title: Acute effects and recovery time following concussion in collegiate football players: the NCAA Concussion Study.
abstract: BACKGROUND
  Lack of empirical data on recovery time following sport-related concussion hampers clinical decision making about return to play after injury.
  
  
  OBJECTIVE
  To prospectively measure immediate effects and natural recovery course relating to symptoms, cognitive functioning, and postural stability following sport-related concussion.
  
  
  METHODS
  Prospective cohort study of 1631 football players from 15 US colleges. All players underwent preseason baseline testing on concussion assessment measures in 1999, 2000, and 2001. Ninety-four players with concussion (based on American Academy of Neurology criteria) and 56 noninjured controls underwent assessment of symptoms, cognitive functioning, and postural stability immediately, 3 hours, and 1, 2, 3, 5, 7, and 90 days after injury.
  
  
  METHODS
  Scores on the Graded Symptom Checklist (GSC), Standardized Assessment of Concussion (SAC), Balance Error Scoring System (BESS), and a neuropsychological test battery.
  
  
  RESULTS
  No player with concussion was excluded from participation; 79 players with concussion (84%) completed the protocol through day 90. Players with concussion exhibited more severe symptoms (mean GSC score 20.93 [95% confidence interval [CI], 15.65-26.21] points higher than that of controls), cognitive impairment (mean SAC score 2.94 [95% CI, 1.50-4.38] points lower than that of controls), and balance problems (mean BESS score 5.81 [95% CI, -0.67 to 12.30] points higher than that of controls) immediately after concussion. On average, symptoms gradually resolved by day 7 (GSC mean difference, 0.33; 95% CI, -1.41 to 2.06), cognitive functioning improved to baseline levels within 5 to 7 days (day 7 SAC mean difference, -0.03; 95% CI, -1.33 to 1.26), and balance deficits dissipated within 3 to 5 days after injury (day 5 BESS mean difference, -0.31; 95% CI, -3.02 to 2.40). Mild impairments in cognitive processing and verbal memory evident on neuropsychological testing 2 days after concussion resolved by day 7. There were no significant differences in symptoms or functional impairments in the concussion and control groups 90 days after concussion.
  
  
  CONCLUSIONS
  Collegiate football players may require several days for recovery of symptoms, cognitive dysfunction, and postural instability after concussion. Further research is required to determine factors that predict variability in recovery time after concussion. Standardized measurement of postconcussive symptoms, cognitive functioning, and postural stability may enhance clinical management of athletes recovering from concussion.
authors: Neuroscience Center, Waukesha Memorial Hospital, Waukesha, Wis 53188, USA. michael.mccrea@phci.org
authors: Michael
authors: M
authors: McCrea
authors: Kevin M
authors: KM
authors: Guskiewicz
authors: Stephen W
authors: SW
authors: Marshall
authors: William
authors: W
authors: Barr
authors: Christopher
authors: C
authors: Randolph
authors: Robert C
authors: RC
authors: Cantu
authors: James A
authors: JA
authors: Onate
authors: Jingzhen
authors: J
authors: Yang
authors: James P
authors: JP
authors: Kelly
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000503:physiopathology; D001924:Brain Concussion / Q000503:physiopathology*; D003071:Cognition; D005538:Football / Q000293:injuries*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D004856:Postural Balance; D011446:Prospective Studies; D020127:Recovery of Function; D015599:Trauma Severity Indices