History of CISG

The Concussion in Sport Group (CISG)

In 2018, the Concussion in Sport Group (CISG) was established as a ‘not-for-profit’ association under Swiss law. The founding members of the Association were: Jiří Dvořák, MD; Paul McCrory, MD; Willem Meeuwisse, MD; Jon Patricios, MD; Ruben Echemendia, PhD; Gavin Davis, MBBS; David Maddocks, PhD; Kathryn Schneider, PhD; and Michael Makdissi, MD.

The aim of this association is to organize the scientific content for conferences and educational events, facilitate research, and to hold the intellectual property and copyright of CISG material. In order to avoid potential conflict of interest, only individuals (i.e., not sports organisations) can be members of this association. CISG membership is open to the members of the Expert Panel appointed for each CISG meeting, co-authors of the systematic reviews as well as observers according the CISG statutes version 2022.

Associate membership is available to all other individuals with clinical, research, technical administrative or policy interest in the field of concussion. Associate members shall not have a right to vote or to take part in elections and shall not be entitled to be on the Board or be members of councils, committees or sub-committees unless stated otherwise in the by-laws.

The Board aims to represent a diverse range of perspectives on concussion and is committed to becoming more culturally diverse and inclusive through a process of rotation of some Board members every two years. The first step towards diversifying membership was to include 2 members of the Concussion in Para-sport (CIPS) group as Board members. Board meetings occur at least twice though typically 4 times a year.

The Concussion in Para Sport group (CIPS)

The membership of CISG was diversified in 2021 through the inclusion of two members of the Concussion in ParaSport (CIPS) group as CISG board members. The CIPS group was established in 2020 to provide a dedicated focus on the unique needs of the para athlete. It compromises a multidisciplinary panel of experts who are academically and/or clinically experienced in para sport or concussion, including clinicians, researchers, para athletes with experience of concussion, and other expert professionals with experience in this field. Following the publication of the CIPS group 1st Position Statement on Concussion in Sport in 2021, the CISG invited the CIPS group to nominate 2 members to sit on the CISG board and the initial two members selected for this were Osman Ahmed, PhD (Senior Physiotherapist, University Hospitals Dorset NHS Foundation Trust, United Kingdom) and Cheri Blauwet, MD (Associate Professor of PM&R, Harvard Medical School).

Weiler R, Blauwet C, Clarke D, Dalton K, Derman W, Fagher K, Gouttebarge V, Kissick J, Lee K, Lexell J, Van de Vliet P, Verhagen E, Webborn N, Ahmed OH. Concussion in para sport: the first position statement of the Concussion in Para Sport (CIPS) Group. Br J Sports Med. 2021 Nov;55(21):1187-1195.

History of the CISG and the Consensus Conferences on Concussion in Sport

Contributions and editorial review by: Jiri Dvorak, Jon Patricios, Willem Meeuwisse, Ruben Echemendia, Kathryn Schneider, Cheri Blauwet, Michael Makdissi, Gavin Davis, Osman Ahmed, David Maddocks, Steven Broglio, Donna Broshek, Christopher Giza, Christina Master, Margot Putukian, and Vicki Anderson.

At the forefront of sports medicine and athlete welfare, the inaugural International Conference on Concussion in Sport was convened in Vienna in 2001. With the participation of experts from various medical disciplines, the conference set a mission to enhance the safety and health of athletes affected by sport-related concussions (SRC). The conference aimed to provide a global platform for discussion on a complex and growing issue in sports. The scientific committee established the foundation for what would be a series of discussions shaping the future of SRC management for the decades that followed. The conference culminated with the formation of the ‘Concussion in Sport Group’ (CISG), entrusted to draft summary and agreement statements that later evolved into consensus statements that outlined the collective insights from the symposium.

The Vienna conference initiated quadrennial meetings to continue this critical dialogue. The subsequent conferences in Prague (2004) and Zurich (2008 and 2012) further advanced the understanding of SRC, introducing tools such as the Sport Concussion Assessment Tool (SCAT®), and continuously refining the approaches to prevention, recognition, management, and recovery of concussions in sport. Each conference built progressively on the pillars established in 2001, with additional focus on pediatric concussion and incorporating ethical considerations into care.

As the consensus process evolved, so did recognition of the diverse needs within the sporting community, leading to the development of targeted tools for different age groups and the inclusion of considerations for para-athletes. These ideas were prominently addressed at the 5th International Conference in Berlin in 2016, and the 6th International Conference in Amsterdam in 2022.

Embedded in these conferences is an acknowledgment of the dynamic nature of SRC research—it is neither static nor taken as dogma, but rather as a body of knowledge that evolves with scientific discovery and clinical insights. This enduring dedication to athlete safety and wellbeing through rigorous, open, and collaborative discussion embodies the spirit of the Vienna conference and its subsequent iterations. The legacy of the first conference extends well beyond its initial mandate, firmly entrenching sport-related concussion as a serious consideration within the tapestry of global sports culture.

This document is designed to recognize and document the history of the Concussion in Sport Group and the contributions made by a myriad of researchers, clinicians, and advocates from across the globe in their efforts to advance the health and safety of health of athletes affected by sport-related concussions.

First International Conference on Concussion in Sport (Vienna 2001)

The International Ice Hockey Federation (IIHF) organized the first concussion symposium in Vienna, Austria at the Marriott Hotel in October 2001. Mr. Murray Costello (Executive Member of IIHF Council and Chairman of Medical Committee), Mr. David Fitzpatrick (IIHF Sport Director) and Dr. Mark Aubry (Chief Medical Officer), developed the concept of a scientific meeting on sport-related concussion and approached known experts in this field. With no consistent guidance for the medical management of SRC, the mission statement for the meeting was “to provide recommendations for the improvement of safety and health of athletes who suffer concussive injuries in sports.” One of the key drivers for the timing of the meeting was the forthcoming 2002 Salt Lake City Winter Olympics and the need to develop clear guidelines for the IIHF ahead of that event.

The IIHF invited a range of experts to address specific issues on epidemiology, basic and clinical science, grading systems, cognitive assessment, new research methods, protective equipment, management, prevention, and long-term outcome, and to discuss a unitary model for understanding concussive injury. The invited experts, clinicians, and active researchers from around the world, included Drs. Robert Cantu (Director of Neurosurgery, Emerson Hospital, Concord Mass, USA), James Kelly (Associate Professor of Clinical Neurology, Northwestern University Medical School, Chicago Neurological Institute, Chicago, IL, USA), Mark Aubry (Chief Medical Officer, IIHF), Jiří Dvořák (Chair of the Dept of Neurology, Schulthess Clinic Zurich, Chief Medical Officer, FIFA, Chairman, FIFA Medical Research and Assessment Center), Toni Graf-Baumann (Director, Office for Science Management, Administration and Scientific Director, German Society for Musculo-Skeletal Medicine and Pain Therapy), Karen Johnston (Director of Neurotrauma, McGill University Health Centre, Montreal, Canada), Mark Lovell (Director, Sports Medicine Concussion Program, University of Pittsburgh, USA), Willem Meeuwisse (Professor, University of Calgary, Sport Medicine Center, Calgary, Canada), Patrick Schamasch (Director, International Olympic Committee Medical Commission, Lausanne, Switzerland), and Paul McCrory (Neurologist, University of Melbourne, Australia).

A scientific committee was established to determine the conference program and its membership included Karen Johnston, Willem Meeuwisse, Mark Aubry, and Paul McCrory. The IIHF invited the Federation Internationale de Football Association (FIFA) and International Olympic Committee (IOC) to participate as co-sponsors of the meeting and Jiri Dvorak (FIFA/F-MARC) and Patrick Schamasch (IOC) joined the committee to help develop the program.

The symposium was organized over a two-day period in October 2001. At the conclusion of the conference, a small group of experts (known as ‘Concussion in Sport Group’ (CISG)) was given a mandate by the conference delegates to draft a document “describing the agreement position reached by those in attendance at that meeting.” This group comprised: M Aubry, R Cantu, J Dvorak, T Graf-Baumann, K Johnston, J Kelly, M Lovell, P McCrory, W Meeuwisse, and P Schamasch. The audience of approximately 150 delegates was mainly European as the symposium took place shortly after the 9/11 terrorist attacks, which limited the US and international delegate participation. There was a clearly identified mandate of the organizers and participants to have future meetings and to update the document taking into consideration subsequent new knowledge. The outcome paper was co-published in the British Journal of Sports Medicine, the Clinical Journal of Sport Medicine, and Physician and Sports Medicine.

Aubry, M., Cantu, R., Dvorak, J., Graf-Baumann, T., Johnston, K., Kelly, J., Graf-Baumann T, Johnston K, Kelly J, Lovell, Ml, McCrory P, Meeuwisse W, and Schamasch, P. (2002). Summary and agreement statement of the First International Conference on Concussion in Sport, Vienna 2001. Recommendations for the improvement of safety and health of athletes who may suffer concussive injuries. Br J Sports Med, 36(1), 6-10.

The 2nd International Conference on Concussion in Sport (Prague 2004)

The 2nd meeting, held in Prague, came about after discussions within IIHF regarding the need for another meeting to update any research that may have occurred in the intervening period. The IIHF agreed to start discussions with the same sponsor groups as for Vienna in 2001, with the additional potential involvement of the International Rugby Board (IRB, later to become World Rugby). IIHF organized the meeting, supported by the Charles University Prague and the conference took place at the Hilton Hotel in Prague, Czech Republic.

A wider group of experts attended this meeting, including representation from different groups such as trauma surgeons, neurosurgeons, paediatric emergency room specialists, neuroscientists, and sports psychologists. The keynote speaker was Professor Sir Graham Teasdale, an eminent neurosurgeon from Scotland who had authored the Glasgow Coma Scale and was a pioneer in traumatic brain injury research.

The scientific committee that developed the program consisted of Karen Johnston, Willem Meeuwisse, Mark Aubry, Robert Cantu, Jiří Dvořák, Toni Graf-Baumann, James Kelly, Mark Lovell, Patrick Schamasch, and Paul McCrory.

The summary statement from this meeting reported no changes to the general definition of concussion, “beyond noting that in some cases post-concussive symptoms may be prolonged or persistent.” However, the CISG did attempt to categorize different subtypes of concussion. After lengthy discussion, rather than using grading systems, the group reached an agreement that, for management purposes, concussion could be classified as either “simple” or “complex” based on the duration of symptoms. There was extensive discussion around this point; although the delegates supported the concept of differential symptomatic durations of injury, there was concern about the terminology, but it was accepted.

In addition to creating these classifications, the statement reassessed the tools available for concussion evaluation. Some months after the meeting, the group released the Sport Concussion Assessment Tool (SCAT) for sideline use in the evaluation of concussion. The intent was to create a standardised tool that could be used for patient education as well as for clinician assessment. It combined several pre-existing tools and was evaluated for face and content validity based on the scientific literature and clinical experience of the authors. The SCAT was co-authored by Paul McCrory, Karen Johnson and Willem Meeuwisse, on behalf of CISG and was included as an appendix to the 2005 Summary and Agreement Statement and was published alongside a supporting commentary.

McCrory, P., Johnston, K., Meeuwisse, W., Aubry, M., Cantu, B., Dvorak, J., . . . Schamasch, P. (2005). Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague, 2004. Br J Sports Med, 39(4), 196-204. doi: 10.1136/bjsm.2005.018614.

The 3rd International Conference on Concussion in Sport (Zurich 2008)

Following the initial CISG meetings, the IIHF, with the assistance of the previous supporting organisations (IOC, FIFA and IRB), perceived a need to update SRC injury management recommendations with current scientific research published since 2004. These organizations established the Organizing and Scientific committees to begin that process for the 2008 meeting, which included Willem Meeuwisse, Karen Johnston, Jiří Dvořák, Mark Aubry, Mick Molloy (Chief Medical Officer, International Rugby Board), Robert Cantu, and Paul McCrory. FIFA provided the logistical support and organized the meeting at FIFA headquarters in Zurich.

The role of the Organizing Committee was to provide funding to support the costs associated with the quadrennial consensus conference (e.g., speaker travel, hotel food and beverage charges, funding for methodologists and librarian assistance for the systematic reviews, etc.). In contrast, the role of the Scientific Committee was to develop, monitor, and execute all scientific components related to the conference (e.g., identify speakers/expert panel members, identify questions for the systematic reviews, establish and monitor the methodology for the systematic reviews, aggregate discussions and conclusions, revise the SCAT tools as needed, hold and maintain the intellectual property rights of the tools, and disseminate the conference proceedings, systematic reviews, consensus documents, and tools through scientific journals).

Unlike the first two conferences, which put forward “agreement” papers, the recommendation of the Scientific Committee was that the meeting be designed as a formal meeting that produced a consensus statement, adhering as closely as possible to the protocols outlined by the U.S. National Institutes of Health (NIH). The NIH process (https://www.ncbi.nlm.nih.gov/books/NBK235517/#:~:text=NIH%20consensus%20development%20conferences%20include,statement%20based%20on%20its%20) judgment, which is paraphrased below included:

A broad-based non-government, non-advocacy panel be assembled to give balanced, objective and knowledgeable attention to the topic. Panel membership should exclude anyone with scientific or commercial conflicts of interest and include researchers in clinical medicine, sports medicine, neuroscience, neuroimaging, athletic training, and sports science. Each expert and speaker provided a standardized disclosure, conflict of interest, and affiliation form.
The experts presented data in a public session, followed by inquiry and discussion.
Several specific questions were prepared and posed in advance to define the scope and guide the direction of the conference. The principal task of the panel was to elucidate responses to these questions.
The panel then met in an executive session to prepare the consensus statement.
A systematic literature review was prepared and circulated in advance for use by the panel in addressing the conference questions.
The consensus statement was created to serve as the scientific record of the conference.
The consensus statement was widely disseminated to achieve maximum impact on both current healthcare practice and future medical research.

The panel that drafted the consensus statement following the process outlined above
consisted of Willem Meeuwisse, Karen Johnston, Jiří Dvořák, Mark Aubry, Mick Molloy, Robert Cantu, and Paul McCrory. In addition to these authors, the consensus panel also included Steven Broglio, (Director, NeuroTrauma Research Laboratory, at the University of Illinois at Urbana-Champaign ), Gavin A. Davis (Neurosurgeon, Australia), Randall Dick (Assistant Director of the National Collegiate Athletic Association Research/Injury Surveillance System), Jiří Dvořák(Dept of Neurology, Schulthess Clinic Zurich, CH), Ruben Echemendia (Founding President, Sports Neuropsychology Society USA), Gerard Gioia (Chief, Division of Pediatric Neuropsychology, Children’s National Health System; Professor, at George Washington School of Medicine, USA), Kevin Guskiewicz (Chair of Exercise and Sport Science at the University of North Carolina at Chapel Hill), Stanley Herring (Clinical Professor Departments of Rehabilitation Medicine, Orthopaedics and Sports Medicine and Neurological Surgery at the University of Washington in Seattle, Washington), Grant Iverson (University of British Columbia), James Kelly (University of Colorado School of Medicine, Denver, CO, USA), James Kissick (Sport Medicine Physician at Ottawa Sport Medicine Centre, Canada), Michael Makdissi (Research Fellow, The Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, Austin Campus, Melbourne, Australia), Michael McCrea (Professor & Director of Brain Injury Research, Departments of Neurosurgery and Neurology, at the Medical College of Wisconsin), Alain Ptito (Director, Department of Psychology, McGill University, Montreal, Canada), Laura Purcell (Associate Professor, Department of Pediatrics, McMaster University, Ontario, Canada; and Founding President, Pediatric Sport and Exercise Medicine Section of the Canadian Pediatric Society), and Margot Putukian (Director of Athletic Medicine and Assistant Director of Medical Services, Princeton University).

The Organizing and Scientific Committees elected to broaden the expert panel, speakers, and attendees to include, athletic trainers, emergency physicians, pediatricians, neuropsychologists, rehabilitation physicians, physiatrists, and orthopaedic surgeons. The Zurich consensus statement put forth a definition of concussion that was similar to that used in prior statements, with few revisions to clarify or strengthen past positions.

At the meeting, the panel unanimously agreed to abandon the “simple versus complex” terminology that had been proposed in the Prague agreement statement because the “terminology itself did not fully describe the entities.” Moreover, it was felt that the use of the term “simple” concussion might give an incorrect message to readers that the injury was trivial. However, the panel unanimously retained the concept that the majority (80-90%) of concussions “resolve in a short (7-10 day) period, although the recovery time frame may be longer in children and adolescents.” In many ways, the ability for the CISG conference to discuss and overturn previous recommendations based on subsequent research and/or clinical evidence rather than recommendations being seen as dogma, is a strength of the process.

In addition to the consensus statement and a supporting commentary, the meeting produced the SCAT2, and a tool for use by non-medical personnel, the Pocket SCAT2.

McCrory, P., Meeuwisse, W. H., Johnston, K., Dvorak, J., Aubry, M., Molloy, M., & Cantu, R. (2009). Consensus Statement on Concussion in Sport: the 3rd International Conference on Concussion in Sport held in Zurich, November 2008. Br J Sports Med, 43 Suppl 1(3), i76-90.

The 4th International Conference on Concussion in Sport (Zurich 2012)

The 4th International Conference on Concussion in Sport followed the same consensus process as the third meeting, but did not require complete agreement on each topic; individual members could either withdraw from the group or file a dissenting opinion that would be published as part of the Consensus document.

The Scientific Committee consisted of Willem H. Meeuwisse, Mark Aubry, Robert Cantu, Jiří Dvořák, Ruben Echemendia, Lars Engebretsen (Professor, Department of Orthopaedic Surgery, Oslo University Hospital, and Faculty of Medicine, University of Oslo, Norway), Karen Johnston, Jeffrey S. Kutcher (Associate Professor and Director, Michigan NeuroSport, Department of Neurology, University of Michigan), Martin Raftery (Chief Medical Ofﬁcer, International Rugby Board, Dublin, Ireland), Allen Sills (Associate Professor of Neurosurgery, Orthopaedic Surgery and Rehabilitation, Vanderbilt Sports Concussion Center, Vanderbilt University Medical Center), Brian W. Benson (Clinical Assistant Professor, Department of Family Medicine, University of Calgary, Calgary, Alberta, Canada), Gavin A. Davis, Richard G. Ellenbogen (Professor and Chairman, Theodore S. Roberts Endowed Chair, Department of Neurological Surgery, University of Washington; co-Director of NFL Head, Neck and Spine Medical Committee), Kevin Guskiewicz, Stanley A. Herring, Grant Iverson, Barry D. Jordan (Associate Professor of Clinical Neurology at Weill Medical College of Cornell University, Assistant Medical Director of the Burke Rehabilitation Hospital, White Plains, New York), James Kissick, Michael McCrea, Andrew S. McIntosh (Adjunct Associate Professor, Australian Centre for Research into Injury in Sports and its Prevention, Monash Injury Research Institute, at Monash University, Australia), David Maddocks (Barrister & Solicitor at Perry Maddocks Trollope Lawyers, Melbourne, Australia), Michael Makdissi, Laura Purcell, Margot Putukian, Kathryn Schneider (Assistant Professor and Clinical Scientist (Physiotherapist), Sport Injury Prevention Research Centre, at the University of Calgary, Canada), Charles H. Tator (Professor of Neurosurgery at Toronto Western Hospital), Michael Turner (Chief Medical Adviser for the British Horseracing Authority in the United Kingdom), and Paul McCrory.

To provide transparency regarding affiliations and potential conflicts of interest of participants, the Scientific Committee ensured that the British Journal of Sports Medicine (BJSM) published a spreadsheet detailing all the affiliations and financial conflicts of interest (COI) declarations by each author as a supplemental file to the summary paper.

The panel again started with the definition of concussion and made minor changes. The panel also discussed how the definition of concussion is different from the definition of mTBI. The panel acknowledged, “that although the terms mTBI and concussion are often used interchangeably in the sporting context and particularly in the US literature, others use the term to refer to different injury constructs.” The consensus statement sought to clarify that concussion is a subset of TBI and “is the historical term representing low-velocity injuries that cause brain ‘shaking’ resulting in clinical symptoms and that are not necessarily related to a pathological injury.” The group’s statement regarding neuroimaging, fMRI, and other alternative imaging technologies, such as PET scans and diffusion tensor imaging, remained unchanged. The same is true of the group’s assessment of genetic markers, as well as biochemical serum and cerebral spinal fluid biomarkers. Modern Chronic Traumatic Encephalopathy (CTE) had only been identified a few years earlier, but the consensus statement reissued a warning that “clinicians need to be mindful of the potential for long-term problems in the management of all athletes.” However, unlike in its 2008 statement, the group “agreed that CTE represents a distinct tauopathy with an unknown incidence in athletic populations…” It was further agreed that “…a cause-and-effect relationship has not as yet been demonstrated between CTE and concussions or exposure to contact sports.” The consensus statement observed there were no published epidemiological, cohort, or prospective studies relating to modern CTE, and due to the nature of case reports and pathological case series, it was not possible to determine the causality or risk factors with any certainty, underscoring the speculation that repeated concussion or sub-concussive impacts cause CTE remained unproven. The statement also recognized that the published literature largely failed to account for the role of age-related changes, psychiatric or mental health illness, alcohol/drug use, co-existing medical illnesses, or dementia contributing to this process. Based on the existing studies, the consensus statement advised that the interpretation of causation in modern CTE case studies should proceed cautiously. The consensus statement also recognized it was important to address the fears of parents/athletes about the possibility of CTE due to growing media coverage of CTE.

The CISG updated the SCAT®, with publication of the SCAT3®, and revised the Pocket Concussion Recognition Tool developed for use by laypersons. The meeting considered that paediatric concussion warranted specific and separate tools from those used in adult concussion, and charged Gavin Davis, Laura Purcell, Michael McCrea, Gerard Gioia, Rich Ellenbogen, Christopher Vaughan (Pediatric Neuropsychologist, Children’s National Health System; Assistant Professor, at George Washington School of Medicine, USA), Kevin Guskiewicz, Jeffrey Kutcher, Willem Meeuwisse, Paul McCrory, Michael Kirkwood, Ruben Echemendia, and Keith Yeates with the task of developing a child-specific SCAT®, the Child SCAT3®.

Consensus statement:

McCrory, P., Meeuwisse, W. H., Aubry, M., Cantu, R., Dvorak, J., Echemendia, R. J., Turner, M. (2013). Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. Br J Sports Med, 47(5), 250-258. doi: 10.1136/bjsports- 2013-092313,

Systematic Reviews:

McCrory P, Meeuwisse WH, Echemendia RJ, et al. What is the lowest threshold to make a diagnosis of concussion? British Journal of Sports Medicine 2013;47:268-271.

Guskiewicz, K. M., Register-Mihalik, J., McCrory, P., McCrea, M., Johnston, K., Makdissi, M., Meeuwisse, W. H.. Evidence-based approach to revising the SCAT2: introducing the SCAT3. Br J Sports Med, 2013; 47(5), 289-293. doi: 10.1136/bjsports-2013-092225.

McCrea M, Iverson GL, Echemendia RJ, et al. Day of injury assessment of sport-related concussion. British Journal of Sports Medicine 2013;47:272-284.

Putukian M, Raftery M, Guskiewicz K, et al. Onfield assessment of concussion in the adult athlete. British Journal of Sports Medicine 2013;47:285-288.

Echemendia RJ, Iverson GL, McCrea M, et al. Advances in neuropsychological assessment of sport-related concussion. British Journal of Sports Medicine 2013;47:294-298.

Kutcher JS, McCrory P, Davis G, et al. What evidence exists for new strategies or technologies in the diagnosis of sports concussion and assessment of recovery? British Journal of Sports Medicine 2013;47:299-303.

Schneider KJ, Iverson GL, Emery CA, et al. The effects of rest and treatment following sport-related concussion: a systematic review of the literature. British Journal of Sports Medicine 2013;47:304-307.

Makdissi M, Cantu RC, Johnston KM, et al. The difficult concussion patient: what is the best approach to investigation and management of persistent (>10 days) postconcussive symptoms? British Journal of Sports Medicine 2013;47:308-313.

Makdissi M, Davis G, Jordan B, et al. Revisiting the modifiers: how should the evaluation and management of acute concussions differ in specific groups? British Journal of Sports Medicine 2013;47:314-320.

Benson BW, McIntosh AS, Maddocks D, et al. What are the most effective risk-reduction strategies in sport concussion? British Journal of Sports Medicine 2013;47:321-326.

McCrory P, Meeuwisse WH, Kutcher JS, et al. What is the evidence for chronic concussion-related changes in retired athletes: behavioural, pathological and clinical outcomes? British Journal of Sports Medicine 2013;47:327-330.

Provvidenza C, Engebretsen L, Tator C, et al. From consensus to action: knowledge transfer, education and influencing policy on sports concussion. British Journal of Sports Medicine 2013;47:332-338.

The 5th International Conference on Concussion in Sport (Berlin 2016)

The 5th International Conference on Concussion in Sport took place in Berlin in October 2016. The IIHF provided the logistical support and organized the meeting and, in addition to the previous members of the Organizing Committee, the International Equestrian Federation (FEI) joined as a co-sponsor.

The meeting followed similar processes to the previous two conferences. The group also adhered to the same rules regarding reaching consensus employed in 2012, allowing individual members to either withdraw from the group or file a dissenting opinion that would be published as part of the Consensus document. No authors availed themselves of this option.

In the public consensus session, the conference hosted 420 participants from 24 countries. The Scientific Committee included Willem Meeuwisse, Jiri Dvorak, Lars Engebretsen, Nina Feddermann-Demont (University Hospital Zurich, Zurich, Switzerland; Sports Neuroscience, University of Zurich, Zurich, Switzerland, Michael Makdissi, Ruben Echemendia, Mike McCrea, Jon Patricios, Kathryn Schneider, Allen Sills, and Paul McCrory. There were 36 faculty experts representing a variety of disciplines both within and outside the sports realm that formed the Expert Panel and tasked with drafting the consensus statement. These included: Paul McCrory, Willem H. Meeuwisse, Jiří Dvořák, Mark Aubry, Julian Bailes, Steven P. Broglio, Robert C. Cantu, David Cassidy (Division of Health Care and Outcomes Research, Toronto Western Research Institute, Toronto, Canada), Rudolph J. Castellani (Department of Pathology, University of Maryland, Baltimore, Baltimore, Maryland, USA), Gavin A. Davis, Ruben J. Echemendia, Richard G. Ellenbogen, Carolyn A. Emery (Department of Kinesiology, University of Calgary, Calgary, Canada), Lars Engebretsen, Nina Feddermann-Demont, Christopher C. Giza, Kevin Guskiewicz, Stanley A. Herring, Grant L. Iverson, Karen Johnston, James Kissick, Jeffrey Kutcher, John Leddy (Department of Orthopaedics, SUNY Buffalo, Buffalo, New York, USA), David Maddocks, Michael Makdissi, Geoffrey T. Manley (Department of Neurosurgery, University of California San Francisco, San Francisco, California, USA), Michael McCrea, William Meehan, Shinji Nagahiro (Tokushima Daigaku Byoin, Tokushima, Japan), Jon Patricios, Margot Putukian, Kathryn Schneider, Allen Sills, Charles H. Tator, Michael Turner, and Pieter Vos (Department of Neurology, Slingeland Ziekenhuis, Doetinchem, The Netherlands).

A methodology paper was published alongside the outputs from the conference to summarize the methodology of the process to inform the consensus statement (Meeuwisse et al, 2017). A modified Delphi technique was used to identify the most meaningful questions, which would be addressed through systematic reviews. Twelve systematic reviews were subsequently performed that ultimately informed the consensus process. Lead authors were selected based on their contributions to the literature and clinical and scientific expertise as leaders in the field, with co-authors selected from the expert panel in a similar fashion, and additional co-authors selected in the case where additional expertise was needed. Panelists were drawn from clinical practice, academics and research in the field of SRC. They do not represent organisations per se, but were selected for their expertise, experience and understanding of this field.

To ensure the rigour of the review process, the systematic reviews followed a standardized process using the “Enhancing the Quality and Transparency of Health Research (EQUATOR) network” based on BJSM author guidelines and following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All reviews had a focus on sport-related concussion; however, in cases where the literature was sparse or of poor methodological quality, it was recommended that the discussion section of the papers draw upon other literature relating to other causes of mild traumatic brain injury or concussion.

In addition, there were additional experts who did not contribute to the consensus statement, but participated in the CISG process as co-authors of the accompanying systematic reviews and /or the SCAT updates. Approximately 60,000 published papers were reviewed as part of the systematic review process. The areas covered in the management of concussion included: recognition, removal from play, evaluation, the role of rest, rehabilitation, referral to specialist services, recovery strategies, safe return to sport, residual effects, and risk reduction. The consensus statement summarizes the “CISG 11R” – Recognize, Remove, Re-evaluate, Rest, Rehabilitate, Refer, Recovery, Return to Play, Reconsider, Residual effects, Risk reduction, which should facilitate the process for the managing health care provider. The outcome papers, methodology process, including the selection of expert panel, SCAT updates, and systematic reviews, were published in BJSM.

Furthermore, to provide transparency regarding affiliations and potential conflicts of interest of participants, the scientific committee ensured that the BJSM made available all the author COI forms. These are the standard forms completed by all authors submitting manuscripts to journals and list all potential or perceived COIs.

Consensus Statement:

McCrory P, Meeuwisse WH, Dvořák J, Echemendia RJ, Engebretsen L, Feddermann Demont N, McCrea M, Makdissi M, Patricios J, Schneider KJ, Sills AK. 5th International Conference on Concussion in Sport (Berlin). Br J Sports Med. 2017 Jun;51(11):837.

Systematic Reviews and Associated Papers:

Meeuwisse WH, Schneider KJ, Dvořák J, Omu OT, Finch CF, Hayden KA, McCrory P. The Berlin 2016 process: a summary of methodology for the 5th International Consensus Conference on Concussion in Sport. Br J Sports Med. 2017 Jun;51(11):873-876.

Manley G, Gardner AJ, Schneider KJ, Guskiewicz KM, Bailes J, Cantu RC, Castellani RJ, Turner M, Jordan BD, Randolph C, Dvořák J, Hayden KA, Tator CH, McCrory P, Iverson GL. A systematic review of potential long-term effects of sport-related concussion. Br J Sports Med. 2017 Jun;51(12):969-977.

Echemendia RJ, Meeuwisse W, McCrory P, Davis GA, Putukian M, Leddy J, Makdissi M, Sullivan SJ, Broglio SP, Raftery M, Schneider K, Kissick J, McCrea M, Dvořák J, Sills AK, Aubry M, Engebretsen L, Loosemore M, Fuller G, Kutcher J, Ellenbogen R, Guskiewicz K, Patricios J, Herring S. The Concussion Recognition Tool 5th Edition (CRT5): Background and rationale.Br J Sports Med. 2017 Jun;51(11):870-871.

McCrory P, Meeuwisse W, Dvorak J, Aubry M, Bailes J, Broglio S, Cantu RC, Cassidy D, Echemendia RJ, Castellani RJ, Davis GA, Ellenbogen R, Emery C, Engebretsen L, Feddermann-Demont N, Giza CC, Guskiewicz KM, Herring S, Iverson GL, Johnston KM, Kissick J, Kutcher J, Leddy JJ, Maddocks D, Makdissi M, Manley G, McCrea M, Meehan WP, Nagahiro S, Patricios J, Putukian M, Schneider KJ, Sills A, Tator CH, Turner M, Vos PE. Infographic: Consensus statement on concussion in sport. Br J Sports Med. 2017 Nov;51(21):1557-1558.

Davis G, Purcell L, Schneider K, Yeates K, Gioia G, Anderson V, Ellenbogen R, Echemendia R, Makdissi M, Sills A, Iverson G, Dvorak J, McCrory P, Meeuwisse W. The Child Sport Concussion Assessment Tool 5 th Edition (Child SCAT5). BJSM 2017:51(11); 859-861. Child SCAT5 Tool: Pages 862-869.

Patricios J, Fuller G, Ellenbogen R, Herring S, Kutcher J, Loosemore M, Makdissi M, McCrea M, Putukian M, Schneider K. What are the critical elements of sideline screening that can be used to establish the diagnosis of concussion? A systematic review. BJSM 2017:51(11);888-894.

Echemendia R, Broglio S, Davis G, Guskiewicz K, Hayden A, Leddy J, Meehan W, Putukian M, Sullivan J, Schneider K, McCrory P. What tests and measures should be added to the SCAT3 and related tests to improve their reliability, sensitivity and/or specificity in sideline concussion diagnosis? A systematic review. BJSM. 2017:51(11);895-901. https://bjsm.bmj.com/content/51/11/895.long

Feddermann-Demont N, Echemendia R, Schneider K, Solomon G, Hayden A, Turner M, Dvorak J, Straumann D, Tarnutzer A. What domains of clinical function should be assessed post-injury (concussion)? A systematic review. BJSM 2017:51;903-918.

McCrea M, Meier T, Huber D, Ptito A, Bigler E, Debert C, Manley G, Menon D, Chen J, Wall R, Schneider K, McAllister T. Role of advanced neuroimaging, fluid biomarkers and genetic testing in the assessment of sport-related concussion: A systematic review. BJSM. 2017:51;919-929.

Schneider K, Leddy J, Guskiewicz K, Seifert T, McCrea M, Silverberg N, Feddermann Demont N, Iverson G, Hayden A, Makdissi M. Rest and specific treatments following sport-related concussion: A systematic review. BJSM. 2017:51;930-934.

Kamins J, Bigler E, Covassin T, Henry L, Kemp S, Leddy J, Mayer A, McCrea M, Prins M, Schneider K, Valovich McLeod T, Zemek R, Giza C. What is the physiological time to recovery after concussion? BJSM. 2017:51;935-940.

Davis G, Anderson V, Babl F, Gioia G, Giza C, Meehan W, Moser R, Purcell L, Schatz P, Schneider K, Takagi M, Yeates K, Zemek R. What is the difference in concussion management in children as compared to adults? A systematic review. BJSM. 2017:51(12);949-957. https://bjsm.bmj.com/content/51/12/949.

Makdissi M, Schneider K, Feddermann-Demont N, Guskiewicz K, Hinds S, Leddy J, McCrea M, Turner M, Johnston K. Approach to investigation and treatment of persistent symptoms following sport-related concussion: A systematic review. BJSM. 2017:51:958-968.

Emery C, Kolstad A, Martinez G, Black A, Nettel-Aguirre A, Engebretsen L, Johnson K, Kissick J, Maddocks D, Tator C, Aubry M, Dvorak J, Nagahiro S, Schneider K. What strategies can be used to effectively reduce the risk of concussion in sport? A systematic review and meta-analysis. BJSM. 2017:51;978-984.

Iverson GI, Gardner AJ, Terry DP, Ponsford JL, Sills AK, Broshek DK, Soloman GS. Predictors of clinical recovery from concussion a systematic review. BJSM 2017:51;941-948.

Paediatric Concussion

The Vienna meeting and subsequent published statement were focused on adult concussion. In Prague, a meeting session was devoted to paediatric concussion and the agreement statement suggested that the adult recommendations were also applicable to children ages 5-18 years. In Zurich 2008, specific paediatric questions were addressed during the meeting and were included in the consensus statement, and the application of the majority of the adult recommendations was deemed appropriate for children 10-18 years, and it was agreed that age-appropriate recommendations were required for younger children. In Zurich 2012 the application of adult recommendations was limited to children 13-18 years, and the Child SCAT3 was developed for use in children 5-12 years. In all the meetings, the consensus was that a more conservative approach be adopted in managing concussion in children.

The first CISG systematic review dedicated to paediatric concussion was presented in Berlin, and specific recommendations for children 5-12 years and 13-18 years were published, in addition to the Child SCAT5® for children 5-12 years. In preparation for Amsterdam 2022, each of the 10 systematic reviews included paediatric-specific content, and the SCAT® continued to include paediatric versions.

The 6th International Conference on Concussion in Sport (Amsterdam 2022)

The 6th International Conference on Concussion in Sport was held in Amsterdam, Netherlands in October 2022. The consensus process began early in 2018 as the initially proposed date for the conference was October 2020 in Paris, France. The details of the methodological processes that were set a priori are outlined in the Methodology paper that accompanied the consensus statement (see Schneider et al, 2023). The Organizing Committee was composed of the funding associations (FEI, FIFA, Fédération Internationale de l'Automobile (FIA), IIHF, IOC, WR). The Organizing Committee consisted of Fredrik Bendiksen, Mark Aubrey (IIHF), Martin Raftery (World Rugby), Allen Sills (FEI), Martin Vaso (FIFA), Lars Engebretsen (IOC), and Paul Rea (FAI). Subsequently, Éanna Falvey replaced Martin Raftery representing WR; Catherine Bollon replaced Allen Sills representing FEI; and Andy Massey represented FIFA. Contributing partners providing unrestricted educational grants to the conference include the National Football League (NFL, USA) and National Hockey League (NHL, USA).

The Scientific Committee appointed for the meeting consisted of Gavin Davis, Jiri Dvorak, Ruben Echemendia, Michael Makdissi, Paul McCrory, Willem Meeuwisse, Jon Patricios, and Kathryn Schneider. The need to diversify both the Scientific Committee and the conference programme was identified. In August of 2020, Willem Meeuwisse stepped down as co-chair of the Scientific Committee due to additional COVID-19 pandemic work-related commitments and Kathryn Schneider was appointed as co-chair of the Scientific Committee. In August 2021, the Concussion in Para Sport Group (CIPS) was engaged in the process and Cheri Blauwet and Osman Ahmed were invited to join the Scientific Committee. Paul McCrory subsequently resigned from the CISG and all actions related to the conference in March 2022, and Kathryn Schneider and Jon Patricios were appointed co-chairs of the Scientific Committee. Michael McNamee (medical ethicist) and Robert Cantu were also invited by the Organizing Committee to join the Scientific Committee to contribute ethical perspectives and expertise on potential long term outcomes of concussion, respectively.

It was again emphasised that a key tenet was scientific independence. The high profile of SRC around the world warranted a transparent process that was as free of bias as possible. As such, the Organizing Committee and Scientific Committee formally reaffirmed that the Organising committee had no input into the scientific program, co-authors or outputs, which were overseen by the Scientific Committee. As noted previously, the role of the Organizing Committee was to provide funding to support conference logistics and an educational grant to assist with the administrative aspects of the process. These funds provided support for methodologists and librarians. Aside from partial travel support funds provided for the Scientific Committee and systematic review lead authors, none of the speakers, members or authors received any compensation for their time or work.

The Scientific Committee, evolving from the Delphi process that informed the Berlin meeting topics, proposed 10 systematic reviews to be published alongside a methodology paper detailing the process that was undertaken in the Consensus Statement. The process followed the methodology outlined in previously published papers with additional steps to improve the methodology and standardized process. The details of the methodological process that were used to inform the five-year process informing the Amsterdam Consensus Statement was published in the Methodology paper previously referenced (Schneider et al, 2023).

Conference scheduling
The IOC agreed to provide the initial logistical support for the conference. They, in turn, engaged a professional conference organizer, Publi Creations, to organize the meeting in Paris, which was initially planned for 2020. As the COVID-19 pandemic escalated, it became clear that an in-person meeting would be impossible. The Scientific Committee recommended to the Organising Committee that the meeting be postponed by a year. Both the Organising and Scientific Committees felt strongly that a consensus meeting such as this required in-person attendance to optimally facilitate discussion and dialogue. Unfortunately, as the postponed date approached, international travel had not yet opened up and a further delay was recommended by the Scientific Committee. The date was then set for 27-29 October 2022. A lack of hotel accommodation and appropriate conference venues in Paris necessitated a change of venue. The conference organizers recommended a venue in Amsterdam which was accepted by the Organizing Committee.

Amsterdam methodology
The questions and outcomes from the 5 th International Conference were used to help steer a Delphi process with the Scientific Committee identifying key questions which sought to capture the extant science in SRC and used to further develop clinical practice. Author groups conducted systematic reviews on their assigned topics. Due to the pandemic delays, a second rerun of the literature searches was conducted at the end of March 2022.

The Scientific Committee made every effort to make the process leading up to the conference and the methodology of the publications as robust as possible. The a priori consensus processes was informed by previous consensus processes, criticisms, and the BJSM Author Guidelines for Consensus Statements. The initial draft consensus process was reviewed independently by experts in consensus methodology and/or with experience in other recent consensus processes. To ensure that the ethical perspectives were captured, Mike McNamee was engaged in discussions throughout the process and a section on ethical perspectives was included in the consensus statement. Any potential conflicts were declared by speakers (podium and floor) at the conference, made publicly available online and published in BJSM with every consensus output. Questionnaires were circulated to all Scientific Committee members to survey the committee make-up from the perspective of equity, diversity and inclusion (EDI) with the aim of better future representation.

The Amsterdam Conference
The conference consisted of 2 days of an open meeting that included systematic review presentations, panel discussions, question and answer engagement with the 600 attendees, and abstract presentations. This was followed by a closed third day of consensus deliberations by an expert panel of 29 with observers in attendance. The fourth day, also closed, was dedicated to a workshop to discuss and refine the sports concussion tools [Concussion Recognition Tool 6 (CRT6), Sport Concussion Assessment Tool-6th Edition (SCAT6), Child SCAT6, and two new tools, the Sport Concussion Office Assessment Tool 6 (SCOAT6), and Child SCOAT6].

The consensus process integrated additional features including a focus on para athletes, incorporating the athlete’s perspective, concussion-specific medical ethics, and sessions dedicated to both retirement and potential long-term effects, including a focus on neurodegenerative disease.

The outcomes of the meeting were published in 2 dedicated editions of BJSM on 14 June 2023. These included several editorials, the methodology paper, 5 “Tools” (CRT6, SCAT6®, Child SCAT6®, SCOAT6, Child SCOAT6). On 13 June 2023 BJSM hosted a media release of the concussion outcomes followed by a “BJSM Live” webinar on 11 July 2023.

The main publication outputs from the conference were:

Consensus Statement:

Patricios JS, Schneider KJ, Dvorak J et al; Consensus Statement on Concussion in Sport – The 6 th International Conference on Concussion in Sport Held in Amsterdam, October 2022 . Br J Sports Med 2023;57:695–711.

Systematic Reviews and Associated Papers:

Davis GA, Echemendia RJ, Ahmed OH, et al. Introducing the Child Sport Concussion Assessment Tool 6 (Child SCAT6). Br J Sports Med 2023;57:632-635. Child SCAT6. Br J Sports Medi 2023;57:636-647.

Davis GA, Patricios JS, Purcell LK, et al. Introducing the Child Sport Concussion Office Assessment Tool 6 (Child SCOAT6). Br J Sports Med 2023;57:668-671. Child SCOAT6. Br J Sports Med 2023;57:672-688.

Davis, Gavin A, Jon Patricios, Kathryn J Schneider, Grant L Iverson, and Noah D Silverberg. 2023. "Definition of sport-related concussion: the 6th International Conference on Concussion in Sport." British Journal of Sports Medicine 57 (11):617-618. doi: 10.1136/bjsports-2022-106650.

Echemendia RJ, Burma JS, Bruce JM, et al. Acute evaluation of sport-related concussion and implications for the Sport Concussion Assessment Tool (SCAT6) for adults, adolescents and children: a systematic review. Br J Sports Med. 2023 Jun;57(11):722-735. doi: 10.1136/bjsports-2022-106661. PMID: 37316213.

Echemendia RJ, Ahmed OH, Bailey CM, et al. Introducing the Concussion Recognition Tool 6 (CRT6). Br J Sports Med 2023;57:689-691. The Concussion Recognition Tool 6 (CRT6). Br J Sports Med 2023;57:692-694.

Echemendia RJ, Brett BL, Broglio S, et al. Introducing the Sport Concussion Assessment Tool 6 (SCAT6). Br J Sports Med 2023;57:619-621. Sport Concussion Assessment Tool 6 (SCAT6). Br J Sports Med 2023;57:622-631.

Eliason PH, Galarneau JM, Kolstad AT, et al. Prevention strategies and modifiable risk factors for sport-related concussions and head impacts: a systematic review and meta-analysis. Br J Sports Med. 2023 Jun;57(12):749-761. doi: 10.1136/bjsports-2022-106656. PMID: 37316182

Iverson GL, Castellani RJ, Cassidy JD, et al. Examining later-in-life health risks associated with sport-related concussion and repetitive head impacts: a systematic review of case-control and cohort studies. Br J Sports Med. 2023 Jun;57(12):810-821. doi: 10.1136/bjsports-2023-106890. PMID: 37316187.

Leddy JJ, Burma JS, Toomey CM, et al. Rest and exercise early after sport-related concussion: a systematic review and meta-analysis. Br J Sports Med. 2023 Jun;57(12):762-770. doi: 10.1136/bjsports-2022-106676. PMID: 37316185.

Makdissi M, Critchley ML, Cantu RC, et a. lWhen should an athlete retire or discontinue participating in contact or collision sports following sport-related concussion? A systematic review. Br J Sports Med. 2023 Jun;57(12):822-830. doi: 10.1136/bjsports-2023-106815. PMID: 37316181.

Patricios JS, Davis GA, Ahmed OH, et al. Introducing the Sport Concussion Office Assessment Tool 6 (SCOAT6). Br J Sports Med 2023;57:648-650. Sport Concussion Office Assessment Tool 6 (SCOAT6). Br J Sports Med 2023;57:651-667.

Patricios JS, Schneider GM, van IersselJ, et al. Beyond acute assessment to office management: a systematic review informing the development of a sport concussion office assessment tool (SCOAT6) for adults and children. Br J Sports Med 2023.57:737–748.

Putukian M, Purcell L, Schneider KJ, et al. Clinical recovery from concussion-return to school and sport: a systematic review and meta-analysis. Br J Sports Med. 2023 Jun;57(12):798-809. doi: 10.1136/bjsports-2022-106682. PMID: 37316183.

Schneider, Kathryn J, and Jon S Patricios. 2023. Amsterdam 2022 International Consensus on Concussion in Sport: calling clinicians to action! British Journal of Sports Medicine 57 (11):615-616. doi:10.1136/bjsports-2023-107127.

Schneider KJ, Critchley ML, Anderson V, et al Targeted interventions and their effect on recovery in children, adolescents and adults who have sustained a sport-related concussion: a systematic review British Journal of Sports Medicine 2023;57:771-779.

Schneider KJ, Patricios JS, Meeuwisse W, et al. Amsterdam 2022 process: A summary of the methodology for the Amsterdam International Consensus on Concussion in Sport. Br J Sports Med 2023;57:712-721.

Tabor JB, Brett BL, Nelson L, et al Role of biomarkers and emerging technologies in defining and assessing neurobiological recovery after sport-related concussion: a systematic review British Journal of Sports Medicine 2023;57:789-797.

Yeates KO, Räisänen AM, Premji Z, et al. What tests and measures accurately diagnose persisting post-concussive symptoms in children, adolescents and adults following sport-related concussion? A systematic review. Br J Sports Med. 2023 Jun;57(12):780-788. doi: 10.1136/bjsports-2022-106657. PMID:37316186.

Concussion in Sport Group (CISG)

As of 2023 CISG is registered as a not-for-profit entity in the USA. Formal approval as a 501(c)(3) entity was received from the US Internal Revenue Service in May, 2024. It has an elected Board that meets monthly and numerous sub-committees, all of which aim to improve knowledge translation and implementation of the outputs of the consensus conferences. Central tenets of CISG include expanding global representation, providing educational platforms, facilitating research into sport-related concussion, enhancing clinical concussion care, and ensuring free access to the “Tools” in English and numerous cultural adaptations (see www.concussioninsportgroup.com). Board members receive no remuneration.

The CISG is launching its first Clinical and Educational Symposium, which is independent and apart from the quadrennial International Consensus Conference and will be held in Milwaukee, Wisconsin on April 30th and May 1st , 2025 at the Pfister Hotel. This unique joint meeting with the Sports Neuropsychology Society will feature two related but separate educational experiences for showcasing clinical advances and research (e.g., poster sessions, brief podium presentations, invited speaker presentations/workshops, panel discussions, etc.). The symposium will not only provide opportunities to share advances in research and clinical practice, it will also create ample opportunities to meet and network with like- minded clinicians and researchers from around the world in a casual collegial setting.

Revised: December 2024