Risk Factors For Concussion Research Articles

A cohort study to identify and evaluate concussion risk factors across multiple injury settings: findings from the CARE Consortium

BackgroundConcussion, or mild traumatic brain injury, is a major public health concern affecting 42 million individuals globally each year. However, little is known regarding concussion risk factors across all concussion settings as most concussion research has focused on only sport-related or military-related concussive injuries.MethodsThe current study is part of the Concussion, Assessment, Research, and Education (CARE) Consortium, a multi-site investigation on the natural history of concussion. Cadets at three participating service academies completed annual baseline assessments, which included demographics, medical history, and concussion history, along with the Sport Concussion Assessment Tool (SCAT) symptom checklist and Brief Symptom Inventory (BSI-18). Clinical and research staff recorded the date and injury setting at time of concussion. Generalized mixed models estimated concussion risk with service academy as a random effect. Since concussion was a rare event, the odds ratios were assumed to approximate relative risk.ResultsBeginning in 2014, 10,604 (n = 2421, 22.83% female) cadets enrolled over 3 years. A total of 738 (6.96%) cadets experienced a concussion, 301 (2.84%) concussed cadets were female. Female sex and previous concussion were the most consistent estimators of concussion risk across all concussion settings. Compared to males, females had 2.02 (95% CI: 1.70–2.40) times the risk of a concussion regardless of injury setting, and greater relative risk when the concussion occurred during sport (Odds Ratio (OR): 1.38 95% CI: 1.07–1.78). Previous concussion was associated with 1.98 (95% CI: 1.65–2.37) times increased risk for any incident concussion, and the magnitude was relatively stable across all concussion settings (OR: 1.73 to 2.01). Freshman status was also associated with increased overall concussion risk, but was driven by increased risk for academy training-related concussions (OR: 8.17 95% CI: 5.87–11.37). Medical history of headaches in the past 3 months, diagnosed ADD/ADHD, and BSI-18 Somatization symptoms increased overall concussion risk.ConclusionsVarious demographic and medical history factors are associated with increased concussion risk. While certain factors (e.g. sex and previous concussion) are consistently associated with increased concussion risk, regardless of concussion injury setting, other factors significantly influence concussion risk within specific injury settings. Further research is required to determine whether these risk factors may aid in concussion risk reduction or prevention.

Premorbid migraine history as a risk factor for vestibular and oculomotor baseline concussion assessment in pediatric athletes.

Migraine history has recently been identified as a risk factor for concussion and recovery. The authors performed a cross-sectional study examining baseline outcome measures on newly developed and implemented concussion assessment tools in pediatrics. The purpose of this study was to examine the effects of premorbid, diagnosed migraine headaches as a risk factor on vestibular and oculomotor baseline assessment in pediatric athletes. Pediatric athletes between the ages of 8 and 14 years with a diagnosed history of migraine headache (n = 28) and matched controls without a history of diagnosed migraine headache (n = 28) were administered a baseline concussion assessment battery, consisting of the Vestibular/Ocular Motor Screening (VOMS), near point of convergence (NPC), and the King-Devick (K-D) tests. Between-groups comparisons were performed for vestibular symptoms and provocation scores on the VOMS (smooth pursuit, saccades, convergence, vestibular/ocular reflex, visual motion sensitivity), NPC (average distance), and K-D (time). Individuals diagnosed with migraine headaches reported greater VOMS smooth pursuit scores (p = 0.02), convergence scores (p = 0.04), vestibular ocular reflex scores (p value range 0.002-0.04), and visual motion sensitivity scores (p = 0.009). Differences were also observed on K-D oculomotor performance with worse times in those diagnosed with migraine headache (p = 0.02). No differences were reported on NPC distance (p = 0.06) or headache symptom reporting (p = 0.07) prior to the VOMS assessment. Pediatric athletes diagnosed with migraine headaches reported higher baseline symptom provocation scores on the VOMS. Athletes with migraine headaches also performed worse on the K-D test, further illustrating the influence of premorbid migraine headaches as a risk factor for elevated concussion assessment outcomes at baseline. Special consideration may be warranted for post-concussion assessment in athletes with migraine headaches.

The changing nature of concussion in rugby union: Looking back to look forward

Introduction Concussion is regularly observed in rugby union and has generated a growing public health concern, yet remains one of the least understood injuries facing the sports medicine community. Evidence suggests that multiple concussions may increase susceptibility to long-term neurological complications that present decades after the initial injury for reasons that remain unclear. We aimed to determine the incidence rate and risk factors for concussion amongst community-level rugby union-15s players active during the 1980s given that it may help to better understand the risks and mechanisms of injury. Methods Injury data were collected from clubs by the coach at the time of injury in players using a 15-item questionnaire (1982–1984). Results Seventy games were recorded throughout 1982–1983 and 1983–1984 rugby union seasons. Forty-two documented concussions accounted for ∼6% of injuries corresponding to an incidence rate of 0.64 per 1000 playing hours, more than a third lower than the ‘modern-day’ equivalent. Tackling (relative risk 1.60, p < 0.05), collisions (relative risk 0.95, p < 0.05) and gum shield use (relative risk 1.69, p < 0.05) were independently associated with concussion whereas no associations were observed for ground condition, quarter of play or players playing out of position ( p > 0.05). Conclusion Despite limitations due to the retrospective focus and reliance on questionnaire data notwithstanding raised awareness of concussion, the incidence rate of concussion during the 1980s appears to be appreciably lower compared to the present-day game. This is the likely outcome of improvements in the clinical understanding of concussion, data collection tools, reporting methods and clinical management of concussive injuries, including changes to both player and game. However, the findings of this study help better understand the risks and mechanisms of injury once encountered by rugby union players active during the 1980s, of which some of those risks are still apparent.

What the research says about concussion risk factors and prevention strategies for youth sports: A scoping review of six commonly played sports

Introduction: Given the growing research on potential adverse outcomes related to concussion and other serious brain injuries and the increased susceptibility for concussion among youth athletes, primary prevention is vital to protect the health and safety of this population. The purpose of this study is to summarize the current research on risk factors and primary concussion prevention strategies focused on specific youth sports, and to identify research gaps. Methods: A literature search was conducted using six electronic databases. A scoping review method was used to identify studies that addressed risk factors or primary concussion prevention strategies focused on youth athletes (ages 5–18 years) in six sports (football, ice hockey, soccer, lacrosse, basketball, and wrestling). Results: Of the 18 publications identified, the publications focused on risk factors (N = 11), policy (N = 1), rule changes (N = 3), education (N = 2), equipment (N = 2), and playing technique (N = 0). Some articles had information related to multiple topics. Conclusions: Current research on concussion prevention has primarily been focused on risk factors. There are a dearth of studies that examine primary concussion prevention in sports. When studies do exist, most focus on football and ice hockey. Only a small number of studies focus solely on risk factors or primary prevention in soccer, lacrosse, basketball, and wrestling—all sports in which concussions are common. Practical applications: This scoping review summarizes current research on concussion risk factors and primary prevention strategies in specific sports focused on youth athletes and identifies research gaps to help inform future efforts.

Risk factors associated with injury and concussion in sanctioned amateur and professional mixed martial arts bouts in Calgary, Alberta

BackgroundThere is limited literature that examines risk factors for injury and mild traumatic brain injury (mTBI) in mixed martial arts (MMA). An examination of previously unstudied bout and athlete characteristics...

Reliability of a Novel Technique for the Measurement of Neck Strength

Reliable assessment of neck strength is required to fully understand the role of decreased neck strength as a risk factor for concussion. The purpose of this study was to assess the intrarater and interrater reliability of a standardized isometric neck-strength-testing protocol using a custom-designed frame, and a digital force gauge. Assessment of intrarater and interrater reliability of a custom neck-strength-testing frame and protocol yielded intraclass correlation values > .890 and > .900 when using maximum peak and average peak values of neck strength, respectively. Our neck-strength-testing frame and protocol provided data of good to excellent reliability, and may be used in future studies to investigate the relationship between neck strength and incidence of injuries.

Attention problems as a risk factor for concussion in youth ice-hockey players

ObjectiveTo examine attention problems in youth ice-hockey players as a risk factor for concussion.DesignSecondary analysis of two prospective cohort studies.SettingIce-rinks and Sport Medicine Centres in two Canadian cities over three ice-hockey seasons (2011/12, 2012/13, 2014/15).Assessment of risk factorsSelf-report of formal diagnosis of attention or learning disorders were collected on previously validated preseason baseline questionnaires by all participating players. Parents and players completed the Behaviour Assessment System for Children (BASC-2), which includes inattention and hyperactivity scales.Participants2,364 Canadian ice-hockey players (11–17 years old, 87% male).Outcome measuresA previously validated prospective injury surveillance system was used. All suspected concussions were referred to the study physician for confirmation of diagnosis. Concussion risk ratios (RR) were estimated, including stratification by known risk factors.ResultsOne-hundred ninety-two of 2,215 players (9%) self-reported attention and/or learning disorders at baseline. Overall, 256 players (11%) sustained one or more concussions during a season. Players identified as “at-risk” for attention-deficit hyperactivity disorder (ADHD), based on BASC-2 T-scores (inattention and/or hyperactivity scale) greater than 60, had a greater risk of concussion during the season based on child report [RR=1.51 (95% CI 1.13–2.04)] and parent report [2.97 (95% CI 1.65–5.34)]. In players with no history of previous concussion, the RR based on child report was 1.88 (95% CI 1.22–2.90) and based on parent report was 5.03 (95% CI 2.45–10.29).ConclusionsIce-hockey players identified as “at-risk” for ADHD on the basis of baseline BASC-2 scores are at a greater risk of concussion.Competing interestsNone.

Mining standardized neurological signs and symptoms data for concussion identification.

The Centers for Disease Control estimate that 1.6 to 3.8 million concussions occur in sports and recreational activities annually. Studies have shown that concussions increase the risk of future injuries and mild cognitive disorders. Despite extensive research on sports related concussion risk factors, the factors which are most predictive of concussion outcome and recovery time course remain unknown. In order to overcome the issue of physician bias and to identify the factors which can best predict concussion diagnosis, we propose a multi-variate logistic regression based analysis. We demonstrate our results on a dataset with 126 subjects (ages 12-31). Our results indicate that among 322 features, our model selected 27-29 features which included a history of playing sports, history of a previous concussion, drowsiness, nausea, trouble focusing as measured by a common symptom list, and oculomotor function. The features picked using our model were found to be highly predictive of concussions and gave a prediction performance accuracy greater than 90%, Matthews correlation coefficient greater than 0.8 and the area under the curve greater than 0.95.

Genetics and Other Risk Factors for Past Concussions in Active-Duty Soldiers.

Risk factors for concussion in active-duty military service members are poorly understood. The present study examined the association between self-reported concussion history and genetics (apolipoprotein E [APOE], brain-derived neurotrophic factor [BDNF], and D2 dopamine receptor genes [DRD2]), trait personality measures (impulsive-sensation seeking and trait aggression-hostility), and current alcohol use. The sample included 458 soldiers who were preparing to deploy for Operation Iraqi Freedom/Operation Enduring Freedom. For those with the BDNF Met/Met genotype, 57.9% (11/19) had a history of one or more prior concussions, compared with 35.6% (154/432) of those with other BDNF genotypes (p = 0.049, odds ratio [OR] = 2.48). APOE and DRD2 genotypes were not associated with risk for past concussions. Those with the BDNF Met/Met genotype also reported greater aggression and hostility personality characteristics. When combined in a predictive model, prior military deployments, being male, and having the BDNF Met/Met genotype were independently associated with increased lifetime history of concussions in active-duty soldiers. Replication in larger independent samples is necessary to have more confidence in both the positive and negative genetic associations reported in this study.

Risk Factors for Concussion in Collegiate NCAA Division II Men's and Women's Soccer Athletes

Risk Factors for Concussion in Collegiate NCAA Division II Men's and Women's Soccer Athletes

Head and Neck Circumference Not Risk Factors For Game Concussions Among Youth American Football Players

Neck to head circumference ratio (NHR) has been reported as a potential risk factor for concussion (CONC) among high school athletes. Research examining anthropometrics and neck (NC) and head (HC) circumferences and NHR in youth football is limited. PURPOSE: To examine the relationship between player anthropometrics and CONC injury rates (IR) among youth football players. METHODS: 1212 male youth football players (11.9±1.2 years) with 2.6±1.9 years experience participating in a large metropolitan youth football league were followed prospectively throughout 3 seasons (2012-2014). Height (HT, cm); weight (WT, kg); and NC and HC, cm; data were collected pre-season. CONC injury information, including mechanism of injury (MOI, for games was tracked each season by the leagues certified athletic trainer (AT) using an electronic medical record-keeping system. At each event, ATs collected injury and athlete-exposure (AE) data. CONC injury frequencies and rates with 95% confidence intervals (CI) were calculated based on 1000 AE. Descriptive statistics characterized anthropometrics and CONC. Binary logistic regression with forward step-wise elimination examined relationships between anthropometric characteristics (HT, WT, BMI, HC, NC, NHR) and the incidence of CONC (p≤0.05). RESULTS: Participants (n=1068) mean anthropometrics’: 157.4cm, 49.8kg, and 21.8.kg/m2. The mean NC, HC and HNR ratio (n=951): 32.2cm, 52.07cm, and 0.53, respectively. 71 of 1212 participants (5.9%) were diagnosed with a CONC. CONC IR for games for all 3 seasons was 5.65 /1000 AE (95%CI: 4.34 -6.97). Majority CONC occurred during the 2nd half of play (n=52, 73.3%) as a result of helmet-to-helmet (31, 43.7%), and head-to-ground (n=15, 21.1%) collisions. Binary logistic regression identified no significant predictors of concussion 2(1, N=854)=94%, p = .92. CONCLUSIONS: Incidence of CONC was similar to those previously reported in same age group of youth football players. While anthropometrics, NC, HC and NHR and BMI did not predict CONC, future research should examine these factors as well as neck strength as potential predictors of CONC. Research should also examine if the high incidence of CONC during the 2nd half of game play is related with other modifiable risk factors. Supported by Potomac Health Foundation.

Concussion Incidence in Professional Football

Background:In the United States alone, millions of athletes participate in sports with potential for head injury each year. Although poorly understood, possible long-term neurological consequences of repetitive sports-related concussions have received increased recognition and attention in recent years. A better understanding of the risk factors for concussion remains a public health priority. Despite the attention focused on mild traumatic brain injury (mTBI) in football, gaps remain in the understanding of the optimal methodology to determine concussion incidence and position-specific risk factors.Purpose:To calculate the rates of concussion in professional football players using established and novel metrics on a group and position-specific basis.Study Design:Case-control study; Level of evidence, 3.Methods:Athletes from the 2012-2013 and 2013-2014 National Football League (NFL) seasons were included in this analysis of publicly available data. Concussion incidence rates were analyzed using established (athlete exposure [AE], game position [GP]) and novel (position play [PP]) metrics cumulatively, by game unit and position type (offensive skill players and linemen, defensive skill players and linemen), and by position.Results:In 480 games, there were 292 concussions, resulting in 0.61 concussions per game (95% CI, 0.54-0.68), 6.61 concussions per 1000 AEs (95% CI, 5.85-7.37), 1.38 concussions per 100 GPs (95% CI, 1.22-1.54), and 0.17 concussions per 1000 PPs (95% CI, 0.15-0.19). Depending on the method of calculation, the relative order of at-risk positions changed. In addition, using the PP metric, offensive skill players had a significantly greater rate of concussion than offensive linemen, defensive skill players, and defensive linemen (P < .05).Conclusion:For this study period, concussion incidence by position and unit varied depending on which metric was used. Compared with AE and GP, the PP metric found that the relative risk of concussion for offensive skill players was significantly greater than other position types. The strengths and limitations of various concussion incidence metrics need further evaluation.Clinical Relevance:A better understanding of the relative risks of the different positions/units is needed to help athletes, team personnel, and medical staff make optimal player safety decisions and enhance rules and equipment.

A Conclusion for Most CEOs: Your Corporation Should Not Pay Dividends

<h3>Objective:</h3> To examine the ethical and legal issues physicians face when evaluating and managing athletes with sports-related concussions, and to offer guidance to physicians as they navigate these situations. <h3>Results:</h3> This position paper reviews and compares the components of sports-related concussion laws, including education, removal from play, and clearance for return to play. It highlights the challenges privacy laws present relevant to providing care to concussed athletes and suggests ways to help physicians overcome these obstacles. The report also explores the ethical considerations physicians should bear in mind as they evaluate and manage concussed athletes, addressing them through a framework that includes considerations of professionalism, informed decision-making, patient autonomy, beneficence, nonmaleficence, conflicts of interest, and distributive justice. <h3>Conclusions:</h3> Physicians caring for concussed athletes have an ethical obligation to ensure that their primary responsibility is to safeguard the current and future physical and mental health of their patients. Physicians have a duty to provide athletes and their parents with information about concussion risk factors, symptoms, and the risks for postconcussion neurologic impairments. Physicians should facilitate informed and shared decision-making among athletes, parents, and medical teams while protecting athletes from potential harm. Additionally, including concussion evaluation and management training in neurology residency programs, as well as developing a national concussion registry, will benefit patients by the development of policies and clinical guidelines that optimize prevention and treatment of concussive head injury.

Frequency of head-impact-related outcomes by position in NCAA division I collegiate football players.

Concussions and subconcussive impacts sustained in American football have been associated with short- and long-term neurological impairment, but differences in head impact outcomes across playing positions are not well understood. The American Medical Society for Sports Medicine has identified playing position as a key risk factor for concussion in football and one for which additional research is needed. This study examined variation in head impact outcomes across primary football playing positions in a group of 730 National Collegiate Athletic Association Division I Football Championship Series athletes, using a self-report questionnaire. Although there were no significant differences between position groups in the number of diagnosed concussions during the 2012 football season, there were significant differences between groups in undiagnosed concussions (p=0.008) and "dings" (p<0.001); offensive linemen reported significantly higher numbers than most other positions. Significant differences were found between position groups in the frequencies of several postimpact symptoms, including dizziness (p<0.001), headache (p<0.001), and seeing stars (p<0.001) during the 2012 football season, with offensive linemen reporting significantly more symptoms compared to most other groups. There were also positional differences in frequency of returning to play while symptomatic (p<0.001) and frequency of participating in full-contact practice (p<0.001). Offensive linemen reported having returned to play while experiencing symptoms more frequently and participating in more full-contact practices than other groups. These findings suggest that offensive linemen, a position group that experiences frequent, but low-magnitude, head impacts, develop more postimpact symptoms than other playing positions, but do not report these symptoms as a concussion.

Concussion risk factors and strategies for prevention.

Concussion in children is frequently related to participation in sports. It requires a traumatic event to occur that transmits acceleration to the brain. Some children may have intrinsic risk factors that place them at greater risk for this type of injury. Comorbidities such as attention-deficit/hyperactivity disorder, migraine headaches, and mood disorders may place athletes at increased risk of more severe injury. A previous concussion is probably the most important influence on risk for future injury. Extrinsic risk factors include coaching techniques, officiating, and choice of sport. Helmet choice does not diminish concussion risk, nor does the use of mouth guards. Education of athletes, coaches, parents, and physicians is very important in improving recognition of potential concussive injury and helping child athletes and their parents understand the risks involved in sport participation.

Legal and ethical implications in the evaluation and management of sports-related concussion.

To examine the ethical and legal issues physicians face when evaluating and managing athletes with sports-related concussions, and to offer guidance to physicians as they navigate these situations. This position paper reviews and compares the components of sports-related concussion laws, including education, removal from play, and clearance for return to play. It highlights the challenges privacy laws present relevant to providing care to concussed athletes and suggests ways to help physicians overcome these obstacles. The report also explores the ethical considerations physicians should bear in mind as they evaluate and manage concussed athletes, addressing them through a framework that includes considerations of professionalism, informed decision-making, patient autonomy, beneficence, nonmaleficence, conflicts of interest, and distributive justice. Physicians caring for concussed athletes have an ethical obligation to ensure that their primary responsibility is to safeguard the current and future physical and mental health of their patients. Physicians have a duty to provide athletes and their parents with information about concussion risk factors, symptoms, and the risks for postconcussion neurologic impairments. Physicians should facilitate informed and shared decision-making among athletes, parents, and medical teams while protecting athletes from potential harm. Additionally, including concussion evaluation and management training in neurology residency programs, as well as developing a national concussion registry, will benefit patients by the development of policies and clinical guidelines that optimize prevention and treatment of concussive head injury.

ARE CLINICAL MEASURES OF CERVICAL SPINE STRENGTH AND CERVICAL FLEXOR ENDURANCE RISK FACTORS FOR CONCUSSION IN ELITE YOUTH ICE HOCKEY PLAYERS?

BackgroundSymptoms of dizziness, neck pain and headaches have previously been identified as risk factors for concussion. Clinical measures associated with these symptoms have not previously been evaluated as risk factors...

DO RISK FACTORS DIFFER FOR CONCUSSION AND PROLONGED RECOVERY FOLLOWING CONCUSSION IN ELITE YOUTH ICE HOCKEY PLAYERS?

BackgroundPediatric concussion risk factor identification will facilitate targeted injury prevention strategy development.ObjectiveTo examine risk factors for concussion and prolonged recovery amongst elite youth ice hockey players.DesignCohort study.SettingCommunity ice rinks and...

Sports Concussion Management: part II.

Millions of concussions occur every year in the United States. The public interest in concussion has increased after a number of high-profile deaths in high school athletes from sports-related head trauma and in some professional athletes from chronic traumatic encephalopathy. One of the most active areas of research in sports medicine during the last decade has been the evaluation and management of concussion. In this second article of a two-part series, we provide an overview of the latest scientific advances in concussion research. This overview includes an update on the pathobiological changes that occur during concussion and the results of biomechanical studies. In addition, to aid the practicing clinician, we review the literature on proven and currently studied concussion risk factors, including a history of concussion, fatigue, and age. Genetic polymorphisms and biomarkers may provide risk-prediction capability, but at present the research remains inconclusive. Diffusion tensor imaging and functional magnetic resonance imaging are promising technologies that reveal more sophisticated data about the impact of concussion on the brain. We review the existing literature on the application of these neuroimaging modalities to sports concussion. An update from the Fourth International Conference on Concussion in Sport, with highlights of new recommendations, and the presentation of the third edition of the Sports Concussion Assessment Tool to evaluate acute concussion, concludes our review.

Effect of Neck Muscle Strength and Anticipatory Cervical Muscle Activation on the Kinematic Response of the Head to Impulsive Loads

Background: Greater neck strength and activating the neck muscles to brace for impact are both thought to reduce an athlete’s risk of concussion during a collision by attenuating the head’s kinematic response after impact. However, the literature reporting the neck’s role in controlling postimpact head kinematics is mixed. Furthermore, these relationships have not been examined in the coronal or transverse planes or in pediatric athletes. Hypotheses: In each anatomic plane, peak linear velocity (ΔV) and peak angular velocity (Δω) of the head are inversely related to maximal isometric cervical muscle strength in the opposing direction (H1). Under impulsive loading, ΔV and Δω will be decreased during anticipatory cervical muscle activation compared with the baseline state (H2). Study Design: Descriptive laboratory study. Methods: Maximum isometric neck strength was measured in each anatomic plane in 46 male and female contact sport athletes aged 8 to 30 years. A loading apparatus applied impulsive test forces to athletes’ heads in flexion, extension, lateral flexion, and axial rotation during baseline and anticipatory cervical muscle activation conditions. Multivariate linear mixed models were used to determine the effects of neck strength and cervical muscle activation on head ΔV and Δω. Results: Greater isometric neck strength and anticipatory activation were independently associated with decreased head ΔV and Δω after impulsive loading across all planes of motion (all P < .001). Inverse relationships between neck strength and head ΔV and Δω presented moderately strong effect sizes (r = 0.417 to r = 0.657), varying by direction of motion and cervical muscle activation. Conclusion: In male and female athletes across the age spectrum, greater neck strength and anticipatory cervical muscle activation (“bracing for impact”) can reduce the magnitude of the head’s kinematic response. Future studies should determine whether neck strength contributes to the observed sex and age group differences in concussion incidence. Clinical Relevance: Neck strength and impact anticipation are 2 potentially modifiable risk factors for concussion. Interventions aimed at increasing athletes’ neck strength and reducing unanticipated impacts may decrease the risk of concussion associated with sport participation.