Convergent Validity: The Relationship Between Perceived Pain and the Manual Ability Measure–20 (MAM–20)

Abstract

Date Presented 4/18/2015

Hand pain is common, but how much does pain contribute to deficits in manual ability? In this study, we examined the relationship between perceived pain and the Manual Ability Measure—20 (MAM–20). The results suggest that occupational therapists (OTs) should assess pain and manual ability, as there does not appear to be substantial overlap between these concepts.

SIGNIFICANCE: We explored psychometric properties of the Manual Ability Measure—20 (MAM–20) by assessing the relationship between the MAM–20 and perceived pain. We aimed to provide evidence to support shifting from primarily biomechanical-based assessments to occupation-based assessments that have strong psychometrics.

INNOVATION: Many assessments used in hand clinics measure body functions and structures (e.g., sensation, strength, range). We should focus more on assessments that provide a picture of current and desired occupational performance patterns. As occupation-based assessments are created, we need to scrutinize their psychometrics.

APPROACH: In this study, we attempted to answer the following research question: At admission and discharge, is there a relationship between perceived pain, as measured by the Visual Analog Scale, and perceived manual ability, as measured by the MAM–20?

Pain from trauma/chronic conditions is common, and we need to understand how pain affects performance. The MAM–20 is an occupation-based assessment of manual ability (the capacity to manage daily activities with the upper limbs and hands). There is little research comparing hand disability and perceived hand pain.

METHOD: We used a retrospective, records review design to assess convergent validity of the MAM–20. The setting was an outpatient hand clinic, and we used selected records of patients, aged 21yr and older, who were receiving occupational therapy for upper-extremity diagnoses (e.g., arthritis, trauma).

The MAM–20 is the current version of the MAM, a self-report of 20 items that measures hand function. Previous versions have established reliability and validity. Clients rate how difficult it is to complete tasks without assistive devices. Ratings are 0 (never or rarely performed), 1 (impossible to complete), 2 (very hard to do), 3 (a little hard to do), and 4 (easy to do). A Visual Analog Scale for pain is part of the MAM–20.

Using correlational analyses, we examined the relationships between initial MAM–20 scores and initial pain, and between discharge MAM–20 scores and discharge pain. Correlations are commonly used to explore convergent validity.

RESULTS: Initial MAM–20 scores and initial pain in the affected hand or hands (N = 121) had a negligible correlation of r = −.13 (p = .17). Discharge MAM–20 scores and discharge pain (n = 52) showed a moderate correlation of r = −.55 (p = .001).

CONCLUSION: Perceived manual ability at initial evaluation is not related to perceived pain; however, by discharge, perceived pain is more strongly associated with perceived manual ability, accounting for about 30% of variability. Manual ability appears to involve factors beyond pain, such as age and hand strength. We suggest that occupational therapists document pain in addition to manual ability, especially at initial evaluation, as there does not appear to be overlap between these concepts. A limitation includes the lack of discharge data for all patients. Missing data were due to doctors discharging patients at follow-up appointments or discontinuing patients due to no-shows.

References

Chen, C. (2011, July 18). The Manual Ability Measure: An occupation-based hand assessment. Retrieved from http://occupational-therapy.advanceweb.com/Archives/Article-Archives/The-Manual-Ability-Measure.aspx

Chen, C. C., & Bode, R. K. (2010). Psychometric validation of the Manual Ability Measure—36 (MAM–36) in patients with neurological and musculoskeletal disorders. Archives of Physical Medicine and Rehabilitation, 91, 414–420. http://dx.doi.org/10.1016/j.apmr.2009.11.012

Dahaghin, S., Bierma Zeinstra, S. M., Reijman, M., Pols, H. A., Hazes, J. M., & Koes, B.W. (2005). Prevalence and determinants of one month hand pain and hand related disability in the elderly (Rotterdam study). Annals of the Rheumatic Diseases, 64, 99–104. http://dx.doi.org/10.1136/ard.2003.017087