Human Vestibular Response During 3 Gz Centrifuge Stimulation.
Abstract
The use of centrifuges in training aircrew to avoid GLOC is increasing. The purpose of this study was to record the vestibulo-ocular reflex (VOR) and subjective sensations to gain insight into reports of asymmetrical disorientation and disturbance during acceleration and deceleration of GLOC training centrifuges. Horizontal and vertical eye movements and post run sensations were recorded from 15 naive male human subjects seated head erect in a 20.5-ft radius pendulous chair centrifuge. Centrifuge profile was acceleration from 1 to 3 Gz in 19 s, 5 min of sustained 3 Gz, and deceleration to 1 Gz in 19 s. Tests were repeated up to three times with the subject facing the motion, and three times with the subject's back to the motion. Eye position was recorded in the dark using an ISCAN infrared video system. Six subjects experienced GLOC, and 1 withdrew due to unrelated sickness. Slow phase velocity (SPV) and sensations from the 8 subjects who completed all 6 runs were analyzed. Roll of the chair during acceleration and deceleration produced strong pitch, roll, and yaw sensations and eye movements attributable to vestibular Coriolis stimulation. Subjective pitch amplitude change was consistently greater during deceleration than acceleration, regardless of rotation direction. The SPV magnitude during the first run in a given direction was significantly different than the two subsequent runs. A sustained upbeating ('Lz') nystagmus (1-21 deg/ s, mean 8 deg/s at 100 s; 1-12 deg/s at 315 s) was observed in 7 of 8 subjects. VOR during centrifugation is composed of interacting transient angular and sustained linear VOR components. Sensation asymmetries are not observed in the VOR. Lz nystagmus magnitude is an individual subject characteristic. Centrifuge, Vestibulo-ocular, Lz nystagmus, Spatial Orientation
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1990
- Accession Number
- ADA283653
Entities
People
- R. J. Mcgrath
Organizations
- Naval Aerospace Medical Research Laboratory