The Reliability and Validity of Measures of Gait Variability in Community-Dwelling Older Adults
Presented at the International Society for Posture and Gait Research, Burlington, VT, July 14–18, 2007.
Abstract
Brach JS, Perera S, Studenski S, Newman AB. The reliability and validity of measures of gait variability in community-dwelling older adults.
Objective
To examine the test-retest reliability and concurrent validity of variability of gait characteristics.
Design
Cross-sectional study.
Setting
Research laboratory.
Participants
Older adults (N=558) from the Cardiovascular Health Study.
Interventions
Not applicable.
Main Outcome Measures
Gait characteristics were measured using a 4-m computerized walkway. SD determined from the steps recorded were used as the measures of variability. Intraclass correlation coefficients (ICC) were calculated to examine test-retest reliability of a 4-m walk and two 4-m walks. To establish concurrent validity, the measures of gait variability were compared across levels of health, functional status, and physical activity using independent t tests and analysis of variances.
Results
Gait variability measures from the two 4-m walks demonstrated greater test-retest reliability than those from the single 4-m walk (ICC=.22–.48 and ICC=.40–.63, respectively). Greater step length and stance time variability were associated with poorer health, functional status and physical activity (P<.05).
Conclusions
Gait variability calculated from a limited number of steps has fair to good test-retest reliability and concurrent validity. Reliability of gait variability calculated from a greater number of steps should be assessed to determine if the consistency can be improved.
aDepartment of Physical Therapy, University of Pittsburgh, Pittsburgh, PA
bDivision of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA
cDepartment of Epidemiology, University of Pittsburgh, Pittsburgh, PA
Correspondence to Jennifer S. Brach, PhD, PT, Department of Physical Therapy, University of Pittsburgh, 6035 Forbes Tower, Pittsburgh, PA 15260
Supported by the National Institutes of Health Public Health Service (grant no. TG32 AG00181) and the National Institutes of Health contracts (grant no. N01-HC-75150, N01-HC-45133, N01-HC-85079 through 85085, and HL 87079 through 87086); and the University of Pittsburgh Older American's Independence Center (grant no. P30 AG024827); the National Institutes of Health Public Health Service (grant no. TG32 AG00181); a National Institutes on Aging and American Federation of Aging Research Paul Beeson Career Development Award (grant no. K23 AG026766). The sponsor had no direct role in the design, methods, subject recruitment, data collection, analysis, or preparation of the manuscript.
No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.
ABSTRACT