Original article
Psychometric Properties of a Modified Wolf Motor Function Test for People With Mild and Moderate Upper-Extremity Hemiparesis

https://doi.org/10.1016/j.apmr.2006.02.004Get rights and content

Abstract

Whitall J, Savin DN, Harris-Love M, McCombe Waller S. 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 ICC2,1 ranged from .97 to .99; stability of the test showed that administration 1 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 1 repeat testing is recommended when practical.

Section snippets

Participants

All participants were part of a larger training intervention study, and reliability measurements were performed in the context of pretraining baseline testing. Participants were recruited through local hospitals and advertisements. Informed consent, approved by the joint Veterans Affairs–University of Maryland institutional review board, was obtained from all participants before inclusion in the study. Initial evaluations included a medical history, the Folstein Mini-Mental State Examination,

Step 1: Videotape Versus Observation

Scores for the mean and median performance times and median functional ability scales are presented in table 1. Because our sample included patients with a range of disability severity, it is noteworthy that using the median time results in a floor effect for subjects 2 and 9. The ICCs for mean and median time were .99 and .96, respectively, and .99 for functional ability.

Step 2: Test-Retest Reliability, Item Stability, and Criterion Validity

The test-retest ICC2,1 values of the total scores were high, ranging from .92 to .99, whether or not the subjects were

Discussion

In this study, we determined the psychometric properties of a modified WMFT for subjects with mild- and moderate-severity hemiparesis. As a preliminary step, in a small sample, we compared results from videotaping with direct observation and determined that the latter provided similar results with a higher correlation as did 3 raters using the videotape. In a larger sample we showed good test-retest reliability and stability of the timed and functional ability scores and individual items across

Conclusions

The WMFT (modified for more impaired subjects) can be used without videotape and has good interrater reliability and high criterion validity with the UE FMA in subjects with both mild- and moderate-severity hemiparesis. The test-retest reliability results are high, but the stability assessment shows that it may be prudent to administer the WMFT a second time to obtain stable measures. Overall, the clinical and scientific applicability of the WMFT is broadened.

Acknowledgments

We thank Richard Macko, MD, for screening subjects; Jennifer Sulin-Stair for assistance with data collection; and Steven Wolf, PT, PhD, for helpful comments on an earlier draft of this article.

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    Supported by the National Institute of Disability and Rehabilitation Research (grant no. H133G010111) and the Claude Pepper Older Americans Independence Center, National Institute on Aging (grant no. P6012583).

    No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.

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