Development and Validation of Person-Centered Cut-Points for the Figure-of-8-Walk Test of Mobility in Community-Dwelling Older Adults

BACKGROUND

The Figure-of-8-Walk test (F8WT) is a performance measure of the motor skill of walking. Unlike walking speed over a straight path, it captures curved path walking, which is essential to real-world activity, but meaningful cut-points have yet to be developed for the F8WT.

METHODS

A secondary analysis of 421 community-dwelling older adults (mean age 80.7 ± 7.8), who participated in a community-based exercise clinical trial, was performed. Area under receiver operating characteristic curves (AUROCC) were calculated using baseline data, with F8WT performance discriminating different self-reported global mobility and balance dichotomies. Cut-points for the F8WT were chosen to optimize sensitivity and specificity. For validation, F8WT cut-points were applied to postintervention F8WT data. Participants were called monthly for 12 months after intervention completion to record self-reported incident falls, emergency department visits, and hospitalizations; risks of the outcomes were compared between those who performed well and poorly on the F8WT.

RESULTS

F8WT performance times of ≤9.09 seconds and ≤9.27 seconds can discriminate those with excellent (sensitivity = 0.647; specificity = 0.654) and excellent/very good global mobility (sensitivity = 0.649; specificity = 0.648), respectively. A total number of steps ≤17 on the F8WT can discriminate those with excellent/very good/good global balance (sensitivity = 0.646; specificity = 0.608). Compared to those who performed poorly, those who performed well had a lower incidence of negative outcomes: F8WT time ≤9.09 seconds = 46%-59% lower; F8WT time ≤9.27 seconds = 46%-56% lower; F8WT steps ≤17 = 44%-50% lower.

CONCLUSIONS

Clinicians may consider these preliminary cut-points to aid in their clinical decision making, but further study is needed for definitive recommendations.

Spatiotemporal variability underlying skill in curved-path walking

BACKGROUND

Daily life walking frequently involves curved paths. While mean gait characteristics and orientation of the body during curved path walking have been described, little has been reported about spatiotemporal variability during curved path walking and its relation to the motor skill of walking in older adults.

RESEARCH QUESTION

Among community-dwelling older adults, is greater spatiotemporal variability during curved path walking related to better curved path walking ability?

METHODS

Community dwelling older adults (n = 34) completed the Figure-of-8 Walk Test (F8W, a measure of curved path walking ability) and usual straight path walking on an instrumented walkway. Standard deviations for step length, stride width and step time (step length variability, SLV, stride width variability, SWV, step time variability, STV) during both conditions were determined, along with time and number of steps to complete F8W. Associations were examined with Pearson r correlation coefficients, regressions determined contributions of variability during curved path walking to F8W performance, and AUC analyses were used to determine the ability of variability during curved path walking to distinguish better vs poorer F8W performance.

RESULTS

F8W time and steps were negatively associated with both SLV (r's = -0.37, p < 0.05) and SWV (r's = -0.67 to -0.82, p < 0.001). Both SLV and SWV independently contributed to F8W performance (SLV βs = -0.26 to -0.29, p < 0.03; SWV βs = -0.74 to -0.76, p < 0.001). The AUC of the ROC curve for SLV was 0.716, and for SWV was 0.765.

SIGNIFICANCE

Greater spatial variability, particularly SWV, was associated with better motor skill of curved path walking. It is important for clinicians to understand the variables that contribute to successful performance of complex walking tasks as these can be targets for rehabilitation. The findings suggest that practice of adjustment of stride width and step length during walking are important.