Rewarding Approach Behaviour Attenuates the Return of Pain-Related Avoidance After Successful Extinction with Response Prevention.

After successful exposure treatment for chronic pain, pain-related fear and avoidance may return, i.e., relapse may occur. This return of fear and avoidance may be modulated by various post-treatment factors. In this study, we aimed to investigate two potential factors that may affect return of fear and avoidance, i.e. cognitive load and rewarding approach behaviour. In an operant pain-related avoidance conditioning paradigm, healthy pain-free volunteers first learned to fear and avoid an arm-reaching movement that was often paired with painful electrocutaneous stimulation (T1), by performing alternative movements that were less often (T2) or never (T3) paired with pain. During extinction with response prevention, participants were only allowed to perform T1, and pain was omitted. To model relapse, two unexpected painful stimuli were presented (i.e., reinstatement manipulation), after which participants could freely choose among the three arm-reaching movements again. During test, the Low Load group performed an additional easy digit task, whereas the High Load group performed a more cognitively demanding digit task. The Reward group performed the demanding digit task, whilst being rewarded to perform T1. Results showed that pain-related fear and avoidance returned, irrespective of cognitive load imposed. When participants were rewarded to approach T1, however, the return of avoidance, but not fear, was attenuated. Our findings suggest that engaging in rewarding activities may facilitate the maintenance of treatment outcomes, and provide additional support to the growing body of literature indicating a divergent relationship between fear and avoidance. PERSPECTIVE: Results of this experiment suggest that engaging in rewarding activities may optimize exposure treatment for chronic pain, by dampening the return of pain-related avoidance - though not of pain-related fear - after extinction.

Generalization of pain-related avoidance behavior based on de novo categorical knowledge.

ABSTRACT: People with chronic pain often fear and avoid movements and activities that were never paired with pain. Safe movements may be avoided if they share some semantic relationship with an actual pain-associated movement. This study investigated whether pain-associated operant responses (movements) can become categorically associated with perceptually dissimilar responses, thus motivating avoidance of new classes of safe movements-a phenomenon known as category-based avoidance generalization. Using a robotic arm, 2 groups were trained to categorize arm movements in different ways. Subsequently, the groups learned through operant conditioning that an arm movement from one of the categories was paired with a high probability of pain, whereas the others were paired with either a medium probability of pain or no pain (acquisition phase). Self-reported pain-related fear and pain expectancy were collected as indices of fear learning. During a final generalization test phase, the movements categorically related to those from the acquisition phase were made available but in the absence of pain. Results showed that the generalization of outcome measures depended on the categorical connections between arm movements, ie, the groups avoided and feared the novel generalization movement categorically related to the pain-associated acquisition movement, depending on how they had previously learned to categorize the movements. This suggests that operant pain-related avoidance can generalize to safe behaviors, which are not perceptually, but categorically, similar to a pain-associated behavior. This form of pain-related avoidance generalization is problematic because category-based relations can be extremely wide reaching and idiosyncratic. Thus, category-based generalization of operant pain-related avoidance merits further investigation.

Pain and avoidance: The potential benefits of imagining your best possible self.

Positive affect is hypothesized to improve safety learning taking place during extinction (i.e., the core mechanism of exposure treatment), therefore improving the maintenance of treatment outcomes. We investigated whether positive affect during extinction attenuates the subsequent return of pain-related avoidance and fear. In an operant pain-related avoidance conditioning paradigm, sixty healthy volunteers performed arm-reaching movements using a robotic arm. During acquisition, they learned to avoid an easy but painful movement (T1) by choosing more effortful movements that were sometimes (T2) or never (T3) painful. Then, the Positive affect group wrote about and imagined their best possible self, which is known to induce positive affect, whereas the Control group wrote about and imagined a typical day. During extinction with response prevention (RPE), participants were only allowed to perform T1, which was no longer paired with pain. Next, two painful stimuli were presented when participants were not moving (i.e., reinstatement manipulation). During test, all movements were available, and we examined whether fear and avoidance of the previously painful movements would re-emerge. Pain-related avoidance returned in both groups, but the two groups did not differ herein. The Positive affect group reported increased positive affect, though not more than the Control group. Nevertheless, they generalized the learned safety of T1 to the other movements during RPE, whereas they also retrospectively rated the pain as less intense and less unpleasant. These results add to the literature of positive affect as a resilience factor.

Safety behaviours or safety precautions? The role of subtle avoidance in anxiety disorders in the context of chronic physical illness.

Avoidance is a hallmark symptom and a primary maintaining factor in anxiety disorders. Theories of anxiety disorders have focused not only on overt avoidance, but also on more subtle avoidance known as 'safety behaviours'. Safety behaviours involve behaviours which aim to reduce anxiety or prevent a feared outcome from occurring. In the long-term, however, these behaviours prevent the disconfirmation of threat because safety is incorrectly attributed to the safety behaviour, thus perpetuating anxiety. As a result, reducing or eliminating safety behaviours is an important target for many cognitive behaviourally oriented treatments. Notably, despite the relevance of anxiety to people with chronic health problems, the role of safety behaviours is rarely discussed in these contexts. Further, safety behaviours among those with chronic health problems pose a particularly complex problem. Distinguishing adaptive safety precautions from maladaptive safety behaviours can be a difficult task. In this paper, we discuss the role of safety behaviours in maintaining and treating anxiety problems in healthy adults, and whether these same principles apply to those with chronic illness. We propose a functional and contextual model of differentiating between safety behaviours and safety precautions amongst those with chronic physical illness. Lastly, we propose methods for adapting the treatment of anxiety disorders in the context of chronic physical illness.

No differences in return of pain-related fear after extinction and counterconditioning.

Extinction-based protocols such as exposure-in-vivo successfully reduce pain-related fear in chronic pain conditions, but return of fear and clinical relapse often occur. Counterconditioning is assumed to attenuate return of fear, likely through changing the negative affective valence of the conditioned stimulus (CS). We hypothesized that counterconditioning would outperform extinction in mitigating return of pain-related fear and decrease CS negative affective valence. Healthy participants performed a conditioning task, in which 2 joystick movements (CSs+) were paired with a painful electrocutaneous stimulus (unconditioned stimulus; pain-US), whereas 2 other movements (CSs-) were not. Subsequently, in the extinction group, 1 CS+ was extinguished (pain-US omission) and the other not, whereas in the counterconditioning group, 1 CS+ was presented with a US of opposite valence (reward-US) and the other was paired with both USs. We tested reinstatement of pain-related fear after 2 unsignalled pain-US presentations. Results showed no group differences in fear reduction and no differences in CS affective valence changes between the extinguished and counterconditioned CS. Remarkably, none of the groups showed reinstatement. Overall, counterconditioning did not appear to be more effective than extinction in reducing pain-related fear and its return. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Optimizing Long-term Outcomes of Exposure for Chronic Primary Pain from the Lens of Learning Theory.

Exposure in vivo is a theory-driven and widely used treatment to tackle functional disability in people with chronic primary pain. Exposure is quite effective; yet, in line with exposure outcomes for anxiety disorders, a number of patients may not profit from it, or relapse. In this focus article, we critically reflect on the current exposure protocols in chronic primary pain, and provide recommendations on how to optimize them. We propose several adaptations that are expected to strengthen inhibitory learning and/or retrieval of the extinction memory, thus likely decreasing relapse. We summarize the limited, but emerging experimental data in the pain domain, and draw parallels with experimental evidence in the anxiety literature. Our reflections and suggestions pertain to the use of the fear hierarchy, reassurance, positive psychology interventions, exposure with a range of stimuli and within different contexts, and the use of safety behaviors during treatment, as well as associating the fear-inducing stimuli with novel outcomes. In addition, we reflect on the importance of specifically tackling (the return of) pain-related avoidance behavior with techniques such as disentangling fear from avoidance and reinforcing approach behaviors. Finally, we discuss challenges in the clinical application of exposure to improve functioning in chronic primary pain and possible avenues for future research. PERSPECTIVE: Inspired by recent advances in learning theory and its applications on the treatment of anxiety disorders, we reflect on the delivery of exposure treatment for chronic primary pain and propose strategies to improve its long-term outcomes.

When Do We Not Face Our Fears? Investigating the Boundary Conditions of Costly Pain-Related Avoidance Generalization.

Excessive generalization of fear and avoidance are hallmark symptoms of chronic pain disability, yet research focusing on the mechanisms underlying generalization of avoidance specifically, is scarce. Two experiments investigated the boundary conditions of costly pain-related avoidance generalization in healthy participants who learned to avoid pain by performing increasingly effortful (in terms of deviation and force) arm-movements using a robot-arm (acquisition). During generalization, novel, but similar arm-movements, without pain, were tested. Experiment 1 (N = 64) aimed to facilitate generalization to these movements by reducing visual contextual changes between acquisition and generalization, whereas Experiment 2 (N = 70) aimed to prevent extinction by increasing pain uncertainty. Both experiments showed generalization of pain-expectancies and pain-related fear. However, Experiment 2 was the first and only to also demonstrate generalization of avoidance, ie, choosing the novel effortful arm-movements in the absence of pain. These results suggest that uncertainty about the occurrence of pain may delay recovery, due to reduced disconfirmation of threat beliefs when exploring, resulting in persistent avoidance. PERSPECTIVE: This article demonstrates generalization of instrumentally acquired costly pain-related avoidance in healthy people under conditions of uncertainty. The results suggest that targeting pain-related uncertainty may be a useful tool for clinicians adopting a psychological approach to treating excessive pain-related avoidance in chronic pain.

Will that hurt? A contingency learning task to assess pain-expectancy judgments for low back postures.

BACKGROUND AND OBJECTIVES: Contingency learning, i.e. learning that a cue predicts the presence (or absence) of an event, is central to the formation of beliefs regarding painfulness of body postures. Such beliefs may spread to safe cues due to compromised learning (e.g., excessive generalization, impaired safety learning), prompting avoidance and leading to disability. Despite its importance, compromised learning about low back pain is underinvestigated. We propose a low back pain scenario contingency learning task for the investigation of back pain-related learning. METHODS: Sixty healthy participants viewed pictures of an avatar in various back postures, and for each posture gave pain-expectancy judgments and viewed the verbal outcome (pain/no pain) for a fictive back pain patient. During acquisition, one posture was followed by pain (conditioned stimulus; CS+), whereas another was not (CS-). During generalization, unreinforced novel intermediate back postures (generalization stimuli; GSs) were tested. During extinction, only the CSs were presented, not followed by pain. During generalization of extinction, only the GSs were presented, not followed by pain. RESULTS: Participants expected pain more for the CS + than the CS- (differential acquisition) and generalized their pain-expectancy to the GS most similar to the CS+ (generalization). During extinction, pain-expectancy for the CS + decreased and generalized to the GS most similar to the CS+ (generalization of extinction). LIMITATIONS: Future research should investigate generalizability of findings to clinical samples and consider the role of pre-existing pain threat beliefs. CONCLUSIONS: This task is an easily applicable, non-invasive way to investigate the formation of back pain-related threat beliefs.

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 paradigms to experimentally investigate pain-related avoidance. To fill this gap, we developed a paradigm (the robotic arm-reaching paradigm) to investigate the mechanisms underlying the development of pain-related avoidance behavior. Existing avoidance paradigms (mostly in the context of anxiety research) have often operationalized avoidance as an experimenter-instructed, low-cost response, superimposed on stimuli associated with threat during a Pavlovian fear conditioning procedure. In contrast, the current method offers increased ecological validity in terms of instrumental learning (acquisition) of avoidance, and by adding a cost to the avoidance response. In the paradigm, participants perform arm-reaching movements from a starting point to a target using a robotic arm, and freely choose between three different movement trajectories to do so. The movement trajectories differ in probability of being paired with a painful electrocutaneous stimulus, and in required effort in terms of deviation and resistance. Specifically, the painful stimulus can be (partly) avoided at the cost of performing movements requiring increased effort. Avoidance behavior is operationalized as the maximal deviation from the shortest trajectory on each trial. In addition to explaining how the new paradigm can help understand the acquisition of avoidance, we describe adaptations of the robotic arm-reaching paradigm for (1) examining the spread of avoidance to other stimuli (generalization), (2) modeling clinical treatment in the lab (extinction of avoidance using response prevention), as well as (3) modeling relapse, and return of avoidance following extinction (spontaneous recovery). Given the increased ecological validity, and numerous possibilities for extensions and/or adaptations, the robotic arm-reaching paradigm offers a promising tool to facilitate the investigation of avoidance behavior and to further our understanding of its underlying processes.

Once an Avoider Always an Avoider? Return of Pain-Related Avoidance After Extinction With Response Prevention.

In exposure for chronic pain, avoidance is often forbidden (extinction with response prevention; RPE) to prevent misattributions of safety. Although exposure is an effective treatment, relapse is common. Little is known about the underlying mechanisms of return of pain-related avoidance. We hypothesized that pain-related avoidance would recover when becoming available again after RPE and after unexpected pain episodes ("reinstatement"), especially when restricting avoidance during RPE (compared to instructing not to use it). In an operant pain-related avoidance conditioning paradigm, healthy volunteers used a robotic arm to perform various arm reaching movements differing in pain-effort trade-off. During acquisition, participants learned to avoid pain by performing more effortful movements. During RPE they only performed the formerly pain-associated movement under extinction, and were either forbidden (Restricted group) or merely instructed (Instructed group) not to perform other movements. One day later, we tested spontaneous recovery and reinstatement of pain-related fear and avoidance with availability of all movements. Results showed that pain-related fear and avoidance re-emerge after RPE, though not to pretreatment levels. The reinstatement manipulation had no additional effect. No group differences were observed. We discuss findings in the context of learning processes in (chronic) pain disability and relapse prevention in chronic pain treatment. Perspective: Using experimental models of relapse, we investigated the return of pain-related avoidance behavior after extinction with response prevention. Findings are potentially informative for clinicians performing exposure treatment with chronic pain patients.

Generalization of instrumentally acquired pain-related avoidance to novel but similar movements using a robotic arm-reaching paradigm.

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.

A break from pain! Interruption management in the context of pain.

Activity interruptions, namely temporary suspensions of an ongoing task with the intention to resume it later, are common in pain. First, pain is a threat signal that urges us to interrupt ongoing activities in order to manage the pain and its cause. Second, activity interruptions are used in chronic pain management. However, activity interruptions by pain may carry costs for activity performance. These costs have recently started to be systematically investigated. We review the evidence on the consequences of activity interruptions by pain for the performance of the interrupted activity. Further, inspired by literature on interruptions from other research fields, we suggest ways to improve interruption management in the field of pain, and provide a future research agenda.

Effects of activity interruptions by pain on pattern of activity performance - an experimental investigation.

BACKGROUND AND AIMS: Suspending an ongoing activity with the intention to resume it again later is a natural response to pain. This response facilitates coping with the pain, but it may also have negative consequences for the resumption and performance of the activity. For example, people with pain problems are often forced to take a break from doing their household chores because of their pain. They might delay resuming their chore, eventually needing longer time to finish it. We investigated how activity interruptions by pain influence the pattern of subsequent activity performance. We expected that when an activity is interrupted by pain (compared to non-pain), people spend longer time away from the activity, need longer time to complete it, and are less motivated to perform it. METHODS: Sixty healthy volunteers performed an ongoing task that required them to make joystick movements in different directions according to a specific rule. Occasionally, participants received either a painful electrocutaneous stimulus or a non-painful and non-aversive auditory stimulus (between-subjects) as an interruption cue. The interruption cue was followed by the temporary suspension of the ongoing task and the initiation of a different activity (interruption task). The latter required the categorization of cards and had a maximum duration, but participants could also stop it earlier by pressing a button. We measured time away from the (interrupted) ongoing task, total time to complete the ongoing task (including the interruptions) and self-reported motivation to perform both the ongoing as well as the interruption task. RESULTS: Groups did not differ in the time away from the ongoing task, total time to complete the ongoing task, or self-reported motivation to perform the two tasks. CONCLUSIONS: Activity interruptions by pain did not impair the pattern of activity performance more than activity interruptions by non-pain. Potential explanations and suggestions for future research are discussed. IMPLICATIONS: Interrupting ongoing activities is a common response to pain. However, activity interruptions by pain do not appear to influence the pattern of activity performance in a different way than activity interruptions by pain-irrelevant external stimuli.

Activity interruptions by pain impair activity resumption, but not more than activity interruptions by other stimuli: an experimental investigation.

Interrupting ongoing activities whilst intending to resume them later is a natural response to pain. Whereas this response facilitates pain management, at the same time it may also disrupt task performance. Previous research has shown that activity interruptions by pain impair subsequent resumption of the activity, but not more than pain-irrelevant interruptions. Ongoing task complexity and pain threat value might influence interruption effects. In this experiment, we adjusted a paradigm from outside the field of pain to investigate how activity interruptions by pain affect task performance. Healthy participants (n = 69) were required to answer a series of questions, in a specific sequence, about presented letter-digit combinations. This ongoing task was occasionally interrupted by painful electrocutaneous or nonpainful vibrotactile stimulation (between-subjects), followed by a typing task. On interruption completion, participants were required to resume the ongoing task at the next step of the question sequence. Results indicate impaired sequence accuracy (less frequent resumption at the correct step of the sequence) but preserved nonsequence accuracy (similarly frequent correct responses to question content) immediately after an interruption. Effects were not larger for interruptions by pain compared with nonpain. Furthermore, participants in the 2 conditions reported similar task experience, namely task motivation, perceived difficulty, and confidence to resume the interrupted task. Pain catastrophizing did not influence the results. As in previous studies, activity interruptions by pain were shown to impair the resumption of a task that requires keeping to a step sequence, but not more than interruptions by nonpainful stimuli. Potential explanations are discussed.

Taking a break in response to pain. An experimental investigation of the effects of interruptions by pain on subsequent activity resumption.

BACKGROUND AND AIMS: Interrupting ongoing activities with the intention to resume them again later is a natural response to pain. However, such interruptions might have negative consequences for the subsequent resumption and performance of the interrupted activity. Activity interruptions by pain may be more impairing than interruptions by non-painful stimuli, and also be subjectively experienced as such. These effects might be more pronounced in people high in pain catastrophizing. These hypotheses were investigated in two experiments. METHODS: In Experiment 1, healthy volunteers (n=24) performed an ongoing task requiring a sequence of joystick movements. Occasionally, they received either a painful electrocutaneous or a non-painful vibrotactile stimulus, followed by suspension of the ongoing task and temporary engagement in a different task (interruption task). After performing the interruption task for 30s, participants resumed the ongoing task. As the ongoing task of Experiment 1 was rather simple, Experiment 2 (n=30) included a modified, somewhat more complex version of the task, in order to examine the effects of activity interruptions by pain. RESULTS: Participants made more errors and were slower to initiate movements (Experiment 1 & 2) and to complete movements (Experiment 2) when they resumed the ongoing task after an interruption, indicating that interruptions impaired subsequent performance. However, these impairments were not larger when the interruption was prompted by painful than by non-painful stimulation. Pain catastrophizing did not influence the results. CONCLUSIONS: Results indicate that activity interruptions by pain have negative consequences for the performance of an activity upon its resumption, but not more so than interruptions by non-painful stimuli. Potential explanations and avenues for future research are discussed. IMPLICATIONS: Interrupting ongoing activities is a common response to pain. In two experiments using a novel paradigm we showed that activity interruptions by pain impair subsequent activity resumption and performance. However, this effect seems to not be specific to pain.

Operant learning theory in pain and chronic pain rehabilitation.

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.