Wolf Motor Function Test (WMFT)

Evidence Reviewed as of before: 11-01-2011
Author(s): Sabrina Figueiredo, BSc
Editor(s): Nicol Korner-Bitensky, PhD OT
Content consistency: Gabriel Plumier

Purpose

The Wolf Motor Function Test (WMFT) quantifies upper extremity (UE) motor ability through timed and functional tasks (Wolf, Catlin, Ellis, Archer, Morgan & Piacentino, 1995).

In-Depth Review

Purpose of the measure

The Wolf Motor Function Test (WMFT) quantifies upper extremity (UE) motor ability through timed and functional tasks (Wolf, Catlin, Ellis, Archer, Morgan & Piacentino, 1995).

Available versions

The original version of the WMFT was developed by Wolf, Lecraw, Barton, and Jann in 1989 to examine the effects of constraint-induced movement therapy in clients with mild to moderate stroke and traumatic brain injury. In 1999, a graded WMFT was developed by Uswatte and Taub to assess the motor abilities of patients who were functioning at a lower level (Morris, Uswatte, Crago, Cook & Taub, 2001).

Features of the measure

Items:

The original version of the WMFT consisted of 21 items. The widely used version of the WMFT consists of 17 items. The first 6 items involve timed functional tasks, items 7 and 14 are measures of strength, and the remaining 9 items consist of analyzing movement quality when completing various tasks (Wolf et al., 1995; Whitall, Savin, Harris-Love, & Waller, 2006).

The examiner should test the less affected upper extremity followed by the most affected side. The following items should be performed as quickly as possible, truncated at 120 seconds (Wolf, Thompson, Morris, Rose, Winstein, Taub, et al., 2005):

  1. Forearm to table (side): client attempts to place forearm on a table by abducting at the shoulder
  2. Forearm to box (side): client attempts to place forearm on a box, 25.4cm tall, by abduction at the shoulder
  3. Extended elbow (side): client attempts to reach across a table, 28cm long, by extending the elbow (to the side)
  4. Extended elbow (to the side) with 1lb weight: client attempts to push the weight against outer wrist joint across the table by extending the elbow
  5. Hand to table (front): client attempts to place involved hand on a table
  6. Hand to box (front): client attempts to place hand on the box placed on the tabletop
  7. Weight to box: client attempts to place the heaviest possible weight on the box placed on the tabletop
  8. Reach and retrieve (front): client attempts to pull 1lb weight across the table by using elbow flexion and cupped wrist
  9. Lift can (front): client attempts to lift a can and bring it close to his/her lips with a cylindrical grasp
  10. Lift pencil (front): client attempts to pick up a pencil by using 3-jaw chuck grasp.
  11. Pick-up paper clip (front): client attempts to pick up a paper clip by using a pincer grasp
  12. Stack checkers (front): client attempts to stack checkers onto the center checker
  13. Flip 3 cards (front): using the pincer grasp, client attempts to flip each card over
  14. Grip strength
  15. Turning the key in lock (front): using pincer grasp, while maintaining contact, client turns key 180 degrees to the left and right
  16. Fold towel (front): client grasps towel, folds it lengthwise, and then uses the tested hand to fold the towel in half again
  17. Lift basket (standing): client picks up a 3lb basket from a chair, by grasping the handles, and placing it on a bedside table

Scoring:

The items are rated on a 6-point scale as outlined below (Wolf et al., 2005):

0. “Does not attempt with UE being tested”

1. “UE being tested does not participate functionally; however, an attempt is made to use the UE. In unilateral tasks, the UE not being tested may be used to move the UE being tested”.

2. “Does attempt, but requires assistance of the UE not being tested for minor readjustments or change of position, or requires more than 2 attempts to complete, or accomplishes very slowly. In bilateral tasks, the UE being tested may serve only as a helper”.

3. “Does attempt, but movement is influenced to some degree by synergy or is performed slowly or with effort”.

4. “Does attempt; movement is similar to the non-affected side but slightly slower; may lack precision, fine coordination or fluidity”.

5. “Does attempt, movement appears to be normal”.

Lower scores are indicative of lower functioning levels.

Time:

Not reported, but since a maximum of 120 seconds is allocated to each item, it should take approximately 30 minutes with additional time for measuring grip strength (item 14).

Subscales:

None officially documented. However, many studies use the Performance Time (WMFT-PT) and Functional Capacity (WMFT-FA) scales as subtests of the WFMT.

Equipment:

  • Table 28 cm long (height not reported)
  • Chair (dimensions not reported)
  • Bedside table (dimensions not reported)
  • Box (25.4 cm tall)
  • Free-weights
  • Can
  • Pencil
  • Paperclip
  • Checkers
  • Cards
  • Key lock with the key
  • Towel
  • Basket
  • Dynamometer for measuring hand grip strength

Training:

Not reported.

Alternative form of the WMFT

  • The original version (21 items)
  • The modified version (17 items): The modified version is most widely used and allows assessment of clients with severe, moderate and mild stroke.

Client suitability

Can be used with:

  • Clients with stroke
  • Clients with upper limb functional deficits/li>

Should not be used with:

  • Severe cases of upper limb spasticity, and upper limb amputees

In what languages is the measure available?

French and English.

Summary

Wolf Motor Function Test (WMFT) Evaluation Summary

What does the tool measure? The WMFT quantifies upper extremity motor ability through timed and functional tasks.
What types of clients can the tool be used for? The WMFT can be used with, but is not limited to clients with stroke.
Is this a screening or assessment tool? Assessment
Time to administer The WMFT takes approximately 30 minutes to administer.
Versions The original version (21 items), and the modified version (17 items)
Other Languages English
Measurement Properties
Reliability
  • Two studies examined the internal consistency of the WMFT and reported excellent internal consistency using Cronbach’s alpha.
  • Two studies examined the test-retest reliability of the WMFT and reported excellent reliability using Pearson and Intraclass correlations coefficients (ICC).
  • One study examined the inter-rater reliability of the WFMT and reported excellent inter-rater reliability using the ICC.
  • Four studies examined the inter-rater reliability of the WMFT and reported excellent reliability using the ICC.
Validity

Content:

No studies have reported the content validity of the WMFT.

Criterion:

Two studies examined the concurrent validity of the WMFT and reported moderate to excellent correlations with the Fugl-Meyer Assessment, as the gold standard measure.

One study examined the concurrent validity of the WMFT and reported excellent correlations with the Action Research Arm Test.

Construct:

Known Groups:

One study examined the known groups validity of the WMFT using Wilcoxon Test and reported that the WMFT is able to discriminate between healthy individuals and those with upper extremity impairments.

Floor/Ceiling Effects No studies have examined floor/ceiling effects of the WMFT in clients with stroke.
Does the tool detect change in patients? No studies have examined the responsiveness of the WMFT in clients with stroke.
Acceptability The WMFT is the widely used as an outcome measure for constraint-induced movement therapy.
Feasibility The administration of the WMFT is quick and simple.
How to obtain the tool? The WMFT can be found at: Wolf, S., Thompson, P., Morris, D., Rose, D., Winstein, C., Taub, E., Giuliani, C., & Pearson, S. (2005). The EXCITE Trial: Atrributes of the Wolf Motor Function test in patients with Subacute Stroke. Neurorehabil Neural Repair, 19, 194-205.

Psychometric Properties

Overview

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

Floor/Ceiling Effects

Nijland et al. (2010) investigated the psychometric properties of the WMFT and the 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 score

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.

See The Measure

The WMFT can be obtained from the following publication or by clicking here.:

Wolf, S., Thompson, P., Morris, D., Rose, D., Winstein, C., Taub, E., Giuliani, C., & Pearson, S. (2005). The EXCITE Trial: Atrributes of the Wolf Motor Function test in patients with Subacute Stroke. Neurorehabil Neural Repair, 19, 194-205.

Table of contents
What do you think?