title: Initial symptom burden predicts duration of symptoms after concussion.
abstract: OBJECTIVE
  To determine which variables predict prolonged (>28 days) duration of symptoms after a concussion.
  
  
  METHODS
  We conducted a prospective cohort study of adult (>18yo) patients cared for in a specialty concussion clinic.
  
  
  METHODS
  Symptoms were assessed using the Post-Concussion Symptom Scale (PCSS) developed at the 3rd International Conference on Concussion in Sports. Possible predictors including age, sex, loss of consciousness, amnesia, history of prior concussion, prior treatment for headaches, history of migraines, and family history of concussions, were measured by self-report. We recorded a PCSS score at each clinical visit and defined time to symptom resolution as the number of days between the date of injury and date of last symptoms.
  
  
  RESULTS
  Of 64 adult patients included in the study, 53.3% were male; 20.3% reported experiencing a loss of consciousness at the time of injury while 23.4% reported amnesia. Patients ranged in age from 18 to 27 years (mean 21±2 years). Most concussions (92.2%) occurred during sports. The mean initial PCSS score for those suffering symptoms for longer than 28 days was significantly higher than those who symptoms resolved within 28 days (42.5 vs. 19.2, p<0.01). Of all potential predictor variables, only the initial PCSS score was independently associated with the odds of symptoms lasting longer than 28 days (aOR 1.037; 95% CI 1.011, 1.063).
  
  
  CONCLUSIONS
  Among adult patients with concussions, those with a higher symptom burden after injury have an increased odds of suffering from prolonged symptoms. Other potential predictor variables are not associated with the risk of prolonged recovery.
authors.affiliation: The Micheli Center for Sports Injury Prevention, United States; Sports Concussion Clinic, Division of Sports Medicine, Boston Children's Hospital, United States; Brain Injury Center, Boston Children's Hospital, United States; Division of Emergency Medicine, Boston Children's Hospital, United States. Electronic address: William.meehan@childrens.harvard.edu.
authors.forename: William P
authors.initials: WP
authors.lastname: Meehan
authors.affiliation: The Micheli Center for Sports Injury Prevention, United States; Sports Concussion Clinic, Division of Sports Medicine, Boston Children's Hospital, United States; Brain Injury Center, Boston Children's Hospital, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: O'Brien
authors.affiliation: The Micheli Center for Sports Injury Prevention, United States; Sports Concussion Clinic, Division of Sports Medicine, Boston Children's Hospital, United States.
authors.forename: Ellen
authors.initials: E
authors.lastname: Geminiani
authors.affiliation: The Micheli Center for Sports Injury Prevention, United States; Brain Injury Center, Boston Children's Hospital, United States; Division of Emergency Medicine, Boston Children's Hospital, United States.
authors.forename: Rebekah
authors.initials: R
authors.lastname: Mannix
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000150:complications* / Q000175:diagnosis; D001924:Brain Concussion / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D038223:Post-Concussion Syndrome / Q000175:diagnosis* / Q000209:etiology; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D057566:Self Report; D063189:Symptom Assessment / Q000379:methods*; D013997:Time Factors; D055815:Young Adult
keywords: Head trauma; Mild traumatic brain injury; Sports; Sports injury