Steven P. Broglio

National Athletic Trainers' Association Position Statement: Management of Sport Concussion

OBJECTIVE To provide athletic trainers, physicians, and other health care professionals with best-practice guidelines for the management of sport-related concussions. BACKGROUND An estimated 3.8 million concussions occur each year in the United States as a result of sport and physical activity. Athletic trainers are commonly the first medical providers available onsite to identify and evaluate these injuries. RECOMMENDATIONS The recommendations for concussion management provided here are based on the most current research and divided into sections on education and prevention, documentation and legal aspects, evaluation and return to play, and other considerations.

Assessment of metabolic brain damage and recovery following mild traumatic brain injury: a multicentre, proton magnetic resonance spectroscopic study in concussed patients

Concussive head injury opens a temporary window of brain vulnerability due to the impairment of cellular energetic metabolism. As experimentally demonstrated, a second mild injury occurring during this period can lead to severe brain damage, a condition clinically described as the second impact syndrome. To corroborate the validity of proton magnetic resonance spectroscopy in monitoring cerebral metabolic changes following mild traumatic brain injury, apart from the magnetic field strength (1.5 or 3.0 T) and mode of acquisition, we undertook a multicentre prospective study in which a cohort of 40 athletes suffering from concussion and a group of 30 control healthy subjects were admitted. Athletes (aged 16-35 years) were recruited and examined at three different institutions between September 2007 and June 2009. They underwent assessment of brain metabolism at 3, 15, 22 and 30 days post-injury through proton magnetic resonance spectroscopy for the determination of N-acetylaspartate, creatine and choline-containing compounds. Values of these representative brain metabolites were compared with those observed in the group of non-injured controls. Comparison of spectroscopic data, obtained in controls using different field strength and/or mode of acquisition, did not show any difference in the brain metabolite ratios. Athletes with concussion exhibited the most significant alteration of metabolite ratios at Day 3 post-injury (N-acetylaspartate/creatine: -17.6%, N-acetylaspartate/choline: -21.4%; P < 0.001 with respect to controls). On average, metabolic disturbance gradually recovered, initially in a slow fashion and, following Day 15, more rapidly. At 30 days post-injury, all athletes showed complete recovery, having metabolite ratios returned to values detected in controls. Athletes self-declared symptom clearance between 3 and 15 days after concussion. Results indicate that N-acetylaspartate determination by proton magnetic resonance spectroscopy represents a non-invasive tool to accurately measure changes in cerebral energy metabolism occurring in mild traumatic brain injury. In particular, this metabolic evaluation may significantly improve, along with other clinical assessments, the management of athletes suffering from concussion. Further studies to verify the effects of a second concussive event occurring at different time points of the recovery curve of brain metabolism are needed.

Sensitivity of the concussion assessment battery.

OBJECTIVESports medicine clinicians commonly use multiple tests when evaluating patients with concussion. The specific tests vary but often include symptom inventories, posturography, and neurocognitive examinations. The sensitivity of these tests to concussion is vital in reducing the risk for additional injury by prematurely returning an athlete to play. Our study investigated the sensitivity of concussion-related symptoms, a postural control evaluation, and neurocognitive functioning in concussed collegiate athletes. METHODSFrom 1998 to 2005, all high-risk athletes completed a baseline concussion-assessment battery that consisted of a self-reported symptom inventory, a postural control evaluation, and a neurocognitive assessment. Postconcussion assessments were administered within 24 hours of injury to 75 athletes who had physician-diagnosed concussion. Individual tests and the complete battery were evaluated for sensitivity to concussion. RESULTSThe computerized Immediate Post-Concussion Assessment and Cognitive Testing and HeadMinder Concussion Resolution Index (neurocognitive tests) were the most sensitive to concussion (79.2 and 78.6%, respectively). These tests were followed by self-reported symptoms (68.0%), the postural control evaluation (61.9%), and a brief pencil-and-paper assessment of neurocognitive function (43.5%). When the complete battery was assessed, sensitivity exceeded 90%. CONCLUSIONCurrently recommended concussion-assessment batteries accurately identified decrements in one or more areas in most of the athletes with concussion. These findings support previous recommendations that sports-related concussion should be approached through a multifaceted assessment with components focusing on distinct aspects of the athletes function.

Consensus statement on concussion in sport-the 5th international conference on concussion in sport held in Berlin, October 2016

The 2017 Concussion in Sport Group (CISG) consensus statement is designed to build on the principles outlined in the previous statements1–4 and to develop further conceptual understanding of sport-related concussion (SRC) using an expert consensus-based approach. This document is developed for physicians and healthcare providers who are involved in athlete care, whether at a recreational, elite or professional level. While agreement exists on the principal messages conveyed by this document, the authors acknowledge that the science of SRC is evolving and therefore individual management and return-to-play decisions remain in the realm of clinical judgement. This consensus document reflects the current state of knowledge and will need to be modified as new knowledge develops. It provides an overview of issues that may be of importance to healthcare providers involved in the management of SRC. This paper should be read in conjunction with the systematic reviews and methodology paper that accompany it. First and foremost, this document is intended to guide clinical practice; however, the authors feel that it can also help form the agenda for future research relevant to SRC by identifying knowledge gaps. A series of specific clinical questions were developed as part of the consensus process for the Berlin 2016 meeting. Each consensus question was the subject of a specific formal systematic review, which is published concurrently with this summary statement. Readers are directed to these background papers in conjunction with this summary statement as they provide the context for the issues and include the scope of published research, search strategy and citations reviewed for each question. This 2017 consensus statement also summarises each topic and recommendations in the context of all five CISG meetings (that is, 2001, 2004, 2008, 2012 as well as 2016). Approximately 60 000 published articles were screened by the expert panels for the Berlin …

The Effect of Sport Concussion on Neurocognitive Function, Self-Report Symptoms and Postural Control

Sport concussion is commonly assessed using a battery of tests that evaluate neurocognitive functioning, postural control and self-report symptoms. The degree to which concussion affects each of these measures is unclear. Thus, the purpose of this meta-analysis is to systematically review and quantify the effect of sport concussion on each assessment measure when administered immediately post-injury and in the 2 weeks following injury. PubMed and PsychINFO databases were searched from January 1970 to June 2006, from which 39 were included for review. Studies were selected for review if they included concussed athletes who were evaluated using one of the three assessment measures. One post-morbid assessment must have been completed within 14 days of injury and compared with a baseline measure or control group. Study design, type of neurocognitive assessment, timing of assessment following injury and number of post-concussion assessments were extracted as potential moderators. Sport-related concussion had a large negative effect (mean Δ 95% confidence interval) on neurocognitive functioning (−0.81; −1.01, −0.60), self-report symptoms (−3.31; −6.35, −0.27) and postural control (−2.56; −6.44, 1.32) in the initial assessment following injury. A reduced, but large effect, was also seen in the 14 days following the initial assessment for neurocognitive functioning (−0.26; −0.46, −0.06), self-report symptoms (−1.09; −2.07, −0.11) and postural control (−1.16; −2.59, 0.27). Our findings demonstrated large effects for each aspect of the assessment battery. These findings support the use of the multifaceted concussion evaluation.

Head Impacts During High School Football: A Biomechanical Assessment

CONTEXT Little is known about the impact biomechanics sustained by players during interscholastic football. OBJECTIVE To characterize the location and magnitude of impacts sustained by players during an interscholastic football season. DESIGN Observational design. SETTING On the field. PATIENTS OR OTHER PARTICIPANTS High school varsity football team (n = 35; age = 16.85 +/- 0.75 years, height = 183.49 +/- 5.31 cm, mass = 89.42 +/- 12.88 kg). MAIN OUTCOME MEASURE(S) Biomechanical variables (linear acceleration, rotational acceleration, jerk, force, impulse, and impact duration) related to head impacts were categorized by session type, player position, and helmet impact location. RESULTS Differences in grouping variables were found for each impact descriptor. Impacts occurred more frequently and with greater intensity during games. Linear acceleration was greatest in defensive linemen and offensive skill players and when the impact occurred at the top of the helmet. The largest rotational acceleration occurred in defensive linemen and with impacts to the front of the helmet. Impacts with the highest-magnitude jerk, force, and impulse and shortest duration occurred in the offensive skill, defensive line, offensive line, and defensive skill players, respectively. Top-of-the-helmet impacts yielded the greatest magnitude for the same variables. CONCLUSIONS We are the first to provide a biomechanical characterization of head impacts in an interscholastic football team across a season of play. The intensity of game play manifested with more frequent and intense impacts. The highest-magnitude variables were distributed across all player groups, but impacts to the top of the helmet yielded the highest values. These high school football athletes appeared to sustain greater accelerations after impact than their older counterparts did. How this finding relates to concussion occurrence has yet to be elucidated.

Biomechanical properties of concussions in high school football

INTRODUCTION Sport concussion represents the majority of brain injuries occurring in the United States with 1.6–3.8 million cases annually. Understanding the biomechanical properties of this injury will support the development of better diagnostics and preventative techniques. METHODS We monitored all football related head impacts in 78 high school athletes (mean age = 16.7 yr) from 2005 to 2008 to better understand the biomechanical characteristics of concussive impacts. RESULTS Using the Head Impact Telemetry System, a total of 54,247 impacts were recorded, and 13 concussive episodes were captured for analysis. A classification and regression tree analysis of impacts indicated that rotational acceleration (95582.3 rad·s−²), linear acceleration (996.1g), and impact location (front, top, and back) yielded the highest predictive value of concussion. CONCLUSIONS These threshold values are nearly identical with those reported at the collegiate and professional level. If the Head Impact Telemetry System were implemented for medical use, sideline personnel can expect to diagnose one of every five athletes with a concussion when the impact exceeds these tolerance levels. Why all athletes did not sustain a concussion when the impacts generated variables in excess of our threshold criteria is not entirely clear, although individual differences between participants may play a role. A similar threshold to concussion in adolescent athletes compared with their collegiate and professional counterparts suggests an equal concussion risk at all levels of play.

No Evidence of Impaired Neurocognitive Performance in Collegiate Soccer Players

A high incidence of cerebral concussion has been reported among soccer players. We studied whether long-term or chronic neuropsychological dysfunction was present in collegiate soccer players. Two hundred forty subjects from a National Collegiate Athletic Association division I institution were stratified into three groups: soccer athletes (91), nonsoccer athletes (96 womens field hockey, womens lacrosse, and baseball players), and controls (53 college students). Subjects completed a concussion history questionnaire and underwent preseason baseline neuropsychological testing before the start of either the freshman or sophomore year. Data were collected on the results of six neuropsychological tests and from a concussion history questionnaire for number of previous concussions, Scholastic Aptitude Test results, and exposure to soccer and heading. Despite an average of 15.3 seasons of soccer exposure and a higher prevalence of previous concussions, the soccer athletes did not demonstrate impaired neurocognitive function or scholastic aptitude when compared with the nonsoccer athletes or the student nonathletes. Additionally, there was no significant relationship between a history of soccer-related concussion and either neurocognitive performance or scholastic aptitude. Neither participation in soccer nor a history of soccer-related concussions was associated with impaired performance of neurocognitive function in high-level United States soccer players.

Cumulative head impact burden in high school football

Impacts to the head are common in collision sports such as football. Emerging research has begun to elucidate concussion tolerance levels, but sub-concussive impacts that do not result in clinical signs or symptoms of concussion are much more common, and are speculated to lead to alterations in cerebral structure and function later in life. We investigated the cumulative number of head impacts and their associated acceleration burden in 95 high school football players across four seasons of play using the Head Impact Telemetry System (HITS). The 4-year investigation resulted in 101,994 impacts collected across 190 practice sessions and 50 games. The number of impacts per 14-week season varied by playing position and starting status, with the average player sustaining 652 impacts. Linemen sustained the highest number of impacts per season (868); followed by tight ends, running backs, and linebackers (619); then quarterbacks (467); and receivers, cornerbacks, and safeties (372). Post-impact accelerations of the head also varied by playing position and starting status, with a seasonal linear acceleration burden of 16,746.1g, while the rotational acceleration and HIT severity profile burdens were 1,090,697.7 rad/sec(2) and 10,021, respectively. The adolescent athletes in this study clearly sustained a large number of impacts to the head, with an impressive associated acceleration burden as a direct result of football participation. These findings raise concern about the relationship between sub-concussive head impacts incurred during football participation and late-life cerebral pathogenesis, and justify consideration of ways to best minimize impacts and mitigate cognitive declines.

Advances in sport concussion assessment: from behavioral to brain imaging measures.

Given that the incidence of sports-related concussion is considered to have reached epidemic proportions, in the past 15 years we have witnessed an explosion of research in this field. The purpose of the current review is to compare the results provided by the different assessment tools used in the scientific literature in order to gain a better understanding of the sequelae and recovery following a concussion. Until recently, the bulk of the has literature focused on the immediate outcome in the hours and days post-injury as a means to plan the safest return-to-play strategy. This has led to the development of several assessment batteries that are relatively easy and rapid to administer and that allow for multiple testing sessions. The main conclusion derived from that literature is that cognitive symptoms tend to resolve within 1 week. However, accumulating evidence indicates that cognitive testing should be viewed as one of several complementary tools necessary for a comprehensive assessment of concussion. Including an objective measure of postural stability increases the sensitivity of the return-to-play decision-making process and minimizes the consequences of mitigating factors (e.g., practice effects and motivation) on neuropsychological test results. This is consistent with findings that symptom severity, neuropsychological function, and postural stability do not appear to be related or affected to the same degree after a concussion. Furthermore, recent evidence from brain imaging, including event-related potentials and functional and metabolic imaging, suggest abnormalities in the electrical responses, metabolic balance, and oxygen consumption of neurons that persist several months after the incident. We explain this apparent discrepancy in recovery by suggesting an initial and rapid phase of functional recovery driven by compensatory mechanisms and brain plasticity, which is followed by a prolonged neuronal recovery period during which subtle deficits in brain functioning are present but not apparent to standard clinical assessment tools.