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Subject of the scale: Impairment: prehension

Wolf Motor Function Test (WMFT)


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Initially developed by Wolf in 1987 [1], it was later modified by Taub [9]. The WMFT quantifies the ability to move the upper limb by simple or multi-joint movements and timed functional tasks in patients in post-stroke chronic phase [7, 11] or sub-acute [12] phase.

It is frequently used to assess motor recovery of the upper member of a brain-injured patient.

Tasks are listed in order of complexity, progressing from the participation of proximal joints to the more distal, and testing overall movements and speed of movement.

This assessment requires few tools and minimal training to run the test [11] and thus avoid ambiguity in how each performance can be scored [8].

All tasks are performed on the same side as quickly as possible and are limited to 120 seconds.

There are 15 tasks and 2 trials of strength.

There are 2 different scores: the WMFT -Time (time required to complete the tasks) and WMFT -FAS (functional Ability Scale, where a score of 6 points is used to assess the functional capacity of each task: 0 indicating that the patient cannot attempt the task, and 5 where the movement seems normal) [5].

It takes a period of 30 to 45 minutes to complete the entire test [2].

There is no difference between the use of video and direct observation by evaluators [10].

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Psychometric properties:


Psychometric properties



Face validity


Content validity


Criterion validity

Concurrent validity

[2] [3] [6] [8] [10] [11] [12]

Predictive validity

[2] [5] [6]

Construct validity

Convergent validity

[3] [5] [11]

Divergent validity

[3] [5] [11]

Discriminant validity
(sensitivity and distinctiveness)

[3] [5] [11]


Intra-rater reliability

[4] [8]

Inter-rater reliability

[2] [4] [5] [6] [7] [8] [11]


[5] [6] [7] [10]

Internal consistency (alpha)

[2] [3] [7] [8] [11]


[3] [5] [6]

General comment on reliability:

The WMFT is a highly reliable tool [2, 7] (ICC between 0.96 and 0.98) [4]. Internal consistency [2, 7, 8, 11] and inter and intra-judge reproducibility [2, 6, 8, 11] is high. However, according to Nijland [8], the inter-judge reproducibility is worse than intra judge reproducibility, hence the need to train observers for better standardisation of the test.
Post acute stroke, WMFT has an acceptable internal coherence, validity and sensitivity to change. However, compared to the ARAT, the burden of training and testing is not compensated by the much higher psychometric advantages [3].
If we look at the different components of the test: moderate predictive validity for the WMFT Time (compared to the FIM score) and good built validity. For the WMFT FAS, average built validity and low predictive validity. Sensitivity to change is better for the WMFT-FAS than TIME [5]. For WMFT -Time, MDC is 0.7 seconds. For the WMFT -FAS, the MDC is 0.1 percentage point [4].
Concurrent validity is raised using as criterion against the FMA [2, 6, 11] or ARAT [8]. Satisfactory predictive validity [6].
Sensitivity to change is moderate [6]
The MDC (Minimal Change Detection, which is a statistical estimate of the smallest amount of change that can be detected by a measure which corresponds to a significant change) is satisfactory for the ARAT and FMA, hence the usefulness of the 2 tests in a clinical setting with respect to the WMFT [6].

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For more details of the scale, the comments or the psychometric properties presented here, please contact Dr. Thibaud Honoré :


Inaugural references:

[1] Wolf SL, Lecraw DE, Barton LA, Jann BB. "Forced use in hemiplegic upper extremities to reserve the effect of learned nonuse among chronic stroke and headinjured patients". Exp Neurol. 1989 May;104(2):125-32.

Psychometric references:

[2] Bürge E, Kupper D, Badan Bâ M, Leemann B, Berchtold A. "Qualities of a French version of the Wolf Motor Function Test: a multicenter study." nn Phys Rehabil Med. 2013 May;56(4):288-99. doi: 10.1016/ Epub 2013 Mar 28.

[3] Edwards DF, Lang CE, Wagner JM, Birkenmeier R, Dromerick AW. "An evaluation of the Wolf Motor Function Test in motor trials early after stroke." Arch Phys Med Rehabil. 2012 Apr;93(4):660-8. doi: 10.1016/j.apmr.2011.10.005. Epub 2012 Feb 13.

[4] Fritz SL, Blanton S, Uswatte G, Taub E, Wolf SL. "Minimal detectable change scores for the Wolf Motor Function Test." Neurorehabil Neural Repair. 2009 Sep;23(7):662-7. doi: 10.1177/1545968309335975. Epub 2009 Jun 4.

[5] Hsieh YW, Wu CY, Lin KC, Chang YF, Chen CL, Liu JS. "Responsiveness and validity of three outcome measures of motor function after stroke rehabilitation." Stroke. 2009 Apr;40(4):1386-91. doi: 10.1161/STROKEAHA.108.530584. Epub 2009 Feb 19.

[6] Lin JH, Hsu MJ, Sheu CF, Wu TS, Lin RT, Chen CH, Hsieh CL. "Psychometric comparisons of 4 measures for assessing upper-extremity function in people with stroke." Phys Ther. 2009 Aug;89(8):840-50. doi: 10.2522/ptj.20080285. Epub 2009 Jun 25.

[7] Morris DM, Uswatte G, Crago JE, Cook EW 3rd, Taub E. "The reliability of the wolf motor function test for assessing upper extremity function after stroke." Arch Phys Med Rehabil. 2001 Jun;82(6):750-5.

[8] Nijland R, van Wegen E, Verbunt J, van Wijk R, van Kordelaar J, Kwakkel G. "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. 2010 Jul;42(7):694-6. doi: 10.2340/16501977-0560.

[9] Taub E, Miller NE, Novack TA, Cook EW 3rd, Fleming WC, Nepomuceno CS, Connell JS, Crago JE. "Technique to improve chronic motor deficit after stroke". Arch Phys Med Rehabil. 1993 Apr;74(4):347-54.

[10] Whitall J, Savin DN Jr, Harris-Love M, Waller SM. "Psychometric properties of a modified Wolf Motor Function test for people with mild and moderate upper-extremity hemiparesis." Arch Phys Med Rehabil. 2006 May;87(5):656-60.

[11] Wolf SL, Catlin PA, Ellis M, Archer AL, Morgan B, Piacentino A. "Assessing Wolf motor function test as outcome measure for research in patients after stroke." Stroke. 2001 Jul;32(7):1635-9.

[12] Wolf SL, Thompson PA, Morris DM, Rose DK, Winstein CJ, Taub E, Giuliani C, Pearson SL. "The EXCITE trial: attributes of the Wolf Motor Function Test in patients with subacute stroke." Neurorehabil Neural Repair. 2005 Sep;19(3):194-205.

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