Effect of Acceleration Frequency on Spatial Orientation Mechanisms

http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA529816&Location=U2&doc=GetTRDoc.pdf

Effect of Acceleration Frequency on Spatial Orientation Mechanisms

NAMRL-10-55

Frederick R. Patterson; Joseph F. Chandler

Extreme motion environments can induce loss of visual acuity, motion sickness, and spatial disorientation. Understanding how human sensory integration of acceleration stimuli affects spatial awareness will improve models of spatial disorientation and mishap analysis. Vestibular gaze reflex data were successfully collected from 10 subjects, each of whom completed three separate trials at sequences of low, medium, and high off-vertical axis rotation (OVAR) spin rates. The results of these tests revealed no significant change in horizontal and torsional eye movements between the low OVAR spin frequency of 0.03 Hz and the predicted crossover point of 0.25 Hz; however, there did appear to be a trend toward reduction of horizontal eye movement when the high OVAR rate of 0.55 Hz was compared with the low (0.03 Hz) and medium (0.25 Hz) rates. Based upon the collected data, a revised crossover rate of 0.42 Hz was extrapolated as the most probable spin frequency for inducing gaze reflex changes with the potential for triggering motion sickness. The results of this study have identified a potential range of circular motion with potential implications for designing future flight simulators used for
training or assessment of cockpit designs.