Safety on stairs: Influence of a tread edge highlighter and its position

BACKGROUND Falls sustained when descending stairs are the leading cause of accidental death in older adults. Highly visible edge highlighters/friction strips (often set back from the tread edge) are sometimes used to improve stair safety, but there is no evidence for the usefulness of either. OBJECTIVE To determine whether an edge highlighter and its location relative to the tread edge affect foot placement/clearance and accidental foot contacts when descending stairs. METHOD Sixteen older adults (mean±1SD age; 71±7years) with normal vision (experiment 1) and eight young adults (mean±1SD age; 24±4years) with visual impairment due to simulated age-related cataract (experiment 2) completed step descent trials during which a high contrast edge highlighter was either not present, placed flush with the tread edge, or set back from the edge by 10mm or 30mm. Foot placement/clearance and the number of accidental foot contacts were compared across conditions. RESULTS In experiment 1, a highlighter set back by 30mm led to a reduction in final foot placement (p<0.001) and foot clearance (p<0.001) compared to a highlighter placed flush with the tread edge, and the percentage of foot clearances that were less than 5mm increased from 2% (abutting) to 17% (away30). In experiment 2, a highlighter placed flush with the tread edge led to a decrease in within-subject variability in final foot placement (p=0.004) and horizontal foot clearance (p=0.022), a decrease in descent duration (p=0.009), and a decrease in the number of low clearances (<5mm, from 8% to 0%) and the number of accidental foot contacts (15% to 3%) when compared to a tread edge with no highlighter present. CONCLUSIONS Changes to foot clearance parameters as a result of highlighter presence and position suggest that stairs with high-contrast edge highlighters positioned flush with the tread edge will improve safety on stairs, particularly for those with age-related visual impairment.