Examination of movement in patients with long-lasting musculoskeletal pain: reliability and validity.

Abstract

An examination method based on psychosomatic physiotherapy, with 24 standardized tests related to general aspects of mobility, flexibility and the ability to relax, is used in some pain and rehabilitation clinics in Scandinavia in order to document where--and to what degree--patients have aberrations within the domain 'movement'. The measurement properties of the movement tests have, however, not been investigated in patients with long-lasting musculoskeletal pain. The aims of the present study were, therefore, to investigate inter-tester reliability and validity (construct, discriminative and concurrent validity) related to movement. The study design was cross-sectional. Reliability was examined by three physiotherapists examining 19 people. Construct validity was studied by means of structural equation modelling (SEM). Discriminative validity was examined by comparing movement data from 247 patients with long-lasting musculoskeletal pain, and 104 healthy subjects. The patient sample was categorized according to localized or widespread pain, and movement scores compared between the groups. Most patients filled in a psychological screening questionnaire (MMPI-2), plus information about pain intensity and function, and concurrent validity of the movement measures were examined by correlation. SEM results indicated a modified movement scale, consisting of 16 items in four subscales. Both the original and modified versions showed good reliability, and scores differed significantly between healthy subjects and patients, and between patients with localized versus widespread pain. A relationship was found between the movement tests and psychological characteristics, but mainly in patients with widespread pain. Significant relationships were found between the ability to relax and pain, and between all aspects of movement and function. Movement may be reliably and validly assessed with composite scores from 4 x 4 items. The method may be useful as a global screening instrument in order to examine where, and to what extent, patients with long-lasting pain problems have movement aberrations; findings to be addressed in treatment.