Reliability and Validity of the Streamlined Wolf Motor Function Test for Chronic Stroke

Abstract

Background: The present study evaluated the reliability and validity of the Streamlined Wolf Motor Function Test for Chronic Stroke (SWMFT-C), a shortened and redesigned version of the Wolf Motor Function Test (WMFT) to determine upper extremity (UE) motor abilities. Methods: Twenty individuals with chronic stroke were included in a cross-sectional study design. The Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) and the Stroke Impact Scale (SIS) were used to assess impaired motor recovery of the UE in these patients. The SWMFT-C’s test-retest (two weeks) reliability and inter-rater reliability (three physical therapists) were examined using the intra-class correlation coefficients (ICCs) ICC2,1 and ICC3,1. Validity was analysed by FMA-UE and SIS–hand function at baseline and 2 weeks using Pearson’s r values. Results: The SWMFT-C performance time(s) demonstrated excellent test-retest reliability (ICC3,1 = 0.943, 95% confidence interval [CI] = 0.859–0.978, standard error of measurement [SEM] = 0.15) and outstanding inter-rater reliability (ICC2,1 = 0.999, 95% CI = 0.998–1.000, SEM = 1.15). The functional ability scale (FAS) also demonstrated excellent test-retest reliability (ICC3,1 = 0.945, 95% CI = 0.861–0.978, SEM = 0.12) and inter-rater reliability (ICC2,1 = 0.973, 95% CI = 0.944–0.989, SEM = 0.18). Internal consistency (IC) was calculated using the overall Cronbach’s alpha and demonstrated outstanding agreement as shown by values of 0.99 and 0.94 in performance time(s) and FAS, respectively; the values of minimum detectable change (MDC95) were 2.26 seconds and 0.34 seconds, respectively. The validity was good to excellent as correlated with FMA-UE and SIS– hand function, ranging from −0.86 to −0.52 in performance time(s) and 0.65 to 0.80 in FAS. Conclusion: The SWMFT-C is a valid, reliable clinical instrument for the population with chronic stroke.