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The vestibulo-ocular reflex (VOR) and spatial orientation perceptions were recorded in 15 subjects during a 3-Gz centrifuge run. These data were obtained to study two issues; first, to gain insight into reports of asymmetrical disorientation and disturbance during acceleration and deceleration of G-induced loss of consciousness (G-LOC) training centrifuges. Secondly, to study the effects of sustained vertical linear acceleration on the vestibular system. The centrifuge run consisted of an acceleration to 3-Gz in 19 s, sustained 3-Gz for 5 min, and a deceleration to 1 Gz in 19 s. The runs were repeated three times with the subject facing the motion, and three times with the subject's back to the motion. The VOR and spatial orientation perceptions from the eight subjects who completed all six runs were analyzed. The total VOR response during acceleration and deceleration of a centrifuge run is composed of interacting angular and linear VOR components. However, the VOR response did not correspond to reported asymmetries in pitch orientation perception between centrifuge acceleration and deceleration. During the constant velocity high G phase of a centrifuge run, a sustained up-beating ("Lz") nystagmus was observed in 14 of the 15 subjects. For the eight subjects analyzed, Lz nystagmus was shown to be an individual subject characteristic, and displayed a range of mean magnitudes from 0 to 10 deg/s at 90 s. Assuming a normal visual suppression ratio of the VOR, the magnitudes of the Lz nystagmus in our subject sample did not appear sufficient to degrade visual acuity.

The effect of adding track angle error (TAE) information to general aviation aircraft cockpit displays used for GPS nonprecision instrument approaches was studied experimentally. Six pilots flew 120 approaches in a Frasca 242 light twin aircraft simulator using crosswind and turbulence. Twenty-five-mile-long approach geometries were used, with and without 45 degree dogleg turns on final approach. Performance and workload using three TAE display formats were compared against results with two control formats presenting cross track error (XTE) only. Pilots found that the TAE displays simplified determination of wind correction angle, and that they consistently chose to use analog rather than numeric TAE data. Statistically significant differences between display formats and between pilots were found. The largest average improvement in initial leg intercept and tracking performance resulted when the conventional 'ten dot' XTE display was supplemented with a sliding pointer display of TAE, moving in the same direction as aircraft bank. A second TAE format, a sliding/rotating pointer integrated display, yielded the greatest improvement (35%) in the width of the short final approach flight technical error envelope, but pilots reported occasional problems interpreting this display. Both of these TAE formats improved final approach intercept and tracking performance after 45 degree turning maneuvers. The addition of TAE information to the receiver display helped pilots create outer Loop Lead, and yielded approach performance improvements comparable to relocating XTE information to an HSI within the pilot's primary scan. Bedford workload scores were not significantly influenced by display format, but were found to depend on approach geometry and phase.

Vestibular stimuli throughout a simple centrifuge run are described in this report, which is the first in a report series that is part of our basic research devoted to an Office of Naval Research accelerated research initiative on vestibular transduction. Herein, we compare stimuli throughout the initial angular acceleration with stimuli during the deceleration that ends the run. We provide tables that show differing rates of change of linear and angular acceleration vectors during the acceleration and deceleration, and we discuss the research steps needed to explain disorientation abhorence reactions and spatial orientation perceptions in centrifuge runs. Keywords: Vestibular transduction, Vestibular stimulus, Centrifuge, Semicircular canals, Otoliths. (js)

Symptoms and signs of space motion sickness and fluid shift were observed by 4 specially trained crewmembers on the physically demanding 10 day flight of Space Shuttle/Spacelab 1 launched on 11/28/83. Anonymous but detailed firsthand reports are presented. Three crewmen experienced persistent overall discomfort, and vomited repeatedly. Symptom pattern was generally similar to that seen in the individuals preflight, except that: prodromal nausea was brief or absent in some cases; facial pallor and cold sweating were usually absent; one subject experienced uncomfortable stomach elevation. However, symptoms were clearly modulated by head movement, were exacerbated by unfamiliar visual cues, and could be reduced by physical restraint providing contact cues around the body. Drugs known to be effective in preventing motion sickness were judged helpful in limiting symptoms, including vomiting. Results support the view that space sickness is a form of motion sickness., This article is from 'The Aerospace Medical Panel Symposium on Motion Sickness: Mechanisms, Prediction, Prevention, and Treatment Held at Williamsburg, Virginia on 3-4 May 1984,' AD-A152 548, P35-1-35-21.

The four Spacelab 1 payload crew members, as experimental subjects, were exposed to a variety of motion sickness tests. Contrary to expectation, the crew member who was most susceptible to these tests was the least susceptible to these tests. On the third day after returning from the mission, one of the preflight tests (KC 135) was repeated, and all of the crew members were found to be non-susceptible. Statements of generalities will have to wait for the accumulation of more experimental subjects., This article is from 'The Aerospace Medical Panel Symposium on Motion Sickness: Mechanisms, Prediction, Prevention, and Treatment Held at Williamsburg, Virginia on 3-4 May 1984,' AD-A152 548, P33-1-33-8.

Presented at the Congress of the International Astronautical Federation (33rd) Paris, France, 27 Sep-2 Oct 82.