Pain-related Fear Research Articles

Avoid or engage? Outcomes of graded exposure in youth with chronic pain using a sequential replicated single-case randomized design.

Pain-related fear is typically associated with avoidance behavior and pain-related disability in youth with chronic pain. Youth with elevated pain-related fear have attenuated treatment responses; thus, targeted treatment is highly warranted. Evidence supporting graded in vivo exposure treatment (GET) for adults with chronic pain is considerable, but just emerging for youth. The current investigation represents the first sequential replicated and randomized single-case experimental phase design with multiple measures evaluating GET for youth with chronic pain, entitled GET Living. A cohort of 27 youth (81% female) with mixed chronic pain completed GET Living. For each participant, a no-treatment randomized baseline period was compared with GET Living and 3- and 6-month follow-ups. Daily changes in primary outcomes fear and avoidance and secondary outcomes pain catastrophizing, pain intensity, and pain acceptance were assessed using electronic diaries and subjected to descriptive and model-based inference analyses. Based on individual effect size calculations, a third of participants significantly improved by the end of treatment on fear, avoidance, and pain acceptance. By follow-up, over 80% of participants had improved across all primary and secondary outcomes. Model-based inference analysis results to examine the series of replicated cases were generally consistent. Improvements during GET Living was superior to the no-treatment randomized baseline period for avoidance, pain acceptance, and pain intensity, whereas fear and pain catastrophizing did not improve. All 5 outcomes emerged as significantly improved at 3- and 6-month follow-ups. The results of this replicated single-case experimental phase design support the effectiveness of graded exposure for youth with chronic pain and elevated pain-related fear avoidance.

Factors influencing health status in older people with knee osteoarthritis.

To examine a causal model of health status among older people with knee osteoarthritis. A cross-sectional, correlational design was used with a convenience sample of 220 older Thai people with knee osteoarthritis (mean age 68.96 years; SD = 6.22). Participants were asked to complete a demographic questionnaire, the Pain Catastrophizing Scale, the Tampa Scale of Kinesiophobia, The Medical Outcomes Study Social Support Survey, and the Arthritis Impact Measurement Scales 2-Short Form. Structural Equation Model was used to examine a hypothesized model. Using Chi-square, hypothesized model was statistically nonsignificant. A model of health status fitted with the empirical data and explained 19.2% of variance. Pain catastrophizing had negative direct effect on self-efficacy and health status. Pain catastrophizing also had negative indirect effect on health status through self-efficacy. Self-efficacy and social support had positive direct effects on health status. However, pain-related fear had no direct or indirect effect on health status. Lower level of pain catastrophizing can improve self-efficacy. Increasing of self-efficacy and social support can then lead to improvement on health status. This study highlighted the effect of psychosocial factors on health status. It is necessary to develop a program to minimize pain catastrophizing, improve social support, and promote self-efficacy to improve the health status of older people with knee osteoarthritis.

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.

67.3 BREAKING THE FEAR AVOIDANCE CYCLE: EXPOSURE TREATMENT FOR YOUTH WITH CHRONIC PAIN

Pain-related fear has been identified as an important factor that increases the likelihood of poor outcomes among individuals who experience pain. We have recently developed and implemented a graded in vivo exposure treatment program, jointly delivered by a psychologist and physical therapist focused on children and adolescents with high pain-related fear and chronic pain. The goal of the current study was to examine clinically meaningful changes in our primary outcome, fear of pain, and in our secondary outcomes, disability, pain acceptance, and pain. We will provide an overview of the treatment, a single-case series analysis approach, and preliminary results.

Pain Education for Adolescents and Young Adults Living Beyond Cancer: An Interdisciplinary Meeting Report.

Pain is an understudied and undertreated consequence of cancer survival. Pain education is now a recommended treatment approach for persistent non-cancer pain, yet it has not been well applied to the context of adolescent and young adult (AYA) cancer survival. In March 2018, an interdisciplinary meeting was held in Adelaide, South Australia to set a research agenda for pain education in AYA cancer survivors. We identified that AYAs with persistent pain and those with heightened pain-related fear have the potential to benefit from pain education. We identified a number of unique challenges of engaging AYA survivors in pain education, and point towards future research directions.

Abstract # 4256 Does acute inflammation change gut memories? Effects of experimental endotoxemia on the extinction of conditioned visceral pain-related fear

Abstract # 4256 Does acute inflammation change gut memories? Effects of experimental endotoxemia on the extinction of conditioned visceral pain-related fear

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.

Changes in Pain-Related Fear and Pain When Avoidance Behavior is no Longer Effective

Avoidance is considered key in the development of chronic pain. However, little is known about how avoidance behavior subsequently affects pain-related fear and pain. We investigated this using a robotic arm reaching avoidance task. In a between-subjects design both Experimental Group (n = 30) and Yoked Control Group (n = 30) participants perform either of 3 movement trajectories (T1–T3) to reach a target location. During acquisition, only participants of the Experimental Group could partially or fully avoid a painful electrocutaneous stimulus by choosing the intermediate trajectory (T2; 50% reinforcement) or the longest trajectory (T3; 0% reinforcement) versus the shortest trajectory (T1: 100% reinforcement). After acquisition, contingencies changed (all trajectories 50% reinforced), and the acquired avoidance behavior no longer effectively prevented pain from occurring. The Yoked Control Group received the same reinforcement schedule as the Experimental Group irrespective of their behavior. When avoidance behavior became ineffective for the Experimental Group, pain-related fear increased for the previously safe(r) trajectories (T2 and T3) and remained the same for T1, whereas pain threshold and tolerance declined. For the Yoked Group, pain-related fear increased for all trajectories. The Experimental Group persisted in emitting avoidance behavior following the contingency change, albeit at a lower frequency than during acquisition. PerspectiveResults indicate participants become more afraid of and sensitive to pain, when previously acquired avoidance is no longer effective. Also, participants continue to show avoidance behavior despite it being not adaptive anymore. These findings suggest that ineffective avoidance may play role in the maintenance and development of chronic pain.

Exposure in vivo Induced Changes in Neural Circuitry for Pain-Related Fear: A Longitudinal fMRI Study in Chronic Low Back Pain.

Exposure in vivo (EXP) is a cognitive-behavioral treatment aimed at reducing pain-related fear in chronic pain, and has proven successful in reducing pain-related disability in patients with chronic low back pain (cLBP). The current longitudinal study aimed to reveal the neural correlates of changes in pain-related fear as a result of EXP. Twenty-three patients with cLBP were included in this study. Patients with cLBP underwent MRI scanning pre-treatment (pre-EXP), post-treatment (post-EXP), and 6 months after end of treatment (FU-EXP). Pain-free controls were scanned at two time points. In the scanner, participants were presented with pictures involving back-related movements, evoking pain-related fear in patients. Pre-treatment, functional MRI revealed increased activation in right posterior insula and increased deactivation in medial prefrontal cortex (mPFC) in patients compared to controls. Post-treatment, patients reported reduced fear and pre-EXP group differences were no longer present. Contrasting pre- to post- and FU-EXP in patients revealed that stimulus-evoked neural responses changed in sensorimotor as well as cognitive/affective brain regions. Lastly, exploratory analyses revealed a tendency toward an association between changes in neural activation and changes in fear ratings, including the hippocampus and temporal lobe (pre- to post-EXP changes), and mPFC and posterior cingulate cortex (pre- to FU-EXP changes). Taken together, we show evidence that neural circuitry for pain-related fear is modulated by EXP, and that changes are associated with self-reported decreases in pain-related fear.

Graded exposure treatment for adolescents with chronic pain (GET Living): Protocol for a randomized controlled trial enhanced with single case experimental design

Chronic musculoskeletal pain in adolescence is a significant public health concern with 3–5% of adolescents suffering from significant pain-related disability. Pain-related fear and avoidance of activities has been found to have a significant influence on pain outcomes in children and adolescents and is a risk factor for less favorable response to treatment. To address this need, we developed graded exposure treatment for youth with chronic pain (GET Living). We describe the rationale, design, and implementation of a two-group randomized controlled trial (RCT) enhanced with single-case experimental design (SCED) methodology with a sample of 74 adolescents with chronic musculosketal pain and their parent caregivers. GET Living includes education, behavioral exposures, and parent intervention jointly delivered by pain psychology and physical therapy providers. The multidisciplinary pain management control group includes pain psychology delivered education and pain self-management skills training (e.g., relaxation, cognitive skills) and separate physical therapy. Assessments include brief daily diaries (baseline to discharge, 7-days at 3-month and 6-month follow-up), comprehensive in-person evaluations at baseline and discharge, and questionnaire across all time points (baseline, discharge, 3-month and 6-month follow-up). Primary outcome is pain-related fear avoidance. Secondary outcome is functional disability. We also outline all additional outcomes, exploratory outcomes, covariates, and implementation measures. The objective is to offer a mechanism-based, targeted intervention to youth with musculoskeletal pain to enhance likelihood of return to function.

A Network Analysis of Potential Antecedents and Consequences of Pain-Related Activity Avoidance and Activity Engagement in Adolescents.

This study sets out to identify potential daily antecedents and consequences of pain-related activity avoidance and engagement behavior in adolescents with chronic pain. Adolescents (N = 65, Mage = 14.41) completed baseline self-reports and a diary for 14 days. Afternoon and evening reports were used to infer a network structure of within-day associations between pain intensity, pain-related fear, pain catastrophizing, affect, and pain-related activity avoidance and engagement behavior. Baseline psychological flexibility was examined as a potential resilience factor. Activity avoidance in the evening was predicted by pain-related fear and avoidance earlier that afternoon. Activity engagement was predicted by positive affect and activity engagement in the afternoon. Pain-related behavior in the afternoon was not related to subsequent changes in pain intensity, pain-related fear, pain catastrophizing, or affect. Pain-related fear in the afternoon was predictive of increased levels of pain and pain catastrophizing in the evening. Both pain-related fear and pain catastrophizing in the evening were predicted by negative affect in the afternoon. Psychological flexibility was associated with lower levels of daily activity avoidance and buffered the negative association between pain intensity and subsequent activity engagement. This study provides insight into unique factors that trigger and maintain activity avoidance and engagement and into the role of psychological flexibility in pediatric pain. Future work should focus on both risk and resilience factors and examine the role of psychological flexibility in chronic pediatric pain in greater detail.

Multiple diagnoses, increased kinesiophobia? - Patients with high kinesiophobia levels showed a greater number of temporomandibular disorder diagnoses

ObjectivesThe aim of this study was to empirically derive subgroups according to pain-related fear of movement beliefs using cluster analysis within a sample of TMD patients and asymptomatic volunteers. Methods129 volunteers participated in this cross-sectional study (34.78, standard deviation [SD]: 12.49 years; 92 TMD patients and 37 symptom-free volunteers). Mechanical pain sensitivity through pressure pain threshold (PPT) on orofacial and remote sites, kinesiophobia, pain catastrophizing, anxiety and depression were assessed. A cluster analysis was used to derive subgroups according to kinesiophobia scores (TSK/TMD). ResultsThree subgroups were derived: cluster 1 (high kinesiophobia [n = 53], TSK score: 33, SD[standard deviation] = 2.9), cluster 2 (moderate kinesiophobia [n = 50], TSK score: 26.2, SD = 2.14) and cluster 3 (no/low kinesiophobia [n = 26], TSK score 12.12, SD = 2.08) which included patients with higher overall PPT and lower scores on psychosocial variables. The group with high kinesiophobia showed high levels of pain catastrophizing, anxiety, and orofacial pain-related disability compared to the other subgroups and mechanical pain hyperalgesia in remote site compared to the low-kinesiophobia group. Also, we found a greater prevalence of triple diagnosis for the high-kinesiophobia subgroup compared to the moderate kinesiophobia group - odds ratio: 12.6 (95% confidence interval [CI]: 3.31–43.52, p < 0.01). ConclusionThese results suggested that patients with TMD and higher levels of kinesiophobia beliefs may show a more complex clinical feature, with high psychosocial distress, widespread mechanical pain sensitivity, and a more complex TMD disorder. In this way, we suggest a relationship between the number of TMD diagnoses and kinesiophobia severity.

The relationship between fear generalization and pain modulation: an investigation in healthy participants.

Background and aims Pain-related fear and its subsequent generalization is key to the development and maintenance of chronic pain disability. Research has shown that pain-related fear acquired through classical conditioning generalizes following a gradient, that is, novel movements that are proprioceptively similar to the original pain-associated movement elicit more fear. Studies suggest that classical conditioning can also modulate pain and conditioned fear seems to mediate this effect. However, it remains uninvestigated whether this is also the case for generalized fear. Methods In a voluntary joystick movement paradigm, one movement (conditioned stimulus; CS+) was followed by pain (pain-US), and another was not (CS-). Generalization to five novel movements (generalization stimuli; GSs) with varying levels of similarity to the CSs was tested when paired with an at-pain-threshold intensity stimulus (threshold-USs). We collected self-reported fear and pain, as well as eyeblink startle responses as an additional index of conditioned fear. Results Results showed a fear generalization gradient in the ratings, but not in the startle measures. The data did not support the idea that fear generalization mediates spreading of pain. Conclusions Despite the lack of effects in the current study, this is a promising novel approach to investigate pain modulation in the context of chronic pain. Implications This study replicates the finding that pain-related fear spreads selectively towards movements that are proprioceptively more similar to the original pain-eliciting movement. Although results did not support the idea that such generalized fear mediates spreading of pain, the study provides a promising approach to investigate pain modulation by pain-associated movements.

Effects of acute pain and pain-related fear on risky decision-making and effort during cognitive tests

ABSTRACTIntroduction: The experience of acute pain and pain-related fear negatively impact cognition and behavior; however, little research has examined their impacts on risky decision-making and effort. The present study investigated the effects of acute pain and pain-related fear on risky decision-making and effort during cognitive tests.Method: Levels of pain-related fear were assessed. Healthy participants (n = 146) experienced acute pain induced via cold pressor task, and then were randomly assigned to one of the four conditions to induce pain-related fear: Pain Threat (n = 36), Pain Threat with Control (n = 39), Cognitive Threat with Control (n = 34), and Control (n = 36). Participants then completed measures of effort (Word Memory Test [WMT], self-reported effort) and risky decision-making (Iowa Gambling Task [IGT], Balloon Analogue Risk Task [BART]).Results: Collapsed across condition, participants did not learn to decide advantageously on the IGT following an acute pain experience. During the early trials (1–40) on the IGT, participants in the Pain Threat condition made riskier decisions. Higher levels of pain during the cold pressor task predicted less risky decisions on the BART, and participants in the Cognitive Threat with Control condition made less risky decisions. Participants in the Pain Threat with Control condition self-reported lower effort on cognitive tests, yet no group-based differences were seen in WMT performance. Greater pain-related fear predicted greater self-reported effort and better WMT performance, but no effects were seen on decision-making task performance.Conclusions: The experience of pain and the threat of additional pain can lead to changes in risky decision-making and effort on cognitive tasks. This threat of additional pain could activate underlying pain-related fear, creating hypervigilance to and avoidance of pain that affects subsequent task performance. Implications for research and clinical evaluation of acute pain and pain-related fear are discussed.

Psychological and physical factors related to disability in chronic low back pain.

Chronic low back pain (CLBP) is a public health problem that causes high levels of disability. Psychological and physical factors could play a critical role in the disability perception of patients. The objective was to identify the psychological and physical factors associated with CLBP disability in patients and assess differences between asymptomatic subjects and CLBP patients through physical tests and psychological self-reports. A cross-sectional study was performed. Total sample of 80 participants were classified into two groups: patients with CLBP (n= 49) and asymptomatic subjects (i.e. the control group) (n= 31). The physical tests included lower back range of motion (LBROM), postural stability, lower back strength (LBS), and lumbopelvic motor control tests. The psychological self-reports included low back disability (Roland Morris Disability Questionnaire), self-efficacy, pain catastrophizing, and pain-related fear. Self-efficacy and LBS displayed moderate negative correlations withdisability in patients with CLBP (R=-0.47 and -0.40, respectively). Disability was predicted by self-efficacy and LBROM (β=-0.45 and -033 respectively, p< 0.01), explaining 30% of the variance in these patients. The comparative analysis showed statistically significant differences between groups in the physical/psychological variables (p< 0.01); however, the effect-sizes were small for all these variables. The results of this study highlight the relevance of psychological and physical factors in CLBP patient disability. Evaluation and treatment in CLBP patients should take these factors into account.

The relation of self-compassion to functioning among adults with chronic pain.

Previous research has shown that self-compassion is associated with improved functioning and health outcomes among multiple chronic illnesses. However, the role of self-compassion in chronic pain-related functioning is understudied. The present study sought to understand the association between self-compassion and important measures of functioning within a sample of patients with chronic pain. Treatment-seeking individuals (N=343 with chronic pain) that were mostly White (97.9%) and female (71%) completed a battery of assessments that included the Self-Compassion Scale (SCS), as well as measures of pain-related fear, depression, disability, pain acceptance, success in valued activity and use of pain coping strategies. Cross-sectional multiple regression analyses that controlled for age, sex, pain intensity and pain duration, revealed that self-compassion accounted for a significant and unique amount of variance in all measures of functioning (r2 range: 0.07-0.32, all p<0.001). Beta weights indicated that higher self-compassion was associated with lower pain-related fear, depression and disability, as well as greater pain acceptance, success in valued activities and utilization of pain coping strategies. These findings suggest that self-compassion may be a relevant adaptive process in those with chronic pain. Targeted interventions to improve self-compassion in those with chronic pain may be useful. Self-compassion is associated with better functioning across multiple general and pain-specific outcomes, with the strongest associations among measures related to psychological functioning and valued living. These findings indicate that self-compassion may be an adaptive process that could minimize the negative impact of chronic pain on important areas of life.

Effectiveness of Simulated Horseback Riding for Patients With Chronic Low Back Pain: A Randomized Controlled Trial.

A simulated horseback riding (SHR) exercise is effective for improvement of pain and functional disability, but its comparative effectiveness with the other is unknown. The authors aimed to demonstrate the effect of a SHR exercise in people with chronic low back pain. A randomized controlled trial. Community and university campus. A total of 48 participants with chronic low back pain were divided into 2 groups, and SHR exercises (n = 24) or stabilization (STB) exercises (n = 24) were performed. The exercises were performed for 30 minutes, 2 days per week for 8 weeks. Numeric rating scale, functional disabilities (Oswestry disability index and Roland-Morris disability), and fear-avoidance beliefs questionnaire (FABQ) scores were measured at baseline and at 4 weeks, 8 weeks, and 6 months. A 2-way repeated analysis of variance identified that between-group comparisons showed significant differences in the FABQ related to work scale (F = 21.422; P = .01). There were no significant differences in the numeric rating scale (F = 1.696; P = .21), Oswestry disability index (F = 1.848; P = .20), Roland-Morris disability (F = 0.069; P = .80), and FABQ related to physical scale (F = 1.579; P = .24). In within-group comparisons, both groups presented significant differences in numeric rating scale (both SHR and STB after 4wk), Oswestry disability index (both SHR and STB after 6mo), and Roland-Morris disability (SHR after 6mo and STB after 8wk) compared with baseline values. In FABQ-related physical (SHR after 4wk) and work scales (SHR after 6mo), there were only significant differences in the SHR compared with baseline values. SHR exercise for 8 weeks had a greater effect than STB exercise for reducing work-related FABQ. The SHR exercise performed in a seated position could substantially decrease pain-related fear disability in young adults with chronic low back pain.

How are pain and traumatic stress symptoms related in acute whiplash-associated disorders? An investigation of the role of pain-related fear in a daily diary study.

Comorbidity of pain and posttraumatic stress disorder is well recognized, but the reason for this association is unclear. This study investigated the direction of the relationship between pain and traumatic stress and the role that pain-related fear plays, for patients with acute whiplash-associated disorder. Participants (n = 99) used an electronic diary to record hourly ratings of pain, traumatic stress, and fear of pain (FOP) symptoms over a day. Relationships between pain, traumatic stress, and pain-related fear symptoms were investigated through multilevel models including variables lagged by 1 hour. Traumatic stress was associated with previous pain, even after controlling for previous traumatic stress and current pain; current pain was not associated with previous traumatic stress. The relationship between traumatic stress and previous pain became negligible after controlling for FOP, except for traumatic stress symptoms of hyperarousal that were driven directly by pain. Overall, these results support a pain primacy model, and suggest that pain-related fear is important in the maintenance and development of comorbid pain and traumatic stress symptoms. They also confirm that traumatic stress symptoms of hyperarousal are central in this relationship. Differences between this study and others that reported mutual maintenance can be understood in terms of different stages of whiplash-associated disorder and different intervals between repeated measurements. Traumatic stress may affect pain over longer time intervals than measured in this study. Future research could explore how relationships between traumatic stress symptoms, pain, and FOP change over time, and whether previous experiences of traumatic stress influence these relationships.

Cortisol affects pain sensitivity and pain-related emotional learning in experimental visceral but not somatic pain: a randomized controlled study in healthy men and women.

Despite growing interest in the role of stress mediators in pain chronicity, the effects of the stress hormone cortisol on acute pain remain incompletely understood. In a randomized, double-blind, placebo-controlled study with N = 100 healthy volunteers, we tested the effects of oral hydrocortisone (20 mg) in 2 widely used pain models for the visceral and somatic modality. Salivary cortisol was increased in the hydrocortisone group (time × group: P < 0.001). For the visceral modality, assessed using pressure-controlled rectal distensions, hydrocortisone decreased the pain threshold from before to after treatment (time × group: P = 0.011), an effect primarily driven by women (time × sex: P = 0.027). For the somatic modality, cutaneous heat pain thresholds remained unaffected by hydrocortisone. Hydrocortisone did not alter perceived pain intensity or unpleasantness of either modality. Conditioned pain-related fear in response to predictive cues was only observed for the visceral modality (time × modality: P = 0.026), an effect that was significantly reduced by hydrocortisone compared with placebo (time × group: P = 0.028). This is the first psychopharmacological study to support that acutely increased cortisol enhances pain sensitivity and impairs pain-related emotional learning within the visceral, but not the somatic pain modality. Stress-induced visceral hyperalgesia and deficits in emotional pain-related learning could play a role in the pathophysiology of chronic visceral pain.

The Effects of Monetary Motivation on the Relationship between Pain-Related Fear and Avoidance Behavior

The Effects of Monetary Motivation on the Relationship between Pain-Related Fear and Avoidance Behavior