title: Simulator-induced spatial disorientation: effects of age, sleep deprivation, and type of conflict.
abstract: BACKGROUND
  Spatial disorientation mishaps are greater at night and with greater time on task, and sleep deprivation is known to decrease cognitive and overall flight performance. However, the ability to perceive and to be influenced by physiologically appropriate simulated SD conflicts has not previously been studied in an automated simulator flight profile.
  
  
  METHODS
  A set of 10 flight profiles were flown by 10 U.S. Air Force (USAF) pilots over a period of 28 h in a specially designed flight simulator for spatial disorientation research and training. Of the 10 flights, 4 had a total of 7 spatial disorientation (SD) conflicts inserted into each of them, 5 simulating motion illusions and 2 involving visual illusions. The percentage of conflict reports was measured along with the effects of four conflicts on flight performance.
  
  
  RESULTS
  The results showed that, with one exception, all motion conflicts were reported over 60% of the time, whereas the two visual illusions were reported on average only 25% of the time, although they both significantly affected flight performance. Pilots older than 35 yr of age were more likely to report conflicts than were those under 30 yr of age (63% vs. 38%), whereas fatigue had little effect overall on either recognized or unrecognized SD.
  
  
  CONCLUSIONS
  The overall effects of these conflicts on perception and performance were generally not altered by sleep deprivation, despite clear indications of fatigue in our pilots.
authors.affiliation: Advanced Technologies Department, Training, Simulation and Performance Improvement Division, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238, USA. fred.previc@swri.org
authors.forename: Fred H
authors.initials: FH
authors.lastname: Previc
authors.forename: William R
authors.initials: WR
authors.lastname: Ercoline
authors.forename: Richard H
authors.initials: RH
authors.lastname: Evans
authors.forename: Nathan
authors.initials: N
authors.lastname: Dillon
authors.forename: Nadia
authors.initials: N
authors.lastname: Lopez
authors.forename: Christina M
authors.initials: CM
authors.lastname: Daluz
authors.forename: Andrew
authors.initials: A
authors.lastname: Workman
mesh_terms: D000328:Adult; D000367:Age Factors; D005221:Fatigue / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008887:Military Medicine; D008889:Military Personnel / Q000523:psychology; D009038:Motion; D010465:Perception; D010468:Perceptual Disorders / Q000209:etiology*; D004856:Postural Balance / Q000502:physiology*; D011446:Prospective Studies; D012892:Sleep Deprivation / Q000150:complications*; D013026:Space Flight; D018561:Space Simulation; D014481:United States