title: The King-Devick test as a determinant of head trauma and concussion in boxers and MMA fighters.
abstract: OBJECTIVE
  Sports-related concussion has received increasing attention as a cause of short- and long-term neurologic symptoms among athletes. The King-Devick (K-D) test is based on measurement of the speed of rapid number naming (reading aloud single-digit numbers from 3 test cards), and captures impairment of eye movements, attention, language, and other correlates of suboptimal brain function. We investigated the K-D test as a potential rapid sideline screening for concussion in a cohort of boxers and mixed martial arts fighters.
  
  
  METHODS
  The K-D test was administered prefight and postfight. The Military Acute Concussion Evaluation (MACE) was administered as a more comprehensive but longer test for concussion. Differences in postfight K-D scores and changes in scores from prefight to postfight were compared for athletes with head trauma during the fight vs those without.
  
  
  RESULTS
  Postfight K-D scores (n = 39 participants) were significantly higher (worse) for those with head trauma during the match (59.1 ± 7.4 vs 41.0 ± 6.7 seconds, p < 0.0001, Wilcoxon rank sum test). Those with loss of consciousness showed the greatest worsening from prefight to postfight. Worse postfight K-D scores (r(s) = -0.79, p = 0.0001) and greater worsening of scores (r(s) = 0.90, p < 0.0001) correlated well with postfight MACE scores. Worsening of K-D scores by ≥5 seconds was a distinguishing characteristic noted only among participants with head trauma. High levels of test-retest reliability were observed (intraclass correlation coefficient 0.97 [95% confidence interval 0.90-1.0]).
  
  
  CONCLUSIONS
  The K-D test is an accurate and reliable method for identifying athletes with head trauma, and is a strong candidate rapid sideline screening test for concussion.
authors.affiliation: Department of Neurology, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Galetta
authors.forename: J
authors.initials: J
authors.lastname: Barrett
authors.forename: M
authors.initials: M
authors.lastname: Allen
authors.forename: F
authors.initials: F
authors.lastname: Madda
authors.forename: D
authors.initials: D
authors.lastname: Delicata
authors.forename: A T
authors.initials: AT
authors.lastname: Tennant
authors.forename: C C
authors.initials: CC
authors.lastname: Branas
authors.forename: M G
authors.initials: MG
authors.lastname: Maguire
authors.forename: L V
authors.initials: LV
authors.lastname: Messner
authors.forename: S
authors.initials: S
authors.lastname: Devick
authors.forename: S L
authors.initials: SL
authors.lastname: Galetta
authors.forename: L J
authors.initials: LJ
authors.lastname: Balcer
mesh_terms: D000293:Adolescent; D000328:Adult; D001914:Boxing / Q000293:injuries*; D001924:Brain Concussion / Q000175:diagnosis*; D015331:Cohort Studies; D006259:Craniocerebral Trauma / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D016139:Martial Arts / Q000293:injuries*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology; D011932:Reading; D015203:Reproducibility of Results; D013223:Statistics as Topic; D015599:Trauma Severity Indices; D055815:Young Adult