Safe Stair Descent in the Elderly: Effects of Visual Conditions on Foot-Stair Interaction

The elderly are at particular risk for stair related accidents due to the prevalence of age related functional declines in the visual, somatosensory and vestibular systems. Certain architectural features of some staircases may further magnify these age-dependent intrinsic risk factors. Altered visual conditions such as the use of bifocals or inadequate lighting may result in altered strategies used during stair descent. The purpose of this study was to examine strategies used to safely negotiate stairs in altered visual conditions (bifocals and low ambient lighting). The dependent variables examined were the ground reaction force profiles and the required coefficient of friction during stair descent.