title: Visual neglect: occurrence and patterns in pilots in a simulated overnight flight.
abstract: BACKGROUND
  Visual neglect is the unconscious inability to recognize or acknowledge some visual information in the presence of a structurally intact visual system, and was hypothesized to occur with less than 24 h of continuous wakefulness. Visual perception was evaluated in military pilots during a simulated overnight flight to explore for the possible occurrence of visual neglect.
  
  
  METHODS
  There were eight military pilots (male, 31-52 yr of age, mean 37 yr) on flight status who were recruited to perform the primary task of flying a simulated 12.5 h overnight mission after a day of continuous wakefulness and the secondary task of responding to repeated 20 min presentations of single- and double-light stimuli displayed in random sequence at 15 degrees intervals across the cockpit instrument panel. In addition to the visual performance task, simulator shutdowns occurring when the tolerances of the simulator were exceeded were measured and simple reaction time on the psychomotor vigilance task was assessed. Total continuous wakefulness was 26.5 h.
  
  
  RESULTS
  Combined performance on the visual perception task showed response omissions increasing at 19 h of continuous wakefulness. Patterns included omissions at all stimulus locations, of primarily peripherally located stimuli, and of one of two simultaneously presented stimuli. Simulator shutdowns began at 21.5 h of continuous wakefulness. Correlation of visual task response omissions with simulator shutdowns was r = 0.95, p < 0.0001.
  
  
  CONCLUSIONS
  Significant neglect of visual stimuli occurred in pilots beginning at 19 h of continuous wakefulness in a simulated overnight fixed wing aircraft flight, preceded simulator shutdowns, and correlated at 0.95 with simulator shutdowns.
authors.affiliation: US Army Aeromedical Research Laboratory, Fort Rucker, AL 36362, USA. michael.russo@us.army.mil
authors.forename: Michael B
authors.initials: MB
authors.lastname: Russo
authors.forename: Helen
authors.initials: H
authors.lastname: Sing
authors.forename: Saul
authors.initials: S
authors.lastname: Santiago
authors.forename: Athena P
authors.initials: AP
authors.lastname: Kendall
authors.forename: Dagny
authors.initials: D
authors.lastname: Johnson
authors.forename: David
authors.initials: D
authors.lastname: Thorne
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Escolas
authors.forename: Dwight
authors.initials: D
authors.lastname: Holland
authors.forename: Stanley
authors.initials: S
authors.lastname: Hall
authors.forename: Daniel
authors.initials: D
authors.lastname: Redmond
mesh_terms: D000401:Aircraft; D001359:Aviation; D001921:Brain / Q000503:physiopathology; D003072:Cognition Disorders / Q000209:etiology*; D003198:Computer Simulation; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel / Q000523:psychology; D010468:Perceptual Disorders / Q000503:physiopathology*; D014481:United States; D014796:Visual Perception / Q000502:physiology*; D014851:Wakefulness