[Effect of head-down tilt hypokinesia on human equilibrium function].

Six test subjects who participated in 182-day head-down study at -4 degrees were examined stabilographically before and during the test. During the first 30 days they showed impaired equilibrium which later was relatively stabilized. Continuation of the bed rest study did not impair drastically stability of upright standing. It was shown that the contribution of optic sensors into the recovery of the equilibrium function increased during the second half of the bed rest study. Provocative tests suggest that bed rest related impairment of equilibrium occurs due to vestibular changes and deconditioning.