Concurrent Validity of the Zeno Walkway for Measuring Spatiotemporal Gait Parameters in Older Adults
Authors: Vallabhajosula Srikant , Humphrey Sarah K. , Cook Alys J. , Freund Jane E. 
Published: December 2017

Background and Purpose:
Previous studies have shown that older adults at high fall risk exhibit altered spatiotemporal gait parameters such as lesser gait speed, shorter step length, and greater step width compared with their healthy counterparts. Measurement of these gait parameters for older adults can play a pivotal role in clinical evaluation. While the GAITRite walkway has been previously validated and used extensively for research purposes, the Zeno walkway validity has not been established. Although both walkways use pressure sensor–based technology, comparison of the spatiotemporal gait measurements between the systems for older adults is unknown. Our purpose was to determine the concurrent validity of the Zeno walkway with the gold-standard GAITRite walkway among healthy older adults and those at high fall risk using a cross-sectional study design.

Methods:
Thirty healthy older adults and 17 older adults at high fall risk performed 5 walking trials barefoot on a 16´ × 4´ Zeno walkway and a 14´ × 2´ GAITRite walkway in a quasi-randomized order. Testing on the Zeno walkway was performed in a continuous manner while testing on the GAITRite walkway was performed using 5 discrete trials. Walking trials were done at self-selected comfortable and fast pace conditions. Data from the Zeno walkway were processed using the PKMAS software. Data from the GAITRite were processed using the GAITRite software. For each group and condition, spatiotemporal gait parameters common to both walkways' footfall processing software were compared using a Wilcoxon signed rank test. Concurrent validity was estimated using intraclass correlation coefficient (ICC(2,5)) and Bland-Altman plots.

Results and Discussion:
Both groups had significantly greater stride width on the GAITRite walkway during both conditions. During the fast pace condition, both groups walked with greater gait speed, cadence, and stride velocity, lesser step time, stance time, and double-support time, greater percentage of gait cycle spent in single-support phase, and lesser percentage of gait cycle spent in double-support phase on the GAITRite walkway. Differences observed could be attributed to surface textures, software used to process the footfalls, dimensions of the walkways, or the continuous versus discrete protocols used in the current study. The ranges of ICC(2,5) values for healthy older adults and adults at high fall risk walking at a comfortable pace were 0.449 to 0.918 and 0.854 to 0.969 and at a fast pace were 0.784 to 0.964 and 0.850 to 0.976, respectively. These values imply that the concurrent validity was moderate for most temporal parameters when healthy older adults walked at comfortable pace and excellent otherwise. Overall, the concurrent validity between both walkways was acceptable.

Conclusion:
Concurrent validity for spatiotemporal parameters between the GAITRite walkway and the Zeno walkway was moderate to excellent for older adults dependent on the specific parameter (spatial vs temporal), population (healthy or fall risk), and walking pace (comfortable or fast).