title: Test-Retest Reliability of the King-Devick Test in an Adolescent Population.
abstract: BACKGROUND
  The King-Devick (KD) test is a screening tool designed to assess cognitive visual impairments, namely saccadic rhythm, postconcussion. Test-retest reliability of the KD in a healthy adolescent population has not yet been established.
  
  
  OBJECTIVE
  To investigate the overall test-retest reliability of the KD among a sample of healthy adolescents. Additionally, we sought to determine if sex and age influenced reliability.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Secondary school.
  
  
  METHODS
  Sixty-eight healthy adolescents, 41 boys (age = 15.4 ± 1.9 years) and 27 girls (age = 15.4 ± 1.9 years).
  
  
  METHODS
  Participants completed the KD (version 1) at 3 testing sessions (days 1, 30, and 45) following standard instructions. We recorded total time to complete the reading of 3 cards for each participant during each testing session. Two-way random-effects intraclass correlation coefficients (ICCs) using single measurements repeated over time and repeatability coefficients were calculated. Linear mixed models were used to determine whether differences existed at each testing time and to examine whether changes that took place among visits were different by sex or age.
  
  
  RESULTS
  Adolescents who completed the KD demonstrated acceptable reliability (ICC = 0.81; 95% confidence interval = 0.73, 0.87); however, the repeatability coefficient was large (±8.76 seconds). The sample demonstrated improvements between visits 1 and 2 (mean ± standard error = 4.3 ± 0.5 seconds, P < .001) and between visits 2 and 3 (2.4 ± 0.5 seconds, P < .001) for a total improvement of 6.9 seconds over 3 tests. No significant visit-by-sex or visit-by-age interactions were observed.
  
  
  CONCLUSIONS
  Despite the ICC being clinically acceptable, providers using the KD test for serial assessment of concussion in adolescents should be cautious in interpreting the results due to a large learning effect. Incorporating multiple measures can ensure accurate detection of sport concussion.
authors.affiliation: Great Plains Health Sports and Therapy, North Platte, NE.
authors.forename: Tyler J
authors.initials: TJ
authors.lastname: Oberlander
authors.affiliation: Health and Nutritional Sciences, South Dakota State University, Brookings.
authors.forename: Bernadette L
authors.initials: BL
authors.lastname: Olson
authors.affiliation: Health and Nutritional Sciences, South Dakota State University, Brookings.
authors.forename: Lee
authors.initials: L
authors.lastname: Weidauer
mesh_terms: D000293:Adolescent; D001265:Athletic Injuries / Q000150:complications*; D001924:Brain Concussion / Q000150:complications*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D015203:Reproducibility of Results; D012438:Saccades / Q000502:physiology; D013647:Task Performance and Analysis; D014786:Vision Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology
keywords: oculomotor function; saccadic rhythm; sport concussion