Gait variability in older adults: Observational rating validated by comparison with a computerized walkway gold standard

Abstract

Background and Purpose. Gait variability has been measured with computerized technology-intensive techniques, which are not practical in clinical settings. The purpose of this study was to validate an observational rating of gait variability for routine clinical practice. Subjects. Community-dwelling older adults aged 65 years and older (n=46; mean age=81.2 years, SD=6.8 years, range=66-91 years) participated in this study. Methods. The standard deviation of stance time (stance time variability) derived from gait characteristics recorded by use of a computerized walkway was used as the gold standard for gait variability. The validity of the diagnostic test evaluated in this study (an observational rating of gait variability) was determined by comparison with the quantitative measure of stance time variability. Results. Six validity indexes were defined for the observational rating of gait variability: sensitivity=81%; specificity=53%; positive predictive value=65%; negative predictive value=71%; positive likelihood ratio=1.72; and negative likelihood ratio=0.36. Discussion and Conclusion. An observational rating of gait variability was validated by comparison with stance time variability derived from a computerized walkway. The concurrent validity of the 2 methods of determining gait variability provides support for the use of the observational rating as an alternative measure of gait variability for the purpose of identifying older adults at risk for mobility disability in clinical settings. © 2008 American Physical Therapy Association.