Psychosocial predictors of physical performance in disabled individuals with chronic pain.

ABSTRACT

OBJECTIVES: First, to identify what physical performance differences existed between a group of disabled individuals with chronic pain and a control group of pain-free individuals with comparable disabilities; and second, to test a psychosocial model designed to evaluate which psychosocial constructs were predictive of performance in disabled individuals with chronic pain. DESIGN: Case-comparison study. SETTING: Ambulatory university laboratory. PARTICIPANTS: A community sample of 62 individuals with lower limb amputations or paraplegia, 31 with chronic pain and 31 pain-free. INTERVENTION Standardized lifting and wheel-turning tasks. MAIN OUTCOME MEASURES: Static strength, endurance, lifting speed, lateral and anterior-posterior sway, and multidimensional psychosocial measures. RESULTS Disabled individuals with chronic pain had decreased endurance for both the lifting (p <0.001) and the wheel-turning (p <0.05) tasks. A psychosocial model of physical performance also was evaluated. Using confirmatory factor analysis, 31 measures were used to validate 8 theoretical constructs emotional functioning, pain intensity, pain cognitions, physical functioning, social functioning, task-specific self-efficacy, performance outcome, and performance style. Regression analyses indicated that more than 90% of the variance in performance was predicted by psychosocial factors, with self-efficacy, perceived emotional and physical functioning, pain intensity, and pain cognitions showing the highest associations. CONCLUSIONS: Chronic pain was found to significantly reduce the performance in individuals with lower limb amputations and paraplegia. A strong association was found between performance and psychosocial factors in disabled individuals with chronic pain. These findings extend the existing literature by validating that psychosocial models of chronic pain can be applied to the disabled population, with results similar to those of other chronic pain samples.