Review article
Systematic Review of Prognosis and Return to Play After Sport Concussion: Results of the International Collaboration on Mild Traumatic Brain Injury Prognosis

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Abstract

Objective

To synthesize the best available evidence on prognosis after sport concussion.

Data Sources

MEDLINE and other databases were searched (2001–2012) with terms including “craniocerebral trauma” and “sports.” Reference lists of eligible articles were also searched.

Study Selection

Randomized controlled trials and cohort and case-control studies were selected according to predefined criteria. Studies had to have a minimum of 30 concussion cases.

Data Extraction

Eligible studies were critically appraised using a modification of the Scottish Intercollegiate Guidelines Network (SIGN) criteria. Two reviewers independently reviewed and extracted data from accepted studies into evidence tables.

Data Synthesis

Evidence was synthesized qualitatively according to modified SIGN criteria, and studies were categorized as exploratory or confirmatory based on the strength of their design and evidence. After 77,914 records were screened, 52 articles were eligible for this review, and 24 articles (representing 19 studies) with a low risk of bias were accepted. Our findings are based on exploratory studies of predominantly male football players at the high school, collegiate, and professional levels. Most athletes recover within days to a few weeks, and American and Australian professional football players return to play quickly after mild traumatic brain injury. Delayed recovery appears more likely in high school athletes, in those with a history of previous concussion, and in those with a higher number and duration of postconcussion symptoms.

Conclusions

The evidence concerning sports concussion course and prognosis is very preliminary, and there is no evidence on the effect of return-to-play guidelines on prognosis. Our findings have implications for further research. Well-designed, confirmatory studies are urgently needed to understand the consequences of sport concussion, including recurrent concussion, across different athletic populations and sports.

Section snippets

Methods

The protocol registration, case definition, literature search, critical review strategy, and data synthesis are outlined in detail elsewhere.10, 11 Briefly, the review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.12 The electronic databases MEDLINE, PsycINFO, Embase, CINAHL, and SPORTDiscus were systematically searched from 2001 to 2012, and the reference lists of all reviews and meta-analyses related to

Results

Of 77,914 records screened for our entire review, 121 full-text articles related to sport concussion were assessed for eligibility (fig 1).11 There were 52 English articles that assessed sport concussion and met our eligibility criteria. About half of these (n=24) were accepted as scientifically admissible articles, represented by 19 studies (table 1). These studies form the basis of our best-evidence synthesis.

We accepted 19 cohort studies, of which 10 were phase II and 9 were phase I.

Discussion

The best available evidence on prognosis after sport concussion suggests that most athletes recover within days to a few weeks to preinjury levels in terms of cognitive performance (as measured by objective traditional and computerized neuropsychological tests) and postconcussion symptoms (as measured by self-report). Our findings indicate that younger players (average age, 16y) have a slightly longer recovery (about 21d) than adults. Our limited findings on RTP after concussion, based mainly

Conclusions

The best evidence, all of which is exploratory at this time, indicates that most concussed athletes recover to preinjury levels, with those at the professional level recovering the most quickly. Additionally, we found that decrements in cognitive performance and postconcussion symptoms are largely resolved within days to a few weeks of the injury, and most athletes RTP soon after sport concussion. Although only 2 studies on the risk of recurrent concussion were admitted in our review, these

Acknowledgments

We thank the other members of the International Collaboration on MTBI Prognosis (ICoMP): Jean-Luc af Geijerstam, MD, PhD, Eleanor Boyle, PhD, Jan Hartvigsen, DC, PhD, Lena Holm, DrMedSc, Alvin Li, BHSc, Connie Marras, MD, PhD, and Peter Rumney, MD; Panos Lambiris, MSc, Information Scientist, University Health Network, for assisting in developing, testing and updating the search strategies; and Meijia Zhou, BSc, for assistance with retrieving and screening articles.

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      In addition, through the use of a unified medical record, all providers are active participants in ongoing progression through rehabilitation, culminating in a coordinated discharge. Cancelliere et al. (2014) in a systematic review, reported a mean RTP time of 4.8 days which is substantially lower than the median reported here (29 days in season 1; 13 days in season 2). However, 17 of the 19 admissible studies were from between 2000 and 2010 (Cancelliere et al., 2014), which may have contributed to the lower RTP time given that approaches to diagnosis and care have changed substantially since then.

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    Supported by the Ontario Neurotrauma Foundation (grant no. 2010-ABI-MTBIWHO-871). The funder was not involved in the design or preparation of the study protocol, or in the management of the project, analysis or interpretation of data, or the preparation of the final article.

    No commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a benefit on the authors or on any organization with which the authors are associated.

    The findings and conclusions in this research are those of the authors alone and do not necessarily represent the official views or policies of the Centers for Disease Control and Prevention or any agency of the United States government. Inclusion of individuals, programs, or organizations in this article does not constitute endorsement by the United States government.

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