title: Perception of the cabin attitude changes in hypergravity.
abstract: BACKGROUND
  The G-excess illusion is becoming increasingly recognized as a cause of aviation fatalities. Studies of this illusion have looked at perception of subjects' orientation by moving the head during hypergravity, but independent of the pilot's head movement with respect to aircraft. This illusion can also occur by aircraft motion, but this has not been studied extensively.
  
  
  OBJECTIVE
  The aim of this study was to investigate the subject's perception of orientation to the simulator cab attitude changes at 1.6 G without making any head movement with respect to the cab, and assess the feasibility of simulating the G-excess illusion on the ground with a centrifuge-like spatial disorientation simulator.
  
  
  METHODS
  The 1.6-G force field was provided by the gravitoinertial force (GIF) of the simulator when it made an off-center (planetary) rotation at a constant velocity of 130 degrees x s(-1). Eleven subjects' perceptions of orientation of the cab attitudes were collected respectively by their report before and after certain cab tilt, in a roll plane of 1.6 G.
  
  
  RESULTS
  When the cab was tilted 20 degrees at 1.6 G, the subjects perceived the angle to be 48.6 +/- 39.4 degrees.
  
  
  CONCLUSIONS
  Most subjects experienced an exaggerated sensation to the cab attitude changes in roll plane. G-excess illusion can be generated in a centrifuge-like device on the ground.
authors.affiliation: Vestibular Laboratory, Institute of Aviation Medicine, Air Force, Beijing, China. tsgsjh@blcu.edu.cn
authors.forename: Hongbo
authors.initials: H
authors.lastname: Jia
authors.forename: Lishen
authors.initials: L
authors.lastname: Yu
authors.forename: Hongzhe
authors.initials: H
authors.lastname: Bi
authors.forename: Kuinian
authors.initials: K
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.forename: Sujiang
authors.initials: S
authors.lastname: Xie
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000531:Altitude; D006257:Head; D006801:Humans; D018471:Hypergravity; D007088:Illusions; D008297:Male; D009068:Movement; D009949:Orientation; D010465:Perception