Positive Affect Protects Against Deficient Safety Learning During Extinction of Fear of Movement-Related Pain in Healthy Individuals Scoring Relatively High on Trait Anxiety

The Influence of the Fear of Negative Evaluation on Activity Avoidance in Fibromyalgia: Exploring Pain Acceptance and Positive Affect as Resilience Variables

To examine the mediating role of pain acceptance (PAcc) between fear of negative evaluation (FNE) and activity avoidance (AV) at different levels of positive affect (PA) (moderator) among women diagnosed with fibromyalgia (FM) (moderate mediation model). This study was cross-sectional in design. A convenience sample of women with FM (n = 231) completed measures of pain severity, FNE, PAcc, AV, and PA. A simple mediation model and a moderate mediation model was constructed and analyzed using the SPSS macro-PROCESS. First, PAcc mediated the effect of FNE on AV (β = .02, SE = 0.008; [95% CI [0.0075, 0.0394]). Second, a mediated effect of PAcc between FNE and AV moderated by PA at medium and high levels of PA were found (m: 0.23; β = -.22, p = .0006; h: 9.59; β = -.34, p = .0002. Future work should seek to validate study findings in diverse samples of FM patients. Additionally, future work should explore how FM self-management interventions that include PAcc can promote increased activity among women suffering from FM with medium to high levels of PA.

[A role of cognitive and emotional factors in formation of pain]

Pain is influenced by multiple emotional and cognitive factors. This paper provides an overview of the most important emotional and cognitive factors affecting pain, which has been confirmed in experimental and clinical studies. Emotional factors that increase pain perception include anxiety, depression, and other negative emotions. Positive emotions lead to a decrease in pain. Cognitive factors such as attention, expectation anxiety, and pain assessment can both increase and decrease pain sensations, depending on their specific focus. It becomes clear that pain is not just a reflection of nociceptive irritation, but also a feeling formed by psychological factors that can be individual in each case.

Imprecise Visual Feedback About Hand Location Increases a Classically Conditioned Pain Expectancy Effect

We tested the hypotheses that rendering sensory input about hand location imprecise increases a classically conditioned pain expectancy effect, increases generalization of the effect to novel locations and reduces extinction of the effect. Forty healthy volunteers performed movements with their right hand along predefined paths. Each path passed through 2 locations that were defined as either i) the conditioned stimulus (CS+; paired with a painful unconditioned stimulus), or ii) unpaired (CS-). During acquisition phase, participants watched their hand as they moved it. Participants were randomly allocated to an Imprecise group, for whom visual feedback of the hand was offset 30 to 50 mm from its true location, or a Precise group, for whom vision was not disrupted. In the test phase, participants moved their hands to 5 locations-the CS+, CS-, and 3 locations that lay between the 2 ("generalization stimuli"). Our primary hypothesis was supported-pain expectancy was greater at the CS+ location in the Imprecise group than in the Precise group (6.9 [SD = 1.9] vs 5.4 [SD = 2.5], P= .02). Pain expectancies generalized to novel locations similarly in both groups and there was no difference in extinction between groups. Our primary hypothesis was supported but our subsequent hypotheses were not. PERSPECTIVE: We conditioned pain expectancy at a certain location of one hand, even though most participants were unaware of the contingency. Conditioned pain expectancy was greater when sensory information about location was less precise. This adds support to the possibility that associative learning may play a role in the progression of an acute pain episode to a more generalized pain disorder.

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.

Violence exposure, affective style, and stress-induced changes in resting state functional connectivity

Chronic childhood stress is linked to greater susceptibility to internalizing disorders in adulthood. Specifically, chronic stress leads to changes in brain connectivity patterns, and, in turn, affects psychological functioning. Violence exposure, a chronic stressor, increases stress reactivity and disrupts emotion regulation processes. However, it is unclear to what extent violence exposure affects the neural circuitry underlying emotion regulation. Individual differences in affective style also moderate the impact of stress on psychological function and can thus alter the relationship between violence exposure and brain function. Resting-state functional connectivity (rsFC) is an index of intrinsic brain activity. Stress-induced changes in rsFC between the amygdala, hippocampus, and prefrontal cortex (PFC) are associated with emotion dysregulation and may elucidate how affective style modulates the relationship between violence exposure and brain connectivity. Therefore, the present study examined the impact of violence exposure and affective style on stress-induced changes in rsFC. Participants (n = 233) completed two 6-minute resting-state functional magnetic resonance imaging scans, one before (pre-stress) and one after (post-stress) a psychosocial stress task. The bilateral amygdala, hippocampus, and ventromedial prefrontal cortex (vmPFC) were used as seed regions for rsFC analyses. Significant stress-induced changes in the prefrontal, fronto-limbic, and parieto-limbic rsFC were observed. Further, pre-stress to post-stress differences in rsFC varied with violence exposure and affective style. These findings suggest that prefrontal, fronto-limbic, and parieto-limbic connectivity is associated with the emotional response to stress and provide new insight into the neural mechanisms through which affective style moderates the impact violence exposure has on the brain.

Freeze-like responses to pain in humans and its modulation by social context

Background

Maladaptive defensive responses such as excessive avoidance behavior have received increasing attention as a main mechanism for the development and maintenance of chronic pain complaints. However, another defensive response which is commonly studied in animals as a proxy for fear is freezing behavior. No research to date has investigated human freezing behavior in the context of pain. In addition, there is an increasing realization that social context can affect pain-relevant processes such as pain experience and pain behavior but less is known about the effects of social context on defensive responses to pain. Hence, this study investigated freezing behavior and facial pain expression in the context of pain, and their modulation by social context.

Methods

Healthy, pain-free participants (N = 39) stood on a stabilometric force platform in a threatening or safe social context, which was manipulated using angry or happy facial stimuli. In some trials, an auditory cue (conditioned stimulus; CS) predicted the occurrence of painful electrocutaneous stimulus (unconditioned stimulus; pain-US). We assessed body sway (an index of freezing), heart rate, facial pain expression, self-reported pain intensity, unpleasantness, and pain-US expectancy during the CS and the context alone (no CS).

Results

The results were mixed. Neither the anticipation of pain, nor social context affected body sway. Heart rate and painful facial expression were reduced in the threatening social context at high anxiety levels. A threatening social context also elicited higher pain-US expectancy ratings. In sum, a threatening social context increases the expectation of pain, but reduces the facial expression of pain and lowers heart rate in highly anxious individuals.

Longitudinal Analysis Supports a Fear-Avoidance Model That Incorporates Pain Resilience Alongside Pain Catastrophizing

Background

The fear-avoidance model of chronic pain holds that individuals who catastrophize in response to injury are at risk for pain-related fear and avoidance behavior, and ultimately prolonged pain and disability.

Purpose

Based on the hypothesis that the predictive power of the fear-avoidance model would be enhanced by consideration of positive psychological constructs, the present study examined inclusion of pain resilience and self-efficacy in the model.

Methods

Men and women (N = 343) who experienced a recent episode of back pain were recruited in a longitudinal online survey study. Over a 3-month interval, participants repeated the Pain Resilience Scale, Pain Catastrophizing Scale, Tampa Scale of Kinesiophobia, Pain Self-Efficacy Questionnaire, the McGill Pain Questionnaire, and NIH-recommended measures of pain, depressive symptoms, and physical dysfunction. Structural equation modeling assessed the combined contribution of pain resilience and pain catastrophizing to 3-month outcomes through the simultaneous combination of kinesiophobia and self-efficacy.

Results

An expanded fear-avoidance model that incorporated pain resilience and self-efficacy provided a good fit to the data, Χ2 (df = 14, N = 343) = 42.09, p = .0001, RMSEA = 0.076 (90% CI: 0.05, 0.10), CFI = 0.97, SRMR = 0.03, with higher levels of pain resilience associated with improved 3-month outcomes on measures of pain intensity, physical dysfunction, and depression symptoms.

Conclusions

This study supports the notion that the predictive power of the fear-avoidance model of pain is enhanced when individual differences in both pain-related vulnerability (e.g., catastrophizing) and pain-related protective resources (e.g., resilience) are considered.

Avoidance Behavioral Difference in Acquisition and Extinction of Pain-Related Fear

Fear of movement-related pain leads to two types of avoidance behavior: excessive avoidance and pain-inhibited movement. Excessive avoidance is an absence of movement by fear, and pain-inhibited movements involve a change in motor behavior for the purpose of protecting the painful part. Here, we sought to clarify the acquisition process and adaptation of fear for each avoidance behavior. Thirty-one female and 13 male (age 20.9 ± 2.1 years) subjects could decide persistent behaviors: approach with an intense pain stimulus, pain-inhibited movement with weak pain stimulus, or excessive avoidance with no pain in acquisition and test phases. In the subsequent extinction phase, the pain stimulus was omitted. Subjects were divided into an approach group (n = 24), a pain-inhibited movement group (n = 10), and an excessive avoidance group (n = 10) by cluster analysis. The response latencies in approach and pain-inhibited movement groups were not affected by conditioned pain. The subjects in the excessive avoidance group exhibited delayed response latencies, and their high-fear responses remained in the acquisition, test, and extinction phases. In addition, the excessive avoidance group showed high harm avoidance and high trait anxiety. This study demonstrated that differences in pain-related avoidance behaviors are affected by psychological traits. Pain-related excessive avoidance behavior indicated a maladaptive fear, but pain-inhibited movement did not.

Placebo analgesia induced by verbal suggestion in the context of experimentally induced fear and anxiety

The role of state anxiety and state fear in placebo effects is still to be determined. We aimed to investigate the effect of fear of movement-related pain (FMRP) and contextual pain related anxiety (CPRA) on the magnitude of placebo analgesia induced by verbal suggestion. Fifty-six female participants completed a modified voluntary joystick movement paradigm (VJMP) where half participated in a predictable pain condition (PC), in which one of the joystick movements is always followed by pain and the other movement is never followed by pain, and half in an unpredictable pain condition (UC), in which pain was delivered unpredictably. By varying the level of pain predictability, FMRP and CPRA were induced in PC and UC respectively. Colour stimuli were presented at the beginning of each trail. Half of the participants were verbally informed that the green or red colour indicated less painful stimuli (experimental groups), the other half did not receive any suggestion (control groups). We measured self-reported pain intensity, expectancy of pain intensity (PC only), pain related fear and anxiety (eyeblink startle response and self-ratings) and avoidance behaviour (movement-onset latency and duration). The results indicate that the placebo effect was successfully induced in both experimental conditions. In the PC, the placebo effect was predicted by expectancy. Despite the fact that FMRP and CPRA were successfully induced, no difference was found in the magnitude of the placebo effect between PC and UC. Concluding, we did not find a divergent effect of fear and anxiety on placebo analgesia.

Evaluating psychosocial contributions to chronic pain outcomes

The biopsychosocial model of pain dominates the scientific community's understanding of chronic pain. Indeed, the biopsychosocial approach describes pain and disability as a multidimensional, dynamic integration among physiological, psychological, and social factors that reciprocally influence one another. In this article, we review two categories of studies that evaluate the contributions of psychosocial factors to the experience of chronic pain. First, we consider general psychosocial variables including distress, trauma, and interpersonal factors. Additionally, we discuss pain-specific psychosocial variables including catastrophizing, expectations, and pain-related coping. Together, we present a diverse array of psychological, social, and contextual factors and highlight the need to consider their roles in the development, maintenance, and treatment of chronic pain conditions.

Psychological Factors Associated with Phantom Limb Pain: A Review of Recent Findings

Phantom limb pain (PLP) is a common phenomenon occurring after the amputation of a limb and can be accompanied by serious suffering. Psychological factors have been shown to play an important role in other types of chronic pain, where they are pivotal in the acquisition and maintenance of pain symptoms. For PLP, however, the interaction between pain and psychological variables is less well documented. In this review, we summarize research on the role of emotional, motivational, cognitive, and perceptual factors in PLP. The reported findings indicate that emotional factors modulate PLP but might be less important compared to other types of chronic pain. Additional factors such as the amount of disability and adjustment to the amputation appear to also play a role. Bidirectional relationships between stress and PLP have been shown quite consistently, and the potential of stress and tension reduction in PLP treatment could be further exploited. Little is known about the role of cognitive variables such as attention or expectation. Catastrophizing seems to aggravate PLP and could be targeted in treatment. Body perception is altered in PLP and poses a potential target for novel mechanistic treatments. More research on psychological factors and their interactions in PLP is needed.

Positive affect skills may improve pain management in people with HIV

Non-opioid pain management strategies are critically needed for people with HIV. We therefore conducted a secondary analysis of pain-related outcomes in a randomized controlled trial of a positive affect skills intervention for adults newly diagnosed with HIV (N = 159). Results suggest that, even if pain prevalence rises, positive affect skills may reduce pain interference and prevent increased use of opioid analgesics by people living with HIV. Future research should replicate and extend these findings by conducting trials that are specifically designed to target pain outcomes.

Reinstatement of contextual conditioned anxiety in virtual reality and the effects of transcutaneous vagus nerve stimulation in humans

Since exposure therapy for anxiety disorders incorporates extinction of contextual anxiety, relapses may be due to reinstatement processes. Animal research demonstrated more stable extinction memory and less anxiety relapse due to vagus nerve stimulation (VNS). We report a valid human three-day context conditioning, extinction and return of anxiety protocol, which we used to examine effects of transcutaneous VNS (tVNS). Seventy-five healthy participants received electric stimuli (unconditioned stimuli, US) during acquisition (Day1) when guided through one virtual office (anxiety context, CTX+) but never in another (safety context, CTX-). During extinction (Day2), participants received tVNS, sham, or no stimulation and revisited both contexts without US delivery. On Day3, participants received three USs for reinstatement followed by a test phase. Successful acquisition, i.e. startle potentiation, lower valence, higher arousal, anxiety and contingency ratings in CTX+ versus CTX-, the disappearance of these effects during extinction, and successful reinstatement indicate validity of this paradigm. Interestingly, we found generalized reinstatement in startle responses and differential reinstatement in valence ratings. Altogether, our protocol serves as valid conditioning paradigm. Reinstatement effects indicate different anxiety networks underlying physiological versus verbal responses. However, tVNS did neither affect extinction nor reinstatement, which asks for validation and improvement of the stimulation protocol.

Can positive affect attenuate (persistent) pain? State of the art and clinical implications

Purpose of Review

Pain is an intense experience that can place a heavy burden on peoples’ lives. The identification of psychosocial risk factors led to the development of effective pain treatments. However, effect sizes are modest. Accumulating evidence suggests that enhancing protective factors might also impact on (well-being despite) pain. Recent findings on positive affect (interventions) towards pain-related outcomes will be reviewed, and new avenues for treatment of persistent pain will be discussed.

Recent Findings

Positive affect significantly attenuates the experience of pain in healthy and clinical populations. Positive affect interventions effectively reduce pain sensitivity and bolster well-being despite pain. Through both psychological and (neuro-)biological pathways, but also through its effect on central treatment processes such as inhibitory learning, positive affect can optimize the efficacy of existing treatments.

Summary

Comprehensive understanding of the unique roles and dynamic interplay of positive and negative affect in moderating pain may optimize the treatment of (persistent) pain.

Stories of Growth and Wisdom: A Mixed-Methods Study of People Living Well With Pain

Chronic pain remains a daunting clinical challenge, affecting 30% of people in the United States and 20% of the global population. People meeting this challenge by achieving wellbeing while living with pain are a virtually untapped source of wisdom about this persistent problem. Employing a concurrent mixed-methods design, we studied 80 people living with chronic pain with "positive stories to tell" using semi-structured interviews and standardized questionnaires. In-depth interviews focused on what helped, what hindered, how they changed, and advice for others in similar circumstances. Major qualitative themes included acceptance, openness, self-efficacy, hope, perseverance, self-regulation, kinesthetic awareness, holistic approaches and integrative therapies, self-care, spirituality, social support, and therapeutic lifestyle behaviors such as music, writing, art, gardening, and spending time in nature. Themes of growth and wisdom included enhanced relationships, perspective, clarity, strength, gratitude, compassion, new directions, and spiritual change. Based on narrative analysis of the interviews and Ardelt's Three-Dimensional Wisdom Model, participants were divided into 2 groups: 59 wisdom exemplars and 21 nonexemplars. Non-exemplar themes were largely negative and in direct contrast to the exemplar themes. Quantitatively, wisdom exemplars scored significantly higher in Openness and Agreeableness and lower in Neuroticism compared to non-exemplars. Wisdom exemplars also scored higher in Wisdom, Gratitude, Forgiveness, and Posttraumatic Growth than nonexemplars, and more exemplars used integrative therapies compared to the non-exemplars. As a whole, the exemplar narratives illustrate a Positive Approach Model (PAM) for living well with pain, which allows for a more expansive pain narrative, provides positive role models for patients and clinicians, and contributes to a broader theoretical perspective on persistent pain.

The key role of extinction learning in anxiety disorders: behavioral strategies to enhance exposure-based treatments

PURPOSE OF REVIEW

Extinction learning is a major mechanism for fear reduction by means of exposure. Current research targets innovative strategies to enhance fear extinction and thereby optimize exposure-based treatments for anxiety disorders. This selective review updates novel behavioral strategies that may provide cutting-edge clinical implications.

RECENT FINDINGS

Recent studies provide further support for two types of enhancement strategies. Procedural enhancement strategies implemented during extinction training translate to how exposure exercises may be conducted to optimize fear extinction. These strategies mostly focus on a maximized violation of dysfunctional threat expectancies and on reducing context and stimulus specificity of extinction learning. Flanking enhancement strategies target periods before and after extinction training and inform optimal preparation and post-processing of exposure exercises. These flanking strategies focus on the enhancement of learning in general, memory (re-)consolidation, and memory retrieval.

SUMMARY

Behavioral strategies to enhance fear extinction may provide powerful clinical applications to further maximize the efficacy of exposure-based interventions. However, future replications, mechanistic examinations, and translational studies are warranted to verify long-term effects and naturalistic utility. Future directions also comprise the interplay of optimized fear extinction with (avoidance) behavior and motivational antecedents of exposure.

Could Stress Contribute to Pain-Related Fear in Chronic Pain?

Learning to predict pain based on internal or external cues constitutes a fundamental and highly adaptive process aimed at self-protection. Pain-related fear is an essential component of this response, which is formed by associative and instrumental learning processes. In chronic pain, pain-related fear may become maladaptive, drive avoidance behaviors and contribute to symptom chronicity. Pavlovian fear conditioning has proven fruitful to elucidate associative learning and extinction involving aversive stimuli, including pain, but studies in chronic pain remain scarce. Stress demonstrably exerts differential effects on emotional learning and memory processes, but this has not been transferred to pain-related fear. Within this perspective, we propose that stress could contribute to impaired pain-related associative learning and extinction processes and call for interdisciplinary research. Specifically, we suggest to test the hypotheses that: (1) extinction-related phenomena inducing a re-activation of maladaptive pain-related fear (e.g., reinstatement, renewal) likely occur in everyday life of chronic pain patients and may alter pain processing, impair perceptual discrimination and favor overgeneralization; (2) acute stress prior to or during acquisition of pain-related fear may facilitate the formation and/or consolidation of pain-related fear memories; (3) stress during or after extinction may impair extinction efficacy resulting in greater reinstatement or context-dependent renewal of pain-related fear; and (4) these effects could be amplified by chronic stress due to early adversity and/or psychiatric comorbidity such depression or anxiety in patients with chronic pain.

Neural circuitry underlying effects of context on human pain-related fear extinction in a renewal paradigm

OBJECTIVES

The role of context in pain-related extinction learning remains poorly understood. We analyzed the neural mechanisms underlying context-dependent extinction and renewal in a clinically relevant model of conditioned abdominal pain-related fear.

EXPERIMENTAL DESIGN

In this functional magnetic resonance imaging study, two groups of healthy volunteers underwent differential fear conditioning with painful rectal distensions as unconditioned stimuli (US) and visual conditioned stimuli (CS(+) ; CS(-) ). The extinction context was changed in an experimental group (context group), which was subsequently returned into the original learning context to test for renewal. No context changes occurred in the control group. Group differences in CS-induced differential neural activation were analyzed along with skin conductance responses (SCR), CS valence and CS-US contingency ratings.

PRINCIPAL OBSERVATIONS

During extinction, group differences in differential neural activation were observed in dorsolateral (dlPFC) and ventromedial (vmPFC) prefrontal cortex and amygdala, mainly driven by enhanced activation in response to the CS(-) in the control group. During renewal, observed group differences in activation of dlPFC and orbitofrontal cortex (OFC) resulted primarily from differential modulation of the CS(-) in the absence of group differences in response to CS(+) or SCR.

CONCLUSION

The extinction context affects the neural processing of nonpain predictive safety cues, supporting a role of safety learning in pain-related memory processes.

Brain morphology correlates of interindividual differences in conditioned fear acquisition and extinction learning

The neural circuits underlying fear learning have been intensively investigated in pavlovian fear conditioning paradigms across species. These studies established a predominant role for the amygdala in fear acquisition, while the ventromedial prefrontal cortex (vmPFC) has been shown to be important in the extinction of conditioned fear. However, studies on morphological correlates of fear learning could not consistently confirm an association with these structures. The objective of the present study was to investigate if interindividual differences in morphology of the amygdala and the vmPFC are related to differences in fear acquisition and extinction learning in humans. We performed structural magnetic resonance imaging in 68 healthy participants who underwent a differential cued fear conditioning paradigm. Volumes of subcortical structures as well as cortical thickness were computed by the semi-automated segmentation software Freesurfer. Stronger acquisition of fear as indexed by skin conductance responses was associated with larger right amygdala volume, while the degree of extinction learning was positively correlated with cortical thickness of the right vmPFC. Both findings could be conceptually replicated in an independent sample of 53 subjects. The data complement our understanding of the role of human brain morphology in the mechanisms of the acquisition and extinction of conditioned fear.