title: Reaction time in pilots during intervals of high sustained g.
abstract: BACKGROUND
  An important problem for pilots is visual disturbances occurring under +Gz acceleration. Assessment of the degree of intensification of these disturbances is generally accepted as the acceleration tolerance level (ATL) criterion determined in human centrifuges. The aim of this research was to evaluate the visual-motor responses of pilots during rapidly increasing acceleration contained in cyclic intervals of +6 Gz to the maximum ATL.
  
  
  METHODS
  The study involved 40 male pilots ages 32-41 yr. The task was a quick and faultless response to the light stimuli presented on a light bar during exposure to acceleration until reaching the ATL. Simple response time (SRT) measurements were performed using a visual-motor analysis system throughout the exposures which allowed assessment of a pilot's ATL.
  
  
  RESULTS
  There were 29 pilots who tolerated the initial phase of interval acceleration and achieved +6 Gz, completing the test at ATL. Relative to the control measurements, the obtained results indicate a significant effect of the applied acceleration on response time. SRT during +6 Gz exposure was not significantly longer compared with the reaction time between each of the intervals. SRT and erroneous reactions indicated no statistically significant differences between the "lower" and "higher" ATL groups.
  
  
  CONCLUSIONS
  SRT measurements over the +6-Gz exposure intervals did not vary between "lower" and "higher" ATL groups and, therefore, are not useful in predicting pilot performance. The gradual exposure to the maximum value of +6 Gz with exposure to the first three intervals on the +6-Gz plateau effectively differentiated pilots.
authors.affiliation: Department of Flight Safety, the Aeromedical Training Division, the Department of Aviation Physiology, and the Department of Aviation Psychology, Military Institute of Aviation Medicine, Warsaw, Poland.
authors.forename: Olaf
authors.initials: O
authors.lastname: Truszczynski
authors.forename: Rafal
authors.initials: R
authors.lastname: Lewkowicz
authors.forename: Mieczyslaw
authors.initials: M
authors.lastname: Wojtkowiak
authors.forename: Marcin P
authors.initials: MP
authors.lastname: Biernacki
mesh_terms: D000054:Acceleration; D000328:Adult; D000337:Aerospace Medicine; D001273:Atmosphere Exposure Chambers; D001288:Attention; D003198:Computer Simulation; D006112:Gravitation; D006801:Humans; D008297:Male; D011930:Reaction Time; D014796:Visual Perception