title: Predicting slow recovery from sport-related concussion: the new simple-complex distinction.
abstract: OBJECTIVE
  Following the Second International Conference on Concussion in Sport in 2005, a summary agreement statement was published that introduced new terminology for sport-related concussions. This new classification system is binary (ie, "simple" versus "complex" concussions). Athletes who are slow to recover (ie, >10 days) are classified as having complex concussions. The purpose of this study was to determine if high school football players, retrospectively classified as having a simple or a complex concussion, could be differentiated in the first 48 after injury on the basis of symptom reporting or neuropsychological testing.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Pennsylvania high school football programs.
  
  
  METHODS
  The total sample consisted of 114 concussed high school football players who were identified through a 3 year prospective cohort study.
  
  
  METHODS
  All completed a computerized neuropsychological screening evaluation within 72 hours of injury. They were followed clinically until they recovered and were cleared to return to play. They were classified retrospectively as having a simple (n = 55) or complex (n = 59) concussion based on their recovery times.
  
  
  METHODS
  Neurocognitive test performance and symptom ratings.
  
  
  RESULTS
  Within 72 hours after injury, athletes with complex concussions performed more poorly on neuropsychological testing and reported more symptoms than those with simple concussions. Athletes with complex concussions who were slow to recover were 18 times more likely to have 3 unusually low neuropsychological test scores than those with simple concussions (95% CI = 2.3-144.9). Athletes with previous concussions did not recover more slowly.
  
  
  CONCLUSIONS
  This study provides evidence that supports and refutes the clinical usefulness of the new simple-complex concussion classification system.
authors.affiliation: University of British Columbia and Riverview Hospital, 2255 Wesbrook Mall, Vancouver, British Columbia, Canada. giverson@interchange.ubc.ca
authors.forename: Grant
authors.initials: G
authors.lastname: Iverson
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000534:rehabilitation*; D001924:Brain Concussion / Q000145:classification / Q000534:rehabilitation*; D001930:Brain Injuries / Q000534:rehabilitation; D016022:Case-Control Studies; D005538:Football; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010414:Pennsylvania; D012720:Severity of Illness Index; D013177:Sports