Summary

In the past decade, few issues at the intersection of medicine and sports have had as high a profile or have generated as much public interest as sports-related concussions. In recent years there has been a growing awareness and understanding that all concussions involve some level of injury to the brain and that athletes suspected of having a concussion should be removed from play for further evaluation (CDC, 2013; Halstead et al., 2010). Despite the increased attention, however, confusion and controversy persist in many areas, from how to define a concussion and how multiple concussions affect the vulnerability of athletes to future injury, to when it is safe for a player to return to sports and the effectiveness of protective devices and other interventions in reducing the incidence and severity of concussive injuries (Wilde et al., 2012). Parents worry about choosing sports that are safe for their children to play, about finding the equipment that can best protect their children, and about when, if a child does receive a concussion, it will be safe for him or her to return to play or if it might be time to quit a much-loved sport entirely.

It is within this context that the Institute of Medicine (IOM) and National Research Council (NRC), in October 2012, convened the Committee on Sports-Related Concussions in Youth to review the science of sports-related concussions in youth from elementary school through young adulthood, including military personnel and their dependents, and to prepare a report on that topic based on that review. The committee was charged with reviewing the available literature on concussions within the context of developmental neurobiology, specifically relating to the causes of concussions, their relationship to impacts to the head or body during sports, the



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Summary In the past decade, few issues at the intersection of medicine and sports have had as high a profile or have generated as much public interest as sports-related concussions. In recent years there has been a growing aware- ness and understanding that all concussions involve some level of injury to the brain and that athletes suspected of having a concussion should be re- moved from play for further evaluation (CDC, 2013; Halstead et al., 2010). Despite the increased attention, however, confusion and controversy persist in many areas, from how to define a concussion and how multiple concus- sions affect the vulnerability of athletes to future injury, to when it is safe for a player to return to sports and the effectiveness of protective devices and other interventions in reducing the incidence and severity of concussive injuries (Wilde et al., 2012). Parents worry about choosing sports that are safe for their children to play, about finding the equipment that can best protect their children, and about when, if a child does receive a concussion, it will be safe for him or her to return to play or if it might be time to quit a much-loved sport entirely. It is within this context that the Institute of Medicine (IOM) and Na- tional Research Council (NRC), in October 2012, convened the Committee on Sports-Related Concussions in Youth to review the science of sports- related concussions in youth from elementary school through young adult- hood, including military personnel and their dependents, and to prepare a report on that topic based on that review. The committee was charged with reviewing the available literature on concussions within the context of developmental neurobiology, specifically relating to the causes of concus- sions, their relationship to impacts to the head or body during sports, the 1

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2 SPORTS-RELATED CONCUSSIONS IN YOUTH effectiveness of protective devices and equipment, screening for and diag- nosis of concussions, their treatment and management, and their long-term consequences. Specific topics of interest included • the acute, subacute, and chronic effects of single and repetitive concussive and non-concussive head impacts on the brain; • risk factors for sports concussions, post-concussion syndrome, and chronic traumatic encephalopathy; • the spectrum of cognitive, affective, and behavioral alterations that can occur during acute, subacute, and chronic posttraumatic phases; • physical and biological triggers and thresholds for injury; • the effectiveness of equipment and sports regulations in preventing injury; • hospital- and non-hospital-based diagnostic tools; and • treatments for sports concussions. Based on its review of the available evidence, the committee was asked to identify findings in each of the above topic areas and to make recom- mendations geared toward research funding agencies, legislatures, state and school superintendents and athletic directors, athletic personnel, military personnel, parents, and equipment manufacturers. The study was sponsored by the Centers for Disease Control and Prevention (CDC), the CDC Foundation with support from the National Football League, the Department of Defense, the Department of Education, the Health Resources and Services Administration, the National Athletic Trainers’ Association Research and Education Foundation, and the Na- tional Institutes of Health. EPIDEMIOLOGY As this report discusses, there is currently a lack of data to accurately estimate the incidence of sports-related concussions across a variety of sports and for youth across the pediatric age spectrum. Nevertheless, ex- isting data suggest that sports-related concussions represent a significant public health concern. It has been estimated that as many as 1.6 million to 3.8 million sports- and recreation-related traumatic brain injuries (TBIs), including concussions and other head injuries, occur in the United States each year (Langlois et al., 2006). Because many concussions go unreported, this figure likely represents a conservative estimate. Data also suggest that an increase in reported sports-related concussions has occurred in recent years, a trend that may have been caused by a greater awareness of con- cussions. For example, a review of National Collegiate Athletic Associa-

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SUMMARY 3 tion data for 15 sports showed that the overall reported concussion rate doubled from 1.7 to 3.4 concussions per 1,000 athletic exposures1 between the 1988-1989 and 2003-2004 academic years (Hootman et al., 2007). Among youth ages 19 and under, the reported number of individuals treated for concussions and other nonfatal, sports- and recreation-related TBIs increased from 150,000 to 250,000 between 2001 and 2009. The rate of emergency department visits for such injuries increased 57 percent over the same time period (Gilchrist et al., 2011). The incidence of reported concussions varies substantially by sport (see Table S-1). Available data show that among male athletes in the United States at the high school and collegiate levels, football, ice hockey, lacrosse, wrestling, and soccer consistently are associated with the highest rates of reported concussions (Datalys Center, 2013a,b; Gessel et al., 2007; Hootman et al., 2007; Lincoln et al., 2011; Marar et al., 2012). For female athletes, the high school and college sports associated with the highest rates of reported concussions are soccer, lacrosse, and basketball (Datalys Center, 2013a,b; Gessel et al., 2007; Hootman et al., 2007; Lincoln et al., 2011; Marar et al., 2012). Women’s ice hockey has one of the highest rates of reported concussions at the collegiate level (Agel and Harvey, 2010; Datalys Center, 2013b; Hootman et al., 2007), but data on the incidence of concussions for female ice hockey players at the high school level are currently unavailable. A major limitation to existing data on sports-related concussions in youth is a lack of research on the incidence of such injuries in nonacademic settings, such as in intramural and club sports, and for athletes younger than high school age. Part of the committee’s charge was to examine sports-related con- cussions among military dependents as well as concussions in military p ­ ersonnel ages 18 to 21 that result from sports and physical training at military service academies or during recruit training. There is no evidence about whether the risks for concussion are different for these youth than for youth in general, although there is no reason to think that they would be (­ oldman, 2013; Tsao, 2013). The committee also found that among mili- G tary personnel, mild traumatic brain injuries (mTBIs)—of which concus- sions are one category—represent the majority (about 85 percent in 2012) of all TBIs and that most mTBIs (about 80 percent in 2012) do not occur in the deployed setting. These TBIs are instead most commonly caused by motor vehicle crashes (privately owned and military vehicles), falls, sports and recreation activities, and military training (DVBIC, 2013). However, it is unknown what proportion of these injuries are concussions and, among those, what proportions occur during sports and recreation activities or 1  Athletic exposures are the number of practices and competitions in which an individual actively participates (i.e., in which he or she is exposed to the possibility of athletic injury).

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4 SPORTS-RELATED CONCUSSIONS IN YOUTH Table S-1 Reported Concussion Rates by Sport, Sex, and Competition Level (High School and College) (Rates per 10,000 Athletic Exposures) High School Datalys Lincoln et al. Gessel et al. Marar et al. Centera Sport (1997-2008) (2005-2006) (2008-2010) (2010-2012) Football 6.0 4.7 6.4 11.2 Ice Hockey (W) — — — — Ice Hockey (M) — — 5.4 — Lacrosse (W) 2.0 — 3.5 5.2 Lacrosse (M) 3.0 — 4.0 6.9 Soccer (W) 3.5 3.6 3.4 6.7 Soccer (M) 1.7 2.2 1.9 4.2 Wrestling 1.7 1.8 2.2 6.2 Field Hockey 1.0 — 2.2 4.2 Basketball (W) 1.6 2.1 2.1 5.6 Basketball (M) 1.0 0.7 1.6 2.8 Softball 1.1 0.7 1.6 1.6 Baseball 0.6 0.5 0.5 1.2 Volleyball — 0.5 0.6 2.4 aReportedrates are based on preliminary data from NATA NATION reported by athletic trainers in participating high schools. Data collection began with 25 schools in 2010-2011 and currently has more than 100 participants in the 2013-2014 academic year. bThe data from Hootman and colleagues (2007) represent 16 years (1988-2004), except in the case of women’s ice hockey for which data collection began in 2000. during military training. Concerning concussions sustained by military personnel ages 18 to 21 who play intramural or service academy sports, there is no reason to suspect that the concussion risks are different from those for nonmilitary athletes of the same age, although military service academies require certain physical training activities, such as combatives and ropes courses, and offer other activities, such as boxing, that may pose a high risk of concussion (Kelly, 2013; Wolfe, 2013). Although the com- mittee found anecdotal evidence that military personnel sustain concussions during hand-to-hand combatives training courses (Sapien and Zwerdling, 2012), there are no published data on the occurrence of concussions during such training. COMMITTEE’S APPROACH In approaching its task, the committee performed a review of the peer- reviewed scientific literature that was relevant to the various aspects of the

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SUMMARY 5 College Datalys Hootman et al. Gessel et al. Agel and Harvey Datalys Centerc Centerc (1988-2004) (2005-2006) (2000-2007) (2004-2009) (2009-2013) 3.7 6.1 — 6.0 6.3 9.1b — 8.2 7.0 5.0 4.1 — 7.2 6.0 8.2 2.5 — — 6.2 5.5 2.6 — — 6.0 3.1 4.1 6.3 — 6.7 6.5 2.8 4.9 — 4.2 3.1 2.5 4.2 — 4.9 12.4 1.8 — — 4.0 14.5d 2.2 4.3 — 4.8 6.1 1.6 2.7 — 3.4 3.5 1.4 1.9 — 2.3 3.5 0.7 0.9 — 1.1 0.7e 0.9 1.8 — 1.8 3.3 cData for the period 2004-2009 are from the NCAA Injury Surveillance System. The Datalys Center for Sports Injury Research and Prevention, Inc., assumed management of the NCAA injury surveillance program in 2009. dRate calculated with fewer than 30 raw frequencies. eAverage of participating teams over the time period. SOURCES: Agel and Harvey, 2010; Datalys Center, 2013a,b; Gessel et al., 2007; Hootman et al., 2007; Lincoln et al., 2011; Marar et al., 2012. statement of task. In doing so the committee identified several limitations to the current scientific evidence base. One such limitation is the use of terminology that is poorly defined and applied inconsistently across studies (e.g., “concussion” versus “mild traumatic brain injury”), which made it challenging for the committee to determine the applicability of many stud- ies to concussions in youth. The committee acknowledges that there is no single, universally used definition of “concussion.” A concussion may be de- scribed as a brain injury that has been induced by biomechanical forces and that may be identified by a constellation of physical, cognitive, behavioral, and emotional symptoms and may also be associated with physiological changes. Of the many existing definitions of “concussion,” the committee found that the one that is currently most widely used is the definition set forth at the Fourth International Conference on Concussion in Sport held in Zurich in November 2012, which states, in part, “Concussion is a brain injury and is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces” (McCrory et al., 2013, p. 1).

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6 SPORTS-RELATED CONCUSSIONS IN YOUTH Other limitations to the existing evidence base include the fact that relatively little research has focused specifically on concussions versus the more severe forms of TBI, particularly in youth ages 5 to 12; that there are few published studies on the effectiveness of protective devices and other interventions to reduce the occurrence of sports-related concussions in youth; and that there are relatively few data on the psychometric properties of sideline screening tools. Furthermore, many studies have small sample sizes and methodological weaknesses that limit the validity of their findings. However, the committee determined that even studies of limited strength could provide some useful information and inform future research needs. As a supplement to its literature review, the committee hosted two public workshops with presentations and panel discussions on the various elements of the committee’s statement of task. Speakers included experts in: the diagnosis, management, and rehabilitation of concussed youth ath- letes, including their reintegration into academic and athletic settings; the genetic and neurogenetic sources of increased risk; the development of biomarkers and imaging technologies for concussion diagnosis and evalu- ation; protective equipment safety standards and effectiveness; and the role of sports rules and training in the prevention of sports-related concus- sions. To help address the portion of its charge concerning concussions among military personnel and their dependents, an area for which there is little published research, the committee heard from experts on concus- sions in military and service academy training programs. In addition, the committee heard the perspectives of stakeholder representatives, including athletes, parents, coaches, officials, and youth sports organizations. The committee’s information gathering also included reviews of previous IOM and NRC reports such as Is Soccer Bad for Children’s Heads?: Summary of the IOM Workshop on Neuropsychological Consequences of Head Impact in Youth Soccer (IOM, 2002), From Neurons to Neighborhoods: The Sci- ence of Early Childhood Development (IOM and NRC, 2000), and Gulf War and Health: Volume 7: Long-Term Consequences of Traumatic Brain Injury (IOM, 2008). Finally, the committee took into consideration cur- rent consensus and position statements on the diagnosis and management of sports-related concussions developed by the international Concussion in Sport Group (McCrory et al., 2013), the American Academy of Neurology (Giza et al., 2013), the American Academy of Pediatrics (Halstead et al., 2010), and the American Medical Society for Sports Medicine (Harmon et al., 2013). A central part of the committee’s responsibility in preparing this report was to carefully review the science and evidence related to the causes, in- cidence, and biophysiology of concussions in youth. The findings, conclu- sions, and recommendations presented in this report reflect this approach. Yet, as we did our research, listened to public testimony, and reflected on

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SUMMARY 7 our own experiences, we came to have a growing appreciation for the role of “culture” in the current recognition and management of concussions in young athletes. Culture is created by the sum of beliefs and behaviors within a group. And it is clear to us that currently, in many settings, the seriousness of the threat to the health of an athlete, both acute and long term, from suffering a concussion is not fully appreciated or acted upon. Too many times the committee read or heard first-person accounts of young athletes being encouraged by coaches or peers to “play through it.” This attitude is an insidious influence that can cause athletes to feel that they should jeopardize their own individual health as a sign of commitment to their teams. COMMITTEE’S FINDINGS2 Culture of Resistance in Sports Concussion Despite increased knowledge about concussions and a growing rec- ognition in recent years that concussions involve some level of injury to the brain and therefore need to be diagnosed promptly and managed ap- propriately, there is still a culture among athletes and military personnel that resists both the self-reporting of concussions and compliance with ap- propriate concussion management plans. In surveys, youth profess that the game and the team are more important than their individual health and that they may play through a concussion to avoid letting down their teammates, coaches, schools, and parents. Concussion Definition and Surveillance Needs The National Collegiate Athletic Association Injury Surveillance Sys- tem and High School RIOTM (Reporting Information Online) data systems are the only ongoing, comprehensive sources of sports-related injury data, including data on concussions, in youth athletes. Such data are not avail- able for athletes younger than high-school age, nor are they available for participants in club sports and other youth engaging in competitive and recreational sports outside of an academic setting. There is currently no comprehensive system for acquiring accurate data on the incidence of sports and recreation-related concussions across all youth age groups and sports. Furthermore, studies of sports-related concussions in youth do not routinely include information on the race, ethnicity, or socioeconomic 2  This section does not include references. Citations to support the committee’s findings are given in the body of the report.

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8 SPORTS-RELATED CONCUSSIONS IN YOUTH status of the participants.3 There are no published data on the incidence of reported concussions during basic training for military recruits. More complete epidemiologic data would help researchers identify possible dif- ferences in the rates of sports-related concussions across subpopulations of youth and help them assess the effectiveness of interventions in reducing the incidence of such injuries. The published literature includes numerous working definitions of “concussion” and exhibits an inconsistent use of terminology (e.g., con- founding “concussion” and “mild TBI” even though the latter includes more severe brain injuries). These differences pose challenges for interpret- ing and comparing findings across studies on concussion. Effects of Single and Multiple Concussive and Non-Concussive Head Impacts Research primarily involving animals and individuals with more se- vere head injury has provided a limited framework for understanding the neuroscience of concussions. This research indicates that there is a series of molecular and functional changes that take place in the brain following a head injury, some of which may serve as important biomarkers for the pathophysiology of concussion. However, little research has been conducted specifically on changes in the brain following concussions in youth, and little research has attempted to evaluate differences in such changes be- tween female and male youth. Research using newer noninvasive imaging techniques in the first hours and days following injury may help to improve understanding of the neurobiology of concussion. Findings of studies of repetitive head impacts (sometimes called “sub- concussive” impacts) have been mixed, with some showing an association between such impacts and functional impairments, and others not. Pre- liminary imaging research suggests that changes in brain white matter may appear after repetitive head impacts; this preliminary finding is supported by the animal literature. Although the findings of studies on the effects of multiple concussions on cognitive function and symptom presentation have been mixed, more studies report unfavorable changes than do not. The most commonly ob- served neuropsychological impairments have been in the areas of memory and processing speed. Some studies have found that symptom load (i.e., the 3 Racial and ethnic differences in rates of reported injury may reflect a number of factors.   These include cultural and psychosocial factors, real or perceived experiences of discrimina- tion in the health care system that can affect how and whether individuals seek care and the quality of the care that they receive, socioeconomic status, education, and access to care. Such differences, if they are found to exist, will suggest areas for future investigation.

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SUMMARY 9 number and severity of symptoms) is increased in athletes with a history of two or more concussions, but the strongest studies show no differences. There is some evidence from surveys of retired professional football players of a positive association between the number of concussions an individual has sustained and risk for depression. Athletes who have already had one or more concussions may subsequently have more severe concussions and may take longer to recover. Preliminary evidence indicates that, in addition to the number of concussions an individual has sustained, the time interval between concussions may be an important factor in the risk for and severity of subsequent concussions. Risk Factors for Sports-Related Concussions, Post-Concussion Syndrome, and Chronic Traumatic Encephalopathy There are normal changes in brain structure, blood flow, and metabo- lism that occur with brain development that may influence the susceptibility to and prognosis following concussions in youth. Available data indicate that female youth athletes and youth with a history of prior concussions have higher rates of reported sports-related concussions. The extent to which these findings are due to physiological, biomechanical, and other fac- tors (e.g., possible differences between males and females in the reporting of concussion symptoms, player aggressiveness) is not yet well understood. Concussion rates appear to be higher among college athletes than among high school athletes, higher during competition than during practice (except for cheerleading), and higher in certain sports than in others. While it has been suggested that the physiological and biomechanical risks for concus- sion may differ between younger children and older youth and adults, there are not yet sufficient epidemiologic data from various sports to calculate and compare rates of sports-related concussions across the age spectrum. The findings of studies examining associations between genetic factors and the risk of concussion have been mixed, and their validity is limited by their small sample sizes. Short-term predictors of prolonged recovery and post-concussion syn- drome vary across studies but appear to include older age (adolescent versus child), high initial symptom load, and initial presenting symptoms of amne- sia and loss of consciousness. Some evidence supports premorbid conditions (e.g., previous concussions, learning difficulties, psychiatric difficulties) as contributing to symptom persistence. Whether repetitive head impacts and multiple concussions sustained in youth lead to long-term neurodegenerative diseases, such as chronic traumatic encephalopathy (cte), remains unclear. Additional research is needed to determine whether CTE represents a unique disease entity and, if so, to develop diagnostic criteria for it. There is preliminary evidence that

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10 SPORTS-RELATED CONCUSSIONS IN YOUTH a genetic variant (e4) of apolipoprotein E (APOE) is associated with neu- ropathological features of CTE in individuals with a history of head injury. Cognitive, Affective, and Behavioral Changes Following Concussion The signs and symptoms of concussions typically fall into four catego- ries—physical, cognitive, emotional, and sleep—with patients experiencing one or more symptoms from one or more categories. Very few studies—and none that included pre-high-school-age athletes—have tracked the course of recovery for youth from sports concussion over time in order to elucidate the typical cognitive, affective, and behavioral changes that occur following a concussion. Thresholds for Concussive Injury Available studies of head injury biomechanics have identified the im- portance of linear and rotational movements of the head in injury causa- tion. However, they are based on models that have limited applicability to concussions in youth or to concussions that occur in sports environments. Thus there are currently inadequate data to define the direction- and age- related thresholds for linear and rotational acceleration specifically associ- ated with concussions in youth. In addition, it is unclear if or when the threshold of injury for a second concussion might be lower than for an initial concussive injury. Effectiveness of Equipment and Sports Regulations for the Prevention of Sports-Related Concussions There is limited evidence from epidemiological and biomechanical stud- ies that current helmet designs reduce the risk of sports-related concussions. However, there is evidence that helmets reduce the risk of other injuries, such as skull fracture, and thus the use of properly fitted helmets should be promoted. There is currently no evidence that mouthguards or facial protection, such as facemasks worn in ice hockey, reduce concussion risk, although their use should be promoted to prevent other sports-related injuries, such as those to the eyes, face, mouth, and teeth. The marketing of some protective devices designed specifically for youth athletes, such as mouthguards and soccer head gear, has included statements that these devices reduce concussion risk without sufficient scientific foundation to support such claims. Because of the nonlinear relationship between the mechanical input and injury risk, reductions in a specific biomechanical parameter, such as head acceleration, by a particular protective device do not correspond to an

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SUMMARY 11 equivalent reduction in concussion risk. Furthermore, current testing stan- dards and rating systems for protective devices do not incorporate measures of rotational head acceleration or velocity and therefore do not compre- hensively evaluate a particular device’s ability to mitigate concussion risk. Although additional research across a variety of sports is needed, some studies involving youth ice hockey and soccer players have shown that the enforcement of rules and fair play policies contributes to reductions in the incidence of sports-related injuries, including concussions. In response to concerns about the long-term consequences of repetitive head impacts, several organizations have called for a “hit count” in youth sports, which is defined as a limit on the amount of head contact a particular player experiences over a given amount of time. While the concept of limiting the number of head impacts is fundamentally sound, the committee found that, based on the evidence available at this time, implementing a specific threshold for the number of impacts or the magnitude of impacts per week or per season is without scientific basis. Research indicates that concussion education programs are effective in improving concussion knowledge and awareness, although there is limited evidence concerning the effect of these programs on behavior. Preliminary evidence suggests a need for additional research to evaluate the effectiveness of educational programs that emphasize improving attitudes and beliefs about concussions among athletes, coaches, and parents in order to im- prove concussion reporting among youth athletes. Most state concussion laws include requirements for concussion educa- tion, criteria for removal from play, and standards for health care providers who make return-to-play decisions. There is variation across states in the specific educational requirements for coaches, student athletes, and parents; in the qualifications of providers who are permitted to make return-to-play decisions; and in the populations to which the legislation applies. Given that most states are still in the early stages of implementing these laws, there is so far very little evidence of their efficacy. Hospital- and Non-Hospital-Based Assessment Tools Currently concussion diagnosis is based primarily on the symptoms reported by the individual rather than on objective diagnostic markers, which might also serve as objective markers of recovery. The use of multiple evaluation tools—such as symptom scales and checklists, balance testing, and neurocognitive testing—may increase the sensitivity and specificity of concussion identification, although there is currently insufficient evidence to determine the best combination of measures. Such traditional ­ euroimaging n techniques as computerized tomography and magnetic resonance imaging (MRI) are of little diagnostic value for concussions per se, because struc-

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12 SPORTS-RELATED CONCUSSIONS IN YOUTH tural imaging results are usually normal in concussions that are uncompli- cated by a skull fracture or hematoma. Typically, individuals recover from a concussion within 2 weeks of the injury, but in 10 to 20 percent of cases, the concussive symptoms persist for a number of weeks, months, or even years. In these cases, the individuals may be said to be experiencing post- concussion syndrome. Neuropsychological testing has a long tradition in measuring cogni- tive function after TBI and is one of several tools (along with symptom assessment, clinical evaluation, etc.) that may aid in the diagnosis and management of concussions in youth. Studies of the effectiveness of these tests to predict diagnosis and track recovery are mixed and individuals’ performances on neuropsychological tests can be influenced by many fac- tors, including effort and the presence of concussion symptoms (e.g., fatigue resulting from sleep disturbance). It appears that high scores on neuropsy- chological tests, indicating good cognitive function, are predictive of not having a concussion. In group studies these tests have been shown to be useful for tracking cognitive recovery for up to 2 weeks post injury, with a majority of concussions considered to be resolved by that time. The results of reliability studies for computerized neuropsychological tests are quite variable, with some studies demonstrating adequate reliability and others indicating less than adequate reliability. There are many possible reasons for this variability, including differences in sample sizes, testing conditions, and variable item pools. Most computerized tests produce multiple forms through a quasi-randomization of items. All commercial test batteries re- viewed had some studies indicating acceptable reliability. Newer imaging techniques—e.g., magnetic resonance spectroscopy, positron emission tomography, single-photon emission computed tomogra- phy, functional magnetic resonance imaging, and diffusion tensor imaging— may be useful in the future for assessing sports-related concussions, but at present they have not been validated for clinical use. There is some con- sensus in the literature that both quantitative electroencephalography and event-related potential procedures can detect differences in performance and neural responses in concussed versus non-concussed student athletes in high school and college even when behavior measures fail. However, these findings are true for a relatively small set of tasks that assess a limited array of cognitive abilities. Use of a broader range of tasks that measure different aspects of cognitive processes is necessary to provide a comprehensive view of behaviors most likely affected and those more likely spared by concus- sion. There is little research on the use of serum biomarkers in pediatric concussion. Although appropriately sensitive and specific serum biomarkers could be of great diagnostic and prognostic value in sports-related concus- sion, there currently is no evidence to support their use. There is some

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SUMMARY 13 evidence, however, to suggest that normal levels of S-100B following head injury may predict individuals who do not have intracranial injury. Treatments for Sports-Related Concussions The expert consensus opinion is that an individualized treatment plan including physical and cognitive rest is beneficial for recovery from concus- sion. There is little empirical evidence for the optimal degree and duration of physical rest needed to promote recovery or the best timing and ap- proach for returning to full physical activity, including the use of graded return-to-play protocols. However, there is evidence that the brain is more susceptible to injury while recovering; thus, common sense dictates reducing the risks of a repeat injury. Similarly, there is little evidence regarding the efficacy of cognitive rest following concussion or to inform the best timing and approach for return to cognitive activity following concussion, includ- ing protocols for returning students to school. There are no randomized clinical trials testing the efficacy of psychosocial or psychopharmacological treatments for children and adolescents with post-concussion symptoms and prolonged recovery. Randomized controlled trials or other appropriately designed studies on the management of concussion in youth are needed in order to develop empirically based clinical guidelines, including studies to determine the ef- ficacy of physical and cognitive rest following a concussion, the optimal pe- riod of rest, and the best protocol for returning individuals to full physical activity as well as to inform the development of evidence-based protocols and appropriate accommodations for students returning to school. To address the many information gaps highlighted in these findings, the committee identified several recommendations for further research. These are provided in Box S-1.

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14 SPORTS-RELATED CONCUSSIONS IN YOUTH BOX S-1 Committee’s Recommendations Recommendation 1. The Centers for Disease Control and Prevention, taking account of existing surveillance systems and relevant federal data collection ef- forts, should establish and oversee a national surveillance system to accurately determine the incidence of sports-related concussions, including those in youth ages 5 to 21. The data collected should include, but not be limited to, demographic information (e.g., age, sex, race and ethnicity), preexisting conditions (e.g., atten- tion deficit hyperactivity disorder, learning disabilities), concussion history (number and dates of prior concussions), the use of protective equipment and impact monitoring devices, and the qualifications of personnel making the concussion diagnosis. Data on the cause, nature, and extent of the concussive injury also should be collected, including • Sport or activity • Level of competition (e.g., recreational or competitive level) • Event type (e.g., practice or competition) •  mpact location (e.g., head or body) and nature (e.g., contact with playing I surface, another player, equipment) • Signs and symptoms consistent with a concussion Recommendation 2. The National Institutes of Health and the Department of Defense should support research to (1) establish objective, sensitive, and specific metrics and markers of concussion diagnosis, prognosis, and recovery in youth and (2) inform the creation of age-specific, evidence-based guidelines for the management of short- and long-term sequelae of concussion in youth. Recommendation 3. The National Institutes of Health and the Department of Defense should conduct controlled, longitudinal, large-scale studies to assess short- and long-term cognitive, emotional, behavioral, neurobiological, and neu- ropathological consequences of concussions and repetitive head impacts over the life span. Assessments should also include an examination of the effects of concussions and repetitive head impacts on quality of life and activities of daily living. It is critical that such studies identify predictors and modifiers of outcomes, REFERENCES Agel, J., and E. J. Harvey. 2010. A 7-year review of men’s and women’s ice hockey injuries in the NCAA. Canadian Journal of Surgery 53(5):319-323. CDC (Centers for Disease Control and Prevention). 2013. Concussion in Sports. http://www. cdc.gov/concussion/sports/index.html (accessed March 28, 2013). Datalys Center (Datalys Center for Sports Injury Research and Prevention, Inc.). 2013a. NATA NATION Preliminary Concussion Rates, 2010-2012. Institute of Medicine-National Research Council request. October 3.

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SUMMARY 15 including the influence of socioeconomic status, race, ethnicity, sex, and comor- bidities. To aid this research, the National Institutes of Health should maintain a national brain tissue and biological sample repository to collect, archive, and distribute material for research on concussions. Recommendation 4. The National Collegiate Athletic Association, in conjunction with the National Federation of State High School Associations, national govern- ing bodies for youth sports, and youth sport organizations, should undertake a rigorous scientific evaluation of the effectiveness of age-appropriate techniques, rules, and playing and practice standards in reducing sports-related concussions and sequelae. The Department of Defense should conduct equivalent research for sports and physical training, including combatives, at military service academies and for military personnel. Recommendation 5. The National Institutes of Health and the Department of De- fense should fund research on age- and sex-related biomechanical determinants of injury risk for concussion in youth, including how injury thresholds are modified by the number of and time interval between head impacts and concussions. These data are critical for informing the development of rules of play, effective protec- tive equipment and equipment safety standards, impact-monitoring systems, and athletic and military training programs. Recommendation 6. The National Collegiate Athletic Association and the Na- tional Federation of State High School Associations, in conjunction with the Cen- ters for Disease Control and Prevention, the Health Resources and Services Administration, the National Athletic Trainers’ Association, and the Department of Education, should develop, implement, and evaluate the effectiveness of large- scale efforts to increase knowledge about concussions and change the culture (social norms, attitudes, and behaviors) surrounding concussions among elemen- tary school through college-age youth and their parents, coaches, sports officials, educators, athletic trainers, and health care professionals. These efforts should take into account demographic variations (e.g., socioeconomic status, race and ethnicity, and age) across population groups. The Department of Defense should conduct equivalent research for military personnel and their families. Datalys Center. 2013b. NCAA Concussion Rates, 2004-2009 and 2009-2013. Institute of Medicine-National Research Council request. September 23. DVBIC (Defense and Veterans Brain Injury Center). 2013. DoD worldwide numbers for TBI. http://www.dvbic.org/dod-worldwide-numbers-tbi (accessed June 27, 2013). Gessel, L. M., S. K. Fields, C. L. Collins, R. W. Dick, and R. D. Comstock. 2007. Concussions among United States high school and collegiate athletes. Journal of Athletic Training 42:495-503.

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16 SPORTS-RELATED CONCUSSIONS IN YOUTH Gilchrist, J., K. E. Thomas, L. Xu, L. C. McGuire, and V. Coronado. 2011. Nonfatal traumatic brain injuries related to sports and recreation activities among persons ≤19 years—United States, 2001-2009. Morbidity and Mortality Weekly Report 60(39):1337-1342. Giza, C. C., J. S. Kutcher, S. Ashwal, J. Barth, T. S. D. Getchius, G. A. Gioia, G. S. Gronseth, K. Guskiewicz, S. Mandel, G. Manley, D. B. McKeag, D. J. Thurman, and R. Zafonte. 2013. Evidence-Based Guideline Update: Evaluation and Management of Concussion in Sports. Report of the Guideline Development Subcommittee of the American Academy of Neurology. American Academy of Neurology. Goldman, S. B. 2013. Army TBI Program Overview. Presentation before the committee, Washington, DC, February 25. Halstead, M. E., K. D. Walter, and American Academy of Pediatrics, Council on Sports Medi- cine and Fitness. 2010. Sport-related concussion in children and adolescents. Pediatrics 126(3):597-615. Harmon, K. G., J. A. Drezner, M. Gammons, K. M. Guskiewicz, M. Halstead, S. A. Herring, J. S. Kutcher, A. Pana, M. Putakian, and W. O. Roberts. 2013. American Medical Society of Sports Medicine position statement: Concussion in sport. British Journal of Sports Medicine 47(1):15-26. Hootman, J., R. Dick, and J. Agel. 2007. Epidemiology of collegiate injuries for 15 sports: Summary and recommendations for injury prevention initiatives. Journal of Athletic Training 42(2):311-319. IOM (Institute of Medicine). 2002. Is Soccer Bad for Children’s Heads?: Summary of the IOM Workshop on Neuropsychological Consequences of Head Impact in Youth Soccer. Washington, DC: National Academy Press. IOM. 2008. Gulf War and Health: Volume 7: Long-Term Consequences of Traumatic Brain Injury. Washington, DC: The National Academies Press. IOM and NRC (National Research Council). 2000. From Neurons to Neighborhoods: The Science of Early Childhood Development. Washington, DC: National Academy Press. Kelly, T. 2013. Sports and Physical Training-Related Concussion in Military Personnel. Pre- sentation before the committee, Washington, DC, February 25. Langlois, J., W. Rutland-Brown, and M. Wald. 2006. The epidemiology and impact of trau- matic brain injury: A brief overview. Journal of Head Trauma Rehabilitation 21(5): 375-378. Lincoln, A., S. Caswell, J. Almquist, R. Dunn, J. Norris, and R. Hinton. 2011. Trends in con- cussion incidence in high school sports: A prospective 11-year study. American Journal of Sports Medicine 39(5):958-963. Marar, M., N. McIlvain, S. Fields, and R. Comstock. 2012. Epidemiology of concussions among United States high school athletes in 20 sports. American Journal of Sports Medicine 40(4):747-755. McCrory, P., W. H. Meeuwisse, M. Aubry, B. Cantu, J. Dvořák, R. J. Echemendia, L. Engebretsen, K. Johnston, J. S. Kutcher, M. Raftery, A. Sills, B. W. Benson, G. A. Davis, R. G. Ellenbogen, K. Guskiewicz, S. A. Herring, G. L. Iverson, B. D. Jordan, J. Kissick, M. McCrea, A. S. McIntosh, D. Maddocks, M. Makdissi, L. Purcell, M. Putukian, K. Schneider, C. H. Tator, and M. Turner. 2013. Consensus statement on concussion in sport: The 4th International Conference on Concussion in Sport held in Zurich, Novem- ber 2012. British Journal of Sports Medicine 47(5):250-258. Sapien, J., and D. Zwerdling. 2012. Army study finds troops suffer concussions in train- ing. http://www.propublica.org/article/army-study-finds-troops-suffer-concussions-in- training# comments (accessed October 13, 2013). Tsao, J. W. 2013. Navy and Marine Corps TBI Efforts. Presentation before the committee, Washington, DC, February 25.

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SUMMARY 17 Wilde, E. A., S. R. McCauley, G. Hanten, G, Avci, A. P. Ibarra, and H. S. Levin. 2012. His- tory, diagnostic considerations, and controversies. In Mild Traumatic Brain Injuries in Children and Adolescents: From Basic Science to Clinical Management, edited by M. Kirkwood and K. O. Yeates. New York: Guilford Press. Pp. 3-21. Wolfe, C. L. 2013. West Point health care providers focus on brain injury prevention, diagno- sis, treatment. (March 28). http://www.army.mil/article/99664 (accessed July 25, 2013).

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