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RehabMeasures Instrument

Wolf Motor Function Test

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Purpose

The WMFT is a quantitative measure of upper extremity motor ability through timed and functional tasks.

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Instrument Details

Acronym WMFT

Area of Assessment

Dexterity
Strength
Upper Extremity Function

Assessment Type

Performance Measure

Administration Mode

Computer

Cost

Free

Diagnosis/Conditions

  • Brain Injury
  • Stroke Recovery

Key Descriptions

  • The original version consisted of 21 items; the widely used version of the WMFT consists of 17 items.
  • Composed of 3 parts:
    1) Time
    2) Functional ability
    3) Strength
  • Includes 15 function-based tasks and 2 strength based tasks
    1) Performance time is referred to as WMFT-TIME
    2) Functional ability is referred to as WMFT-FAS
  • Items 1-6 involve timed functional tasks, items 7-14 are measures of strength, and the remaining 9 items consist of analyzing movement quality when completing various tasks.
  • Examiner should test the less affected upper extremity followed by the most affected side.
  • Uses a 6-point ordinal scale:
    -"0" = “does not attempt with the involved arm” to
    -"5" = “arm does participate; movement appears to be normal.”
  • Maximum score is 75
  • Lower scores are indicative of lower functioning levels
  • WMFT-TIME allows 120 seconds per task

Number of Items

21

Equipment Required

  • Standardized table (54 inches long, 30 inches wide, and 29 inches high) and chair
  • Standardized test item template
  • Height-adjustable bedside table
  • Box (one that does not require patient to flex or abduct shoulder more than 90 degrees)
  • Individual wrist weights, 1-20 pounds
  • 12-oz beverage can, unopened
  • 7” pencil with 6 flat sides
  • 2” paper clip
  • 3 checkers
  • Three 3” x 5” note cards
  • Standardized lock and key board at 45 degree angle
  • Standardized face towel
  • Standardized basket
  • Dynamometer
  • Talcum powder to reduce friction as needed
  • Stopwatch
  • Video camera (optional)

Time to Administer

35 minutes

Required Training

No Training

Age Ranges

Adult

18 - 64

years

Elderly Adult

65 +

years

Instrument Reviewers

Initially reviewed by Jason Raad MS and the Rehabilitation Measures Team; Updated by Irene Ward, PT, DPT, NCS and the TBI EDGE task force of the Neurology Section of the APTA in 2012; Updated by Heather Anderson and Rie Yoshida of the StrokEdge II task force in 2016.

Body Part

Upper Extremity

ICF Domain

Activity

Measurement Domain

Motor

Professional Association Recommendation

Recommendations for use of the instrument from the Neurology Section of the American Physical Therapy Association’s Multiple Sclerosis Taskforce (MSEDGE), Parkinson’s Taskforce (PD EDGE), Spinal Cord Injury Taskforce (PD EDGE), Stroke Taskforce (StrokEDGE), Traumatic Brain Injury Taskforce (TBI EDGE), and Vestibular Taskforce (Vestibular EDGE) are listed below. These recommendations were developed by a panel of research and clinical experts using a modified Delphi process.

For detailed information about how recommendations were made, please visit:  http://www.neuropt.org/go/healthcare-professionals/neurology-section-outcome-measures-recommendations

Abbreviations:

 

HR

Highly Recommend

R

Recommend

LS / UR

Reasonable to use, but limited study in target group  / Unable to Recommend

NR

Not Recommended

Recommendations for use based on acuity level of the patient:

 

Acute

(CVA < 2 months post)

(SCI < 1 month post) 

(Vestibular < 6 weeks post)

Subacute

(CVA 2 to 6 months)

(SCI 3 to 6 months)

Chronic

(> 6 months)

StrokEDGE

R

R

R

Recommendations based on level of care in which the assessment is taken:

 

Acute Care

Inpatient Rehabilitation

Skilled Nursing Facility

Outpatient

Rehabilitation

Home Health

StrokEDGE

R

R

R

R

R

TBI EDGE

NR

LS

LS

LS

NR

Recommendations for use based on ambulatory status after brain injury:

 

Completely Independent

Mildly dependant

Moderately Dependant

Severely Dependant

TBI EDGE

N/A

N/A

N/A

N/A

Recommendations for entry-level physical therapy education and use in research:

 

Students should learn to administer this tool? (Y/N)

Students should be exposed to tool? (Y/N)

Appropriate for use in intervention research studies? (Y/N)

Is additional research warranted for this tool (Y/N)

StrokEDGE

No

Yes

Yes

Not reported

TBI EDGE

No

No

Yes

Not reported

Considerations

Observer plots were a less stable method of scoring the WMFT, suggesting relatively higher measurement error for the WMFT than for the ARAT (Nijland et al., 2010).

Stroke

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Standard Error of Measurement (SEM)

Chronic Stroke: (Fritz et al. 2009; n = 96; mean age = 62.3 (range, 19–90) years)

  • Standard error of measurement (SEM) in stroke: 0.2 seconds

Reliability Indices for WMFT:

 

 

Item No.

Item Description

SEM

Average WMFT time score

 

0.2

1

Forearm to table

0.8

2

Forearm to box

0.6

3

Extend elbow

0.6

4

Extend elbow with weight

0.8

5

Hand to table (front)

0.5

6

Hand to box (front)

0.7

7

Weight to box (lbs)

1.9

8

Reach and retrieve

1.2

9

Lift can

1.2

10

Lift pencil

1.1

11

Lift paper clip

0.8

12

Stack checkers

1.1

13

Flip cards

0.4

14

Grip strength (lbs)

0.0

15

Turn key in lock

0.4

16

Fold towel

0.4

17

Lift basket

0.7

Average WMFT FAS

 

0.1

Minimal Detectable Change (MDC)

Chronic Stroke: (Fritz et al, 2009)

  • Average for timed items: 0.7 seconds

  • Average for WMFT Functional Ability Scale: 0.1 points

Reliability Indices for WMFT:

 

 

Item No.

Item Description

95% MDC

Average WMFT time score

 

0.7

1

Forearm to table

2.1

2

Forearm to box

1.6

3

Extend elbow

1.7

4

Extend elbow with weight

2.4

5

Hand to table (front)

1.5

6

Hand to box (front)

1.9

7

Weight to box (lbs)

5.2

8

Reach and retrieve

3.4

9

Lift can

2.0

10

Lift pencil

3.0

11

Lift paper clip

2.2

12

Stack checkers

3.2

13

Flip cards

1.2

14

Grip strength (lbs)

0.1

15

Turn key in lock

1.0

16

Fold towel

1.2

17

Lift basket

2.0

Average WMFT FAS

 

0.1

Minimally Clinically Important Difference (MCID)

Acute Stroke: (Lang et al, 2008; n = 52; mean age = 64 (14) years; < 28 days post-stroke)

  • MCID (Functional Ability): 

    • 1.0 points (Dominant Side Affected)

    • 1.2 points (Non-dominant Side Affected)

    • 17% change (Dominant Side Affected)

    • 20% change (Non-dominant Side Affected)

  • MCID (time): 

    • -19.0 seconds (Dominant Side Affected)

    • 16% change (Dominant Side Affected)

Normative Data

Chronic Stroke: (Wing et al, 2006; n = 35; mean age = 60.2 (14.1) years; rehab = 3–6 hours/day, 4–5 days/week, ≥ 2 weeks; mean time since stroke = 40.9 (29.1) months)

Outcome measure:

 

 

 

Measure

n

Pretest mean

Posttest mean

Wolf Motor Function Test (mean)

29

55.6 s

45.2 s

TUG

30

31.0 s

20.2 s

Berg Balance

32

46.5

47.2

Fugl-Meyer (m)

34

31.8

37.0

Box and Block

11

11.2

18.0

s = seconds; all means were significant; TUG = Timed Up & Go Test; Fugl-Meyer (m) = 66-point Fugl-Meyer motor assessment

Test/Retest Reliability

Chronic Stroke: (Morris et al, 2001; n = 24; mean age 61; mean time since one set = 6 years; Whithall et al, 2006; n = 66; mean age = 58 (14) years; >6 months post-stroke)

  • Excellent test-retest reliability, Functional ability and performance tests (r= 0.95; 0.90, respectively)

  • Excellent overall total score (= 66; ICC = 0.97)

Interrater/Intrarater Reliability

Chronic Stroke: (Morris et al, 2001; Whithall, 2006; Wolf et al, 2001; n = 19, mean age = 61.4 (9.5) years; mean time since stroke = 4.9 (6.4) years)

  • Excellent inter-rater reliability:

    • Study1: = 24: ICC = 0.93; 0.99, functional ability and performance test, respectively.

    • Study 2: n = 10; ICC = 0.99

    • Study 3: n = 19: ICC = 0.97

Internal Consistency

Chronic Stroke: (Morris et al, 2001)

  • Excellent Internal Consistency (Cronbach's alpha = 0.92)

Criterion Validity (Predictive/Concurrent)

Chronic Stroke: (Wolf et al, 2001; Whithall et al, 2006)

  • Adequate concurrent validity with:

    • Upper Extremity Fugl-Meyer Assessment 

      • Study 1: n = 19 (r = - 0.57)

      • Study 2: n = 66 (r = - 0.88)

Construct Validity

  • 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 significant higher when compared to the most and to the least affected upper extremities of clients with stroke.

Responsiveness

Acute Stroke: (Hsieh et al, 2009; n = 57; mean age = 54.56 (11.52) years; Taiwanese sample)

Responsiveness of 3 Outcome Measures:

 

 

Scale Name

SRM (95% CI)

Wilcoxon Test Z-Value

WMFT-TIME

0.38 (0.22, 0.59)

5.97*

WMFT-FAS

1.30 (1.03, 1.67)

5.59*

FIM-total

0.36 (0.17, 0.59)

3.39*

FIM-motor

0.37 (0.17, 0.58)

3.18*

FMA

1.42 (1.19, 1.80)

6.33*

ARAT

0.95 (0.75, 1.20)

4.64*

*p < 0.001; WMFT-TIME = performance time of the Wolf Motor Function Test; WMFT-FAS = functional ability scale of the Wolf Motor Function Test; FIM = Functional Independence Measure; FMA = Fugl-Meyer Assessment; ARAT = Action Research Arm Test; SRM = standardized response mean; CI = confidence interval

Brain Injury

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Test/Retest Reliability

Chronic Traumatic Brain Injury: (Shaw et al., 2005; n = 22; Mean age = 39.3 (14.4) years, onset at least 1 year prior to assessment; relative hemiparesis)

  • Excellent ICC = 0.97 (range = 0.89 - 0.97); agreement between the self-report and objective measures

Bibliography

Chen, H. F., Lin KC, Wu CY, Chen CL. Rasch validation and predictive validity of the action research arm test in patients receiving stroke rehabilitation. Arch Phys Med Rehabil. 2012;93(6):1039-1045. Find it on PubMed

Edwards, D. F., Lang, C. E., Wagner, J. M., Birkenmeier, R., Dromerick, A. W. An evaluation of the Wolf Motor Function Test in motor trials early after stroke. Arch Phys Med Rehabil. 2012 93(4): 660-668. Find it on PubMed

Fritz, S. L., Blanton, S., et al. (2009). "Minimal detectable change scores for the Wolf Motor Function Test." Neurorehabil Neural Repair 23: 662-667. Find it on PubMed

Lang, C. E., Edwards, D. F., et al. (2008). "Estimating minimal clinically important differences of upper-extremity measures early after stroke." Arch Phys Med Rehabil 89(9): 1693-1700. Find it on PubMed

Lin, K.-C., Hsieh, Y.-W., et al., (2009). “Minimum detectable change and clinically important difference of the Wolf Motor Function Test in stroke patients.” Neurohabilitation and Neural Repair 23(5): 429-434. Find it on PubMed

Morris, D. M., Uswatte, G., et al. (2001). "The reliability of the wolf motor function test for assessing upper extremity function after stroke." Arch Phys Med Rehabil 82: 750-755. Find it on PubMed

Nijland, R., van Wegen, E., et al. (2010). "A comparison of two validated tests for upper limb function after stroke: The Wolf Motor Function Test and the Action Research Arm Test." J Rehabil Med 42(7): 694-696. Find it on PubMed

O’Dell, M. W., Grace, K., et al., (2013). “A psychometric evaluation of the Arm Motor Ability Test.” J Rehabil Med 45(6): 519–527. Find it on PubMed

Shaw, S. E., Morris, D. M., et al. (2005). "Constraint-induced movement therapy for recovery of upper-limb function following traumatic brain injury." J Rehabil Res Dev 42(6): 769-778. Find it on PubMed

Whitall, J., Savin, D. N., Jr., et al. (2006). "Psychometric properties of a modified Wolf Motor Function test for people with mild and moderate upper-extremity hemiparesis." Arch Phys Med Rehabil 87(5): 656-660. Find it on PubMed

Wing, K., Lynskey, J. V., et al. (2008). "Whole-body intensive rehabilitation is feasible and effective in chronic stroke survivors: a retrospective data analysis." Top Stroke Rehabil 15(3): 247-255. Find it on PubMed

Wolf, S. L., Catlin, P. A., et al. (2001). "Assessing Wolf motor function test as outcome measure for research in patients after stroke." Stroke 32: 1635-1639. Find it on PubMed

Woodbury, M., Velozo C. A., et al., (2010). “Measurement structure of the Wolf Motor Function Test: Implications for motor control theory.” Neurorehabil Neural Repair 24(9):  791–801. Find it on PubMed

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