Human visual and auditory analyzers under the conditions of acceleration: Comparative analysis of the development of disturbances

Abstract

More than 500 pinpoint physiological experiments were performed to compare the state and development of visual and auditory disturbances during rotation on an 8-m armed centrifuge at 14 g. A high level instrumentation provided a broad variety of measurements within very short intervals, including the acuity and angle of vision, absolute light sensitivity, critical flicker frequency, thresholds of tone hearing, and speech intelligibility. The state of eyeground blood vessels under acceleration was estimated both remotely and by an ophthalmologist sitting by the subject during rotation. Experimental results showed the impairment of the visual function during an acceleration increase and an almost complete loss of vision at 12–14 g. As regards the hearing function, acoustic energy incurred some loss on the way to Corti’s organ and yet hearing remained good enough to support operator’s orientation in the whole range of accelerations not resulting in the loss of consciousness. The significance of hearing retention is confirmed by successful experience of using audio information in the study of effectiveness of manual spacecraft operation at 18 g at the same laboratory. Comparative analysis of these and other laboratory and literature data makes it possible to assess the functional state of different components of light and acoustic energy transportation and conversion on the way to the central representations and to reveal the weak points of both analyzers. The data favor the view of retina as a blocker of light energy transportation. Development of this phenomenon is associated primarily with blood circulation impairment in the a. centralis retinae.