Footnotes

• Twitter @BenjaminBrett1, @jonpatricios, @ZapTheLibrarian, @Kat_Schneider7

• Contributors All authors contributed to article review and interpretation of data, drafting and revision of the manuscript and final approval of the manuscript, and agreed to be accountable for all aspects of the work. JBT and MAM act as guarantor.

• Funding Education grant from the Concussion in Sport International Consensus Conference Organizing Committee through Publi Creations for partial administrative and operational costs associated with the writing of the systematic review.

• Competing interests SB, LP and ZP have no competing interests. BB reports grant funding from the National Institute on Aging and National and National Institute of Neurological Disorders and Stroke. He also received speaker honoraria and travel reimbursement for academic conference presentations. GAD is a member of the Scientific Committee of the 6th International Conference on Concussion in Sport; an honorary member of the AFL Concussion Scientific Committee; Section Editor, Sport and Rehabilitation, NEUROSURGERY; and has attended meetings organised by sporting organisations including the NFL, NRL, IIHF, IOC and FIFA; however, has not received any payment, research funding or other monies from these groups other than for travel costs. RJE is a paid consultant for the National Hockey League and co-chair of the National Hockey League /National Hockey League Players Association Concussion Subcommittee, Major League Soccer’s Concussion Committee and the US Soccer Federation. He provides expert testimony in matters related to mTBI and reports a grant from Boston Children’s Hospital (sub-award from the National Football League) and travel support for the CIS conference and other professional conferences, an unpaid board member of CISG and a member of the Scientific Committee of the 6th International Conference on Concussion in Sport. He has served in leadership roles (unpaid) in many professional organisations. MM is a sport and exercise medicine physician working in private consulting practice. He is the Chief Medical Officer for the Australian Football League (AFL) and an Independent Concussion Consultant for World Rugby. He is a shareholder in Olympic Park Sports Medicine Centre in Melbourne. He previously held positions as the senior physician at the Hawthorn Football Club (AFL) and Chief Officer of the AFL Doctors Association. He has received research grants from the Australian Football League, outside the submitted work. He has received travel support from the AFL, FIFA and the International Olympic Committee to attend and present at international conferences. He is a member of the Scientific Committee for the 6th International Conference on Concussion in Sport, an honorary member of the International Concussion in Sport Group and of the Australian Rugby Union Concussion Advisory Group. AM is funded by various NIH and DoD grants but has no financial disclosures. TM reports concussion research grants from NIH; US Dept of Defense; US Department of Energy; & the NCAA; travel expense reimbursement to present findings at various scientific meetings; royalties from American Psychiatric Association Publishing for Textbook of TBI; serving as a member OSMB for NIH sponsored RECOVER study of Long Covid (uncompensated); serving as member, Concussion Scientific Advisory Committee, Australian Football League (uncompensated); Honorarium for TBI lecture at the Harvard Medical School Neuropsychiatry CME course. MAM has received research funding to the Medical College of Wisconsin from the National Institutes of Health, Department of Veterans Affairs, Centers for Disease Control and Prevention, Department of Defense, National Collegiate Athletic Association, National Football League and Abbott Laboratories. He receives book royalties from Oxford University Press. He serves as clinical consultant to Milwaukee Bucks, Milwaukee Brewers, and Green Bay Packers and is Co-Director of the NFL Neuropsychology Consultants without compensation. He serves as consultant for Neurotrauma Sciences, Inc. He receives travel support and speaker honorariums for professional activities. WM reports Dr Meehan receives royalties from ABC-Clio publishing for the sale of his books, Kids, Sports, and Concussion: A guide for coaches and parents, and Concussions; Springer International for the book Head and Neck Injuries in Young Athlete; Wolters Kluwer for working as an author for UpToDate. His research is funded, in part, by philanthropic support from the National Hockey League Alumni Association through the Corey C Griffin Pro-Am Tournament and a grant from the National Football League. TM receives compensation as a member of the Clinical and Scientific Advisory Board for Quadrant Biosciences Inc. LN received funding for unrelated research from the National Institute of Neurological Disorders and Stroke (NINDS), and Centers for Disease Control and Prevention, the Department of Defense, the Medical Technology Enterprise Consortium and the Medical College of Wisconsin Advancing a Healthier Wisconsin Endowment. Dr Nelson has also recently received consulting stipends for grant reviewing (Department of Defense) and research (NINDS). JP is an editor of BJSM for which he receives an honorarium. He is an unpaid consultant to the World Rugby Concussion Advisory Group for which he also serves as an Independent Concussion Advisor (fee per consultation). Other unpaid positions include being medical advisor to South African Rugby, Co-chair of the Scientific Committee, 6^th International Conference on Concussion in Sport (travel and accommodation subsidised), Board member of the Concussion in Sport Group and a Scientific Advisory Board member of EyeGuide. KS has received grant funding from the CIHR, NFL Scientific Advisory Board, International Olympic Committee Medical and Scientific Research Fund, World Rugby, Mitacs Accelerate, University of Calgary, with funds paid to her institution and not to her personally. She is an Associate Editor of BJSM (unpaid) and has received travel and accommodation support for meetings where she has presented. She is coordinating the writing of the systematic reviews that will inform the 6th International Consensus on Concussion in Sport, for which she has received an educational grant to assist with the administrative costs associated with the writing of the reviews. She is a member of the AFL Concussion Scientific Committee (unpaid position) and Brain Canada (unpaid positions). She works as a physiotherapy consultant and treats athletes of all levels of sport from grass roots to professional. JT reports doctoral funding through the Canadian Institutes of Health Research (CIHR); Jason also received an honorarium for the administrative parts of the review. HZ has served at scientific advisory boards and/or as a consultant for Abbvie, Acumen, Alector, Alzinova, ALZPath, Annexon, Apellis, Artery Therapeutics, AZTherapies, CogRx, Denali, Eisai, Nervgen, Novo Nordisk, Optoceutics, Passage Bio, Pinteon Therapeutics, Prothena, Red Abbey Labs, reMYND, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics and Wave, has given lectures in symposia sponsored by Cellectricon, Fujirebio, Alzecure, Biogen and Roche and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program.

• Provenance and peer review Not commissioned; externally peer reviewed.

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