Ambulatory monitoring as a measure of disability in chronic low back pain populations.

PURPOSE: The link between chronic back pain and disability is well established. Despite this, the literature also reflects an inconsistency in methods of assessing disability, as studies interchangeably use self-report measures, clinical tests, and electronic monitoring. The purpose of this study was to conduct a multimethod comparison of disability measures to identify similarities and differences in the constructs measured by each.
METHOD: Twenty chronic back pain patients participated in a clinic visit to complete questionnaires and clinical tests, followed by 5 days of wearing a wrist-worn electronic ambulatory monitoring device to measure activity.
RESULTS: Multiple regression analyses were conducted to identify the significant predictors of each disability assessment. Results showed that operant variables were predictive of physical activity, cognitive-behavioral variables were predictive of perceived disability, and no variables were predictive of physical ability. DISCUSSION: The results indicate substantial differences in the types of variables that predict disability when measured through 3 different methods. This is suggestive of differences in the constructs measured by each type of disability assessment. The implications for researchers who assess predictors of disability and clinicians who use disability measures in their assessment of patients are that the measures of disability they select should be carefully matched to the proposed purposes. Strong theoretical and practical considerations support using electronic ambulatory monitoring in future research and clinical service.