title: Can visible signs predict concussion diagnosis in the National Hockey League?
abstract: BACKGROUND
  Early identification and evaluation of concussions is critical. We examined the utility of using visible signs (VS) of concussion in predicting subsequent diagnosis of concussion in NHL players.
  
  
  METHODS
  VS of concussion were identified through video review. Coders were trained to detect and record specific visual signs while viewing videos of NHL regular season games. 2460 games were reviewed by at least two independent coders across two seasons. The reliability, sensitivity and specificity of these VS were examined.
  
  
  RESULTS
  VS were reliably coded with inter-rater agreement rates ranging from 73% to 98.9%. 1215 VS were identified in 861 events that occurred in 735 games. 47% of diagnosed concussions were associated with a VS but 53% of diagnosed concussions had no VS. Of the VS, only loss of consciousness, motor incoordination, and blank/vacant look had positive likelihood ratios greater than 1, indicating a positive association with concussion diagnoses. Slow to get up and clutching of the head were observed frequently but had low positive predictive values. Sensitivity decreased and specificity increased when multiple VS occurred together.
  
  
  CONCLUSIONS
  Non-medical personnel can be trained to reliably identify events in which VS occur and to reliably identify specific VS within each of those events. VS can be useful to detect concussion early but they are not enough since more than half of physician diagnosed concussions occurred without the presence of a visual sign. The results underscore the complexity of this injury and highlight the need for comprehensive approaches to injury detection.
authors.affiliation: University Orthopedic Center Concussion Care Clinic, State College, Pennsylvania, USA.|Department of Psychology, University of Missouri - Kansas City, Missouri, USA.
authors.forename: Ruben J
authors.initials: RJ
authors.lastname: Echemendia
authors.affiliation: Department of Psychology, University of Missouri - Kansas City, Missouri, USA.
authors.forename: Jared M
authors.initials: JM
authors.lastname: Bruce
authors.affiliation: Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Willem
authors.initials: W
authors.lastname: Meeuwisse
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Canada.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hutchison
authors.affiliation: Toronto Rehabilitation Institute, Toronto, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Comper
authors.affiliation: Ottawa Sport Medicine Centre, Ottawa, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Aubry
mesh_terms: D056352:Athletes; D001265:Athletic Injuries / Q000175:diagnosis*; D001924:Brain Concussion / Q000175:diagnosis*; D006688:Hockey / Q000293:injuries*; D006801:Humans; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013178:Sports Medicine / Q000379:methods
keywords: Concussion; Concussion Diagnoses; Concussion Signs; Ice Hockey; Video analyses