THE “4 METER WALK TEST” IOS APPLICATION IS A VALID MEASURE OF GAIT SPEED

Fell D.W.¹, Wall J.C.¹, Quebedeaux L.¹, Rogers K.¹, Roscigno C.¹, Tyler L.¹

¹University of South Alabama, Department of Physical Therapy, Mobile, United States

Background: Gait velocity and the ability to intentionally increase gait velocity is an essential marker of functional ability that physical therapists must be able to measure easily. The NIH Toolbox includes the 4-Meter Walk Test to measure gait velocity.

Purpose: This study examined the validity of a newly-developed iOS mobile application called “4 Meter Walk Test” (4MWT) that uses the established 4-Meter Walk Test procedure, but automatically calculates walking speed, with comparison to walking speed calculated from stopwatch data.

Methods: Healthy subjects across a wide lifespan, age 21-89 years, (n=110) participated in the study. The 4MWT, developed by the NIH, was performed by each subject per NIH standard protocol, while one researcher measured walk time using a stopwatch and gait speed was manually calculated and recorded for each trial. Another researcher used the 4MWT application to register the start and stop time for each trial and the app automatically calculated the gait speed. Gait speed from the two methods was compared to determine the application’s validity. If valid, this application could be utilized by physical therapists to more efficiently complete objective measures of function.

Results: Across the sample, the mean difference in gait speed between stopwatch and the iOS application methods was 0.03 m/s, and the standard deviation of these differences was 0.06m/s. The 95% confidence interval, including -0.02 upper limit and -0.04 lower limits, indicates a slight but significant difference in the iOS application & stopwatch, with the stopwatch times slightly less than those measured with the application. However, the interval is so small and close to zero that this difference is negligible. The minimal detectable change for gait speed has been reported to be 0.1m/s.

Conclusion(s): Since results indicate such a negligible difference in speeds between the two measurement methods, and the difference is less than reported minimal detectable change, the difference can be considered clinically insignificant, and the application clinically valid.

Implications: The “4 Meter Walk Test” iOS application is a valid tool to measure gait speed of patients with ease of use in a clinical setting. Physical therapists will be able to efficiently and accurately conduct a functional evaluation of gait through the utilization of this application, to enhance goal-setting and planning treatments with the additional information provided by the application. This study validates the “4 Meter Walk Test” iOS application as a measure of gait speed, with the added value that it is calculated automatically by the program.

Funding acknowledgements: None

Topic: Neurology

Ethics approval: The project was approved by the University of South Alabama Institutional Review Board.

All authors, affiliations and abstracts have been published as submitted.