Age Affects the Attentional Demands of Stair Ambulation: Evidence From a Dual-Task Approach

Abstract

Approximately 75% of all injury-producing falls on steps for people of all ages occur in people 65 years of age and older. Diminished attentional capacity contributes to fall risk in older adults, particularly when task demands are high. The purpose of this study was to compare the attentional demands of ascending and descending a set of stairs (stair ambulation) in older adults and younger adults. This was a nonblinded, prospective, single-site, observational cohort study. Ten older (>65 years of age) and 10 younger (21-33 years of age) adults without disabilities were recruited. A dual-task approach was used for 2 task conditions: the first task was standing and responding verbally to an unanticipated auditory tone as quickly as possible (probe task), and the second task was ascending or descending a set of stairs with the same probe task. A 2-factor (group x task) analysis of variance with repeated measures on task (standing and stair ambulation) was performed for voice response time (VRT). Significance for the analysis was set at P<.05. The group x task interaction was significant for VRT. Post hoc analyses indicated that during stair ambulation, the VRT for older adults was significantly longer than that for younger adults. For the standing task, the VRTs (X+/-SD) were similar for younger (322+/-65 milliseconds) and older (306+/-22 milliseconds) participants. For stair ascent and descent, the average VRTs were more than 100 milliseconds longer for older participants (493+/-113 and 470+/-127 milliseconds, respectively) than for younger participants (365+/-56 and 356+/-67 milliseconds, respectively). Because of the small sample size and generally fit older group, generalization of findings to older people at risk for falls is not recommended until further research is done. The results demonstrated that although both older and younger adults required similar attentional resources for the standing task, older adults required significantly more resources during stair ambulation. The findings suggested that the dual-task method used here provided a clinically useful measure for detecting important changes in attentional demands in older adults who are healthy.