis remaining largely elusive. Finite element (FE) head models are promising tools to bridge the gap between mechanical insult, localized brain response, and resultant injury. In particular, the FE-derived deformation along the direction of white matter (WM) tracts (i.e., tract-oriented strain) has been shown to be an appropriate predictor for TAI. The evolution of fiber orientation in time during the impact and its potential influence on the tract-oriented strain remains unknown, however. To address this question, the present study leveraged an embedded element approach to track real-time fiber orientation during impacts. A new scheme to calculate the tract-oriented strain was proposed by projecting the strain tensors from pre-computed simulations along the temporal fiber direction instead of its static counterpart directly obtained from diffuse tensor imaging. The results revealed that incorporating the real-time fiber orientation not only altered the direction but also amplified the magnitude of the tract-oriented strain, resulting in a generally more extended distribution and a larger volume ratio of WM exposed to high deformation along fiber tracts. These effects were exacerbated with the impact severities characterized by the acceleration magnitudes. Results of this study provide insights into how best to incorporate fiber orientation in head injury models and derive the WM tract-oriented deformation from computational simulations, which is important for furthering our understanding of the underlying mechanisms of TAI.

Examining the Relationship between Concussion and Neurodegenerative Disorders: A Review on Amyotrophic Lateral Sclerosis (ALS) and Alzheimer’s Disease (AD)

Background Current epidemiological studies have examined the associations between moderate and severe traumatic brain injury (TBI) and their risks of developing neurodegenerative diseases. Concussion, also known as mild TBI (mTBI), is however quite distinct from moderate or severe TBIs. Only few studies in this burgeoning area have examined concussion—especially repetitive episodes—and neurodegenerative diseases. Thus, no definite relationship has been established between them.

Objectives This review will discuss the available literatures linking concussion and amyotrophic lateral sclerosis (ALS) and Alzheimer’s disease (AD).

Materials and Methods Given the complexity of this subject, a realist review methodology was selected which includes clarifying the scope and developing a theoretical framework, developing a search strategy, selection and appraisal, data extraction, and synthesis. A detailed literature matrix was set out in order to get relevant and recent findings on this topic.

Results Presently, there is no objective clinical test for the diagnosis of concussion because the features are less obvious on physical examination. Absence of an objective test in diagnosing concussion sometimes leads to skepticism when confirming the presence or absence of concussion. Intriguingly, several possible explanations have been proposed in the pathological mechanisms that lead to the development of some neurodegenerative disorders (such as ALS and AD) and concussion but the two major events are deposition of tau proteins (abnormal microtubule proteins) and neuroinflammation, which ranges from glutamate excitotoxicity pathways and inflammatory pathways (which leads to a rise in the metabolic demands of microglia cells and neurons), to mitochondrial function via the oxidative pathways.

Conclusion mTBI constitutes majority of brain injuries. However, studies have focused mostly on moderate-to-severe TBI as highlighted above with inconclusive and paucity of studies linking concussion and neurodegenerative disorders. Although, it is highly probable that repetitive concussion (mTBI) and subconcussive head injuries may be risk factors for ALS) and AD from this review. It will be imperative therefore to conduct more research with a focus on mTBI and its association with ALS and AD.

Research Evaluating Sports ConcUssion Events-Rapid Assessment of Concussion and Evidence for Return (RESCUE-RACER): a two-year longitudinal observational study of concussion in motorsport

INTRODUCTION

Concussion is a clinical diagnosis, based on self-reported patient symptoms supported by clinical assessments across many domains including postural control, ocular/vestibular dysfunction, and neurocognition. Concussion incidence may be rising in motorsport which, combined with unresolved challenges to accurate diagnosis and lack of guidance on the optimal return-to-race timeframe, creates a difficult environment for healthcare practitioners.

METHODS AND ANALYSIS

Research Evaluating Sports ConcUssion Events-Rapid Assessment of Concussion and Evidence for Return (RESCUE-RACER) evaluates motorsports competitors at baseline (Competitor Assessment at Baseline; Ocular, Neuroscientific (CArBON) study) and post-injury (Concussion Assessment and Return to motorSport (CARS) study), including longitudinal data. CArBON collects pre-injury neuroscientific data; CARS repeats the CArBON battery sequentially during recovery for competitors involved in a potentially concussive event. As its primary outcome, RESCUE-RACER will develop the evidence base for an accurate trackside diagnostic tool. Baseline objective clinical scoring (Sport Concussion Assessment Tool-5th edition (SCAT5)) and neurocognitive data (Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT)) will be assessed for specificity to motorsport and relationship to existing examinations. Changes to SCAT5 and ocular, vestibular, and reaction time function (Dx 100) will be estimated by the reliability change index as a practical tool for trackside diagnosis. Neuropsychological (Cambridge Neuropsychological Test Automated Battery (CANTAB)) assessments, brain MRI (7 Tesla) and salivary biomarkers will be compared with the new tool to establish utility in diagnosing and monitoring concussive injuries.

ETHICS AND DISSEMINATION

Ethical approval was received from East of England-Cambridge Central Research Ethics Committee (18/EE/0141). Participants will be notified of study outcomes via publications (to administrators) and summary reports (funder communications). Ideally, all publications will be open access.

TRIAL REGISTRATION NUMBER

February 2019 nationally (Central Portfolio Management System 38259) and internationally (ClinicalTrials.gov NCT03844282).

Reinjury After Moderate to Severe TBI: Rates and Risk Factors in the NIDILRR Traumatic Brain Injury Model Systems

OBJECTIVES

To compare characteristics of those who do and do not sustain subsequent traumatic brain injuries (TBIs) following index TBI and to identify reinjury risk factors.

DESIGN

Secondary data analysis of an ongoing longitudinal cohort study.

SETTING

TBI Model Systems Centers.

PARTICIPANTS

In total, 11 353 individuals aged 16+ years.

MAIN OUTCOME MEASURES

Ohio State University TBI Identification Method.

RESULTS

In total, 7.9% of individuals reported sustaining a TBI post-index TBI. Twenty percent of reinjuries occurred within a year of the index TBI. Reinjury risk followed an approximate U-shaped distribution such that risk was higher in the first year, declined 2 to 10 years postinjury, and then increased after 10 years. A multivariable Weibull model identified predictors of reinjury: younger (<29 years) and middle-aged and older (50+ years) age at index TBI relative to middle age, pre-index TBI, pre-index alcohol and illicit drug use, incarceration history, and less severe index TBI.

CONCLUSIONS

A subset of individuals who receive inpatient rehabilitation for TBI are at an increased risk for reinjury, and an injury-prone phenotype may be characterized by engagement in risk behaviors. Factors associated with reinjury risk may differ for younger versus middle-aged and older adults. Findings underscore the need for empirically informed risk stratification models to identify TBI survivors at risk for reinjury.

Predicting Risk of Sport-Related Concussion in Collegiate Athletes and Military Cadets: A Machine Learning Approach Using Baseline Data from the CARE Consortium Study

OBJECTIVE

To develop a predictive model for sport-related concussion in collegiate athletes and military service academy cadets using baseline data collecting during the pre-participation examination.

METHODS

Baseline assessments were performed in 15,682 participants from 21 US academic institutions and military service academies participating in the CARE Consortium Study during the 2015-2016 academic year. Participants were monitored for sport-related concussion during the subsequent season. 176 baseline covariates mapped to 957 binary features were used as input into a support vector machine model with the goal of learning to stratify participants according to their risk for sport-related concussion. Performance was evaluated in terms of area under the receiver operating characteristic curve (AUROC) on a held-out test set. Model inputs significantly associated with either increased or decreased risk were identified.

RESULTS

595 participants (3.79%) sustained a concussion during the study period. The predictive model achieved an AUROC of 0.73 (95% confidence interval 0.70-0.76), with variable performance across sports. Features with significant positive and negative associations with subsequent sport-related concussion were identified.

CONCLUSION(S)

This predictive model using only baseline data identified athletes and cadets who would go on to sustain sport-related concussion with comparable accuracy to many existing concussion assessment tools for identifying concussion. Furthermore, this study provides insight into potential concussion risk and protective factors.

The possible role of hydration in concussions and long-term symptoms of concussion for athletes. A review of the evidence

The purpose of this review is to address what is known, speculated, and hypothesized regarding the issue of hydration and concussions. Based on the question, “What impact does hydration have on the relative risk for suffering concussive injuries along with long-term ramifications that have been associated with concussive (and repeated subconcussive) traumas to the cerebral cortex?,” a search of available literature was performed through June 2019. Deducing from the available literature, we can stipulate that changes in hydration within the cerebral cortex increase the likelihood for disruption of neurofilament proteins, dysregulation of membrane dynamics of the neurons and exacerbate inflammation responses following head trauma. As such, it can be speculated that differences in incidence rates may be attributed to difference in tissue fluid based on athlete demographics, level of whole-body water balance, and degree of tissue dehydration more than selection of sport. Moreover, tissue hydration in combination with other inflammation factors provides the scaffolding for the development of long-term issues (e.g. chronic traumatic encephalopathy) associated with repetitive head trauma in athletes.

Post-Traumatic Epilepsy after Sports-Related Concussion: A Case Report

Sports-related concussions (SRCs) are a public health concern across the United States, and they lead to neurological sequelae that can last long after the event itself. Concussive convulsions at the time of injury are common and rarely require additional workup or treatment. Post-traumatic epilepsy (PTE), however, is a rare phenomenon that can develop after traumatic brain injury and must be managed with adequate medical therapy. Herein we present the case of a 15-year-old football player who developed PTE after an SRC. This condition must be identified through proper education of sports clinicians and those involved in care and management of athletes.

Motor Deficits in Youth with Concussion History: Issues with Task Novelty or Task Demand?

The present study expands previous work on eye-hand decoupling deficits in youth with concussion history. It examines whether deficits can be linked to difficulties adapting to new task constraints or meeting ongoing task demands. Data from 59 youth with concussion history (M=11 months post-concussion) and 55 no history controls were analyzed. All 114 participants (M=12.5 yrs.) performed two touchscreen-based eye-hand coordination tasks: A standard task with vision and motor action in alignment, and an eye-hand decoupling task with both spatially decoupled, with twenty trials per task condition. First (trial 1-4), middle (trial 9-12), and last (trial 17-20) trial blocks were analyzed in each condition across groups, as well as first and last blocks only. The latter analysis showed in the first block longer response times in the concussion history group in the eye-hand decoupling condition due to a general slowdown of the reaction times across blocks and a trend for higher movement times. Our findings suggest that youth with concussion history have difficulty to adapt to new task constraints associated with complex skill performance during a short series of trials. These results are relevant for athletic trainers, therapists and coaches who work with youth with concussion history.

Analysis of Football Injuries by Position Group in Division I College Football: A 5-Year Program Review

OBJECTIVE

The purpose of this study was to evaluate injury characteristics by position groups.

DESIGN

Prospective, observational study.

SETTING

A single, major Division I collegiate football program.

PARTICIPANTS

All players on a collegiate football program each fall regular season.

INDEPENDENT VARIABLES

Exposure to Division I collegiate football and position groups.

MAIN OUTCOME MEASURES

Injury rates (IRs) per 1000 athlete exposures (AEs) and injury rate ratios (IRRs) were calculated and analyzed for all monitored injury variables, which included time in the season, body part, type of injury, game and practice injuries, mechanism of injury, and type of exposure.

RESULTS

During the 2012 to 2016 fall regular seasons, there were 200 reported injuries sustained from 48 615 AE. The overall 5-year IR was 4.11 per 1000 AEs (3.57-4.72 95% confidence intervals). Skill players sustained the highest IR in the preseason (IR, 7.56) compared with line (IR, 4.26) and other (IR, 4.10) position groups. In addition, skill players demonstrated a significantly higher IRR compared with the line (IRR, 1.75, P < 0.05) and other (IRR, 1.85, P < 0.05) position groups.

CONCLUSIONS

Skill players sustained most of their injuries in the preseason, whereas the linemen and other position groups suffered most of their injuries in the first half of the regular season. Skill players demonstrated a significantly higher IR in preseason, noncontact mechanism injuries, and injuries to the upper leg and thigh compared with line and other position groups. Efforts to reduce soft-tissue muscle strains in skill players targeting the preseason may provide one of the best opportunities to significantly decrease current football IRs, whereas efforts to reduce contact exposures may have the greatest effect on concussions and contact mechanism injuries for the other position group. There were no significant differences in IRs between position groups and type of exposure.

Concussion History and Career Status Influence Performance on Baseline Assessments in Elite Football Players

OBJECTIVE

To determine if concussion history and career status is associated with neurocognitive performance in elite football players.

METHODS

The study design was a cross-sectional single assessment. Fifty-seven elite football players (age 29.39 ± 7.49 years) categorized as draft prospects, active professional players, and retired professional players were assessed on the Sport Concussion Assessment Tool - third edition (SCAT-3), in an outpatient therapy setting.

RESULTS

Common symptoms were the following: fatigue (45.6%), trouble falling asleep (35.1%), difficulty remembering (33.3%) and irritability (22.8%); 36.8% reported no symptoms. The low concussion (0-1) group reported fewer symptoms (U = 608.50, p < .001), less symptom severity (U = 598.00, p = -.001), and produced greater scores on the Standardized Assessment of Concussion (SAC) total scores compared to the multiple concussion (2+) group (U = 253.00, p = .024), but no differences were observed on modified Balance Error Scoring System (m-BESS) scores (U = 501.50, p = .066) on the Mann-Whitney U test. The Kruskal-Wallis test and post-hoc analysis indicated retired players were significantly different from draft prospects and current professional players for total symptom scores (p < .001), total symptom severity (p < .001), SAC total scores (p = .030), and m-BESS (p < .001).

CONCLUSIONS

Concussion history and career status appear associated with total symptoms, symptom severity, performance on the SAC, and the m-BESS in elite football players. With this in mind, future research is recommended to determine longitudinal impact for elite football players.

Match Situations Leading to Head Injuries in Professional Male Football (Soccer)-A Video-Based Analysis Over 12 Years

OBJECTIVE

To identify risk situations promoting head injuries in professional male football (soccer) and to investigate the impact of a rule change in 2006 punishing elbow-head contacts.

DESIGN

Analysis of video sequences of head events leading to head injury.

PARTICIPANTS

Professional football players of the first male German Bundesliga.

MAIN OUTCOME MEASURES

Observational criteria of head impacts on video recordings (players' actions preceding head injuries, foul play-referee's decision and assessment of rater, ball possession, on-pitch medical treatment, and consequences of head impact).

RESULTS

Three hundred thirty-four head injuries were reported in kicker Sportmagazin corresponding to an incidence rate of 2.25 (95% confidence interval 2.01-2.51) per 1000 player match hours. The injured player predominantly jumped (60%), headed the ball (36%), or ran forwards (20%); the noninjured players mainly jumped (64%), headed the ball (27%), or raised the elbow to the head (23%). Free ball situations (2 players challenge for the ball) caused most of the head injuries (81%). The players' action "raising the elbow" during a head injury seemed to be lower after the rule change.

CONCLUSIONS

Jumping for the ball with the intention of heading is the predominant action associated with head injury risk. Head injuries occur most often when players challenge for the ball in a header duel. As head injuries bear the potential risk of long-term health sequelae, the identification of situational circumstances is essential to develop preventative means in the future.

Determining Outcome in Children and Adolescents After Concussion: Viewing Things More Holistically

Pediatric and adolescent concussion is an increasingly high-profile public health issue, but it is also a highly heterogeneous phenomenon. Many factors interact dynamically to influence the recovery trajectory of adolescents and children. Diagnostic assessment must include domains other than self-reported symptoms, yet many prognostic models of outcome focus solely on the presence or absence of postconcussion symptoms to determine recovery. Function after concussion (recovery or persistence of problems) is the result of an interaction between biological, psychological, and social factors. Despite biopsychosocial models of assessment being advocated in rehabilitation for the last 20 years, they are still not routinely implemented in the evaluation of concussions, along the recovery trajectory, in children and adolescents. The International Classification of Functioning, Disability and Health is a framework anchored in a biopsychosocial perspective that can guide clinicians and researchers to include multiple perspectives in their assessments or research designs. By focusing on the patient as a person, researchers and clinicians can provide a more holistic approach that has the potential to contribute to a more successful and sustainable pediatric and adolescent concussion care model. J Orthop Sports Phys Ther 2019;49(11):855-863. Epub 9 Oct 2019. doi:10.2519/jospt.2019.8918.

Incidence and Risk of Concussions in Youth Athletes: Comparisons of Age, Sex, Concussion History, Sport, and Football Position

Objective

This study was designed to determine concussion incidence, risk, and relative risk among middle and high school athletes participating in various sports.

Method

Data were retrospectively obtained from 10,334 athletes of 12 different sports in Hawaii. In addition to determining the overall concussion incidence, comparisons of incidence, risk, and relative risk were made according to age, sex, concussion history, sport, and football position.

Results

The overall incidence of concussion among youth athletes was 1,250 (12.1%). The relative risk for a concussion was almost two times greater in 18-year olds than in 13-year-old athletes. In comparable sports, girls had a 1.5 times higher concussion risk than boys. Athletes with a prior concussion had 3-5 times greater risk to sustain a concussion than those with no history of a concussion. Among varied sports, wrestling and martial arts had the highest relative risk of a concussion, followed by cheerleading, football, and track and field. No differences in concussion risks were found among the football players in different positions.

Conclusions

Older youths, females, those with a history of concussion, and those participating in high contact sports were found to have higher risks of sustaining a concussion. The findings increase awareness of concussion patterns in young athletes and raise concerns regarding protective strategies and concussion management in youth sports.

Pediatric Traumatic Brain Injury and Associated Topics: An Overview of Abusive Head Trauma, Nonaccidental Trauma, and Sports Concussions

Pediatric traumatic brain injury (TBI) uniquely affects the pediatric population. Abusive head trauma (AHT) is a subset of severe pediatric TBI usually affecting children in the first year of life. AHT is a form of nonaccidental trauma. Sports-related TBI resulting in concussion is a milder form of TBI affecting older children. Current recommended perioperative management of AHT and sports concussions relies on general pediatric TBI guidelines. Research into more specific pediatric TBI screening and management goals is ongoing. This article reviews the epidemiology, mechanisms, clinical signs, and management of AHT and sports-related concussions.

The Lived Experiences of Retired Collegiate Athletes With a History of 1 or More Concussions

CONTEXT

  Concussions remain misunderstood, underreported, and undiagnosed. Although most concussion symptoms resolve within 2 weeks, some patients experience persistent symptoms that adversely affect physical, emotional, social, or cognitive functioning or a combination of these. Minimal evidence delineating the effect of concussions on recently retired collegiate athletes currently exists.

OBJECTIVE

  To examine the lived experiences of retired collegiate athletes with a history of 1 or more concussions to discern individual concussion histories, knowledge and perceptions of concussions, and postconcussion quality of life.

DESIGN

  Qualitative study.

SETTING

  Telephone interviews.

PATIENTS OR OTHER PARTICIPANTS

  Former National Collegiate Athletic Association Division I athletes (n = 14) with a history of 1 or more concussions and retired from 1 to 5 years.

DATA COLLECTION AND ANALYSIS

  Fourteen semistructured telephone interviews (8 men and 6 women) were audiotaped. Interviews were transcribed and inductively analyzed by 3 athletic trainers with 34 combined years of professional experience. Themes were negotiated through consensual review. Participant checks were completed to ensure trustworthiness of the findings.

RESULTS

  Participants sustained their first concussion during adolescence and often experienced difficulties transitioning back into the postconcussion academic environment. Judgments of injury severity were clearly evident in participants' knowledge and perceptions of concussions. Participants experienced an array of emotional, physical, cognitive, and social challenges during the immediate postconcussion period but did not feel their concussion history decreased their current quality of life.

CONCLUSIONS

  Adolescent exposure to concussions is of concern due to the risk imposed on the developing brain and the potential for adverse outcomes later in life. Although a graduated return to play is heavily emphasized in concussion management, researchers need to investigate barriers inhibiting the implementation of return-to-learn protocols. Concussion education should aim to modify indifferent attitudes toward concussive injuries. Additionally, investigators should continue to assess how a history of concussion affects quality of life in recently retired collegiate athletes.

Physiological underarousal as a mechanism of aggressive behavior in university athletes with a history of concussion

INTRODUCTION

Research has indicated that athletes who engage in high-risk athletic activities, such as football and hockey, have riskier personalities than their low-risk and nonathlete counterparts (Ahmadi et al., 2011, Procedia Soc Behav Sci, 30 and 247-251; Zuckerman, 1983, Biological bases of sensation seeking, impulsivity, and anxiety, Lawrence Erlbaum Assoc Inc.). For instance, increased sensation-seeking and aggression are common in high-risk athletes, rendering these individuals more likely to sustain a subsequent injury, such as concussion. Elevated levels of certain personality traits, including impulsivity and aggression, have also been observed after concussion (Goswami et al., 2016, Brain Struct Funct, 221 and 1911-1925). The purpose of this study therefore was to determine whether aggressive behavior in university athletes may be accounted for, in part, by a history of concussion, rather than exclusively athletic status.

METHODS

Using a quasi-experimental design, 66 university students (n = 18 nonathletes, n = 24 low-risk athletes, n = 24 high-risk athletes) with (n = 27) and without a history of concussion (n = 39) completed the Buss & Perry Aggression Questionnaire (BPAQ; Buss & Perry, , J Pers Soc Psychol, 63 and 452) and provided electrodermal activation (EDA) as an index of physiological arousal.

RESULTS

It was found that decreased physiological arousal among students with a history of concussion was associated with greater endorsement of physical aggression. Moreover, athletic status did not account for this pattern of aggression, as athletes and nonathletes did not differ in terms of self-reported aggressive tendencies.

CONCLUSIONS

Physiological compromise after concussive injury may act as an independent mechanism of aggressive behavior in athletes beyond factors, such as athletic status.

First-Time Sports-Related Concussion Recovery: The Role of Sex, Age, and Sport

Background

Concussion is one of the most common injuries in athletes. Current concussion consensus statements propose that female sex may be a modifying factor in concussion management and recovery.

Objective

To determine whether female athletes in middle school and high school with a first-time, sports-related concussion remained symptomatic longer than their male counterparts.

Methods

A retrospective medical record analysis was performed among athletes who sustained a concussion between 2011 and 2013. Inclusion criteria consisted of age between 11 and 18 years and diagnosis of first-time concussion sustained while playing organized sports. Using the documented notes in the medical record, length of time that each athlete was symptomatic from his or her concussion was calculated.

Results

A total of 110 male and 102 female athletes (N=212) met the eligibility criteria for the study. A significant difference was found in the median number of days female athletes remained symptomatic (28 days) when compared with male athletes (11 days) (P<.001). No statistically significant difference was found in symptom duration between age groups. When matched for sex, no statistically significant differences were found in symptom duration between the type of sports played.

Conclusion

Female athletes aged 11 to 18 years with first-time, sports-related concussions remained symptomatic for a longer period when compared with male athletes of similar age, regardless of sport played. The mechanism behind this difference needs to be further elucidated.

The relationship between concussion and alcohol consumption among university athletes

INTRODUCTION

This study investigated concussion as a potential risk factor for increased alcohol consumption in university athletes.

METHODS

Using a cross-sectional design, 41 university students (37% with a history of concussion) completed self-report measures, while electrodermal activation (EDA) was recorded for each participant to capture baseline physiological arousal.

RESULTS

As expected, concussion status significantly predicted alcohol consumption over and above athletic status, b = 0.34, p = 0.034, 95% CI [0.195, 4.832], such that those with a prior concussion history engaged in greater alcohol consumption. Importantly, concussion status also significantly predicted baseline physiological arousal, b = -0.39, p = 0.014, 95% CI [-0.979, -0.120], such that those with a history of concussion exhibited lower EDA.

CONCLUSIONS

Elevated alcohol consumption among athletes is a pronounced associate of concussion in sports and may be a behavioral reflection of disruption to the orbitofrontal cortex - an area implicated in inhibition.

Effects of the New York State Concussion Management and Awareness Act ("Lystedt Law") on Concussion-Related Emergency Health Care Utilization Among Adolescents, 2005-2015

BACKGROUND

All states have enacted legislation addressing the management of sports-related concussions (SRCs) in adolescent athletes. The effect of these laws on health care utilization is uncertain. Hypothesis/Purpose: The purpose was to evaluate the effects of New York's 2011 Concussion Management and Awareness Act ("Lystedt Law") on emergency department (ED) concussion health care visits (EDCHVs) and brain imaging utilization. It was hypothesized that New York concussion legislation would have a significant temporal effect on EDCHVs.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Using the New York State Department of Health Statewide Planning and Research Cooperative System (SPARCS) database, trends in EDCHVs from 2005 to 2015 were identified among 12- to 18-year-old patients, comprising 5,740,403 total ED visits.

RESULTS

Overall, 208,024 EDCHVs, including 54,669 for an SRC, occurred during the study period. EDCHVs increased from 13,664 (2.74% of all ED visits) in 2005 to a peak of 21,374 (4.26%) in 2013, with greatest relative increases from 2008 to 2013. SRCs followed a similar trend: 3213 (0.64%) in 2005 to a peak of 6197 (1.24%) in 2013. Brain imaging utilization decreased by 5.3% for EDCHVs and 15.4% for SRCs (all comparisons year-by-year and for trends; P < .001).

CONCLUSION

The period of greatest increases in EDCHVs and decreases in brain imaging utilization for SRCs preceded New York concussion legislation by several years, suggesting a minimal direct effect on emergency care-seeking behavior for concussions. Instead, increased public awareness of SRCs and imaging guidelines may have driven EDCHV trends and imaging practices.

Medical retirement from sport after concussions: A practical guide for a difficult discussion

Purpose of review

In patients with a considerable history of sports-related concussion, the decision of when to discontinue participation in sports due to medical concerns including neurologic disorders has potentially life-altering consequences, especially for young athletes, and merits a comprehensive evaluation involving nuanced discussion. Few resources exist to aid the sports medicine provider.

Recent findings

In this narrative review, we describe 10 prototypical vignettes based upon the authors' collective experience in concussion management and propose an algorithm to help clinicians navigate retirement discussions. Issues for consideration include absolute and relative contraindications to return to sport, ranging from clinical or radiographic evidence of lasting neurologic injury to prolonged concussion recovery periods or reduced injury threshold to patient-centered factors including personal identity through sport, financial motivations, and navigating uncertainty in the context of long-term risks.

Summary

The authors propose a novel treatment algorithm based on real patient cases to guide medical retirement decisions after concussion in sport.

Sport and Sex-Specific Reporting Trends in the Epidemiology of Concussions Sustained by High School Athletes

BACKGROUND

Approximately 300,000 U.S. adolescents sustain concussions annually while participating in organized athletics. This study aimed to track sex and sport-specific trends among high school sports-related concussions over time, to identify whether a particular sport predisposes athletes to a higher risk, and to assess whether traumatic brain injury law enactments have been successful in improving recognition.

METHODS

Injury data for academic years 2005 to 2014 were collected from annual reports generated by High School RIO (Reporting Information Online). The relative proportions of total estimated concussions to total estimated injuries were compared using an injury proportion ratio. The concussion rate was defined as the number of concussions per 10,000 athlete exposures (1 athlete participating in 1 practice or competition), with rates compared using a rate ratio. To evaluate the impact of legislation on sports-related concussions in this population, trends in concussion rates and proportions were analyzed before enactment (academic years 2005-2009) and after enactment (academic years 2010-2014).

RESULTS

Between 2005-2006 and 2014-2015, a significant increase (p < 0.0001) in the overall number of concussions for all sports combined, the overall concussion rate (rate ratio, 2.30 [95% confidence interval, 2.04 to 2.59]), and the overall proportion of concussions (injury proportion ratio, 2.68 [95% confidence interval, 2.66 to 2.70]) was seen. Based on the injury proportion ratio, during the 2014-2015 academic year, concussions were more common in girls' soccer than in any other sport (p < 0.0001).

CONCLUSIONS

Because of potentially devastating consequences, concussion prevention and recognition measures continue to be emphasized in high school contact sports. The data in our study suggest that significant increases in the overall rate and proportion of reported concussions during the past decade could have been affected by traumatic brain injury legislation. To our knowledge, this is the first study to show that girls' soccer players may have an even greater risk of sustaining a concussion than all other sports.

CLINICAL RELEVANCE

Sports-related concussions in adolescent athletes can have devastating consequences, and we now know that female athletes, especially girls' soccer players, may be at an even greater risk for sustaining this injury than all other athletes. Knowledge of the trends identified by this study may help lead to policy and prevention measures that can accommodate each sport effectively and potentially halt these trends.

Evaluation and management of sport-related concussions in adolescent athletes

Sport-related concussions in young athletes are common, generally under reported and often go unrecognized. Concussion in sport may result either from a direct impact to the head or from indirect forces transmitted to the brain from impact elsewhere on the body. Concussions may also result from sudden acceleration, deceleration or rotational forces to the brain. The key features of concussion include confusion, impaired memory and reduced speed of information processing. Recovery may occur from a few days to several weeks or months. Both physical and cognitive rests are recommended for recovery. Long-term cognitive and behavioral complications are a concern. Preventive strategies include education, modification of sport rules, use of equipment such as headgears, face masks and mouth guards, and neck muscle training. Evidence is limited to support effectiveness of these preventive measures with the exception of rule modification in some sports. Laws have been enacted that require medical evaluation and clearance prior to return to play; however, evidence thus far does not show that laws have been effective in reducing the incidence of concussions in sport. More research is needed in all areas of preventive measures. Sports participation is a complex personal decision on the part of adolescent and his or her family. They should be provided with all information on inherent risks so that they can make an informed decision.

Computerized neuropsychological test performance of youth football players at different positions: A comparison of high and low contact players

The aim of this study was to examine the effects of head impact frequency on the neuropsychological test results of football players who participate in different positions on the team. Based on the biomechanical measures of head impact frequency reported in high school football, a High Contact group (n = 480) consisting of offensive and defensive linemen was compared with a Low Contact group (n = 640) comprised of receivers and defensive backs. The results revealed that the High Contact group obtained poorer performances on the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) on three Composite scores (Verbal Memory, Visual Motor Speed, Impulse Control) and the Total Symptom score compared to the Low Contact group. The present study is the first, to date, to report differences in the neuropsychological test performances of athletes who participate in high and low contact football positions. The findings raise tentative concerns that youth football players exposed to repetitive head trauma, including subconcussive impacts, may be at risk for lowered neuropsychological functioning and increased symptoms.

Potential factors influencing recovery from concussion in collegiate student-athletes

Background

Factors including sex, previous diagnosis of migraines, previous diagnosis of Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder, and a history of concussion may influence the length of recovery from concussion in collegiate student-athletes.

Purpose

To better understand factors that may influence recovery from concussion in collegiate-student athletes.

Methods

A total of 91 student-athletes from a Division I NCAA University who sustained concussions from the fall of 2011 to the spring of 2015 were evaluated. They were considered recovered from their concussion when neurocognitive and symptom scores returned to baseline and they were cleared by their physician. Analyses of variance were conducted to determine if potential factors influenced concussion recovery ( p < .0125).

Results

No significant differences were found for sex (males = 7.4 ± 5.9; females = 8.3 ± 4.8 days; p = 0.417), previous diagnosis of migraines (diagnosis = 8.0 ± 5.7; no diagnosis = 7.8 ± 5.4 days; p = 0.926), or history of concussion (history = 8.3 ± 5.7; no history = 5.6 ± 3.4 days; p = 0.088). However, a significant difference in the length of recovery was found between those with a previous diagnosis of Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder and those without (diagnosis = 13.3 ± 7.3; no diagnosis = 7.3 ± 4.9 days; p = 0.002).

Conclusion

Student-athletes with Attention Deficit Disorder/Attention Deficit Hyperactivity Disorder show significantly longer recovery from concussions than those without. Further investigation of this and other factors that influence recovery from concussion may help in concussion recovery and return-to-play guidelines that improve student-athlete well-being.

Concussion in Ice Hockey-A Cohort Study Across 29 Seasons

OBJECTIVE

The aim of this study was to analyze the concussion incidence rate ratios across 29 seasons in a Swedish Hockey League team.

DESIGN

Cohort study over 29 seasons within one Swedish elite series ice hockey team.

PARTICIPANTS

All players who were part of one Swedish elite ice hockey team during the research period gave consent for participation in the study.

INDEPENDENT VARIABLES

Exposure to top-level Swedish ice hockey.

MAIN OUTCOME MEASURES

Incidence rate ratio for concussion and rehabilitation periods due to concussion were calculated and analyzed.

RESULTS

During the research period, 267 players in total were part of the team. A total of 1638 traumatic injuries were registered, of which 162 were concussions. Incidence rates (IRs) ranged from 0/1000 games during the first season to 118/1000 games for the final recorded season. The incidence rate ratio was 1.06 (confidence interval, 1.03-1.10) for the entire research period. A shift toward longer rehabilitation periods was discovered.

CONCLUSIONS

This study showed a significant increase of concussion IR and a trend toward longer rehabilitation periods due to concussion. Possible risk factors were discussed. Risk behavior and rehabilitation protocols should be prioritized areas in the research of concussion in ice hockey.

Effect of Exposure Type and Timing of Injuries in Division I College Football: A 4-year Single Program Analysis

BACKGROUND

Football players compete with a high risk of injury due to the sport. With the recent efforts to improve safety, the National Collegiate Athletic Association (NCAA) established new terminology to clearly define exposure types and reduce the number of high contact exposures.

OBJECTIVES

To compare football injury rates (IR) with a focus on game versus practice, time in season of injury, mechanism of injury and utilizing recent exposure types defined by the NCAA (live contact, full-pads and non-contact).

METHODS

Licensed medical professionals monitored a college football program regular season from 2012-2015. Each injury was classified by timing of the injury, mechanism of injury, and whether it occurred in game or practice. Player attendance and type of exposure (non-contact, full-pad or live contact, which involves live tackling to the ground and/or full-speed blocking and can occur in full-pad or half-pad ('shell') equipment) was documented. IR were calculated per 1000 athlete-exposures (AE). Mid-exact P tests compared rates between variables.

RESULTS

The game IR was over three times as high as the practice IR (p < .001). Live contact exposures had the greatest IR of 5.702/1000 AE and were seven times more likely to produce an injury compared to non-contact exposures (p < .001); whereas, live contact exposures were about two times more likely to produce an injury compared to full-pad exposures (p = .004). The majority of injuries observed occurred from a contact mechanism (IR: 2.508/1000 AE). The highest IR during the fall football season occurred in the pre-season at 5.769/1000 AE.

CONCLUSION

Overall IR observed in this cohort were lower than prior studies published before recent NCAA rule changes and guideline implementation to improve athlete safety. Athletes in this cohort were at significantly increased risk of injury from live contact exposures.

Stereotype contrast effect on neuropsychological assessment of contact-sport players: The moderating role of locus of control

INTRODUCTION

Diagnosis threat has been shown to produce detrimental effects on neuropsychological performance in individuals with mild traumatic brain injury (mTBI). Focusing on contact-sport players who are at great risk of mTBI, our study was designed to examine the moderating role of internal locus of control. Specifically, we predicted that following diagnosis threat (reminder of their risk of sustaining mTBI and of its consequences), low-internal contact-sport players would underperform (assimilation to the stereotype), while their high-internal counterparts would outperform (contrast effect). We predicted that effort and anxiety would mediate these effects.

METHOD

Contact-sport players and non-contact-sport players ("control" group) were randomly assigned to one condition (diagnosis threat or neutral) and then completed attention, executive, episodic memory, and working memory tasks. Regarding mediating and moderating variables, participants rated their effort and anxiety (self-report measures) and completed the Levenson (1974) locus of control scale. Regression-based path analyses were carried out to examine the direct and indirect effects.

RESULTS

As expected, there was no effect of condition on the control group's performance. Contact-sport players with moderate and high levels of internal control outperformed (contrast effect) on executive and episodic memory tasks following diagnosis threat compared to the neutral condition. Additionally, the less anxiety moderate- and high-internal contact-sport participants felt, the better they performed on episodic memory and executive tasks. However, contact-sport players low in internal control did not underperform (assimilation effect) under diagnosis threat.

CONCLUSIONS

Our results suggest that diagnosis threat instructions may have challenged moderate- and high-internal contact-sport participants, leading them to outperform compared to the neutral condition. Individuals who have moderate and high levels of internal locus of control may have higher performance under diagnosis threat compared to the neutral condition because of their feeling of control over their cognitive performance.

Executive dysfunction following a mild traumatic brain injury revealed in early adolescence with locomotor-cognitive dual-tasks

OBJECTIVE

To compare gait parameters between children in early adolescence (EA) with and without a mild traumatic brain injury (mTBI) during dual-task walking (DTW).

METHODS

Children in EA with mTBI (n = 14; six girls) were compared to those without (n = 13; five girls) while walking in different combinations of obstacle avoidance and cognitive dual-tasks. Gait speed and fluidity and their related dual-task costs (DTC) were analysed along with foot clearance and proximity to the obstacle.

RESULTS

No group effects were found for gait speed, proximity or clearance, but were found for fluidity DTC, specifically during the dual Stroop task and when crossing the deeper obstacle. There were also group differences for fluidity during the planning of obstacle avoidance for the narrow obstacle combined with the verbal fluency task and the deep obstacle with no cognitive task. Finally, gait fluidity showed group differences across unobstructed dual-task situations.

CONCLUSIONS

Gait fluidity may be a more sensitive variable than gait speed for revealing executive dysfunction following mTBI in EA. Assessing DTW in level walking also seems to show a potential to reveal executive dysfunctions in this age group. These results provide direction for future research on clinical assessment using DTW post-mTBI in adolescents.

Twitter Strategies for Web-Based Surveying: Descriptive Analysis From the International Concussion Study

Background

Social media provides researchers with an efficient means to reach and engage with a large and diverse audience. Twitter allows for the virtual social interaction among a network of users that enables researchers to recruit and administer surveys using snowball sampling. Although using Twitter to administer surveys for research is not new, strategies to improve response rates are yet to be reported.

Objective

To compare the potential and actual reach of 2 Twitter accounts that administered a Web-based concussion survey to rugby players and trainers using 2 distinct Twitter-targeting strategies. Furthermore, the study sought to determine the likelihood of receiving a retweet based on the time of the day and day of the week of posting.

Methods

A survey based on previous concussion research was exported to a Web-based survey website Survey Monkey. The survey comprised 2 questionnaires, one for players, and one for those involved in the game (eg, coaches and athletic trainers). The Web-based survey was administered using 2 existing Twitter accounts, with each account executing a distinct targeting strategy. A list of potential Twitter accounts to target was drawn up, together with a list of predesigned tweets. The list of accounts to target was divided into ‘High-Profile’ and ‘Low-Profile’, based on each accounts’ position to attract publicity with a high social interaction potential. The potential reach (number of followers of the targeted account), and actual reach (number of retweets received by each post) between the 2 strategies were compared. The number of retweets received by each account was further analyzed to understand when the most likely time of day, and day of the week, a retweet would be received.

Results

The number of retweets received by a Twitter account decreased by 72% when using the ‘high-profile strategy’ compared with the ‘low-profile strategy’ (incidence rate ratio (IRR); 0.28, 95% confidence interval (CI) 0.21-0.37, P<.001). When taking into account strategy and day of the week, the IRR for the number of retweets received during the hours of 12 AM to 5:59 AM (IRR 2.98, 95% CI 1.88-4.71, P>.001) and 6 PM to 11:59 PM (IRR 1.48, 95% CI 1.05-2.09, P>.05) were significantly increased relative to 6 AM to 11:59 AM. However, posting tweets during the hours of 12 PM to 5:59 PM, decreased the IRR for retweets by 40% (IRR 0.60, 95% CI 0.46-0.79, P<.001) compared with 6 AM to 11:59 AM. Posting on a Monday (IRR 3.57, 95% CI 2.50-5.09, P<.001) or Wednesday (IRR 1.50, 95% CI 1.11-1.11, P<.01) significantly increased the IRR compared with posting on a Thursday.

Conclusions

Surveys are a useful tool to measure the knowledge, attitudes, and behaviors of a given population. Strategies to improve Twitter engagement include targeting low-profile accounts, posting tweets in the morning (12 AM-11:59 AM) or late evenings (6 PM-11:59 PM), and posting on Mondays and Wednesdays.

The Controversial Second Impact Syndrome: A Review of the Literature

BACKGROUND

Second impact syndrome is a devastating injury that primarily affects athletic children and young adults. It occurs when a second concussion occurs before symptoms from the first concussion have resolved. Diffuse and often catastrophic cerebral edema results. Reports of second impact syndrome are few, and some argue that second impact syndrome is simply diffuse cerebral swelling unrelated to the first concussion.

METHODS

Ovid and PubMed were searched from years 1946 to 2015 using the terms "second impact syndrome," "repeat concussion," and "catastrophic brain injury." In addition, review articles were found using a combination of the terms, "concussion," "second impact syndrome," and "repetitive head trauma."

RESULTS

Seventeen patients in seven publications met the criteria of having two witnessed hits and persistent symptoms from the first to the second concussion. Ten of the 17 (59%) included individuals were football players. All were male. Ages ranged from 13 to 23 years. All children with poor outcomes (death or permanent disability) were younger than 20 years, while four of the five players with good outcomes were older than 19 years. The lag time from first to second concussion ranged from one hour to four weeks, and in many cases, at least one of the two hits appeared minor.

CONCLUSIONS

American football, male gender, and young age appear to be associated with second impact syndrome. Controversies surrounding this syndrome are discussed. There is a need for prospective studies to clarify risk factors and outcomes of second impact syndrome to guide return-to-play recommendations for young athletes.

Short and Long Term Behavioral and Pathological Changes in a Novel Rodent Model of Repetitive Mild Traumatic Brain Injury

A history of concussion, particularly repeated injury, has been linked to an increased risk for the development of neurodegenerative diseases, particularly chronic traumatic encephalopathy (CTE). CTE is characterized by abnormal accumulation of hyperphosphorylated tau and deficits in learning and memory. As yet the mechanisms associated with the development of CTE are unknown. Accordingly, the aim of the current study was to develop and characterize a novel model of repetitive mTBI that accurately reproduces the key short and long-term functional and histopathological features seen clinically. Forty male Sprague-Dawley rats were randomly assigned to receive 0, 1 or 3x mTBI spaced five days apart using a modified version of the Marmarou impact-acceleration diffuse-TBI model to deliver 110G of linear force. Functional outcomes were assessed six and twelve weeks post-injury, with histopathology assessed twenty-four hours and twelve weeks post-injury. Repetitive mTBI resulted in mild spatial and recognition memory deficits as reflected by increased escape latency on the Barnes maze and decreased time spent in the novel arm of the Y maze. There was a trend towards increased anxiety-like behavior, with decreased time spent in the inner portion of the open field. At 24 hours and 12 weeks post injury, repetitive mTBI animals showed increased tau phosphorylation and microglial activation within the cortex. Increases in APP immunoreactivity were observed in repetitive mTBI animals at 12 weeks indicating long-term changes in axonal integrity. This novel model of repetitive mTBI with its persistent cognitive deficits, neuroinflammation, axonal injury and tau hyperphosphorylation, thus represents a clinically relevant experimental approach to further explore the underlying pathogenesis of CTE.

Consistency of Self-Reported Concussion History in Adolescent Athletes

Relying on self-reported concussion injury history is common in both clinical care and research. However, young athletes may not provide consistent medical information. To date, little is known about the reliability of self-reported concussion history in high school students. This study examined whether student athletes reported their lifetime history of concussions consistently over time. Self-reported concussion history was examined in 4792 student athletes (ages 13-18) from Maine who completed a preseason health survey on two occasions (median re-test interval = 23.7 months; standard deviation = 7.3; interquartile range = 12.4-24.5). Consistency of self-reported concussion history was determined by differences in the number of concussions reported during the second survey. Inconsistent concussion history was defined primarily by a decrease in the number of lifetime concussions reported at the second testing, compared with at the first testing. The majority of the sample (80.3%) reported no change in the number of concussions between the two baseline assessments. A minority (15.9%; n = 763) reported more concussions during the second assessment. Only 3.8% (n = 181) of student athletes provided inconsistent concussion histories, defined as fewer concussions at the second assessment. Boys provided inconsistent concussion histories a little more frequently, compared with girls (5.3% and 2.0%, respectively; p < 0.001). Similarly, athletes with self-reported attention-deficit hyperactivity disorder (ADHD) provided inconsistent concussion histories somewhat more frequently, compared with those without ADHD (7.8% and 3.5%, respectively; p < 0.001). Of the athletes with inconsistent concussion histories, greater degree of inconsistency was associated with a greater number of concussions initially reported at baseline (r_s = 0.54; p < 0.001). Only a small proportion of student athletes provided inconsistent concussion histories. Male gender, ADHD, and greater number of baseline concussions were significantly associated with inconsistency in reporting. Overall, these findings suggest that student athletes are quite consistent when reporting their concussion history when surveyed twice during high school.

Priorities for injury prevention in women's Australian football: a compilation of national data from different sources

Background/aim

Participation in Australian football (AF) has traditionally been male dominated and current understanding of injury and priorities for prevention are based solely on reports of injuries in male players. There is evidence in other sports that indicates that injury types differ between males and females. With increasing participation in AF by females, it is important to consider their specific injury and prevention needs. This study aimed to provide a first injury profile from existing sources for female AF.

Methods

Compilation of injury data from four prospectively recorded data sets relating to female AF: (1) hospital admissions in Victoria, 2008/09–13/14, n=500 injuries; (2) emergency department (ED) presentations in Victoria, 2008/09–2012/13, n=1,879 injuries; (3) insurance claims across Australia 2004–2013, n=522 injuries; (4) West Australian Women's Football League (WAWFL), 2014 season club data, n=49 injuries. Descriptive results are presented as injury frequencies, injury types and injury to body parts.

Results

Hospital admissions and ED presentations were dominated by upper limb injuries, representing 47% and 51% of all injuries, respectively, primarily to the wrist/hand at 32% and 40%. Most (65%) insurance claim injuries involved the lower limb, 27% of which were for knee ligament damage. A high proportion of concussions (33%) were reported in the club-collected data.

Conclusions

The results provide the first compilation of existing data sets of women's AF injuries and highlight the need for a rigorous and systematic injury surveillance system to be instituted.