LAUSR

Abstract We investigated the biological systems involved in maintaining equilibrium during unstable and perturbed conditions in 39 healthy older women and estimated the annual difference in performance across the older age spectrum using regression. The largest annual difference in equilibrium occurred when the somatosensory system received inaccurate feedback and visual input was removed. With age, weight distribution became asymmetric at the onset of backwards perturbations, possibly in preparation for executing a stepping strategy. When one sensory system was challenged, postural responses were stable suggesting other systems compensated. When multiple sensory systems were challenged, significant differences in postural control emerged with age.