Natural History of Concussion in Sport Markers of Severity and Implications for Management

BackgroundEvidence-based clinical data are required for safe return to play after concussion in sport.PurposeThe objective of this study was to describe the natural history of concussion in sport and identify clinical features associated with more severe concussive injury, using return-to-sport decisions as a surrogate measure of injury severity.Study DesignCohort study (prognosis); Level of evidence, 3.MethodsMale elite senior, elite junior, and community-based Australian Rules football players had preseason baseline cognitive testing (Digit Symbol Substitution Test, Trail-Making Test—Part B, and CogSport computerized test battery). Players were recruited into the study after a concussive injury sustained while playing football. Concussed players were tested serially until all clinical features of their injury had resolved.ResultsOf 1015 players, 88 concussions were observed in 78 players. Concussion-associated symptoms lasted an average of 48.6 hours (95% confidence interval, 39.5-57.7 hours) with delay...