Postural Sway Characteristics of the Elderly Under Normal and Altered Visual and Support Surface Conditions

TLDR

Older adults exhibit a general slowing of cognitive‑motor responses, and delayed processing of vestibular, visual, and somatosensory information likely contributes to reduced postural stability. The study examined postural sway in elderly and young adults under conditions that challenge integrative, rather than reflexive, postural control mechanisms. Participants performed 80‑second trials of standing on a firm surface or a 5‑cm foam, with or without visual input, to compare sway against normal stance. Removing a single sensory input did not reliably distinguish elderly from young adults due to compensatory mechanisms, but simultaneous visual and surface perturbations markedly increased sway in the elderly compared to the young.

Abstract

One of the most pervasive findings in the literature on the aged is the general slowing of cognitive-motor responses with advancing age. Hence, an increased slowness in the processing of information from vestibular, visual, and somatosensory systems could contribute greatly to a decline in postural stability. To examine this question, in a crosssectional investigation, postural sway behavior of elderly (n = 18) and young (n = 10) adults was examined under conditions that stressed the slower integrative mechanisms rather than the reflexive mechanisms of postural control. The postural sway behavior of young and elderly subjects was examined for a prolonged duration (80 s), under altered visual and/or support surface (5 cm thick foam surface) conditions, and contrasted with normal stance. Results showed that the exclusion or disruption of one of the sensory inputs, alone, was not consistently sufficient to differentiate between elderly and young adults, because of compensation by the remaining sensory sources. Both alterations together (i.e., visual and surface), however, had a substantially greater effect upon the elderly than the young.