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Manual Ability Measure Rehab Measures

Manual Ability Measure

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The Manual Ability Measure (MAM) is designed as an outcome instrument to assess hand function based on the patient's responses to functional questions.

Acronym MAM

Area of Assessment

Upper Extremity Function

Assessment Type

Patient Reported Outcomes

Administration Mode

Paper & Pencil


Not Free


  • Arthritis + Joint Conditions
  • Limb Loss + Impairment
  • Multiple Sclerosis
  • Parkinson's Disease + Neurologic Rehabilitation
  • Stroke Recovery

Key Descriptions

  • Patient rates functional abilities based on his or her perception of the difficulty or ease in completing one or two-handed daily tasks
  • The form consists of two parts: demographic information (gender, age, education, occupation, primary diagnosis, surgical dates and hand dominance) and the list of tasks
  • There are three versions available of the MAM: MAM-16 (original), MAM-36 and MAM-20 each with 16, 36 and 20 items respectively
  • Form can be completed by patient or therapist
  • Item level scores are as follows: 1=cannot do, 2=very hard, 3=a little hard and 4=easy, 0=not applicable/almost never do
  • Therapist can compare overall manual ability change at intake and discharge
  • Each MAM measure is an interval measure calibrated by Rasch computer software
  • Conversion tables are available for MAM-36 and MAM-20

Number of Items

16, 20, or 36

Equipment Required

  • Writing utensil and form

Time to Administer

10-15 minutes

Depending on MAM version

Required Training

No Training

Instrument Reviewers

Louisa Frederick, MOT, OTR/L

Body Part

Upper Extremity

ICF Domain



  • Clinicians may need to consider a performance based measure when further information is need about the quality of hand performance such as speed or coordination of completing a task

  • Further studies with larger samples of sizes and more equal percentages of men and women as the majority of studies tend to have more women across diagnoses and conditions


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Internal Consistency

Rheumatoid Arthritis/Osteoarthritis: (Chen and Giustino, 2007; n=14; 12 female/2 male; mean age =70(12.1))

  • Rasch analysis performed to identify test psychometrics for fit statistics, reliability and item hierarchy. Fit statistics of 35 out of 36 items was ≤2.0 with the exception of carrying a shopping bag with a hand loop with an Infit Mean Square of 2.15. Item reliability was 0.85.
  • Hierarchical ordering of items by difficulty confirmed clinical expectations. Person reliability was 0.92 indicating the ability to discriminate 4-5 levels of participants.

Criterion Validity (Predictive/Concurrent)

Concurrent Validity:

Arthritis: (Chen and Giustino, 2007)

  • Excellent concurrent validity  Role Physical  domain of Short-Form Health Survey (SF-36 Version 1) (r=0.76)

Rheumatoid Arthritis: (Tsai, et al, 2017; n=42,  21 healthy  participants and  21 patients with rheumatoid arthritis of the thumb)

  • Adequate correlation of MAM-36 total score and workspace capacity (thumb’s movement capability) (r=0.572)

Neuromuscular Conditions

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Test/Retest Reliability

Charcot-Marie-Tooth(CMT) Disease:  (Poole et al, 2015; n = 14; mean age = 61.7(17.4 )years; mean duration of CMT=19.6(14.7); CMT Type 1, n=7, Type 2, n=2, and unknown, n=5)

  • Excellent test-retest reliability (ICC = 0.96)

Criterion Validity (Predictive/Concurrent)

Concurrent Validity:

Charcot-Marie-Tooth Disease (Poole et al, 2015)

  • Excellent concurrent validity  with left grip strength, right Box and Blocks Test, and grasp pattern ( r= 0.60, 0.64, -0.62  respectively)

  • Adequate concurrent validity with right grip strength, right and left two-point strength, right and left lateral pinch strength,  right  Nine-hole pinch strength, left Box and Blocks Test, and two-point discrimination (r= 0.48, 0.48,0.50,0.41,0.54,-0.56, 0.56,0.42 respectively).

Mixed Populations

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Internal Consistency

Hand Impairment(Chen et al., 2005); n=115 patients with hand impairments, 66 male/49 female; Age <25 years=7, 26–35 years= 18 , 36–50 years= 54, 51–60 years= 25 and greater than 61=11; Diagnoses: n=25 carpal tunnel syndrome, n=11 arthritis, n=45 traumatic injuries, n=19 tenosynovitis, n=15 other )

  • Rasch analysis was performed to identify test psychometrics for fit statistics, reliability and item hierarchy. Fit statistics of all items was ≤1.4. Item reliability was 0.98.

  • Hierarchical ordering of items by difficulty confirmed clinical expectations. Person reliability was 0.83 indicating the ability to discriminate 3 levels of participants.

Neurological and Musculoskeletal Disorders: (Chen et al, 2010)

  • Excellent person-separation reliability 0.93(PSI=3.74) and item separation reliability 0.99 (ISI=11.08)

  • Point measure correlation for 20 items were ≥0.6 indicating excellent item discrimination and 16 items with point measure correlations ≥ 0.4 indicating  adequate item discrimination

Criterion Validity (Predictive/Concurrent)

Concurrent Validity:

Upper Extremity Conditions: (Chen et al, 2014; n=46; measured at intake and discharge time with interval varying from 2-37 weeks.)

  • Excellent concurrent validity of gains in MAM measure with grip strength of affected hand (r=0.69)

  • Excellent concurrent validity of gains in MAM measure  with MAM score at intake (r=-0.81) and MAM score at discharge (r=0.73)


Construct Validity

Convergent Validity:

Hand Impairment:  (Chen et al, 2005)

  • Adequate  correlations of the MAM-16 with LIFEware Musculoskeletal form with body movement control(r=.47), physical function(r=.51), absence of pain(r=.45), difficulty with driving (r=.49) and distress (r=.33)

  • Adequate  correlation between MAM-16 and perceived health status from the Medical Outcome Study Short-Form 12 item Health Survey (SF-12 ).(r=.44, P<.01)

Hand Impairment:  (Rallon & Chen, 2008, n=30, 20 women/10 men;  mean age =56.07(11.87) years;  diagnosis of most participants fell under orthopedic category of the hand, some had a diagnosis that involved other parts of arm, brachial plexopathy, Charcot Marie Tooth Disease, diabetic neuropathy, reflex sympathetic dystrophy, hand infection stroke, spinal cord injury, and arthritis) 

  • Adequate  correlations of the MAM-36 and the Upper Extremity Performance Test for the Elderly (TEMPA)’s Functional Rating of the Right Hand and Left Hand (both r=.38).

  • Excellent  correlations of the MAM-36 and the Upper Extremity Performance Test for the Elderly (TEMPA)’s Functional Rating of Bilateral Function( r=.68) and Combined Function (r=0.79)

Discriminant Validity:

Neurological and Musculoskeletal Disorders: (Chen et al, 2010)

  • DIF analysis identified 14 items of which seven items with negative DIF contrasts were easier with patients with musculoskeletal conditions. The remaining seven positive DIF contrasts were easier for patients with musculoskeletal conditions.


Upper Extremity Conditions: (Chen et al, 2014; n=46, 32 female/14 male; MAM measures at intake and discharge which varied from 2-37 weeks.)

  • Moderately responsive Standard Response Measure (SRM) was 1.18

Multiple Sclerosis

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Internal Consistency

Multiple Sclerosis:  (Chen et al, 2007; n=44, 32 women/12 men; mean age= 49(9) years)

  • Person reliability was 0.94 indicating the ability to discriminate levels of participants.

  • The 5 most difficult items cutting nails (hardest), using a hammer, peeling fruits or vegetables, buttoning clothes, shuffling and dealing cards. The 5 easiest items eating a sandwich (easiest), washing hands, using a remote control, drinking from a glass and brushing teeth.

Construct Validity

Convergent Validity:

Multiple Sclerosis:  (Chen et al, 2007, n=44, mean age =49(9) years)

  • Adequate  correlations of the MAM-36  manual ability with right and left grip strength; right and left tip pinch, right lateral pinch; right and left 3-point pinch

  • Adequate correlation of the MAM-36 and the Kurtzke Expanded Disability Status Scale (EDSS) (ρ=-0.42)


Chen, C. C., Granger, C. V., Peimer, C. A., Moy, O. J., & Wald, S. (2005). Manual Ability Measure (MAM-16): A preliminary report on a new patient-centred and task-oriented outcome measure of hand function.  Journal of Hand Surgery, 30(2), 207-216.

Chen, C. C., & Giustino, J. (2007). Grip strength, perceived ability, and health status in individuals with arthritis:   An exploratory study. Occupational Therapy in Health Care, 21(4), 1-18.

Chen, C. C., Kasven, N., Karpatkin, H. I., & Sylvester, A. (2007). Hand strength and perceived manual ability among patients with multiple sclerosis. Archives of Physical Medicine and Rehabilitation, 88(6), 794-797.

Chen, C. C., & Bode, R. K. (2010). Psychometric validation of the Manual Ability Measure-36 (MAM-36) in patients with neurologic and musculoskeletal disorders. Archives of Physical Medicine and Rehabilitation, 91(3), 414-420.

Chen, C. C., Palmon, O., & Amini, D. (2014). Responsiveness of the Manual Ability Measure—36 (MAM–36): Changes in hand function using self-reported and clinician-rated assessments. American Journal of Occupational Therapy, 68(2), 187-193. doi:10.5014/ajot.2014.009258

Poole, J. L., Huffman, M., Hunter, A., Mares, C., & Siegel, P. (2015). Reliability and validity of the Manual Ability Measure-36 in persons with Charcot-Marie-Tooth disease.  Journal of Hand Therapy, 28(4), 364-368. doi:10.1016/j.jht.2015.04.003

Rallon, C. R., & Chen, C. C. (2008). Relationship between performance-based and self-reported assessment of hand function. American Journal of Occupational Therapy, 62, (5), 574–579. doi:10.5014/ajot.62.5.574

Tsai, C., Lin, C., Lin, H., Liu, M., Chiu, H., Hsu, H., & Kuo, L. (2017). How kinematic disturbance in the deformed rheumatoid thumb impacts on hand function: A biomechanical and functional perspective. Disability and Rehabilitation, 39(4), 338-345. doi: /09638288.2016.1141244

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