The application of operant learning theory on chronic pain by Fordyce has had a huge impact on chronic pain research and management. The operant model focuses on pain behaviors as a major component of the pain problem, and postulates that they are subject to environmental contingencies. The role of operant learning in pain behaviors generally has been supported by experimental studies, which are reviewed in the present article. Subsequently, the rationale, goals, and methods of operant behavioral treatment of chronic pain are outlined. Special attention is paid to three therapeutic techniques (graded activity, activity pacing, and time-contingent medication management), which are discussed in detail with regard to their operationalization, effectiveness, and (possible) mechanisms of action. Criticisms of the operant model are presented, as are suggestions for the optimization of (operant) behavioral treatment efficacy.

Fear of pain changes movement: Movements associated with pain are performed faster, with more force and higher accuracy than movements that are not associated with pain. These changes can inform us how fear of pain translates into avoidance and escape behaviour, two important constructs in the maintenance of chronic pain.

Avoidance is considered a key contributor to the development and maintenance of chronic pain disability, likely through its excessive generalization. This study investigated whether acquired avoidance behavior generalizes to novel but similar movements. Using a robotic arm, participants moved their arm from a starting to a target location via one of three possible movement trajectories. For the Experimental Group, the shortest, easiest trajectory was always paired with pain (T1 = 100% reinforcement/no resistance and deviation). Pain could be partly or completely avoided by choosing increasingly effortful movements (T2 = 50% reinforcement, moderate resistance/deviation; T3 = 0% reinforcement, strongest resistance/largest deviation). A Yoked Group received the same number of painful stimuli irrespective of their own behavior. Outcomes were self-reported fear of movement-related pain, pain-expectancy, avoidance behavior, (maximal deviation from the shortest trajectory), and trajectory choice behavior. We tested generalization to three novel trajectories (G1-3) positioned between the acquisition trajectories. Whereas acquired fear of movement-related pain and pain-expectancy generalized in the Experimental Group, avoidance behavior did not, suggesting that threat beliefs and high-cost avoidance may not be directly related. The lack of avoidance generalization may be due to a perceived context-switch in the configurations of the acquisition and the generalization phases.

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