[Results of a study of vestibular function and space perception in cosmonauts]

The results of studying the vestibular function and the function of spatial perception in 26 cosmonauts before and after 30 space flights are discussed. The typical postflight changes in these functions were: an increase in the reactivity of the otolith organ, a decrease in the sensitivity of semicircular canals, a decline in the accuracy of perception of spatial coordinates, asymmetry of most parameters, development of illusionary reactions inflight. The cosmonauts also showed individual variations with respect to the degrees of the above responses, the dynamics and length of adaptation, the development of the motion sickness symptom-complex, etc. At R+O some cosmonauts exhibited a change in the direction of the eye counter-rotation, i. e., the negative otolith reflex or at turn towards the tilt direction. Possible mechanisms of these vestibular changes are discussed.