Short-distance walking speed tests in people with Parkinson disease: reliability, responsiveness, and validity.

PURPOSE The aims of this study were to determine test-retest reliability and responsiveness of short-distance walking speed tests for persons with Parkinson disease (PD). Discriminant and convergent validity of walking speed tests were also examined. METHODS Eighty-eight participants with PD (mean age, 66 years) with mild to moderate severity (stages 1-4 on the Hoehn and Yahr Scale) were tested on medications. Measures of activity included the comfortable and fast 10-m walk tests (CWT, FWT), 6-min walk test (6MWT), mini balance evaluations systems test (mini-BEST Test), fear of falling (FoF), and the Activity-Specific Balance Confidence Scale (ABC). The mobility subsection of the PD quality of life-39 (PDQ39-M) served as a participation-based measure. RESULTS Test-retest reliability was high for both walking speed measures (CWT, ICC(2,1) = 0.98; FWT, ICC(2,1) = 0.99). Minimal detectable change (MDC(95)) for the CWT and FWT was 0.09 m/s and 0.13 m/s respectively. Participants at Hoehn & Yahr levels 3/4 demonstrated significantly slower walking speed with the CWT and FWT than participants at Hoehn & Yahr levels 1 and 2 (P < .01). The CWT and FWT were both significantly (P ≤ .002) correlated with all activity and participation-based measures. CONCLUSIONS Short-distance walking speed tests are clinically useful measures for persons with PD. The CWT and FWT are highly reliable and responsive to change in persons with PD. Short distance walking speed can be used to discriminate differences in gait function between persons with mild and moderate PD severity. The CWT and FWT had moderate to strong associations with other activity and participation based measures demonstrating convergent validity.