Background/Purpose

One of the hallmark features of fibromyalgia and other centralized pain states is widespread body pain.  We developed the Michigan Body Map (MBM) to assess widespread body pain in clinical care and in epidemiological studies.  The MBM is a one-sided body image with check boxes for 35 body areas and a box for “No Pain.”  The aim of the present study was to assess patients’ understanding of and accuracy when completing the MBM, as well as to assess preference when compared to the 2011 Survey Criteria for Fibromyalgia widespread pain index (WPI) and the body map from the Brief Pain Inventory (BPI).

Methods

85 patients from the University of Michigan’s Physical Medicine and Rehabilitation Spine Center were included in this study.  Written informed consent was obtained. The first phase (n=25) assessed how well participants understood the questionnaire and concurrent validity when compared to a standardized verbal assessment.  In the second phase, the MBM’s reliability was assessed using a test-retest assessment 1-2 weeks after the first assessment (n=20).  In the third phase, participants were randomized to complete the MBM and either the WPI (n = 20) or BPI (n = 20) to assess construct validity and were also asked preference questions about the body maps. 

Results

In the first phase, participants completed the MBM quickly (76.8+/- 64.5 sec).  The majority of participants correctly noted right and left, marked only areas of chronic pain (3 months or more) , and felt that the measure allowed them to note all of their areas of pain (Table 1).  Of the 875 potential check boxes (25 patients x 35 body areas), 63 (7.2%) were incorrectly endorsed as either missed or reversed right/left.  In the second phase, the majority of participants had slight discrepancies in the test-retest (ICC = .60, median 1.5 body areas different); however, these differences did not lead to significant changes in the calculated widespread pain score.  In the third phase, the MBM was preferred when compared to the 2011 Survey Criteria for Fibromyalgia WPI (Table 2).  There were no differences in participant preferences between the MBM and BPI (Table 2).

Conclusion

Overall, participants demonstrated good understanding of the MBM and preferred it to the WPI from the Fibromyalgia Survey Criteria.  When compared to the BPI body map, the MBM offers advantages in quantifying, as there is no ambiguity as to the area that was checked.  Some participants confused right and left in the MBM and body areas tended to be underreported when compared to verbally assessing each of the 35 possible body areas individually.

Table 1. First phase: Assessment of understanding

Table 2. Third phase: Questionnaire preference