Reliability of Four Functional Tests and Rating of Perceived Exertion in Persons with Multiple Sclerosis

Purpose: Test-retest reliability and convergent and discriminant validity for four commonly used clinical tests of physical function were examined in persons with multiple sclerosis (MS). Method: Twelve ambulatory adults with clinically diagnosed MS (Expanded Disability Status Scale scores: mean = 3.6, range = 2.0−6.5) participated in a test-retest reliability study with a one-week interval between testing sessions. Functional tests included the 6-Minute Walk Test (6MWT), Functional Stair Test (FST), Static Standing Balance Test (BAL), and six-repetition Sit-to-Stand Test (SST). Distance was recorded for the 6MWT. All other tests were timed. Rating of perceived exertion (RPE) was recorded following each test. Intraclass correlation coefficients and Spearman rho correlation coefficients were used to examine agreement between test sessions. Results: Test-retest reliability for best trial of each test was significant for all tests (p < .01): the 6MWT (r 2 = .97), FST (r 2 = .97), BAL (r 2 = .81), and SST (r 2 = .94). Subjects rated RPE consistently each week for all tests (p < .05). RPE was significantly correlated with the associated test for only the BAL and FST. Conclusion: The 6MWT, FST, BAL, and SST are highly reliable tests in ambulatory persons with MS. Although subjects were consistent in the RPE following each of the functional tests, RPE did not always correlate well with performance on functional tests.