JMIR Publications

ABSTRACT

Background:

Inter-step variations in step riser height and tread depth within a stairway could negatively impact safe stair negotiation by decreasing step riser height predictability and, consequently, increasing stair users’ fall risk. Unfortunately, inter-step variations in riser height and depth are common, particularly in older stairways, but its impact may be lessened by highlighting steps’ edges using a high-contrast stripe on the top front edge of each step. Such contrast enhancement may draw greater attention to the steps’ edges and potentially enhance the precision of the edge’s estimated location.

Objective:

To determine (1) if fall-related events are associated with greater inter-step riser height and depth variations and (2) if such fall-related events are reduced in the presence of contrast-enhanced step edges compared to a control stairway.

Methods:

Stair users were video recorded on two public stairways in a university building. One stairway had black vinyl stripes applied to the step’s edges and black-and-white vertical stripes on the last and top steps’ faces. The stairway with striping was switched halfway through data collection. Each stair user recorded was coded for whether they experienced a fall-related event.

Results:

Each flight of stairs had different inter-step riser height variation (e.g., 5, 12, and 14 mm) and inter-step tread depth variation (e.g., 4, 6, and 38 mm). The flights that had 14 mm in inter-step riser height variation and 38 mm in inter-step depth variation were associated with 80% of the fall-related events observed. Two fall-related events were observed for low inter-step variation/no striping, and 2 fall-related events were observed during low inter-step variation/striping. Twenty fall-related events were observed, with four occurring on flights of stairs with low inter-variation in step dimensions. For stairs with high variability in step dimensions, 13 of 16 (81%) fall-related events occurred on the control stairway (no striping) compared to 3 of 16 (19%) on the high-contrast striping stairway. A Monte Carlo simulation was used to estimate the probability of the distribution of fall-related events, given our hypotheses. The distribution of fall-related events we observed between conditions likely did not occur by chance, with probability = 0.0358.

Conclusions:

These data support the premise that a vision-based strategy (i.e., striping) may counteract fall-risk associated with inter-step riser height and tread depth variation. Possibly, perception and action elicited via the horizontal-vertical illusion (striping) may have a positive impact on the incidence of fall-related events in the presence of high inter-step riser height and depth variation. The findings of this study suggest that contrast enhancement (i.e., striping) may be a simple and effective way to reduce the risk of falls associated with inter-step variation, highlighting the potential for this approach to make a significant impact on fall prevention efforts.