title: Early detection of hypoxia-lnduced cognitive impairment using the King-Devick test.
abstract: BACKGROUND
  Hypoxic incapacitation continues to be a significant threat to safety and operations at high altitude. Noninvasive neurocognitive performance testing is desirable to identify presymptomatic cognitive impairment, affording operators at altitude a tool to quantify their performance and safety.
  
  
  METHODS
  There were 25 subjects enrolled in this study. Cognitive performance was assessed by using the King-Devick (K-D) test. The performance of the subjects on the K-D test was measured in normoxia followed by hypoxia (8% 02 equivalent to 7101 m) and then again in normoxia.
  
  
  RESULTS
  K-D test completion time in hypoxia for 3 min was significantly longer than the Baseline Test (54.5 +/- 12.4 s hypoxic vs. 46.3 +/- 10.4 s baseline). Upon returning to normoxia the completion time was significantly shorter than in hypoxia (47.6 +/- 10.6 s post test vs. 54.5 +/- 12.4 s hypoxic). There was no statistically significant difference between baseline test and post test times, indicating that all subjects returned to their normoxic baseline levels. SpO2 decreased from 98 +/- 0.9% to 80 +/- 7.8% after 3 min on hypoxic gas. During the hypoxic K-D test, SpO2 decreased further to 75.8 +/- 8.3%.
  
  
  CONCLUSIONS
  In this study the K-D test has been shown to be an effective neurocognitive test to detect hypoxic impairment at early presymptomatic stages. The K-D test may also be used to afford a reassessment of traditional measures used to determine hypoxic reserve time.
authors.affiliation: Aerospace Medicine and Vestibular Research Laboratory Mayo Clinic, Scottsdale, AZ 85259, USA. stepanek.jan@mayo.edu
authors.forename: Jan
authors.initials: J
authors.lastname: Stepanek
authors.forename: Daniela
authors.initials: D
authors.lastname: Cocco
authors.forename: Gaurav N
authors.initials: GN
authors.lastname: Pradhan
authors.forename: Benn E
authors.initials: BE
authors.lastname: Smith
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bartlett
authors.forename: Marc
authors.initials: M
authors.lastname: Studer
authors.forename: Fabian
authors.initials: F
authors.lastname: Kuhn
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Cevette
mesh_terms: D000293:Adolescent; D000328:Adult; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D002534:Hypoxia, Brain / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D055815:Young Adult