Michael Makdissi

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 …

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 …

CogSport: reliability and correlation with conventional cognitive tests used in postconcussion medical evaluations.

ObjectiveTo determine the repeatability of a computerized cognitive test designed to monitor recovery from concussion and assist team physicians make return to play decisions (CogSport™). To determine the correlation between CogSport and two conventional neuropsychological tests. DesignProspective, serial investigation of cognitive function. SettingProfessional and semi-professional Australian Football clubs and a university affiliated research institute in Melbourne, Australia. ParticipantsThree-hundred healthy young adults, including 240 elite athletes. Main Outcome MeasuresIntra-class correlation (ICC) coefficients for CogSport performance measures administered serially. ICC between CogSport performance measures and conventional neuropsychological tests. Normative data for CogSport performance measures. ResultsMeasures of psychomotor function, decision making, working memory and learning were highly reliable. Some measures also displayed high correlations with conventional neuropsychological tests of information processing and attention. Preliminary normative data is described. ConclusionsCogSport is a highly reliable cognitive function test when administered to healthy young adults and elite athletes. CogSport measures similar cognitive functions as conventional tests used commonly in concussion research.

Natural History of Concussion in Sport Markers of Severity and Implications for Management

Background Evidence-based clinical data are required for safe return to play after concussion in sport. Purpose The objective of this study was to describe the natural history of concussion in sport and identify clinical features associated with more severe concussive injury, using return-to-sport decisions as a surrogate measure of injury severity. Study Design Cohort study (prognosis); Level of evidence, 3. Methods Male elite senior, elite junior, and community-based Australian Rules football players had preseason baseline cognitive testing (Digit Symbol Substitution Test, Trail-Making Test—Part B, and CogSport computerized test battery). Players were recruited into the study after a concussive injury sustained while playing football. Concussed players were tested serially until all clinical features of their injury had resolved. Results Of 1015 players, 88 concussions were observed in 78 players. Concussion-associated symptoms lasted an average of 48.6 hours (95% confidence interval, 39.5-57.7 hours) with delayed return to sport correlated with ≥4 symptoms, headache lasting ≥60 hours, or self-reported “fatigue/fogginess.” Cognitive deficits using the Digit Symbol Substitution Test and Trail-Making Test—part B recovered concomitantly with symptoms, but computerized test results recovered 2 to 3 days later and remained impaired in 35% of concussed players after symptom resolution. Conclusion Delayed return to sport was associated with initially greater symptom load, prolonged headache, or subjective concentration deficits. Cognitive testing recovery varied, taking 2 to 3 days longer for computerized tests, suggesting greater sensitivity to impairment. Therefore, symptom assessment alone may be predictive of but may underestimate time to complete recovery, which may be better estimated with computerized cognitive testing.

Consensus statement on concussion in sport: the 4th international conference on concussion in sport, Zurich, november 2012

Paul McCrory, MBBS, PhD*; Willem H. Meeuwisse, MD, PhD†; Mark Aubry, MD‡; Robert C. Cantu, MD§; Jiři Dvořak, MD||; Ruben J. Echemendia, PhD¶; Lars Engebretsen, MD, PhD#; Karen Johnston, MD, PhD**; Jeffrey S. Kutcher, MD††; Martin Raftery, MBBS‡‡; Allen Sills, MD§§; Brian W. Benson, MD, PhD||||; Gavin A. Davis, MBBS¶¶; Richard Ellenbogen, MD##; Kevin M. Guskiewicz, PhD***; Stanley A. Herring, MD†††; Grant L. Iverson, PhD‡‡‡; Barry D. Jordan, MD§§§; James Kissick, MD||||||; Michael McCrea, PhD¶¶¶; Andrew S. McIntosh, PhD###; David Maddocks, LLB, PhD****; Michael Makdissi, MBBS, PhD††††; Laura Purcell, MD‡‡‡‡; Margot Putukian, MD§§§§; Kathryn Schneider, PhD||||||||; Charles H. Tator, MD, PhD¶¶¶¶; Michael Turner, MD####

Cognition in the days following concussion: comparison of symptomatic versus asymptomatic athletes

Background: Concussion is a common neurological injury occurring during contact sport. Current guidelines recommend that no athlete should return to play while symptomatic or displaying cognitive dysfunction. This study compared post-concussion cognitive function in recently concussed athletes who were symptomatic/asymptomatic at the time of assessment with that of non-injured (control) athletes. Methods: Prospective study of 615 male Australian Rules footballers. Before the season, all participants (while healthy) completed a battery of baseline computerised (CogSport) and paper and pencil cognitive tasks. Sixty one injured athletes (symptomatic = 25 and asymptomatic = 36) were reassessed within 11 days of being concussed; 84 controls were also reassessed. The serial cognitive function of the three groups was compared using analysis of variance. Results: The performance of the symptomatic group declined at the post-concussion assessment on computerised tests of simple, choice, and complex reaction times compared with the asymptomatic and control groups. The magnitude of changes was large according to conventional statistical criteria. On paper and pencil tests, the symptomatic group displayed no change at reassessment, whereas large improvements were seen in the other two groups. Conclusion: Injured athletes experiencing symptoms of concussion displayed impaired motor function and attention, although their learning and memory were preserved. These athletes displayed no change in performance on paper and pencil tests in contrast with the improvement observed in asymptomatic and non-injured athletes. Athletes experiencing symptoms of concussion should be withheld from training and competition until both symptoms and cognitive dysfunction have resolved.

Evidence-based approach to revising the SCAT2: introducing the SCAT3

The Sport Concussion Assessment Tool 2 (SCAT2), which evolved from the 2008 Concussion in Sport Group (CISG) Consensus meeting, has been widely used internationally for the past 4 years. Although the instrument is considered very practical and moderately effective for use by clinicians who manage concussion, the utility and sensitivity of a 100-point scoring system for the SCAT2 has been questioned. The 2012 CISG Consensus Meeting provided an opportunity for several of the worlds leading concussion researchers and clinicians to present data and to share experiences using the SCAT2. The purpose of this report is to consider recommendations by the CISG, and to review the current literature to identify the most sensitive and reliable concussion assessment components for inclusion in a revised version—the SCAT3. Through this process, it was determined that important clinical information can be ascertained in a streamlined manner through the use of a multimodal instrument such as the SCAT3. This test battery should include an initial assessment of injury severity using the Glasgow Coma Scale, immediately followed by observing and documenting concussion signs. Once this is complete, symptom endorsement and symptom severity, neurocognitive function and balance function should be assessed in any athlete suspected of sustaining a concussion. There is no evidence to support the use of a composite/total score; however, there is good evidence to support the use of each component (scored independently) in a revised assessment tool.

Computerised cognitive assessment of concussed Australian Rules footballers

Background—“Paper and pencil” neuropsychological tests play an important role in the management of sports related concussions. They provide objective information on the athletes cognitive function and thus facilitate decisions on safe return to sport. It has been proposed that computerised cognitive tests have many advantages over such conventional tests, but their role in this domain is yet to be established. Objectives—To measure cognitive impairment after concussion in a case series of concussed Australian Rules footballers, using both computerised and paper and pencil neuropsychological tests. To investigate the role of computerised cognitive tests in the assessment and follow up of sports related concussions. Methods—Baseline measures on the Digit Symbol Substitution Test (DSST), Trail Making Test-Part B (TMT), and a simple reaction time (SRT) test from a computerised cognitive test battery (CogState) were obtained in 240 players. Tests were repeated in players who had sustained a concussive injury. A group of non-injured players were used as matched controls. Results—Six concussions were observed over a period of nine weeks. At the follow up, DSST and TMT scores did not significantly differ from baseline scores in both control and concussed groups. However, analysis of the SRT data showed an increase in response variability and latency after concussion in the injured athletes. This was in contrast with a decrease in response variability and no change in latency on follow up of the control players (p<0.02). Conclusion—Increased variability in response time may be an important cognitive deficit after concussion. This has implications for consistency of an athletes performance after injury, as well as for tests used in clinical assessment and follow up of head injuries.

Second impact syndrome or cerebral swelling after sporting head injury.

Second impact syndrome is believed to be the catastrophic consequence of repeated head injury in sport. The scientific evidence to support this concept is nonexistent, and belief in the syndrome is based upon the interpretation of anecdotal cases more often than not, lacking sufficient clinical detail to make definitive statements. The fear of this condition has driven many of the current return-to-play guidelines following concussion. Diffuse cerebral swelling (DCS) following a head injury is a well-recognized condition, more common in children than in adults, and usually has a poor outcome.

The difficult concussion patient: what is the best approach to investigation and management of persistent (>10 days) postconcussive symptoms?

Background Concussion in sport typically recovers clinically within 10 days of injury. In some cases, however, symptoms may be prolonged or complications may develop. The objectives of the current paper are to review the literature regarding the difficult concussion and to provide recommendations for an approach to the investigation and management of patients with persistent symptoms. Methods A qualitative review of the literature on concussion in sport was conducted with a focus on prolonged recovery, long-term complications and management including investigation and treatment strategies. MEDLINE and Sports Discus databases were reviewed. Results Persistent symptoms (>10 days) are generally reported in 10–15% of concussions. This figure may be higher in certain sports (eg, ice hockey) and populations (eg, children). In general, symptoms are not specific to concussion and it is important to consider and manage coexistent pathologies. Investigations may include formal neuropsychological testing and conventional neuroimaging to exclude structural pathology. Currently, there is insufficient evidence to recommend routine clinical use of advanced neuroimaging techniques or genetics markers. Preliminary studies demonstrate the potential benefit of subsymptom threshold activity as part of a comprehensive rehabilitation programme. Limited research is available on pharmacological interventions. Conclusions Cases of concussion in sport where clinical recovery falls outside the expected window (ie, 10 days) should be managed in a multidisciplinary manner by healthcare providers with experience in sports-related concussion. Important components of management, after the initial period of physical and cognitive rest, include associated therapies such as cognitive, vestibular, physical and psychological therapy, assessment for other causes of prolonged symptoms and consideration of a graded exercise programme at a level that does not exacerbate symptoms.