investigating-pain-related-avoidance-behavior-using-robotic-arm

Investigating Pain-Related Avoidance Behavior using a Robotic Arm-Reaching Paradigm

Avoidance behavior is a key contributor to the transition from acute pain to chronic pain disability. Yet, there has been a lack of ecologically valid ...

Maastricht University

KU Leuven

In chronic pain, pain-related fear seems to overgeneralize to safe stimuli, thus contributing to excessive fear and avoidance behavior. Evidence shows that pain-related fear can be acquired and generalized based on conceptual knowledge. Using a fear conditioning paradigm, we investigated whether this concept-based pain-related fear could also be extinguished. During acquisition, exemplars of 1 action category (conditioned stimuli [CSs]; eg, opening boxes) were followed by pain (CS+), whereas exemplars of another action category were not (CS-; eg, closing boxes). Participants reported more pain-related fear and expectancy toward exemplars of the CS+ category compared with those of the CS- category. During generalization, fear and expectancy spread to novel exemplars (generalization stimuli [GSs]) of the CS+ category (GS+), but not to those of the CS- category (GS-). During extinction, exemplars of both categories were presented in the absence of pain. At the end of extinction, participants no longer reported elevated fear or expectancy toward CS+ exemplars compared to CS- exemplars. These findings were not replicated in either the eye-blink startle or skin conductance measures. This is the first study to demonstrate extinction of concept-based pain-related fear, thus providing evidence for the potential of extinction-based techniques in the treatment of conceptual pain-related fear. PERSPECTIVE: This study demonstrates the acquisition, generalization, and extinction of concept-based pain-related fear in healthy participants. These are the first results to show that concept-based pain-related fear can be extinguished, suggesting that conceptual relationships between fear-inducing stimuli may also be important to consider in clinical practice.

Generalization and Extinction of Concept-BasedPain-Related Fear.

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 next to 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.

Article	Year
Generalization and Extinction of Concept-BasedPain-Related Fear. The journal of pain : official journal of the American Pain Society\| PubMed ID: 30296613	2019
Generalization of instrumentally acquired pain-related avoidance to novel but similar movements using a robotic arm-reaching paradigm. Behaviour research and therapy\| PubMed ID: 31785424	2020

Eveliina Glogan

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