Footnotes

• Twitter @BenjaminBrett1, @griz1, @DrKimHarmon, @HowellDR, @jonpatricios, @Mputukian, @SammoWalton, @Kat_Schneider7

• Contributors RJE served as the primary author and responsible for all aspects of the project, including initial preparation, coordination, review, editing and final preparation of the manuscript and SCAT6 tool. All co-authors contributed to the development and critical review of the manuscript and SCAT6 tool, and approved the final version of the manuscript and tool.

• Competing interests BLB reports grants from the National Institute on Aging and National Institute of Neurological Disorders and Stroke and travel support for professional conferences. SB reports current or past research funding from the National Institutes of Health; Centers for Disease Control and Prevention; Department of Defense - USA Medical Research Acquisition Activity, National Collegiate Athletic Association; National Athletic Trainers’ Association Foundation; National Football League/Under Armour/GE; Simbex; and ElmindA. He has consulted for US Soccer (paid), US Cycling (unpaid), University of Calgary SHRed Concussions external advisory board (unpaid), medico-legal litigation, and received speaker honorarium and travel reimbursements for talks given. He is co-author of “Biomechanics of Injury (3rd edition)” and has a patent on “Brain Metabolism Monitoring Through CCO Measurements Using All-Fiber-Integrated Super-Continuum Source” (U.S. 11,529,091 B2). He is on the and is/was on the editorial boards (all unpaid) for Journal of Athletic Training (2015 to present), Concussion (2014 to present), Athletic Training & Sports Health Care (2008 to present), British Journal of Sports Medicine (2008 to 2019) JMB reports being a part-time employee of the NHL. JMB’s institution has received funding from Genzyme, and EyeGuide supporting his work, and he has served as a paid consultant to Med-IQ and Sporting KC. JSB reports receiving methods author funding for this review and Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program. GAD reports grant from Murdoch Children’s Research Institute and travel support for professional conferences. He is a member of the Scientific Committee of the 6th International Consensus Conference on Concussion in Sport; an honorary member of the AFL Concussion Scientific Committee, and a board member of CISG. 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, provides 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 leadership roles (unpaid) in professional organizations. GG Reports grant funding from CDC TEAM and OnTRACK grants, NIMH APNA grant, royalties from PAR, consulting fees from NFL Baltimore Ravens, Zogenix International, and Global Pharma Consultancy, and travel support for professional meetings. He is a member of USA Football Medical Advisory Panel. KMG reports compensation from National Collegiate Athletic Association for other services and grants from Boston Children’s Hospital (sub-award from the National Football League). KH reports research grants from AMSSM and Football Research, Inc. She is the Research Development Director of the PAC-12 and a member of the NFL Head, Neck, And Spine committee and PAC-112 Brain Trauma Task Force. SH reports he is Co-founder and senior advisor, The Sports Institute at UW Medicine (unpaid), Centers for Disease Control and Prevention and National Center for Injury Prevention and Control Board Pediatric Mild Traumatic Brain Injury Guideline Workgroup (unpaid), NCAA Concussion Safety Advisory Group (unpaid), Concussion in Sport Group (travel support), Team Physician, Seattle Mariners, Former Team Physician, Seattle Seahawks, Occasional payment for expert testimony, Travel support for professional meetings. DH reports research support from the Eunice Kennedy Shriver National Institute of Child Health & Human Development, the National Institute of Neurological Disorders And Stroke, the National Institute of Arthritis and Musculoskeletal and Skin Diseases, 59th Medical Wing Department of the Air Force, MINDSOURCE Brain Injury Network, the Tai Foundation, and the Colorado Clinical and Translational Sciences Institute (UL1 TR002535‐05) and he serves on the Scientific/Medical Advisory Board of Synaptek, LLC. CM reports no financial COI. She holds leadership positions with several organizations American College of Sports Medicine, American Medical Society for Sports Medicine, Pediatric Research in Sports Medicine, Council on Sports Medicine and Fitness, American Academy of Pediatrics, Untold Foundation, Pink Concussions, Headway Foundation, and the editorial boards of Journal of Adolescent Health, Frontiers in Neuroergonomics, Exercise, Sport, and Movement. MM reports grants from NIH, Veterans Affairs, Centers for Disease Control and Prevention (CDC), Abbott Laboratories, Department of Defense (DoD), and NCAA outside the submitted work. DN receives consulting fees from the CFL and travel support for professional conferences. He is a team physician for the NHL and CFL. He is CMO for the CFL and a member of NHL and CFL committees. JP reports travel support for the CIS conference and other professional meetings, consulting fees and grant funding from World Rugby, and an unpaid board member of CISG and EyeGuide. MP reports receiving a travel stipend for attending CIS meeting and other professional conferences, grant funds from NCAA-CARE 2.0, royalties from Netters’ Sports Medicine, consulting fees from Major League Soccer as CMO, and occasional expert testimony/serves. She is a member of several professional boards advisory panels. KJS reported receiving an educational grant for assisting with the administrative and operational costs associated with the writing of the reviews and a travel grant from Publi Creations, grant funding from Canadian Institutes of Health Research, Public Health Agency of Canada (through Parachute Canada), National Football League Scientific Advisory Board, International Olympic Committee Medical and Scientific Research Fund, World Rugby, Mitacs Accelerate, University of Calgary; leadership roles in AFL, Federal Provincial Territorial Work Group on Concussion, Canada. JVL reports CIHR Postdoctoral Fellowship Award, UOMBRI Grant, travel stipend from CTRC and Founder of R2P™ Concussion Management. TCVM is a paid member of the NFL Head, Neck, and Spine Committee and an unpaid member of the USA Swimming Concussion Task Force. SRW reports honoraria and travel support for professional meetings and leadership positions in World Federation of Athletic Training and Therapy and Outcomes, International Traumatic Brain Injury Research Initiative.

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

• Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.