Wolf Motor Function Test (WMFT)

Overview

We conducted a literature search to identify all relevant publications on the psychometric properties of the WMFT in individuals with stroke. We identified 3 studies.

Floor/Ceiling Effects

Nijland et al. (2010) investigated the psychometric properties of the WMFT and Action Research Arm Test in 40 patients with stroke with mild to moderate hemiparesis. The WMFT showed adequate floor and ceiling effects with only 5 to 17% of patients scoring the lowest or highest scores.

Reliability

Internal Consistency:
Morris, Uswatte, Crago, Cook, and Taub (2001) evaluated the internal consistency of the WMFT in 24 clients with stroke. The internal consistency of the WMFT, as calculated using Cronbach’s Coefficient Alpha, was excellent (α = 0.92).

Nijland et al. (2010) investigated the internal consistency of the WMFT in 40 patients with stroke with mild to moderate hemiparesis. Internal consistency of the WMFT, as calculated using Cronbach’s Coefficient Alpha was excellent (α = 0.98).

Test-retest reliability:
Morris et al. (2001) analyzed the test-retest reliability of the WMFT in 24 clients with stroke. Participants were re-assessed within a 2-week interval. The test-retest reliability, as calculated using Pearson Correlation Coefficient, was excellent for both functional ability and performance tests (r = 0.95; 0.90, respectively).

Whitall, Savin, Harris-Love, and Waller (2006) examined the test-retest reliability of the WMFT in 66 clients with stroke. Participants were re-assessed within a 2 week interval by the same rater and under the same conditions. Test-retest reliability, as calculated using Intraclass Correlation Coefficient (ICC), was found to be excellent (ICC = 0.97).

Inter-rater
Morris et al. (2001) evaluated the Inter-rater reliability of the WMFT in 24 clients with stroke. Evaluations were conducted by a physiotherapist and were videotaped. The recordings were then rated by two physiotherapists and one occupational therapist. Inter-rater reliability, as calculated using ICC, was excellent for both functional ability and performance tests (ICC = 0.93; 0.99, respectively).

Wolf et al. (2001) verified the Inter-rater reliability of the WMFT in 19 clients with stroke and in 19 healthy individuals. All participants were evaluated by 2 raters, independently. Inter-rater reliability, as calculated using ICC, was excellent (ICC = 0.97)

Whitall et al. (2006) estimated the inter-rater reliability of the WMFT in 10 clients with stroke. The assessment of functional ability was videotaped and rated by three different raters. Inter-rater reliability was excellent (ICC = 0.99).

Nijland et al. (2010) investigated the psychometric properties of the WMFT and Action Research Arm Test in 40 patients with stroke with mild to moderate hemiparesis. 18 patients participated in the reproducibility testing of the WMFT and were assessed twice by the same observer approximately 10 days apart. Intra-rater reliability, as analyzed using the ICC was found to be excellent (ICC = 0.94).

Validity

Content:
No studies have reported the content validity of the WMFT.

Criterion:
Concurrent :
Wolf et al. (2001) examined the concurrent validity of the WMFT by comparing it to the Upper Extremity Fugl-Meyer Assessment (UE-FMA – Fugl-Meyer, Jääskö, Leyman, Olsson, & Steglind, 1975) as the gold standard in 19 clients with stroke. Adequate  correlations were found between the WMFT and the UE-FMA (r = -0.57).

Whitall et al. (2006) assessed the concurrent validity of the WMFT by comparing it to the UE-FMA as the gold standard in 66 clients with stroke. Correlations between the functional ability test of the WMFT and the UE-FMA were excellent (r = -0.88).

Nijland et al. (2010) investigated the concurrent validity of the WMFT by comparing it to the Action Research Arm Test (ARAT – Lyle, 1981) in 40 patients with stroke with mild to moderate hemiparesis. For the purpose of their investigation, the WMFT score was split into 4 variables: Functional Ability Score (FAS), median time score (s), item 7 and item 14 (strength). Correlations were calculated between the ARAT total score and the four variables. Excellent correlations between the ARAT total score and the WMFT FAS (r= 0.86), median time score (r=-0.89) and strength tasks (items 7 and 14) (r=0.70) were found.

Predictive
No studies have reported the predictive validity of the WMFT.

Construct:
Known groups:
Wolf et al. (2001) evaluated whether the WMFT was able to distinguish between individuals with impairment secondary to stroke (n=19) from those without impairment (n=19). Known group’s validity, as calculated using Wilcoxon test, showed that the WMFT scores for the dominant and the non-dominant hand of individuals without impairment were significantly higher when compared to the most and to the least affected upper extremity of clients with stroke.

Responsiveness

No studies have reported the responsiveness of the WMFT.

References
  • Barreca, S.R., Gowland, C.K., Stratford, P.W., et al. (2004). Development of the Chedoke Arm and Hand Activity Inventory: Theoretical constructs, item generation, and selection. Topics in Stroke Rehabilitation, 11(4), 31- 42.
  • Fugl-Meyer, A.R., Jääskö, L., Leyman, I., Olsson, S., & Steglind, S. (1975). The post-stroke hemiplegic patient 1. A method for evaluation of physical performance. Scandinavian Journal of Rehabilitation Medicine, 7, 13-31
  • Lyle, R.C. (1981). A performance test for assessment of upper limb function in physical rehabilitation treatment and research. International Journal of Rehabilitation and Research, 4, 483-492.
  • Morris, D., Uswatte, G., Crago, J., Cook, E., Taub, E. (2001). The reliability of the Wolf Motor Function Test for assessing upper extremity function after stroke. Arch Phys Med Rehabil, 82, 750-755.
  • Nijland, R., van Wegen, E., Verbunt, J, van Wijk, R., van Kordelaar, J. & Kwakkel, G. (2010) A comparison of two validated tests for upper limb function after stroke: The Wolf Motor Function Test and the Action Research Arm Test. Journal of Rehabilitation Medicine, 42, 694-696.
  • Whitall, J., Savin, D., Harris-Love, M., Waller, S. (2006). Psychometric properties of a modified wolf motor function test for people with mild and moderate upper extremity hemiparesis. Arch Phys Med Rehabil, 82, 750-755.
  • Wolf, S., Catlin, P., Ellis, M., Archer, A., Morgan, B., Piacentino, A. (2001). Assessing Wolf Motor Function Test as outcome measure for research in patients after stroke. Stroke, 32, 1635-1639.
  • Wolf, S., Thompson, P., Morris, D., Rose, D., Winstein, C., Taub, E., Giuliani, C., and Pearson, S. (2005). The EXCITE Trial: Atrributes of the Wolf Motor Function test in patients with Subacute Stroke. Neurorehabil Neural Repair, 19, 194-205.