Fear-Avoidance Beliefs and Temporal Summation of Evoked Thermal Pain Influence Self-Report of Disability in Patients With Chronic Low Back Pain

Abstract

Quantitative sensory testing has demonstrated a promising link between experimentally determined pain sensitivity and clinical pain. However, previous studies of quantitative sensory testing have not routinely considered the important influence of psychological factors on clinical pain. This study investigated whether measures of thermal pain sensitivity (temporal summation, first pulse response, and tolerance) contributed to clinical pain reports for patients with chronic low back pain, after controlling for depression or fear-avoidance beliefs about work. Consecutive patients (n=27) with chronic low back pain were recruited from an interdisciplinary pain rehabilitation program in Jacksonville, FL. Patients completed validated self-report questionnaires for depression, fear-avoidance beliefs, clinical pain intensity, and clinical pain related disability. Patients also underwent quantitative sensory testing from previously described protocols to determine thermal pain sensitivity (temporal summation, first pulse response, and tolerance). Hierarchical regression models investigated the contribution of depression and thermal pain sensitivity to clinical pain intensity, and fear-avoidance beliefs and thermal pain sensitivity to clinical pain related disability. None of the measures of thermal pain sensitivity contributed to clinical pain intensity after controlling for depression. Temporal summation of evoked thermal pain significantly contributed to clinical pain disability after controlling for fear-avoidance beliefs about work. Measures of thermal pain sensitivity did not contribute to pain intensity, after controlling for depression. Fear-avoidance beliefs about work and temporal summation of evoked thermal pain significantly influenced pain related disability. These factors should be considered as potential outcome predictors for patients with work-related low back pain. This study supported the neuromatrix theory of pain for patients with CLBP, as cognitive-evaluative factor contributed to pain perception, and cognitive-evaluative and sensory-discriminative factors uniquely contributed to an action program in response to chronic pain. Future research will determine if a predictive model consisting of fear-avoidance beliefs and temporal summation of evoked thermal pain has predictive validity for determining clinical outcome in rehabilitation or vocational settings.