Pain and physical activity in women with MS: Differential pattern of relationships with objective and self-report measures of physical activity

Multiple sclerosis (MS) is a common neurological disease that primarily affects adult Caucasian women. Pain is a frequently reported symptom associated with MS with prevalence estimates ranging from 29% to 90% of patients. The pain associated with MS can interfere with activities of daily living and result in disability, and might be a barrier for participation in physical activity. Accordingly, pain might serve as a partial explanation for the predominance of physical inactivity in persons with MS. This study involved an examination of the relationships between several aspects of pain and selfreport and objective measures of physical activity in two independent samples of women with MS (Ns = 88 and 28). The women in both samples completed the Short-form of the McGill Pain Questionnaire (SF-MPQ) and then wore an accelerometer for seven days and completed the Godin Leisure-Time Exercise Questionnaire (GLTEQ). The SF-MPQ consists of 15 descriptors that yield sensory (SF-MPQS; sensory quality of pain), affective (SF-MPQA; affective qualities of pain), and overall or total (SF-MPQT) pain quality ratings. The SF-MPQ contains an additional item that measures the overall intensity of pain or Present Pain Index (PPI). We conducted Pearson product-moment correlations for examining the relationships between scores on the SF-MPQ, accelerometer, and GLTEQ in the two independent samples separately. Within the first sample (N = 88), there were significant correlations between the SF-MPQT (r = -.29, p = .01), SF-MPQS (r = -.22, p = .04), SF-MPQA (r = -.39, p = .001), and PPI (r = -.29, p = .01) scores and accelerometer counts. Scores from the SF-MPQ were not significantly correlated (p > .05) with GLTEQ scores. Within the second sample (N = 28), there was a similar pattern of results such that SF-MPQT (r = -.40, p = .02), SF-MPQS (r = -.40, p = .02), SF-MPQA (r = -.30, p = .05), and PPI (r = -.45, p = .01) scores from the SF-MPQ were significantly correlated with accelerometer counts. Again, scores from the SF-MPQ were not significantly correlated (p >.05) with GLTEQ scores. The observed pattern of results indicates that sensory and affective dimensions of pain as well as the overall intensity of pain are associated with objectively measured physical activity in the two independent samples of individuals with MS. One potential implication is that pain does play a role in physical activity participation, but the relationship is not immediately recognized by participants based on the lack of relationships with the self-report measurement of physical activity.