title: The King-Devick (K-D) test and concussion diagnosis in semi-professional rugby union players.
abstract: OBJECTIVE
  To determine the utility of the King-Devick (K-D) test in identifying sports-related concussion in semi-professional rugby players.
  
  
  METHODS
  Descriptive cohort study.
  
  
  METHODS
  176 male players were recruited from a semi-professional rugby union competition in New Zealand (NZ). Baseline K-D scores were obtained in the pre-season. Post-match K-D and Pitch Side Concussion Assessment Version 2 (PSCA2) scores were obtained in those with suspected concussion. Post-match K-D scores were also administered to selected control players.
  
  
  RESULTS
  19 concussions in 18 players were analysed. In addition, 33 controls were used for analysis. A positive K-D test was identified in 53% of players with concussion post-match. Conversely, a positive test was identified in 33% of controls. The sensitivity and specificity of the K-D test was calculated as 53% and 69% respectively. The positive predictive value and negative predictive value was 48% and 73% respectively. The PSCA2 correctly identified 74% of concussions. The K-D test identified 3 cases not identified by the PSCA2. When the PSCA2 and K-D were combined, 89% of concussions were correctly identified.
  
  
  CONCLUSIONS
  The K-D test does not appear to be effective if used as a stand-alone test for the diagnosis of concussion. However, if used alongside current side-line cognitive and balance tests, it may assist in more accurately diagnosing sports-related concussion. Further research should look to utilise the K-D test in in-match protocols to establish if this improves the diagnostic accuracy of in-match protocols for sports-related concussion.
authors.affiliation: Australasian College of Sport and Exercise Physicians, Australia. Electronic address: drjohnmolloy@gmail.com.
authors.forename: John H
authors.initials: JH
authors.lastname: Molloy
authors.affiliation: New Zealand Rugby Union, New Zealand Rugby House, New Zealand.
authors.forename: Ian
authors.initials: I
authors.lastname: Murphy
authors.affiliation: School of Sport, Health and Applied Science, St. Mary's University, United Kingdom.
authors.forename: Conor
authors.initials: C
authors.lastname: Gissane
mesh_terms: D000328:Adult; D001924:Brain Concussion / Q000175:diagnosis*; D016022:Case-Control Studies; D015331:Cohort Studies; D005538:Football / Q000293:injuries*; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D055815:Young Adult
keywords: Brain concussion; King–Devick test; Post-concussion syndrome; Rugby; Sport concussion assessment tool; Vision tests