Young, L.R., Sienko, K.H., Lyne, L.E, Hecht, H. & Natapoff, A.

Man-Vehicle Lab

Massachusetts Institute of Technology

Abstract

IAdaptation of the vestibulo-ocular reflex (VOR), subjective tilt, and motion sickness in response to out-of-plane head movements during short-radius centrifugation (radius = 2 m) at 23 rpm was investigated. Dual-adaptation, the ability to transition between rotating and non-rotating environments, is critical for the implementation of artificial gravity. Eight subjects participated in a series of pre-, per- and post-rotation sessions on three days [Day = 1, 2, and 8]. Inappropriate vertical eye movements and subjective tilt were measured in response to 90-degree yaw out-of-plane head movements during rotation. Post-experiment motion-sickness scores (Pensacola Diagnostic Index method and post-motion-sickness survey) were collected following exposure to rotation. Slow phase eye velocity was reconstructed from filtered eye movement data. Significant main adaptation effects were found for normalized slow phase velocity. The reported magnitude of the subjective tilt experienced during head turns decreased significantly between Days 1 and 2. Pensacola motion-sickness scores decreased significantly over all three days. Partial adaptation was achieved for all measures between Days 1 and 2. Retention of adaptation over a six-day rest period (without centrifugation) occurred, but was not complete for all measures; adaptation for VOR was completely maintained, while subjective tilt was marginally maintained and motion sickness scores continued to decrease.