ORIGINAL ARTICLE Psychometric Properties of a Modiﬁed Wolf Motor Function Test for People With Mild and Moderate Upper-Extremity Hemiparesis Jill Whitall, PhD, Douglas N. Savin Jr, MPT, Michelle Harris-Love, PT, PhD, Sandra McCombe Waller, PT, PhD 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-ex- tremity hemiparesis. Arch Phys Med Rehabil 2006;87:656-60. 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 mod- erate 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 hemipare- sis 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 corre- lation coefﬁcient (ICC) for videotape versus direct observation ranged from .96 to .99. For the whole group, test-retest reli- ability using ICC 2,1 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. Key Words: Cerebrovascular accident; Hemiparesis; Reha- bilitation; Reliability and validity. © 2006 by the American Congress of Rehabilitation Medi- cine and the American Academy of Physical Medicine and Rehabilitation S TROKE IS THE LEADING CAUSE of long-term disabil- ity in the United States, with more than 1.1 million adults reporting difﬁculty with activities of daily living and functional limitations as a result of stroke. 1 In addition, an estimated 95% of stroke survivors have some resultant upper-extremity (UE) dysfunction. 2 The importance of investigating novel rehabili- tation techniques, particularly for UE dysfunction, is apparent. Equally important is the development of reliable, valid, and clinically useful tests of UE dysfunction. The recognition that improvement of function is more important than improvement of impairment measures alone, such as strength and range of motion, has resulted in the development of several tests de- signed to measure functional abilities. 3-7 The Wolf Motor Function Test (WMFT), 7 previously called the Emory Motor Test, is 1 such test that was initially developed to assess the impact of forced use on return of UE function in chronic stroke subjects. Subsequently it was modiﬁed and renamed, 8 and it has been used as an outcome measure in several UE rehabili- tation studies, most notably studies of constraint-induced movement therapy. 9-17 The WMFT contains 3 parts: (1) timing, the speed at which functional tasks can be completed; (2) functional ability, the movement quality when completing the tasks; and (3) strength, the ability to lift against gravity. The purpose of the present study was to build on previous assess- ments 7,8,18 of the WMFT’s reliability and validity, in which only subjects with mild hemiparesis were assessed. Morris et al 8 examined the reliability of the WMFT in assessing UE motor function in a group of 24 subjects with mild chronic hemiparesis. Interrater reliability for median per- formance times and mean functional ability both were greater than .93, and the agreement of the raters was also high, at .88 and .97. Test-retest reliability of 2 administrations separated by 2 weeks was high, at .90 (time) and .95 (function). However, some individual items had low correlations across administra- tions and scales (.50). 8 Wolf et al 18 examined the WMFT using a group of 19 subjects with mild chronic UE hemipa- resis who were age- and sex-matched with 19 subjects without impairment. Interrater reliability again was high, ranging from .97 to .99. In addition, construct validity, shown by the WMFT’s ability “to differentiate the more affected extremity and the less affected extremity from either extremity of subjects without impairment” 18(p1637) and criterion validity, shown by a signiﬁcant relation between UE Fugl-Meyer Assessment (FMA) and WMFT scores for the affected extremity, were supported. 18 Test-retest reliability was not reported and only the timed—not the functional ability— portion of the WMFT was used for analysis. From the Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD (Whitall, Savin, McCombe Waller); and the National Institutes of Health, National Institute of Neurological Disorders and Stroke, Human Cortical Physiology Section, Bethesda, MD (Harris-Love). 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. Reprint requests to Jill Whitall, PhD, Dept of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, 100 Penn St, Baltimore, MD 21201, e-mail: jwhitall@som.umaryland.edu. 0003-9993/06/8705-10404$32.00/0 doi:10.1016/j.apmr.2006.02.004 656 Arch Phys Med Rehabil Vol 87, May 2006