Evidence-Based review of sport-related concussion: clinical science

The 10-year decreasing trend of youth soccer head injuries and concussions presenting to U.S. emergency departments

OBJECTIVES

Nearly 3 million children participate in youth soccer annually in the United States. Popularity of youth soccer within recent years has prompted investigation describing youth-soccer concussion trends presenting to United States emergency departments (EDs).

METHODS

Data from National Electronic Injury Surveillance System were analyzed for soccer players 2-18 years old sustaining concussions from January 2013 to December 2022. Patient data included age, sex, mechanism of injury, setting (practice vs. game), diagnosis, loss of consciousness, and disposition. Raw data were used to calculate national estimates based on assigned statistical sample weight of each hospital.

RESULTS

A total of 80,582 youth soccer concussions were diagnosed in US EDs (51.0% female, 49.0% male). The most common mechanism of injury was head to ball (31.0%). On average, overall concussions decreased by 572 per year (p = 0.02). Head to body concussions decreased by 169 per year (p < 0.01) and head to ground concussions decreased by 155 per year (p < 0.01). No changes per year in concussion trends for head to ball, head to head, not specified, and other mechanisms. Exclusion of years 2020 and 2021 (COVID), demonstrated decreases in concussions for head to body by 125 (p = 0.01) and head to ground mechanisms by 135 per year (p = 0.01).

CONCLUSION

There is a decreasing trend in youth soccer head injuries and concussions presenting to US emergency departments from 2013 to 2022. The trends from this study indicate that heading may be the most important aspect of soccer-related concussions presenting to US emergency departments. This study contributes to the growing literature regarding concussions in youth soccer athletes.

Injuries and Overuse Syndromes in Rink Hockey Players

Rink Hockey is a high-speed low-contact sport with a widely recognized injury potential. Played with a hard ball by players wearing little or no protective gear, the rates of concussions and head injuries are of high interest. In this study, we reviewed and investigated injuries sustained by 108 German National League rink hockey players. We conducted an epidemiological cross-sectional study to determine sport-specific injuries and injury patterns in female and male rink hockey players. Data were collected by a standardized questionnaire. A total of 108 players participated in the study. The combined rate of injuries were 9.4/1000 athlete exposures. There was no significant difference between injury rates during games and practice. A sexspecific difference was not detected. Head injuries were the most frequent type (20.8 % of all injuries). Concussions made up 7 % of all head injuries with a rate of 0.76/1000 athlete exposure. Ball contact was the cause for 31 % of injuries, while player contact generated 26.2 % of all injuries. High rates of ball-contact-related injuries resulted in time loss and medical consultations. Head injuries were frequent, however did not result in significant time loss as compared to other injuries. The use of protective gear should be recommended.

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.

Epidemiology of Injuries in National Collegiate Athletic Association Women's Soccer: 2014-2015 Through 2018-2019

CONTEXT

The National Collegiate Athletic Association held the first women's soccer championship in 1982; sponsorship and participation have greatly increased since.

BACKGROUND

Routine examinations of athlete injuries are important for identifying emerging temporal patterns.

METHODS

Exposure and injury data collected in the National Collegiate Athletic Association Injury Surveillance Program during the 2014-2015 through 2018-2019 seasons were analyzed. Injury counts, rates, and proportions were used to describe injury characteristics, and injury rate ratios were used to examine differential injury rates.

RESULTS

The overall injury rate was 8.33 per 1000 athlete-exposures. Lateral ligament complex tears (ankle sprains) (8.6%), concussions (8.3%), and quadriceps tears (5.0%) were the most commonly reported injuries. Rates of lateral ligament complex tears followed an increasing trajectory during the study period, whereas quadriceps tear rates fluctuated during the early years, and concussion rates decreased then increased.

SUMMARY

The findings of this study were mostly consistent with existing evidence; notable temporal patterns were observed with regard to lateral ligament complex tears and concussions.

A Battery of Easily Accessible, Simple Tools for the Assessment of Concussion in Children

OBJECTIVE

To determine whether a non-proprietary, novel testing battery can identify recently concussed children within 8 weeks of injury.

STUDY DESIGN

In total, 568 clinic outpatients aged 10-18 years were sorted into 3 groups: 316 had never been concussed, 162 had ever been concussed before 8 weeks earlier, and 90 had been recently concussed within 8 weeks. At initial and any subsequent visits, a neurologic examination and 4 procedures were performed: Stick Drop, Wall Ball, Sharpened Modified Romberg (SMR), and Animal Naming. Analysis included inter-group and intra-person performance differences using a series of t tests on the Stick Drop, Wall Ball, SMR, and Animal Naming.

RESULTS

The recently concussed group performed worse (P < .01 for all) on Stick Drop, total Wall Ball bounces and drops, and SMR compared with never-concussed and ever-concussed groups. This effect for Stick Drop, SMR, and Wall Ball but not Animal Naming persisted beyond the 4 weeks commonly stated to define recovery. Of 59 recently concussed subjects who returned for ≥1 visit, there were improvements in Stick Drop average (P = .004) and maxima (P = .02) as well as SMR (P = .01) but not Animal Naming between initial and subsequent visits.

CONCLUSIONS

This novel, rapid testing battery distinguished groups of children ages 10-18 years who had and had not experienced a recent concussion. A view that physical concussion symptoms resolve within a month of injury may be incomplete. Deployment of this readily available, inexpensive and non-proprietary battery should be compared with other tools and studied further in serial assessments.

Injuries and Overuse Syndromes in Rink Hockey Players

Rink Hockey is a high-speed low-contact sport with a widely recognized injury potential. Played with a hard ball by players wearing little or no protective gear, the rates of concussions and head injuries are of high interest. In this study, we reviewed and investigated injuries sustained by 108 German National League rink hockey players. We conducted an epidemiological cross-sectional study to determine sport-specific injuries and injury patterns in female and male rink hockey players. Data were collected by a standardized questionnaire. A total of 108 players participated in the study. The combined rate of injuries were 9.4/1000 athlete exposures. There was no significant difference between injury rates during games and practice. A sex-specific difference was not detected. Head injuries were the most frequent type (20.8% of all injuries). Concussions made up 7% of all head injuries with a rate of 0.76/1000 athlete exposure. Ball contact was the cause for 31% of injuries, while player contact generated 26.2% of all injuries. High rates of ball-contact-related injuries resulted in time loss and medical consultations. Head injuries were frequent, however did not result in significant time loss as compared to other injuries. The use of protective gear should be recommended.

Women Are at Higher Risk for Concussions Due to Ball or Equipment Contact in Soccer and Lacrosse

BACKGROUND

There is ample evidence to suggest sex- and gender-based differences in the incidence of sports-related concussions. The mechanisms of concussion may vary between male and female athletes and contribute to this observed difference. Understanding the underlying etiology by pooling data from primary studies across different settings and sport types will inform interventions that can reduce concussion rates.

QUESTIONS/PURPOSES

Specifically, we asked: (1) In which sports are female athletes less likely to experience concussions from player contact? (2) In which sports are female athletes more likely to experience concussions because of ball or equipment contact?

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched to identify articles published from January 2000 to December 2018. Ten studies met the inclusion criteria, which were studies that reported concussion incidence by mechanism for both male and female athletes. Exclusion criteria included non-English studies, conference abstracts, and studies on non-sports related concussions. The sports represented by the 10 studies included ice hockey (n = 4), soccer (n = 5), basketball (n = 4), baseball/softball (n = 4), and lacrosse (n = 5). The rate ratio was calculated as the incidence rate in female athletes/male athletes for each concussion mechanism or activity. Data were pooled using the DerSimonian-Laird random-effects model. Study quality was assessed with the Newcastle-Ottawa Scale.

RESULTS

Female athletes were at lower risk of player-contact-induced concussions in lacrosse (pooled rate ratio 0.33 [95% CI 0.25 to 0.43]; p < 0.001), basketball (pooled rate ratio 0.86 [95% CI 0.76 to 0.97]; p = 0.01), ice hockey (pooled rate ratio 0.64 [95% CI 0.56 to 0.73]; p < 0.001), soccer (pooled rate ratio 0.70 [95% CI 0.66 to 0.75]; p < 0.001), and soccer heading (pooled rate ratio 0.80 [95% CI 0.72 to 0.90]; p < 0.001); in these sports, men were at higher risk of concussions from player contact. Female athletes were more likely to experience concussions because of ball or equipment contact in lacrosse (pooled rate ratio 3.24 [95% CI 2.10 to 4.99]; p < 0.001), soccer (pooled rate ratio 2.04 [95% CI 1.67 to 2.49]; p < 0.001), and soccer heading (pooled rate ratio 2.63 [95% CI 1.84 to 3.77]; p < 0.001).

CONCLUSIONS

The mechanism or activity underlying concussions differs between male and female athletes across different sports. This finding remains the same regardless of whether there are rule differences between the men's and women's games. The implementation of other interventions are required to further ensure player safety, including protective head equipment, concussion prevention training, or rules limiting player contact in the men's game.

LEVEL OF EVIDENCE

Level III, retrospective study.

Sport-Related Concussion in Children and Adolescents

Sport-related concussion is an important topic in nearly all sports and at all levels of sport for children and adolescents. Concussion knowledge and approaches to management have progressed since the American Academy of Pediatrics published its first clinical report on the subject in 2010. Concussion's definition, signs, and symptoms must be understood to diagnose it and rule out more severe intracranial injury. Pediatric health care providers should have a good understanding of diagnostic evaluation and initial management strategies. Effective management can aid recovery and potentially reduce the risk of long-term symptoms and complications. Because concussion symptoms often interfere with school, social life, family relationships, and athletics, a concussion may affect the emotional well-being of the injured athlete. Because every concussion has its own unique spectrum and severity of symptoms, individualized management is appropriate. The reduction, not necessarily elimination, of physical and cognitive activity is the mainstay of treatment. A full return to activity and/or sport is accomplished by using a stepwise program while evaluating for a return of symptoms. An understanding of prolonged symptoms and complications will help the pediatric health care provider know when to refer to a specialist. Additional research is needed in nearly all aspects of concussion in the young athlete. This report provides education on the current state of sport-related concussion knowledge, diagnosis, and management in children and adolescents.

Comparison of baseline and postconcussion SCAT3 scores and symptoms in varsity athletes: an investigation into differences by sex and history of concussion

OBJECTIVE

To investigate the use of the Sport Concussion Assessment Tool 3 (SCAT3) as an assessment tool in the varsity population, as well as the effects of sex and concussion history on both baseline and postconcussion scores.

METHODS

A comparison between baseline and postconcussion SCAT3 scores of varsity level athletes was conducted through retrospective chart review. Differences in both baseline and postconcussion scores were further analysed by sex and history of concussion.

RESULTS

The only clinically significant change on the SCAT3 elicited by a concussion was that of self-reported symptoms. There were no clinically significant differences based on sex or history of concussion.

CONCLUSION

The SCAT3 in its entirety may not be useful in this population. Additional research on sociocultural and sport aspects that may be affecting symptom reporting in this population is needed.

Game Schedules and Rate of Concussions in the National Football League

Background

Concussion prevention in the National Football League (NFL) is an important priority for player safety. The NFL now has modified game schedules, and one concern is that unconventional game schedules, such as a shortened rest period due to playing on a Thursday rather than during the weekend, may lead to an increased risk of injuries.

Hypothesis

Unconventional game schedules in the NFL are associated with an increased rate of concussion.

Study Design

Descriptive epidemiological study.

Methods

This study analyzed concussions and game schedules over the NFL regular seasons from 2012 to 2015 (4 years). Documented numbers of concussions, identified by use of the online database PBS Frontline Concussion Watch, were summarized by regular-season weeks. Association of days of rest and game location (home, away, or overseas) with the rate of concussion was examined by use of the χ² test. Logistic regression analysis was performed to examine the relationships of days of rest and home/away games to the risk of repeated concussions, with adjustment for player position.

Results

A total of 582 concussions were analyzed in this study. A significantly greater number of concussions occurred in the second half of the season (P < .01). No significant association was found between the rate of concussion and the days of rest, game location, or timing of the bye week by the team or the opponent (P > .05). Game schedules were not significantly associated with the occurrence of repeat concussions (P > .05).

Conclusion

Unconventional game schedules in the NFL, including playing on Thursday and playing overseas, do not seem to put players at increased risk of concussions.

Multifactorial examination of sex-differences in head injuries and concussions among collegiate soccer players: NCAA ISS, 2004-2009

Background

While head injuries and concussions are major concerns among soccer players, the multifactorial nature of head injury observations in this group remains relatively undefined. We aim to extend previous analyses and examine sex-differences in the incidence of head injuries, odds of head injuries within an injured sample, and severity of head injuries, among collegiate soccer players between 2004 and 2009.

Methods

Data collected within the National Collegiate Athletic Association (NCAA) Injury Surveillance System (ISS) between the years of 2004 and 2009, were analyzed in this study. Unadjusted rate ratios (RR), compared incidence rates between categories of sex, injury mechanism, setting and competition level. We also examined sex-differences in head injury incidence rates, across categories of the other covariates. Multivariable logistic regression and negative binomial regression modeling tested the relation between sex and head injury corollaries, while controlling for contact, setting, and competition level.

Results

Between 2004 and 2009, head injuries accounted for approximately 11% of all soccer-related injuries reported within the NCAA-ISS. The rate of head injuries among women was higher than among men (RR = 1.23, 95% CI = [1.08, 1.41]). The rate of head injuries due to player-to-player contact was comparable between women and men (RR = 0.95, 95% CI = [0.81, 1.11]). Whereas, the rate of injury due to contact with apparatus (ball/goal) was nearly 2.5 times higher (RR = 2.46, 95% CI = [1.76, 3.44]) and the rate due to contact with a playing surface was over two times higher (RR = 2.29, 95% CI = [1.34, 3.91]) in women than in men. In our multifactorial models, we also observed that the association between sex and head injury corollaries varied by injury mechanism.

Conclusions

Sex-differences in the incidence, odds (given an injury), and severity (concussion diagnosis, time-loss) of head injuries varied by injury mechanism (player-to-player contact vs. all other mechanisms) in this sample.

Somatization in Post-Concussion Syndrome: A Retrospective Study

This is a retrospective study of concussion patient data conducted to analyze the prevalence of somatization in patients presenting with post-concussion symptoms. Patient records from June 2010 to December 2015 were examined for concussion history, psychosocial history, neuropsychological test results, validity scores, and a symptom severity scale. Records meeting inclusion criteria from 33 males and 27 females were located. The sample had an age range of 11–78 years with a mean age of 33.40 (SD +/- 7.5 years). A clinically significant number of patients (55%) were found to be somaticizing their symptoms and a significant majority (78%) of somaticizing patients reported no loss of consciousness, retrograde amnesia, or post-traumatic amnesia but their symptom validity scales were significantly exaggerated. Caution should be exercised by clinicians to ensure that the obtained results of neuropsychological testing are reliable and valid. It is very important for the clinician to take into account the entire patient history, including psychosocial factors (such as pre-existing psychological traits or conditions) and social influences (such as stressors in family dynamics or work/school activities that may be affecting the patient's complaints).

Concussion in Hockey: Compliance with Return to Play Advice and Follow-up Status

Objectives:

To determine the compliance rate among hockey players with concussion or other head injuries who were advised by a physician about return to play. To assess compliance of hockey players with return to play advice and to assess the incidence of long-term post-concussion symptoms.

Methods:

A retrospective chart review, telephone questionnaire and follow-up analysis of income, level of education and professional aspirations. The study examined 40 hockey players with concussion or other head injury treated at a neurosurgical ambulatory clinic, who had initial visits between 1995 and 2003, and had been seen at least two years prior to completing the questionnaire.

Results:

There was a 58% (23 of 40) participation rate in the study. Fifteen (65%) of the 23 participants were advised to never return to play, and 5 (33%) were non-compliant and returned to play. Four (80%) of the five non-compliant players continued to suffer from post concussion symptoms. Overall, 15 (65%) of the 23 players participating in the study continued to suffer post concussion symptoms at least two years after the clinic visit.

Conclusions:

Five (33%) of 15 hockey players advised to never return to play were non-compliant and returned to play, and four continued to suffer from post concussion symptoms two or more years later. After repeated concussions, 65% of hockey players had long-term sequelae that prevented return to play and produced long-term post-concussion symptoms.

Cognitive Rehabilitation After Traumatic Brain Injury: A Reference for Occupational Therapists

Nearly 1.7 million Americans sustain a traumatic brain injury (TBI) each year. These injuries can result in physical, emotional, and cognitive consequences. While many individuals receive cognitive rehabilitation from occupational therapists (OTs), the interdisciplinary nature of TBI research makes it difficult to remain up-to-date on relevant findings. We conducted a literature review to identify and summarize interdisciplinary evidence-based practice targeting cognitive rehabilitation for civilian adults with TBI. Our review summarizes TBI background, and our cognitive remediation section focuses on the findings from 37 recent (since 2006) empirical articles directly related to cognitive rehabilitation for individuals (i.e., excluding special populations such as veterans or athletes). This manuscript is offered as a tool for OTs engaged in cognitive rehabilitation and as a means to highlight arenas where more empirical, interdisciplinary research is needed.

A systematic review of the biomarker S100B: implications for sport-related concussion management

OBJECTIVE

Elevated levels of the astroglial protein S100B have been shown to predict sport-related concussion. However, S100B levels within an athlete can vary depending on the type of physical activity (PA) engaged in and the methodologic approach used to measure them. Thus, appropriate reference values in the diagnosis of concussed athletes remain undefined. The purpose of our systematic literature review was to provide an overview of the current literature examining S100B measurement in the context of PA. The overall goal is to improve the use of the biomarker S100B in the context of sport-related concussion management.

DATA SOURCES

PubMed, SciVerse Scopus, SPORTDiscus, CINAHL, and Cochrane.

STUDY SELECTION

We selected articles that contained (1) research studies focusing exclusively on humans in which (2) either PA was used as an intervention or the test participants or athletes were involved in PA and (3) S100B was measured as a dependent variable.

DATA EXTRACTION

We identified 24 articles. Study variations included the mode of PA used as an intervention, sample types, sample-processing procedures, and analytic techniques.

DATA SYNTHESIS

Given the nonuniformity of the analytical methods used and the data samples collected, as well as differences in the types of PA investigated, we were not able to determine a single consistent reference value of S100B in the context of PA. Thus, a clear distinction between a concussed athlete and a healthy athlete based solely on the existing S100B cutoff value of 0.1 μg/L remains unclear. However, because of its high sensitivity and excellent negative predictive value, S100B measurement seems to have the potential to be a diagnostic adjunct for concussion in sports settings. We recommend that the interpretation of S100B values be based on congruent study designs to ensure measurement reliability and validity.

High School Athletes' Perceptions of Concussion

BACKGROUND

The perception high school athletes have regarding concussions may influence their injury-reporting behavior, and if their perceptions are based on incorrect or incomplete information, they may be at risk for subsequent head injuries.

PURPOSE

To determine whether the recent influx of concussion information has had a positive impact on high school athletes' knowledge of concussions, to determine their perceptions regarding the severity of a concussion injury, and to determine whether receiving correct information will potentially alter their future reporting behavior.

STUDY DESIGN

Cross-sectional study; Level of evidence, 4.

METHODS

A total of 454 high school athletes (212 females, 242 males; mean age, 15.7 ± 1.15 years) from 6 different schools participated in an anonymous survey. The researchers met with teams individually at their high schools to collect data and provide an educational intervention regarding sports-related concussions. The survey questions assessed the athletes' personal injury histories and perceptions and knowledge of the severity of concussion injuries.

RESULTS

There was a difference in the number of athletes who reported having their "bell rung" (n = 297) versus the number of athletes reporting at least 1 concussion (n = 172) (t (453) = -11.60, P = .000, d = -0.54). There was also a difference in the number of athletes who reported a history of at least 1 concussion at the beginning of the study session (n = 172) versus the number of athletes who reported at least 1 concussion at the end of the session (n = 292) (t (453) = -12.018, P = .000, d = 0.732). Fifty percent of athletes also stated that the importance of a game/event should dictate when they return to play.

CONCLUSION

High school athletes continue to fail to realize when they have sustained a concussion. Additionally, athletes lack understanding regarding the severity and seriousness of a concussion. A better effort at formalized education must be made if the culture of sports is to change.

CLINICAL RELEVANCE

Allied health care professionals need to continue to put forth a great effort in educating all student athletes on what a concussion is and the dangers of a concussion injury. Preseason meetings should be used as an opportunity to provide formalized education to all student athletes.

Effect of education and language on baseline concussion screening tests in professional baseball players

OBJECTIVE

The purpose of the present study was to investigate the possible effects of sociocultural influences, specifically pertaining to language and education, on baseline neuropsychological concussion testing as obtained via immediate postconcussion assessment and cognitive testing (ImPACT) of players from a professional baseball team.

DESIGN

A retrospective chart review.

SETTING

Baseline testing of a professional baseball organization.

PARTICIPANTS

Four hundred five professional baseball players.

INDEPENDENT VARIABLES

Age, languages spoken, hometown country location (United States/Canada vs overseas), and years of education.

MAIN OUTCOME MEASURES

The 5 ImPACT composite scores (verbal memory, visual memory, visual motor speed, reaction time, impulse control) and ImPACT total symptom score from the initial baseline testing.

RESULTS

The result of t tests revealed significant differences (P < 0.05) when comparing native English to native Spanish speakers in many scores. Even when corrected for education, the significant differences (P < 0.05) remained in some scores.

CONCLUSIONS

Sociocultural differences may result in differences in computer-based neuropsychological testing scores.

Translating Guidelines for the Diagnosis and Management of Sports-Related Concussion Into Practice

Sports injuries are a significant clinical and public health concern. There is a growing call to improve the translation of available evidence-based and expert-informed sports injury prevention interventions into sustained use in practice by physicians and others (eg, athletic trainers, coaches, and parents) who care for injured athletes. This article provides a brief overview of the current sport injury prevention implementation literature before focusing specifically on the translation of guidelines (including consensus and position statements) developed to assist physicians and others diagnose and manage athletes with sport-related concussion and the associated return-to-play decisions. The outcomes of more than 20 published studies indicate that physician, athletic trainer, coach, parent, and athlete knowledge, use of, and compliance with sport-related concussion guidelines are limited. More concerted, coordinated, and theory-informed efforts are required to facilitate the widespread dissemination, translation, and implementation of such guidelines. An example is provided of how implementation drivers could be used to inform the development of a comprehensive, multilevel implementation strategy targeting the individual, organizational, and system-level changes necessary to support the translation of available sport-related concussion guidelines in both the clinical and sports settings.

Predicting mild traumatic brain injury patients at risk of persistent symptoms in the Emergency Department

OBJECTIVE

To identify factors that can predict which emergency department (ED) patients with mTBI are likely to develop persistent post-concussion symptoms (PPCS).

DESIGN

A matched case-control study was conducted at a Level 1 trauma centre between June 2006 and July 2009. Patients diagnosed with mTBI in the ED and diagnosed at a concussion management programme with at least one PPCS (85 cases) were compared to patients diagnosed with mTBI in the ED (340 controls) to determine if factors assessed at the time of ED presentation could predict patients likely to develop persistent symptoms.

RESULTS

Multivariable hierarchical logistic regression with variables indicating increased risk for PPCS (prior mTBI, history of depression, history of anxiety, multiple injury, forgetfulness/poor memory, noise sensitivity, or light sensitivity) resulted in a final predictive model including prior mTBI, history of anxiety, forgetfulness/poor memory and light sensitivity. The final model had a specificity of 87.9% and a sensitivity of 69.9%.

CONCLUSIONS

A strong prediction model to identify those ED patients with mTBI at risk for PPCS was developed and could be easily implemented in the ED; therefore, helping to target those patients who would potentially benefit from close follow-up.

Trends in concussion return-to-play timelines among high school athletes from 2007 through 2009

CONTEXT

Whereas guidelines about return-to-play (RTP) after concussion have been published, actual prognoses remain elusive.

OBJECTIVE

To develop probability estimates for time until RTP after sport-related concussion.

DESIGN

Descriptive epidemiology study.

SETTING

High school.

PATIENTS OR OTHER PARTICIPANTS

Injured high school varsity, junior varsity, or freshman athletes who participated in 1 of 13 interscholastic sports at 7 area high schools during the 2007-2009 academic years.

INTERVENTION(S)

Athletic trainers employed at each school collected concussion data. The athletic trainer or physician on site determined the presence of a concussion. Athlete-exposures for practices and games also were captured.

MAIN OUTCOME MEASURE(S)

Documented concussions were categorized by time missed from participation using severity outcome intervals (same-day return, 1- to 2-day return, 3- to 6-day return, 7- to 9-day return, 10- to 21-day return, >21-day return, no return [censored data]). We calculated Kaplan-Meier time-to-event probabilities that included censored data to determine the probability of RTP at each of these time intervals.

RESULTS

A total of 81 new concussions were documented in 478 775 athlete-exposures during the study period. After a new concussion, the probability of RTP (95% confidence interval) was 2.5% (95% confidence interval = 0.3, 6.9) for a 1- to 2-day return, 71.3% (95% confidence interval = 59.0, 82.9) for a 7- to 9-day return, and 88.8% (95% confidence interval = 72.0, 97.2) for a 10- to 21-day return.

CONCLUSIONS

For high school athletes, RTP within the first 2 days after concussion was unlikely. After 1 week, the probability of return rose substantially (approximately 71%). Prognostic indicators are used to educate patients about the likely course of disease. Whereas individual symptoms and recovery times vary, prognostic time-to-event probabilities allow clinicians to provide coaches, parents, and athletes with a prediction of the likelihood of RTP within certain timeframes after a concussion.

Sex-specific differences in the severity of symptoms and recovery rate following sports-related concussion in young athletes

INTRODUCTION

While research on adult recovery from concussion indicates sex-specific symptoms and recovery rates, there is little existing data on younger patient populations.

OBJECTIVE

To determine sex-specific differences in the severity of presenting symptoms and recovery rate between groups of young athletes who presented ≤ 7 or > 7 days after sports-related concussion.

METHODS

This study was a retrospective review of athletes aged 9 to 17 years who were referred for evaluation of a sports-related concussion over a 24-month period. The study groups were divided by sex and post-injury presentation to the clinic at ≤ 7 days and > 7 days from the date of injury. Athletes with learning disabilities were excluded from the study and data analysis. Age, height, and weight were recorded for each subject. Each subject also reported their initial degree of confusion, amnesia, or loss of consciousness, and whether a helmet was worn when the injury was sustained. A 22-item post-concussion symptom score (SS) scale was completed by both groups on initial assessment (SS1) and follow-up visit (SS2). The recovery rate (SSR) was calculated as (SS2-SS1)/days between SS2 and SS1. Sex and group comparisons for SS1 and SSR were performed using 2 × 2 analysis of variance. A similar analysis was also performed for effects of sex on SS1 and SSR in patients who were not wearing a helmet.

RESULTS

Thirty-seven athletes aged 15.0 ± 1.9 years were evaluated. Males, regardless of day of presentation, had a lower SS1 evaluation than females (15.8 vs 30.9; P < 0.05). Males without helmets did not differ from females without helmets, but this was not significantly different (14.1 vs 29.6; P = 0.1). There was not a significant difference in SS1 evaluation between the groups who presented at ≤ 7 or > 7 days. The overall mean SSR was -1.2/day, with no significant difference seen between groups or sex. There were no significant differences in degree of loss of consciousness, amnesia, confusion, or age between the sexes or groups.

CONCLUSION

Whether presenting at ≤ 7 or > 7 days following a sports-related concussion, female athletes reported a higher SS1 evaluation. With SSR being similar between sexes, the current data suggest that young, female athletes may take longer to become symptom free following sports-related concussion. This information may be an important factor in returning a young athlete to sport after sports-related concussion.

Differential rates of recovery after acute sport-related concussion: electrophysiologic, symptomatic, and neurocognitive indices

PURPOSE

To determine if motor evoked potentials (MEPs), postconcussion signs and symptoms, and neurocognitive functions follow a similar recovery pattern after concussion.

METHODS

Nine collegiate athletes with acute concussion (>24 hours after injury) participated in this retrospective time series design. Transcranial magnetic stimulation was applied over the motor cortex, and MEPs were recorded from the contralateral upper extremity. Self-reported symptoms were evaluated using the Head Injury Scale, and the Concussion Resolution Index was used to assess neurocognitive function. All measures were repeated on days 3, 5, and 10 after injury.

RESULTS

Composite scores on the Head Injury Scale were significantly higher on day 1 after injury (F3,51 = 15.3; P = 0.0001). Processing speed on the Concussion Resolution Index was slower on days 1, 3, and 5 compared with that on day 10 (F3,24 = 6.75; P = 0.0002). Median MEP latencies were significantly longer on day 10 compared with day 1 after concussion (t8 = -2.69; P = 0.03). Ulnar MEP amplitudes were significantly smaller on day 3 after concussion compared with day 5 (t8 = -3.48; P = 0.008).

CONCLUSIONS

Acutely concussed collegiate athletes demonstrate changes in MEPs, which persist for up to 10 days after injury and do not follow the same recovery pattern as symptoms and neuropsychological test performance. The apparent differential rates of recovery most likely indicate different pathophysiological processes occurring in the immediate postconcussion period.

Rehabilitation of Concussion and Post-concussion Syndrome

CONTEXT

Prolonged symptoms after concussion are called post-concussion syndrome (PCS), which is a controversial disorder with a wide differential diagnosis.

EVIDENCE ACQUISITION

MEDLINE and PubMed searches were conducted for the years 1966 to 2011 using the search terms brain concussion/complications OR brain concussion/diagnosis OR brain concussion/therapy AND sports OR athletic injuries. Secondary search terms included post-concussion syndrome, trauma, symptoms, metabolic, sports medicine, cognitive behavioral therapy, treatment and rehabilitation. Additional articles were identified from the bibliographies of recent reviews.

RESULTS

Of 564 studies that fulfilled preliminary search criteria, 119 focused on the diagnosis, pathophysiology, and treatment/rehabilitation of concussion and PCS and formed the basis of this review. Rest is the primary treatment for the acute symptoms of concussion. Ongoing symptoms are either a prolonged version of the concussion pathophysiology or a manifestation of other processes, such as cervical injury, migraine headaches, depression, chronic pain, vestibular dysfunction, visual dysfunction, or some combination of conditions. The pathophysiology of ongoing symptoms from the original concussion injury may reflect multiple causes: anatomic, neurometabolic, and physiologic.

CONCLUSIONS

Treatment approaches depend on the clinician's ability to differentiate among the various conditions associated with PCS. Early education, cognitive behavioral therapy, and aerobic exercise therapy have shown efficacy in certain patients but have limitations of study design. An algorithm is presented to aid clinicians in the evaluation and treatment of concussion and PCS and in the return-to-activity decision.

Concussions in soccer: a current understanding

OBJECTIVE

Traumatic brain injury (TBI) is a significant public health problem in the United States, with approximately 1.5-2 million TBIs occurring each year. However, it is believed that these figures underestimate the true toll of TBI. Soccer is the most popular sport in the world and has a following of millions in the United States. Soccer is a sport not traditionally identified as high-risk for concussions, yet several studies have shown that concussion rates in soccer are comparable to, and often exceed those of, other contact sports. As many as 22% of all soccer injuries are concussions.

METHODS

Soccer is a sport not traditionally identified as high risk for concussions, yet several studies have shown that concussion rates in soccer are comparable to, and often exceed those of, other contact sports. As many as 22% of all soccer injuries are concussions. Head injury during soccer is usually the result of either "direct contact" or contact with the ball while "heading" the ball. Relationships between the number of headers sustained in a single season and the degree of cognitive impairment (attention and visual/verbal memory) have been demonstrated. It is also likely that multiple concussions may cause cumulative neuropsychologic impairment in soccer players.

RESULTS

Although our understanding of risk factors for sports-related concussions is far from complete, there is great potential for prevention in sports-related concussions. Several measures must be taken to avert the development of concussions in soccer and, when they take place, reduce their effects. These include the development and testing of effective equipment during play, the maintenance of regulatory standards for all such equipment, educating young athletes on the safe and appropriate techniques used during play, and strict adherence to the rules of competition.

CONCLUSIONS

In spite of such preventive measures, concussions in soccer will continue to occur. Considering the frequency of concussions in soccer, the serious sequelae of these concussions, and because almost half of concussed soccer players were noncompliant with recommended American Academy of Neurology return-to-play guidelines, further measures must be taken to protect players, in addition to understanding those criteria that result in removing an injured player from competition and the steps by which to safely return an athlete to competition after injury.

Trauma and impaired consciousness

This article discusses brain trauma and impaired consciousness. It reviews the various states of impaired consciousness related to trauma, with an historical and current literature viewpoint. The causes and pathophysiology of impaired consciousness in concussion, diffuse axonal injury, and focal brain lesions are discussed and management options evaluated.

Sport-related concussions: knowledge translation among minor hockey coaches

OBJECTIVE

The objective of this study was to investigate minor hockey coaches' knowledge base of sport-related concussions.

DESIGN

Cross-sectional survey.

SETTING

Subjects independently completed the written survey at preseason organizational meetings.

PARTICIPANTS

One hundred seventy-eight active coaches spanning 5 age levels (ages 5-15 years). Coaches reported 2.62 ± 3.73 years of coaching experience.

MAIN OUTCOME MEASURES

Resources where coaches obtained information about concussions, perceptions of variables associated with concussions, knowledge level of issues associated with concussions, and decision-making practices.

RESULTS

Newspapers and magazines were the most frequent source of information regarding concussions, yet were rated as not very helpful. Family physicians were less frequently sought but were rated as most helpful. A majority of coaches reported limited knowledge about concussions but rated this knowledge as being important. There was a significant relationship between head coaching experience and concussion knowledge [R = 0.09, F3,156 = 4.41, P = 0.005]. Most coaches demonstrated a good knowledge base of common issues associated with concussions, and a majority of individuals correctly identified return-to-play practices.

CONCLUSIONS

A majority of minor hockey coaches correctly recognized and understood issues related to sport-related concussions. Results suggested that knowledge translation through various formal and informal sources has had a positive effect. However, a majority of coaches reported having limited knowledge about concussions yet consider it an important topic.

Can a clinical test of reaction time predict a functional head-protective response?

PURPOSE

Reaction time is commonly prolonged after a sport-related concussion. Besides being a marker for injury, a rapid reaction time is necessary for protective maneuvers that can reduce the frequency and severity of additional head impacts. The purpose of this study was to determine whether a clinical test of simple visuomotor reaction time predicted the time taken to raise the hands to protect the head from a rapidly approaching ball.

METHODS

Twenty-six healthy adult participants recruited from campus and community recreation and exercise facilities completed two experimental protocols during a single session: a manual visuomotor simple reaction time test (RT(clin)) and a sport-related head-protective response (RT(sprt)). RT(clin) measured the time required to catch a thin vertically oriented device on its release by the tester and was calculated from the distance the device fell before being arrested. RT(sprt) measured the time required to raise the hands from waist level to block a foam tennis ball fired toward the subject's face from an air cannon and was determined using an optoelectronic camera system. A correlation coefficient was calculated between RT(clin) and RT(sprt), with linear regression used to assess for effect modification by other covariates.

RESULTS

A strong positive correlation was found between RT(clin) and RT(sprt) (r = 0.725, P < 0.001) independent of age, gender, height, or weight.

CONCLUSIONS

RT(clin) is predictive of a functional sport-related head-protective response. To our knowledge, this is the first demonstration of a clinical test predicting the ability to protect the head in a simulated sport environment. This correlation with a functional head-protective response is a relevant consideration for the potential use of RT(clin) as part of a multifaceted concussion assessment program.

Cerebrovascular pathophysiology following mild traumatic brain injury

Mild traumatic brain injury (mTBI) or sport-induced concussion has recently become a prominent concern not only in the athletic setting (i.e. sports venue) but also in the general population. The majority of research to date has aimed at understanding the neurological and neuropsychological outcomes of injury as well as return-to-play guidelines. Remaining relatively unexamined has been the pathophysiological aspect of mTBI. Recent technological advances including transcranial Doppler ultrasound and near infrared spectroscopy have allowed researchers to examine the systemic effects of mTBI from rest to exercise, and during both asymptomatic and symptomatic conditions. In this review, we focus on the current research available from both human and experimental (animal) studies surrounding the pathophysiology of mTBI. First, the quest for a unified definition of mTBI, its historical development and implications for future research is discussed. Finally, the impact of mTBI on the control and regulation of cerebral blood flow, cerebrovascular reactivity, cerebral oxygenation and neuroautonomic cardiovascular regulation, all of which may be compromised with mTBI, is discussed.

American Academy of Pediatrics. Clinical report--sport-related concussion in children and adolescents

Sport-related concussion is a "hot topic" in the media and in medicine. It is a common injury that is likely underreported by pediatric and adolescent athletes. Football has the highest incidence of concussion, but girls have higher concussion rates than boys do in similar sports. A clear understanding of the definition, signs, and symptoms of concussion is necessary to recognize it and rule out more severe intracranial injury. Concussion can cause symptoms that interfere with school, social and family relationships, and participation in sports. Recognition and education are paramount, because although proper equipment, sport technique, and adherence to rules of the sport may decrease the incidence or severity of concussions, nothing has been shown to prevent them. Appropriate management is essential for reducing the risk of long-term symptoms and complications. Cognitive and physical rest is the mainstay of management after diagnosis, and neuropsychological testing is a helpful tool in the management of concussion. Return to sport should be accomplished by using a progressive exercise program while evaluating for any return of signs or symptoms. This report serves as a basis for understanding the diagnosis and management of concussion in children and adolescent athletes.

A preliminary investigation of motor evoked potential abnormalities following sport-related concussion

BACKGROUND

Assessment of concussion is primarily based on self-reported symptoms, neurological examination and neuropsychological testing. The neurophysiologic sequelae and the integrity of the corticomotor pathways could be obtained by evaluating motor evoked potentials (MEPs).

OBJECTIVES

To compare MEPs obtained through transcranial magnetic stimulation (TMS) in acutely concussed and non-concussed collegiate athletes.

METHODS

Eighteen collegiate athletes (12 males, six females, aged 20.4 +/- 1.3 years) including nine subjects with acute concussion (<or=24 hours) matched to nine control subjects. TMS was applied over the motor cortex and MEP responses were recorded from the contralateral upper extremity. MEP thresholds (%), latencies (milliseconds per metre) and amplitudes were assessed. Central motor conduction time (CMCT) was calculated from MEP, M response and F wave latencies. Testing was performed on days 1, 3, 5 and 10 post-concussion.

RESULTS

Ulnar MEP amplitudes were significantly different between post-concussion days 3 and 5 (F(3,48) = 3.13, p = 0.041) with smaller amplitudes recorded on day 3 (0.28 +/- 0.10 ms m(-1)). Median MEP latencies were significantly longer (F(3,48) = 4.53, p = 0.023) 10 days post-concussion (27.1 +/- 1.4 ms m(-1)) compared to day 1 (25.7 +/- 1.5 ms m(-1)). No significant differences for motor thresholds or CMCTs were observed (p > 0.05).

CONCLUSION

MEP abnormalities among acutely concussed collegiate athletes provide direct electrophysiologic evidence for the immediate effects of concussion.

Emotional response to sport concussion compared to ACL injury

PRIMARY OBJECTIVES

To ascertain and compare the nature of emotional response of athletes to concussion and to anterior cruciate ligament (ACL) injury.

RESEARCH DESIGN

Pre-injury, post-injury and longitudinal emotional functioning of athletes with concussion (n = 16), athletes with ACL injuries (n = 7) and uninjured athletes (n = 28) were compared in a prospective repeated-measures design.

METHODS AND PROCEDURES

Participants completed the short version of the Profile of Mood States (POMS). ANOVAs and trend analysis were used to examine between and within group differences across time on two sub-scales, Total Mood Disturbance and Depression.

MAIN OUTCOMES AND RESULTS

Athletes with ACL injury reported higher levels of depression for a longer duration than athletes with concussion. Relative to un-injured controls, athletes with concussion reported significant changes in Total Mood Disturbance and Depression post-injury, whereas athletes with ACL injuries reported significant changes in Depression scores only. Different patterns of post-injury emotional disturbance for the injured groups were observed by trend analyses.

CONCLUSIONS

Concussed athletes do not report as much emotional disturbance as athletes with ACL injuries. Differential patterns of emotional disturbance were detected between injured groups. The authors recommended that clinical protocols and educational programmes address emotional sequelae associated with sport concussion and ACL injury.

Incidence, risk, and protective factors of mild traumatic brain injury in a cohort of Australian nonprofessional male rugby players

BACKGROUND

Mild traumatic brain injury (mTBI) is an emerging public health issue in high-contact sports. Understanding the incidence along with the risk and protective factors of mTBI in high-contact sports such as rugby is paramount if appropriate preventive strategies are to be developed.

PURPOSE

To estimate the incidence and identify the risk and protective factors of mTBI in Australian nonprofessional rugby players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A cohort of 3207 male nonprofessional rugby players from Sydney, Australia, was recruited and followed over 1 or more playing seasons. Demographic information, history of recent concussion, and information on risk and protective factors were collected. The incidence of mTBI was estimated and the putative risk and protective factors were modeled in relation to mTBI.

RESULTS

The incidence of mTBI was 7.97 per 1000 player game hours, with 313 players (9.8%) sustaining 1 or more mTBIs during the study. Players who reported always wearing protective headgear during games were at a reduced risk (incident rate ratio [IRR], 0.57; 95% confidence interval [CI], 0.40-0.82) of sustaining an mTBI. In contrast, the likelihood of mTBI was almost 2 times higher among players who reported having sustained either 1 (IRR, 1.75; 95% CI, 1.11-2.76) or more mTBIs (IRR, 1.65; 95% CI, 1.11-2.45) within the 12 months before recruitment.

CONCLUSION

Nonprofessional rugby has a high incidence of mTBI, with the absence of headgear and a recent history of mTBI associated with an increased risk of subsequent mTBI. These findings highlight that both use of headgear and the management of prior concussion would likely be beneficial in reducing the likelihood of mTBI among nonprofessional rugby players, who compose more than 99% of rugby union players in Australia.

Playing soccer increases serum concentrations of the biochemical markers of brain damage S-100B and neuron-specific enolase in elite players: a pilot study

PRIMARY OBJECTIVE

To analyse serum concentrations of two biochemical markers of brain tissue damage, S-100B and NSE (neurone-specific enolase), in male soccer players in connection to the game.

METHODS

Blood samples were taken in players before and after a competitive game and the numbers of headers and of trauma events during soccer play were assessed.

RESULTS

Both S-100B and NSE were significantly raised in serum samples obtained after the game in comparison with the pre-game values (S-100B: 0.118 +/- 0.040 microg L(-1) vs 0.066 +/- 0.025 microg L(-1), p < 0.001; NSE: 10.29 +/- 2.16 microg L(-1) vs 8.57 +/- 2.31 microg L(-1), p < 0.001). Only changes in S-100B concentrations (post-game minus pre-game values) were statistically significantly correlated to the number of headers (r = 0.428, p = 0.02) and to the number of other trauma events (r = 0.453, p = 0.02).

CONCLUSION

Playing competitive elite soccer was found to cause increase in serum concentrations of S-100B and NSE. Increases in S-100B were significantly correlated to the number of headers, and heading may accordingly have contributed to these increases.

What are the real risks of sport-related concussion, and are they modifiable?

Over the past two decades, the management of sport-related concussion has been the topic of increased attention in the scientific literature and in the popular media. Despite a proliferation of competing guidelines for concussion management, the widespread use of neuropsychological "baseline" testing designed to monitor postinjury recovery, and several prospective controlled studies of the natural history of concussion, there has been virtually no attempt to quantify the risks associated with sport-related concussion or to determine whether these risks are modifiable via management strategies. Using American football as a model, the short- and long-term risks of sport-related concussion are reviewed. It is concluded that serious short-term consequences of sport-related concussion are extremely rare and unlikely to be significantly modified via management strategies that rely on baseline testing. Other less serious short-term adverse outcomes are also quite rare, transient, and not likely to be altered by specific management guidelines. The long-term consequences of multiple sport-related head trauma remain unclear but are potentially of greater public health concern and should be the focus of increased research. Based on available evidence, there is little rationale for the use of rigid strategies or guidelines in the place of individual clinical decision-making in the management of these injuries.

A prospective study of postconcussive outcomes after return to play in Australian football

BACKGROUND

Decisions regarding safe return to play after concussion in sport remain difficult.

OBJECTIVE

To determine whether a concussed player returned to play using an individual clinical management strategy is at risk of impaired performance or increased risk of injury or concussion.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All elite Australian football players were followed for 4 seasons. Players were recruited into the study after sustaining a concussive injury. Outcome measures included performance statistics (disposals per hour match-time), injury rates, and recurrence of concussion on return to play. A subset of players had brief screening cognitive tests performed at baseline and after their concussion. Noninjured players matched for team, position, age, and size were chosen as controls.

RESULTS

A total of 199 concussive injuries were observed in 158 players. Sixty-one concussive injuries were excluded from analysis because of incomplete data (45 players) or presence of concurrent injury (16 players). Of the 138 concussive injuries assessed, 127 players returned to play without missing a game (92%). The remainder of concussed players returned to play after missing a single game (8%). Overall, there was no significant decline in disposal rates in concussed players on return to competition. Furthermore, there were no significant differences in injury rates between concussed and team, position, and game-matched controls. In the subset of players who had completed screening cognitive tests, all had returned to their individual baseline performance before being returned to play.

CONCLUSION

Return to play decisions based on individual clinical assessment of recovery allows safe and appropriate return to sport following a concussive injury.

Sport-related concussion

Sport-related concussion is a common injury in children and adolescents. Athletes seldom report concussive symptoms, which makes the diagnosis a challenge. The management of sport-related concussion has changed significantly over the last several years. The previously used grading systems and return-to-play guidelines have been abandoned in favor of more individualized assessment and management. Neuropsychological testing is being used more frequently to assist in management. After recovery, it is recommended that an athlete's return-to-play progress in a gradual, stepwise fashion while being monitored by a health care provider. Proper assessment and management of a sport-related concussion is crucial, because repeat concussions can result in decreased neurocognitive functioning, increased symptomatology, and, at times, catastrophic outcomes.