Psychometric properties of a modified Wolf Motor Function Test for people with mild and moderate upper-extremity hemiparesis

Objective: To test the necessity of videotaping, test-retest reliability, and item stability and validity of a modified Wolf Motor Function Test (WMFT) for people with mild and moderate chronic upper-extremity (UE) hemiparesis caused by stroke. Design: Raters of videotape versus direct observation; test-retest reliability over 3 observations, item stability, and criterion validity with upper-extremity Fugl-Meyer Assessment (FMA) in the mildly and moderately impaired groups. Setting: Academic research center. Participants: Sixty-six subjects with chronic UE hemiparesis who participated in a large intervention study. Subjects were classified into mild and moderate groups for additional analyses. Interventions: Not applicable. Main Outcome Measures: Mean and median times of task completion, functional ability, and strength (weight to box) measures of the WMFT. FMA scores for validity assessment. Results: In a subgroup of 10 Subjects, the intraclass correlation coefficient (ICC) for videotape versus direct observation ranged from .96 to .99. For the whole group, test-retest reliability using ICC(2.1) ranged from .97 to .99; stability of the test showed that administration I differed from administrations 2 and 3 but administrations 2 and 3 did not differ; item analysis showed that 4 of 17 items changed across time, and validity, using a correlation with UE FMA, ranged from .86 to .89. Separate mild-and moderate-group analyses were similar to whole-group results. Conclusions: Videotaping the modified WMFT was not necessary for accurate scoring. The modified WMFT is reliable and valid as an outcome measure for people with chronic moderate and mild UE hemiparesis and is stable, but I repeat testing is recommended when practical.