Fear of (re)injury/movement has been identified as a potential predictor of chronic disability in complex regional pain syndrome type I (CRPS-I). In order to reduce pain-related fears and pain disability, graded exposure in vivo (GEXP) is likely to be an appropriate treatment. Indeed, there is evidence that in chronic pain patients reporting substantial fear of (re)injury/movement, GEXP is successful in reducing pain disability. However, the efficacy of exposure-based protocols in the treatment of CRPS-I patients for reducing pain disability has not been tested. The main research question of this study was whether the reduction of pain-related fear through GEXP also resulted in a decrease of disability in a subgroup of patients with CRPS-I who report substantial pain-related fear. A single-case experimental ABCD-design was used with random determination of the start of the intervention. Eight patients with CRPS-I were included in the study. To assess daily changes in pain intensity, pain-related fear, pain catastrophizing, and activity goal achievement, a diary was used. Standardized questionnaires of pain-related fear, pain disability, and self-reported signs and symptoms of CRPS-I were administered before and after each intervention, and at 6-month follow-up. The current study supports a GEXP approach to chronic CRPS-I. The GEXP was successful in decreasing levels of self-reported pain-related fear, pain intensity, disability, and physiological signs and symptoms. These results support the hypothesis that the meaning people attach to a noxious stimulus influences its experienced painfulness, and that GEXP activates cortical networks and reconciles motor output and sensory feedback.

Complex regional pain syndrome type I (CRPS-I) highly affects patients' ability to perform daily life activities. Pain-related fear might be a key target to reduce disability in chronic pain. Current treatments aiming at reducing pain show little improvements on pain and disability, whereas novel exposure-based treatments targeting pain-related fears have shown to be promising. We conducted a randomized controlled trial (N = 46) comparing exposure in vivo (EXP) with pain-contingent treatment as usual (TAU), for CRPS-I patients with at least moderate levels of pain-related fear. Primary outcome is self-reported disability, for upper and lower extremity, respectively. Secondary outcomes are self-reported pain-intensity, pain-catastrophizing, perceived harmfulness of physical activity, and health-related quality of life. Pretreatment to posttreatment and pretreatment to 6-month follow-up change scores were tested using randomization-based inference. EXP was superior to TAU in reducing upper extremity disability from pretreatment to posttreatment (between-group difference, 1.082; 95% confidence interval [CI], 0.563-1.601; P < 0.001) and from pretreatment to 6-month follow-up (1.303; 95% CI, 0.917-1.690; P < 0.001). EXP was superior in reducing lower extremity disability from pretreatment to 6-month follow-up (3.624; 95% CI, 0.467-6.781; P = 0.02), but not from pretreatment to posttreatment (3.055; 95% CI, -0.018 to 6.128; P = 0.054). All secondary outcomes significantly favored EXP pretreatment to posttreatment, as well as pretreatment to 6-month follow-up. Exposure to daily activities shows to be more effective than a protective pain-contingent TAU in reducing self-reported disability in daily life of CRPS-I patients with at least moderate levels of pain-related fear.

Acute pain informs the individual that there is an imminent threat of body damage, and is associated with the urge to escape and avoid. Fear learning takes place when neutral stimuli receive the propensity to predict the occurrence of pain, and when defensive responses are initiated in anticipation of potential threats to the integrity of the body. Fear-avoidance models have been put forward featuring the role of individual differences in catastrophic interpretations of pain in the modulation of learning and avoidance. Based on extensive literature on fear reduction in anxiety disorders; cognitive-behavioral treatments have been developed and applied to patients with chronic pain reporting substantial pain-related fear. In this article, we discuss mechanisms underlying the acquisition, the assessment and extinction of pain-related fear through the cognitive-behavioral treatment of pain-related fear. Finally, we provide a number of critical notes and directions for future research in the field of chronic pain and pain-related fear.