A temporary threshold shift for self-motion detection following sustained, oscillating linear acceleration

Abstract

Thresholds for detecting linear motion (self-motion) increased following exposure of human observers to sustained linear oscillation (fatiguing stimulus) at 0.26 Hz and approximately 0.5 G peak-to-peak for durations up to 30 min. Recovery to preexposure levels took place over a period of 10 to 15 min following the sustained oscillation termination. Differences in threshold shift magnitudes following sustained oscillation in various orientations support the interpretation that the observed threshold shifts resulted from fatigue of the utricular otolith receptors. Threshold shifts were not obtained following exposure of the human observers to sustained, unidirectional linear acceleration (2G) for durations up to 10 min with a centrifuge. The results of this study suggest a previously unobserved response property of the otolith organs, namely, that these organs can be fatigued in a manner analogous to other receptor systems.