The division of visual attention affects the transition point from level walking to stair descent in healthy, active older adults

Background: Stair descent is a frequent daily activity that poses great risks for injury due to falling. Very little is understood about the attentional demands of stair descent and their changes with aging. The present study compared combined locomotor and cognitive functioning during different phases of stair descent between healthy young and older individuals. Methods: Sixteen young and sixteen healthy older subjects walked down a 5-step staircase, performing a simultaneous visual Stroop task (i.e., a dual task) during the approach, transition or steady-state descent phases in some trials. Three dimensional kinematics of trunk and foot motion were recorded along with the accuracy and dual task costs (DTCs) for responses to the Stroop stimuli. Results: Dual tasking influenced both gait and cognitive performance for all subjects, and older adults generally walked slower with higher foot clearances and had greater DTCs. Specific age differences were found at stair transition where older adults showed more attentional effects. Conclusions: Healthy, active older adults showed changes to attention and planning due to normal aging specifically associated with a crucial point of fall risk during stair descent