Objective To define the time frames, measures used and modifying factors influencing recovery, return to school/learn (RTL) and return to sport (RTS) after sport-related concussion (SRC).
Design Systematic review and meta-analysis.
Data sources 8 databases searched through 22 March 2022.
Eligibility criteria Studies with diagnosed/suspected SRC and interventions facilitating RTL/RTS or investigating the time and modifying factors for clinical recovery. Outcomes included days until symptom free, days until RTL and days until RTS. We documented study design, population, methodology and results. Risk of bias was evaluated using a modified Scottish Intercollegiate Guidelines Network tool.
Results 278 studies were included (80.6% cohort studies and 92.8% from North America). 7.9% were considered high-quality studies, while 23.0% were considered high risk of bias and inadmissible. The mean days until symptom free was 14.0 days (95% CI: 12.7, 15.4; I2=98.0%). The mean days until RTL was 8.3 (95% CI: 5.6, 11.1; I2=99.3%), with 93% of athletes having a full RTL by 10 days without new academic support. The mean days until RTS was 19.8 days (95% CI: 18.8, 20.7; I2=99.3%), with high heterogeneity between studies. Several measures define and track recovery, with initial symptom burden remaining the strongest predictor of longer days until RTS. Continuing to play and delayed access to healthcare providers were associated with longer recovery. Premorbid and postmorbid factors (eg, depression/anxiety, migraine history) may modify recovery time frames. Though point estimates suggest that female sex or younger age cohorts take longer to recover, the heterogeneity of study designs, outcomes and overlap in CIs with male sex or older age cohorts suggests that all have similar recovery patterns.
Conclusion Most athletes have full RTL by 10 days but take twice as long for an RTS.
PROSPERO registration number CRD42020159928.
- Brain Concussion
Data availability statement
All data relevant to the study are included in the article or uploaded as supplemental information.
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Collaborators Concussion in Sport Group (CISG) Expert Panel: Jon Patricios, Kathryn Schneider, Jiri Dvorak, Ruben Echemendia, Chris Giza, Michael Turner, Osman Ahmed, Gavin Davis, Michael Makdissi, Mike McNamee, Stephen Broglio, Carolyn Emery, Robert Cantu, Nina Feddermann, Gordon Fuller, Kevin Guskiewicz, Brian Hainline, Stanley Herring, Grant Iverson, Jeff Kutcher, John Leddy, David Maddocks, Geoffrey Manley, Michael McCrea, Winne Meuwisse, Laura Purcell, Margot Putukian, Markku Tuominen, Keith Yates, Cheri Blauwet, Clodagh Toomey.
Contributors All authors contributed in the following ways: substantial contribution to the data extraction and analysis and interpretation of the data; drafting the work or revising it critically, and providing final approval for the initial submission, the response to reviewers and the final submission. All authors agree to be accountable for all aspects of the work in terms of the accuracy and integrity of the work. MP is the author acting as the guarantor.
Funding Educational 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 reviews.
Competing interests MP is a consultant and Chief Medical Officer for Major League Soccer. She serves as a senior advisor to the NFL’s Head, Neck & Spine Committee, is a member of the FA Research Task Force, the NOCSAE Scientific Advisory Committee and a member of the Concussion in Sport Expert Panel. She also serves on the IOC Mental Health Working Group, the USOPC Mental Health Advisory Committee, the US Soccer Medical Advisory Committee, and has received grant funding from the National Collegiate Athletic Association-Department of Defense CARE 2.0 project. LP is a CASEM board member and the president elect in 2022–2023. She has received research funding from National Institutes of Health. She has received travel expenses and honoraria for conference presentations. KJS has current or past grant funding from the Canadian Institutes of Health Research, NFL Scientific Advisory Board, IOC 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 Sixth 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. AMB has received peer-reviewed research funding from the Social Sciences and Humanities Research Council. She is also a Sport Information Resource Center board member and Canadian Athletic Therapists Association committee member. She received an honorarium for the administrative aspects of the concussion consensus reviews. AC is the director of the National Collegiate Athletic Association Injury Surveillance Program at the Datalys Center for Sports Injury Research and Prevention. He discloses funding from the National Collegiate Athletic Association as director of the National Collegiate Athletic Association Injury Surveillance Program. He also discloses funding from the North Carolina Translational and Clinical Sciences Institute, the Atlantic Coast Conference Center for Research in Intercollegiate Athletics, as well as the Canadian Institutes of Health Research-Human Development, Child and Youth Health Institute, on separate, unrelated projects. AC has also previously received honoraria for speaking engagements with the Sports Neuropsychology Society and the American Medical Society for Sports Medicine, as well as travel support from the American Medical Society for Sports Medicine. He also serves on the editorial/education team of the Football Medicine and Performance Association publication and on the editorial board of the Journal of Sport Rehabilitation. CLM has current or past research grant funding from National Institutes of Health, Department of Defense, Centers for Disease Control and Prevention, National Collegiate Athletic Association, Pennsylvania Department of Health, AMSSM and Children’s Hospital of Philadelphia. She serves (uncompensated) on the editorial boards of the Journal of Adolescent Health, and as an associate editor of the journals Exercise, Sport, and Movement, and Frontiers in Neuroergonomics. She serves (uncompensated) on the medical advisory boards for concussion patient advocacy organisations for Untold Foundation, Pink Concussions and Headway Foundation. JKR-M has received current or past research funding from the Centers for Disease Control and Prevention; Department of Defense-USA Medical Research Acquisition Activity; National Collegiate Athletic Association-Department of Defense Mind Matters Challenge; National Athletic Trainers’ Association Foundation; NFL; and National Operating Committee on Standards for Athletic Equipment. She has consulted for Allied Health Education (paid) and received speaker honorarium and travel reimbursements for talks given. She is on the editorial boards (all unpaid) for Journal of Athletic Training, Journal of Sport Rehabilitation, and Frontiers in Sports and Active Living. Previously, she served on the editorial board for the International Journal of Athletic Training and Therapy (paid). She served previously (unpaid) on USA Football’s Football Development Council and is currently on USA Football’s Girls Football Council. VA receives funding from the Australian National Health and Medical Research Council and the Medical Research Future Fund, and Royalties from Pearson Publishing for the Test of Everyday Attention for Children. She also receives an honorarium for her role as associate editor for the American Psychological Society journal, Neuropsychology. She has a formal partnership with the Australian Football League with any associated funds going to her employer, the Murdoch Children’s Research Institute. GAD is a member of the Scientific Committee of the Sixth International Consensus 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, IOC, IIHF and FIFA, however has not received any payment, research funding or other monies from these groups other than for travel costs. PF received grant funding from the NFL’s 'Play Smart. Play Safe.' Initiative and is an executive committee member of the Canadian Concussion Network (financed by the Canadian Institute of Health Research). JJL receives grant/research support from National Institutes of Health, Department of Defense and the AMSSM. He is a member of the scientific advisory board for Neuronasal, Highmark Innovations and Quadrant Biosciences. He holds minority stock options in Highmark Innovations and in 360 Concussion Care. He is an expert consultant to the National Collegiate Athletic Association. He consults with NFL and NHL teams on athlete care but does not receive any compensation from these organisations. He is a member (unpaid) of the editorial board of the Journal of Head Trauma Rehabilitation. SH is a co-founder and senior advisor, The Sports Institute at UW Medicine, member of the Centers for Disease Control and Prevention and National Center for Injury Prevention and Control Board Pediatric Mild Traumatic Brain Injury Guideline Workgroup, member of the National Collegiate Athletic Association Concussion Safety Advisory Group, member of the Concussion in Sport Expert Panel, a team physician for the Seattle Mariners and a former team physician, Seattle Seahawks. SB has 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), medicolegal litigation, and received speaker honorarium and travel reimbursements (including CISG) for talks given. He is coauthor of 'Biomechanics of Injury (third edition)' and has a patent pending on 'Brain Metabolism Monitoring Through CCO Measurements Using All-Fiber-Integrated Super-Continuum Source' (US application no. 17/164,490). He is on the and is/was on the editorial boards (all unpaid) for Journal of Athletic Training (2015–present), Concussion (2014–present), Athletic Training & Sports Health Care (2008 to present) and British Journal of Sports Medicine (2008–2019).
Provenance and peer review Not commissioned; externally peer reviewed.
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