Michael McCrea

Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012

This paper is a revision and update of the recommendations developed following the 1st (Vienna 2001), 2nd (Prague 2004) and 3rd (Zurich 2008) International Consensus Conferences on Concussion in Sport and is based on the deliberations at the 4th International Conference on Concussion in Sport held in Zurich, November 2012.1–3 The new 2012 Zurich Consensus statement is designed to build on the principles outlined in the previous documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. A detailed description of the consensus process is outlined at the end of this document under the Background section. This document is developed primarily for use by physicians and healthcare professionals who are involved in the care of injured athletes, whether at the recreational, elite or professional level. While agreement exists pertaining to principal messages conveyed within this document, the authors acknowledge that the science of concussion is evolving, and therefore management and return to play (RTP) decisions remain in the realm of clinical judgement on an individualised basis. Readers are encouraged to copy and distribute freely the Zurich Consensus document, the Concussion Recognition Tool (CRT), the Sports Concussion Assessment Tool V.3 (SCAT3) and/or the Child SCAT3 card and none are subject to any restrictions, provided they are not altered in any way or converted to a digital format. The authors request that the document and/or the accompanying tools be distributed in their full and complete format. This consensus paper is broken into a number of sections 1. A summary of concussion and its management, with updates from the previous meetings; 2. Background information about the consensus meeting process; 3. A summary of the specific consensus questions discussed at this meeting; 4. The Consensus paper should be read in conjunction with the SCAT3 assessment tool, the Child SCAT3 and the CRT …

Unreported concussion in high school football players: implications for prevention

ObjectiveTo investigate the frequency of unreported concussion and estimate more accurately the overall rate of concussion in high school football players. DesignRetrospective, confidential survey completed by all subjects at the end of the football season. Setting and ParticipantsA total of 1,532 varsity football players from 20 high schools in the Milwaukee, Wisconsin, area were surveyed. Main Outcome MeasurementsThe structured survey assessed (1) number of concussions before the current season, (2) number of concussions sustained during the current season, (3) whether concussion during the current season was reported, (4) to whom concussion was reported, and (5) reasons for not reporting concussion. ResultsOf respondents, 29.9% reported a previous history of concussion, and 15.3% reported sustaining a concussion during the current football season; of those, 47.3% reported their injury. Concussions were reported most frequently to a certified athletic trainer (76.7% of reported injuries). The most common reasons for concussion not being reported included a player not thinking the injury was serious enough to warrant medical attention (66.4% of unreported injuries), motivation not to be withheld from competition (41.0%), and lack of awareness of probable concussion (36.1%). ConclusionsThese findings reflect a higher prevalence of concussion in high school football players than previously reported in the literature. The ultimate concern associated with unreported concussion is an athlete’s increased risk of cumulative or catastrophic effects from recurrent injury. Future prevention initiatives should focus on education to improve athlete awareness of the signs of concussion and potential risks of unreported injury.

Standardized assessment of concussion (SAC): on-site mental status evaluation of the athlete.

Objective: This study investigated the clinical utility of the Standardized Assessment of Concussion (SAC) in detecting concussion in athletes. Method: Athletic trainers administered the SAC to 568 nonconcussed high school and college football players prior to the 1995 and 1996 football seasons. Thirty-three of these players experienced concussion and were tested immediately following injury; 28 of the 33 underwent additional follow-up testing 48 hours after the injury. Results: Concussed players scored significantly below nonconcussed controls on all SAC measures and significantly below their own pre-injury baseline performance. Follow-up testing documented return to preinjury baseline. Conclusion: These findings support the SACs effectiveness in detecting concussion and tracking recovery in order to determine a players fitness to return to play.

Standardized assessment of concussion in football players

Article abstract-The recent formulation of guidelines for the management of concussion in sports adopted by the American Academy of Neurology specifically calls for the development of a standardized, systematic sideline evaluation for the immediate assessment of concussion in athletes. The present study involved the preliminary investigation of the feasibility and clinical validity of a standardized version of a brief sideline examination complied in accordance with these guidelines. This examination, intended for use by athletic trainers, was administered by three trainers to 141 nonconcussed high school football players at three separate schools. All players suspected of suffering a concussion (N = 6) during the fall 1995 season were also tested immediately following their injury. The examination was easily administered and scored. The concussed players as a group scored significantly below the nonconcussed controls and below their own baseline (pre-injury) performance, despite their all having been considered by the trainers to have suffered mild, grade 1 concussions. Although preliminary, these data suggest that a standardized sideline examination of this type can be useful in detecting concussion and determining fitness to return to play. NEUROLOGY 1997;48: 586-588

Standard regression-based methods for measuring recovery after sport-related concussion

Clinical decision making about an athletes return to competition after concussion is hampered by a lack of systematic methods to measure recovery. We applied standard regression-based methods to statistically measure individual rates of impairment at several time points after concussion in college football players. Postconcussive symptoms, cognitive functioning, and balance were assessed in 94 players with concussion (based on American Academy of Neurology Criteria) and 56 noninjured controls during preseason baseline testing, and immediately, 3 hr, and 1, 2, 3, 5, and 7 days postinjury. Ninety-five percent of injured players exhibited acute concussion symptoms and impairment on cognitive or balance testing immediately after injury, which diminished to 4% who reported elevated symptoms on postinjury day 7. In addition, a small but clinically significant percentage of players who reported being symptom free by day 2 continued to be classified as impaired on the basis of objective balance and cognitive testing. These data suggest that neuropsychological testing may be of incremental utility to subjective symptom checklists in identifying the residual effects of sport-related concussion. The implementation of neuropsychological testing to detect subtle cognitive impairment is most useful once postconcussive symptoms have resolved. This management model is also supported by practical and other methodological considerations.

Immediate Neurocognitive Effects of Concussion

OBJECTIVE To prospectively measure the immediate neurocognitive effects and early course of recovery from concussion and to examine the effects of loss of consciousness (LOC) and posttraumatic amnesia (PTA) on the severity of neurocognitive impairment immediately after concussion. METHODS A sports-related concussion research model was used to allow prospective immediate evaluation of concussion. A total of 2385 high school and college football players were studied. Ninety-one players (3.8%) sustained concussions during the study. A brief neurocognitive and neurological screening measure, the Standardized Assessment of Concussion, was used to assess cognitive functioning before the football season, immediately after injury, and 15 minutes, 48 hours, and 90 days after injury. RESULTS Standardized Assessment of Concussion scores immediately after concussion were significantly lower than the preseason baseline score and the noninjured population baseline mean, even for injured subjects without LOC or PTA. Subjects with LOC were most severely impaired immediately after injury, whereas those without LOC or PTA were least impaired. Significant impairment was also detected 15 minutes after injury, but all three groups returned to baseline levels of cognitive functioning within 48 hours. CONCLUSION These findings are the first to demonstrate not only that a gradient of increasing concussion severity is represented by PTA and LOC but also that measurable neurocognitive abnormalities are evident immediately after injury without PTA or LOC.

An integrated review of recovery after mild traumatic brain injury (MTBI): implications for clinical management.

The diagnosis and treatment of mild traumatic brain injury (MTBI)have historically been hampered by an incomplete base of scientific evidence to guide clinicians. One question has been most elusive to clinicians and researchers alike: What is the true natural history of MTBI? Fortunately, the science of MTBI has advanced more in the last decade than in the previous 50 years, and now reaches a maturity point at which the science can drive an evidence-based approach to clinical management. In particular, technological advances in functional neuroimaging have created a powerful bridge between the clinical and basic science of MTBI in humans. Collectively, findings from clinical, basic science, and functional neuroimaging studies now establish a foundation on which to build integrative theories and testable hypotheses around a comprehensive model of MTBI recovery. We review the current scientific literature on postconcussion symptom recovery, neuropsychological outcome, and neurophysiological healing after MTBI. Special emphasis is placed on how the new evidence base can help guide clinicians in the evaluation and management of military-related MTBI.

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 …

Sensitivity and specificity of standardized neurocognitive testing immediately following sports concussion

Neuropsychology, with its emphasis on standardized and empirically based methods, has made a number of scientific contributions to address growing concerns about concussions resulting from sports injuries. This study employs a test-retest paradigm to determine the immediate effects of concussion in high-school and college athletes. The Standardized Assessment of Concussion (SAC) was administered to 1,313 male athletes prior to the beginning of the competitive season. Reliable change indices and multiple regression models were computed on retest scores obtained from 68 noninjured athletes who were readministered the SAC at either 60 or 120 days following baseline testing. Receiver operating characteristic (ROC) curve analyses were used to test these models with data obtained on 50 athletes tested immediately following concussion. The results indicate that a decline of I point on the SAC at retesting classified injured and noninjured participants with a level of 94% sensitivity and 76% specificity. The RCI and multiple regression models provided comparable levels of group classification, but provided cut-offs that are conservative for use with this population. The results support and extend previous research findings indicating that the SAC is a valid instrument for detecting the immediate effects of mild traumatic brain injury.

Incidence, clinical course, and predictors of prolonged recovery time following sport-related concussion in high school and college athletes.

Sport-related concussion (SRC) is typically followed by clinical recovery within days, but reports of prolonged symptoms are common. We investigated the incidence of prolonged recovery in a large cohort (n = 18,531) of athlete seasons over a 10-year period. A total of 570 athletes with concussion (3.1%) and 166 controls who underwent pre-injury baseline assessments of symptoms, neurocognitive functioning and balance were re-assessed immediately, 3 hr, and 1, 2, 3, 5, 7, and 45 or 90 days after concussion. Concussed athletes were stratified into typical (within 7 days) or prolonged (> 7 days) recovery groups based on symptom recovery time. Ten percent of athletes (n = 57) had a prolonged symptom recovery, which was also associated with lengthier recovery on neurocognitive testing (p < .001). At 45-90 days post-injury, the prolonged recovery group reported elevated symptoms, without deficits on cognitive or balance testing. Prolonged recovery was associated with unconsciousness [odds ratio (OR), 4.15; 95% confidence interval (CI) 2.12-8.15], posttraumatic amnesia (OR, 1.81; 95% CI, 1.00-3.28), and more severe acute symptoms (p < .0001). These results suggest that a small percentage of athletes may experience symptoms and functional impairments beyond the typical window of recovery after SRC, and that prolonged recovery is associated with acute indicators of more severe injury.