Reduction in pain-related fear is not associated with improvement in spinal biomechanics but with decrease in movement-evoked pain in patients with chronic low back pain

Background and aims

While a causal relationship between pain-related fear and spinal movement avoidance in patients with chronic low back pain (CLBP) has frequently been postulated, evidence supporting this relationship is limited. This study aimed to test if decreases in pain-related fear or catastrophizing were associated with improvements in spinal biomechanics, accounting for possible changes in movement-evoked pain.

Methods

Sixty-two patients with CLBP were assessed before and after an interdisciplinary rehabilitation program (IRP). Pain-related fear was assessed with general and task-specific measures. Lower and upper lumbar angular amplitude and velocity as well as paraspinal muscle activity were recorded during five daily-life tasks to evaluate spinal biomechanics. Relationships were tested with multivariable linear regression analyses.

Results

The large decreases in pain-related fear and catastrophizing following the IRP were scarcely and inconsistently associated with changes in spinal biomechanics (< 3% of the models reported a statistically significant association). Results remained comparable for activities inducing more or less fear, for specific or general measures of pain-related fear, and for analyses performed on the entire population or limited to subgroups of patients with higher levels of task-specific fear. In contrast, reductions in task-specific pain-related fear were significantly associated with decreases in movement-evoked pain in all tasks (r = 0.26–0.62, p ≤ 0.02).

Conclusion

This study does not support an association between pain-related fear and spinal movement avoidance. However, it provides evidence supporting a direct relationship between decreased pain-related fear and decreased movement-evoked pain, possibly explaining some mechanisms of the rehabilitation programs.     

Self-efficacy mediates the relation between pain-related fear and outcome in chronic low back pain patients.

This study aimed to determine whether self-efficacy beliefs mediated the relation between pain-related fear and pain, and between pain-related fear and disability in CLBP patients who exhibited high pain-related fear. In a cross-sectional design, 102 chronic low back pain (CLBP) patients completed measures for pain, disability, self-efficacy and pain-related fear (fear of movement and catastrophizing). Multistep regression analyses were performed to determine whether self-efficacy mediated the relation between pain-related fear and outcome (pain and/or disability). Self-efficacy was found to mediate the relation between pain-related fear and pain intensity, and between pain-related fear and disability. Therefore, this study suggests that when self-efficacy is high, elevated pain-related fear might not lead to greater pain and disability. However, in instances where self-efficacy is low, elevated pain-related fear is likely to lead to greater pain and disability. In view of these findings, we conclude that it is imperative to assess both pain-related fear and self-efficacy when treating CLBP patients with high pain-related fear.     

Exposure in vivo versus operant graded activity in chronic low back pain patients: results of a randomized controlled trial

Since pain-related fear may contribute to the development and maintenance of chronic low back pain (CLBP), an exposure in vivo treatment (EXP) was developed for CLBP patients. We examined the effectiveness as well as specific mediating mechanisms of EXP versus operant graded activity (GA) directly and 6 months post-treatment in a multi-centre randomized controlled trial. In total, 85 patients suffering from disabling non-specific CLBP reporting at least moderate pain-related fear were randomly allocated to EXP or GA. It was demonstrated that EXP, despite excelling in diminishing pain catastrophizing and perceived harmfulness of activities, was equally effective as GA in improving functional disability and main complaints, although the group difference almost reached statistical significance favouring EXP. Both treatment conditions did not differ in pain intensity and daily activity levels either. Nor was EXP superior to GA in the subgroup of highly fearful patients. Irrespective of treatment, approximately half the patients reported clinically relevant improvements in main complaints and functional disability, although for the latter outcome the group difference was almost significant favouring EXP. Furthermore, the effect of EXP relative to GA on functional disability and main complaints was mediated by decreases in catastrophizing and perceived harmfulness of activities. In sum, this study demonstrates that up to 6 months after treatment EXP is an effective treatment, but not more effective than GA, in moderately to highly fearful CLBP patients, although its superiority in altering pain catastrophizing and perceived harmfulness of activities is clearly established. Possible explanations for these findings are discussed.     

Reduction of Pain-Related Fear and Disability in Post-Traumatic Neck Pain: A Replicated Single-Case Experimental Study of Exposure In Vivo

For patients with acute post-traumatic neck pain (PTNP), pain-related fear has been identified as a potential predictor of chronic disability. If such is the case, fear reduction should enhance the prevention of further pain disability and distress after traumatic neck pain disability. However, exposure-based treatments have not been tested in patients with PTNP. Using a replicated single-case crossover phase design with multiple measurements, this study examined whether the validity of a graded exposure in vivo, as compared with usual graded activity, extends to PTNP. Eight patients who reported substantial pain-related fear were included in the study. Daily changes in pain intensity, pain-related fear, pain catastrophizing, and activity goal achievement were assessed. Before and after each intervention, and at 6-month follow-up, standardized questionnaires of pain-related fear and pain disability were administered, and, to quantify daily physical activity level, patients carried an ambulatory activity monitor. The results showed decreasing levels of self-reported pain-related fear, pain intensity, disability, and improvements in physical activity level only when graded exposure in vivo was introduced, and not in the graded activity condition. The results are discussed in the context of the search for customized treatments for PTNP.PerspectiveThis is the first study showing that the effects of graded exposure in vivo generalize to patients with chronic PTNP reporting elevated levels of pain-related fear. This could help clinicians to customize treatments for PTNP.     

The treatment of fear of movement/(re)injury in chronic low back pain: further evidence on the effectiveness of exposure in vivo

BACKGROUND AND OBJECTIVE: Several cognitive-behavioral factors contribute to the persistence of pain disability in patients with chronic back pain. Fear-avoidance beliefs and fear of movement/(re)injury in particular have been shown to be strong predictors of physical performance and pain disability. Patients reporting substantial pain-related fear might benefit from exposure in vivo to a set of individually tailored, fear-eliciting, and hierarchically ordered physical movements rather than more general graded activity. PATIENTS AND INTERVENTIONS: Six consecutive patients with chronic low back pain who reported substantial fear of movement/(re)injury were included in the study. After a no-treatment baseline measurement period, the patients were randomly assigned to one of two interventions. In the first intervention, patients received exposure in vivo first, followed by graded activity. In the second intervention, the sequence of treatment modules was reversed. Before each treatment module, treatment credibility was assessed. Daily measures of pain-related fear, pain catastrophizing, and pain intensity were completed using visual analog scales. In addition, standardized measures of pain disability, pain-related fear, and pain vigilance were taken before and after each treatment module and at the 1-year follow-up. To obtain more objective data on actual activity levels, an ambulatory activity monitor was carried by the patients during 1 week before and after each treatment module. RESULTS: Time series analysis of the daily measures showed that improvements in pain-related fear and pain catastrophizing occurred only during the exposure in vivo and not during the graded activity, irrespective of the treatment order. Analysis of the pretreatment to post-treatment differences also revealed that decreases in pain-related fear also concurred with decreases in pain disability and pain vigilance and an increase in physical activity levels. All improvements remained at the 1-year follow-up.     

Decreasing Pain and Fear in Medical Procedures with a Pediatric Population (DREAM): A Pilot Randomized Within-Subject Trial

BackgroundMany children with injuries, including burns and fractures, experience moderate to severe pain during medical procedures. Recent studies claim that nonpharmacologic pain management using virtual reality (VR) could distract children from procedural pain by engaging multiple senses.AimsThe aims of this pilot randomized clinical trial were to assess the acceptability and feasibility of VR distraction in children with burns or fractures undergoing painful medical procedures, as well as the staff nurses, and assess the preliminary efficacy of VR distraction on pain intensity, pain-related fear, and subsequent recall of both.Materials and MethodA within-subject study design, in which participants served as their own control, was used. A total of 20 children from 7 to 17 years old with an injury were recruited at the surgical-trauma outpatient clinics of the Centre hospitalier universitaire Sainte-Justine (CHU Sainte-Justine). Each participant received both standard and experimental treatments through randomized order. Pain (numerical rating scale) and pain-related fear (Children's Fear Scale) measures were taken before the procedure and after each sequence, followed by a measure of children's (graphic rating scale) and nurses' acceptability of the intervention through their satisfaction level. Recall of pain intensity and pain-related fear were assessed 24 hours after the procedure. Wilcoxon signed-rank tests were used, with a significance level at 0.05.ResultsResults showed that VR distraction was an acceptable and feasible intervention for children and nurses of these outpatient clinics. Preliminary effects showed that, compared to standard of care, children participants reported a significant decrease in pain intensity (p = .023) and pain-related fear (p = .011) during VR as well as less recalled pain-related fear (p = .012) at 24 hours after the procedure. No side effects were reported.ConclusionVR is a promising intervention with children undergoing painful procedures because it is immersive and engages multiple senses. It is a low-cost intervention well accepted by children and nursing staff at this clinical site and is easy to implement in daily practice for procedural pain management.     

Fear of movement/(re)injury in chronic low back pain: education or exposure in vivo as mediator to fear reduction?

Clinical research of graded exposure in vivo with behavioral experiments in patients with chronic low back pain who reported fear of movement/(re)injury shows abrupt changes in self-reported pain-related fears and cognitions. The abrupt changes are more characteristics of insight learning rather than the usual gradual progression of trial and error learning. The educational session at the start of the exposure might have contributed to this insight. The current study examines the contribution of education and graded exposure versus graded activity in the reduction of pain-related fear and associated disability and physical activity. Six consecutive patients with chronic low back pain who reported substantial fear of movement/(re)injury were included in the study. After a no-treatment baseline measurement period, all the patients received a single educational session, followed again by a no-treatment period. Patients were then randomly assigned to either a graded exposure with behavioral experiments or an operant graded activity program. A diary was used to assess daily changes in pain intensity, pain-related fear, pain catastrophizing, and activity goal achievement. Standardized questionnaires of pain-related fear, pain vigilance, pain intensity, and pain disability were administered before and after each intervention and at the 6-month follow-up. An activity monitor was carried at baseline, during the interventions, and 1 week at 6-month follow-up. Randomization tests of the daily measures showed that improvements in pain-related fear and catastrophizing occurred after the education was introduced. The results also showed a further improvement when exposure in vivo followed the no-treatment period after the education and not during the operant graded activity program. Performance of relevant daily activities, however, were not affected by the educational session and improved significantly only in the exposure in vivo condition. All improvements remained at half-year follow-up only in patients receiving the exposure in vivo. These patients also reported a significant decrease in pain intensity at follow-up.     

Psychologic Influence on Experimental Pain Sensitivity and Clinical Pain Intensity for Patients with Shoulder Pain

Pain-related fear and pain catastrophizing are 2 central psychologic factors in fear-avoidance models. Our previous studies in healthy subjects indicated that pain-related fear, but not pain catastrophizing, was associated with cold pressor pain outcomes. The current study extends previous work by investigating pain-related fear and pain catastrophizing in a group of subjects with shoulder pain, and included concurrent measures of experimental and clinical pain. Fifty nine consecutive subjects seeking operative treatment of shoulder pain were enrolled in this study (24 women, mean age = 50.4, SD = 14.9). Subjects completed validated measures of pain-related fear, pain catastrophizing, and clinical pain intensity and then underwent a cold pressor task to determine experimental pain sensitivity. Multivariate regression models used sex, age, pain-related fear, and pain catastrophizing to predict experimental pain sensitivity and clinical pain intensity. Results indicated that only pain-related fear uniquely contributed to variance in experimental pain sensitivity (β = ?.42, P < .01). In contrast, sex (β = ?.29, P = .02) and pain catastrophizing (β = .43, P < .01) uniquely contributed to variance in clinical pain intensity. These data provide additional support for application of fear-avoidance models to subjects with shoulder pain. Our results also suggest that pain-related fear and pain catastrophizing may influence different components of the pain experience, providing preliminary support for recent theoretical conceptualizations of the role of pain catastrophizing.PerspectiveThis study provided additional information on how specific psychological variables potentially influence experimental and clinical pain. In this sample of subjects with shoulder pain, we replicated findings from our previous studies involving healthy subjects, as fear of pain was uniquely associated with experimental pain sensitivity. In contrast, pain catastrophizing emerged as the sole psychological variable related to clinical pain intensity.     

The Moderating Role of Attention Control in the Relationship Between Pain Catastrophizing and Negatively-Biased Pain Memories in Youth With Chronic Pain

The present study examined the role of attention control in understanding the development of negatively-biased pain memories as well as its moderating role in the relationship between pain catastrophizing and negatively-biased pain memories. Youth with chronic pain (N = 105) performed a cold pressor task (CPT) and completed self-report measures of state/trait pain catastrophizing and attention control, with the latter comprising both attention focusing and attention shifting. Two weeks after the CPT, youth's pain-related memories were elicited via telephone allowing to compute pain and anxiety memory bias indices (ie, recalling pain intensity or pain-related anxiety, respectively, as higher than initially reported). Results indicated no main effects of attention control and pain catastrophizing on pain memories. However, both components of attention control (ie, attention focusing and attention shifting) moderated the impact of pain catastrophizing on youth's memory bias, with opposite interaction effects. Specifically, whereas high levels of attention shifting buffered the influence of high pain catastrophizing on the development of pain memory bias, high levels of attention focusing strengthened the influence of high pain catastrophizing on the development of anxiety memory bias. Interaction effects were confined to trait catastrophizing (ie, not state catastrophizing). Theoretical and clinical implications are discussed.PerspectiveThis article investigates the role of attention control in the development of negatively-biased pain memories in children with chronic pain. Findings underscore the importance of targeting differential components of attention control and can inform intervention efforts to minimize the development of negatively biased pain memories in youth with chronic pain.     

Reduction of pain-related fear and increased function and participation in work-related upper extremity pain (WRUEP): Effects of exposure in vivo

There is increasing evidence that pain-related fear influences the development and maintenance of pain disability, presumably mediated through the fear-related avoidance of valued activities. Individually tailored graded exposure in vivo (GEXP) has been demonstrated to reduce pain-related fear and increase functional abilities in patients with chronic low back pain, neck pain, and complex regional pain syndrome. The current study aimed to test whether these effects generalize towards patients with work-related upper extremity pain. A sequential replicated and randomized single-case experimental phase design with multiple measurements was used. Within each participant, GEXP was compared to a no-treatment baseline period and a no-treatment 6-month follow-up period. Eight patients who reported a high level of pain-related fear were included in the study. Daily changes in pain catastrophizing, pain-related fear, and pain intensity were assessed using a diary, and subjected to randomization tests. Before the start of the baseline period, just after GEXP, and at 6-month follow-up, clinically relevant changes of pain catastrophizing, pain-related fear, perceived harmfulness of physical activity, pain disability, and participation/autonomy were verified. When GEXP was introduced, levels of pain catastrophizing and pain-related fear decreased significantly. Clinically relevant improvements were observed for pain disability, perceived participation, and autonomy. These favourable changes were maintained until 6-month follow-up. The findings of the current study underscore the external validity of a cognitive-behavioural GEXP treatment for patients with chronic pain reporting increased pain-related fear.     

Pain-related fear in low back pain: a prospective study in the general population.

A cognitive behavioural account of chronic low back pain (CLBP) proposes that the relationship between pain catastrophizing and functional disability is mediated by fear of movement/(re)injury. Several clinical studies already demonstrated the contribution of pain catastrophizing and fear of movement/(re)injury in the development and maintenance of CLBP. This study included people with low back pain (LBP) in the general population, and aimed to investigate whether fear of movement/(re)injury mediated the relationship between pain catastrophizing and functional disability, by examining several prerequisites for mediation. Data from the Dutch population-based Musculoskeletal Complaints and Consequences Cohort (DMC(3)) study were used, including 152 people suffering from LBP who completed both a follow-up questionnaire and a baseline questionnaire 6 months previously. This study was unable to demonstrate that the relationship between pain catastrophizing and functional disability was mediated by fear of movement/(re)injury, since the prerequisite that pain catastrophizing and functional disability were related, was not fulfilled. However, pain catastrophizing was significantly related to fear of movement/(re)injury 6 months later, above and beyond other contributing variables such as fear of movement/(re)injury already present at baseline. On its turn, fear of movement/(re)injury was related to functional disability, in addition to pain intensity. Although this study leaves some indistinctness concerning the actual relationships between pain catastrophizing, fear of movement/(re)injury, and functional disability, it does provide some evidence for the contributing role of these factors in LBP in the general population.     

Differential predictors of the long-term levels of pain intensity, work disability, healthcare use, and medication use in a sample of workers' compensation claimants

The fear avoidance model of pain (FAM) conceptualizes pain catastrophizing as the cognitive antecedent of pain-related fear, and pain-related fear as the emotional antecedent of depression and disability. The FAM is essentially one of mediation whereby pain-related fear becomes the process by which depression or disability ensue. However, emerging literature suggests that pain catastrophizing, pain-related fear, and depression might be at least partially distinct in their prediction of different pain-related outcomes. The primary purpose of the present study was to evaluate whether psychological factors in the FAM (pain catastrophizing, pain-related fear, and depression) differentially predict long-term pain-related outcomes. Toward this objective, we conducted a prospective study using a cohort of 202 individuals with subacute work-related musculoskeletal injuries. Participants completed a 7-week physical therapy program with a functional rehabilitation orientation. Posttreatment measures of fear of movement, pain catastrophizing, depression, and pain self-efficacy were used to predict the persistence of pain symptoms, healthcare use, medication use, and return-to-work at one-year follow-up. Results from hierarchical linear and logistic regression analyses revealed that pain catastrophizing and fear of movement act as differential predictors of long-term pain-related outcomes. Specifically, we found unique relationships between pain catastrophizing and long-term pain intensity, and fear of movement and long-term work disability. After controlling for pain intensity and FAM variables, pain self-efficacy was shown to be a unique predictor of medication use. Implications for the FAM and the clinical management of musculoskeletal pain conditions are discussed.     

Battle of the Appraisals: Pain-Related Injustice Versus Catastrophizing as Mediators in the Relationship Between Pain Intensity and 3-Month Outcomes in Adolescents with Chronic Pain

Pain appraisals are closely tied to pain and functional outcomes. Pain-related injustice and pain catastrophizing appraisals have both been identified as important cognitive-emotional factors in the pain experience of youth. Although pain-related injustice and catastrophizing have been linked to worse pain outcomes – as primary predictors and intermediary variables – little is known about whether they operate as independent or parallel mediators of the relationship between pain and functioning in youth. We tested pain-related injustice and catastrophizing appraisals as candidate mediators of the relationship between baseline pain intensity and 3-month functional outcomes in adolescents. Youth with chronic pain (N = 89, 76% female, 89% White, average age = 15 years) completed measures assessing pain intensity, pain-related injustice, and catastrophizing at baseline, as well as measures assessing functional disability and overall quality of life 3 months later. Multiple mediation analyses indicated that injustice mediated the relationship between pain intensity and 3 month quality of life. Exploratory analyses of specific quality of life domains indicated that injustice mediated the relationship between pain intensity and 3 month emotional functioning, whereas catastrophizing mediated the relationship between pain intensity and 3 month social functioning. The findings suggest these pain-related appraisals play different intermediary roles in the relationships among pain and future psychosocial outcomes.PerspectivePain-related injustice and catastrophizing appraisals play different intermediary roles in the relationships among pain and future psychosocial outcomes in youth with chronic pain. Treatments targeting pain-related injustice appraisals in pediatric populations are needed to complement existing treatments for catastrophizing.     

Distraction from chronic pain during a pain-inducing activity is associated with greater post-activity pain

The aim of this study was to investigate the effects of distraction from pain during and after a pain-inducing lifting task in a sample of chronic low back pain (CLBP) patients. Fifty-two CLBP patients (25 males, 27 females; mean age=46.30 years) performed a pain-inducing lifting task twice, once alone and once with a simultaneous cognitive distraction task. The results revealed that (1) distraction had no effect upon self-reported pain during the lifting task, (2) distraction had a paradoxical effect of more pain immediately after the lifting task, (3) both pain-related fear and pain catastrophizing did not moderate the effects of distraction on pain, but (4) catastrophic thinking about pain during the lifting task was related to more vigilance to pain and less engagement in the distracting task. Further investigation of the catastrophizing data showed that the effect of catastrophizing about pain during the lifting task on the cognitive distraction task was mediated by the amount of attention paid to pain. Clinical implications of these findings are discussed.     

Reduction of pain-related fear in complex regional pain syndrome type I: the application of graded exposure in vivo

Fear of (re)injury/movement has been identified as a potential predictor of chronic disability in complex regional pain syndrome type I (CRPS-I). In order to reduce pain-related fears and pain disability, graded exposure in vivo (GEXP) is likely to be an appropriate treatment. Indeed, there is evidence that in chronic pain patients reporting substantial fear of (re)injury/movement, GEXP is successful in reducing pain disability. However, the efficacy of exposure-based protocols in the treatment of CRPS-I patients for reducing pain disability has not been tested. The main research question of this study was whether the reduction of pain-related fear through GEXP also resulted in a decrease of disability in a subgroup of patients with CRPS-I who report substantial pain-related fear. A single-case experimental ABCD-design was used with random determination of the start of the intervention. Eight patients with CRPS-I were included in the study. To assess daily changes in pain intensity, pain-related fear, pain catastrophizing, and activity goal achievement, a diary was used. Standardized questionnaires of pain-related fear, pain disability, and self-reported signs and symptoms of CRPS-I were administered before and after each intervention, and at 6-month follow-up. The current study supports a GEXP approach to chronic CRPS-I. The GEXP was successful in decreasing levels of self-reported pain-related fear, pain intensity, disability, and physiological signs and symptoms. These results support the hypothesis that the meaning people attach to a noxious stimulus influences its experienced painfulness, and that GEXP activates cortical networks and reconciles motor output and sensory feedback.     

Yoga for veterans with chronic low back pain: Design and methods of a randomized clinical trial

Chronic low back pain (CLBP) afflicts millions of people worldwide, with particularly high prevalence in military veterans. Many treatment options exist for CLBP, but most have limited effectiveness and some have significant side effects. In general populations with CLBP, yoga has been shown to improve health outcomes with few side effects. However, yoga has not been adequately studied in military veteran populations. In the current paper we will describe the design and methods of a randomized clinical trial aimed at examining whether yoga can effectively reduce disability and pain in US military veterans with CLBP. A total of 144 US military veterans with CLBP will be randomized to either yoga or a delayed treatment comparison group. The yoga intervention will consist of 2 × weekly yoga classes for 12 weeks, complemented by regular home practice guided by a manual. The delayed treatment group will receive the same intervention after six months. The primary outcome is the change in back pain-related disability measured with the Roland-Morris Disability Questionnaire at baseline and 12-weeks. Secondary outcomes include pain intensity, pain interference, depression, anxiety, fatigue/energy, quality of life, self-efficacy, sleep quality, and medication usage. Additional process and/or mediational factors will be measured to examine dose response and effect mechanisms. Assessments will be conducted at baseline, 6-weeks, 12-weeks, and 6-months. All randomized participants will be included in intention-to-treat analyses. Study results will provide much needed evidence on the feasibility and effectiveness of yoga as a therapeutic modality for the treatment of CLBP in US military veterans.     

Fear of Pain, Pain Catastrophizing, and Acute Pain Perception: Relative Prediction and Timing of Assessment

Pain-related fear and catastrophizing are important variables of consideration in an individual's pain experience. Methodological limitations of previous studies limit strong conclusions regarding these relationships. In this follow-up study, we examined the relationships between fear of pain, pain catastrophizing, and experimental pain perception. One hundred healthy volunteers completed the Fear of Pain Questionnaire (FPQ-III), Pain Catastrophizing Scale (PCS), and Coping Strategies Questionnaire-Catastrophizing scale (CSQ-CAT) before undergoing the cold pressor test (CPT). The CSQ-CAT and PCS were completed again after the CPT, with participants instructed to complete these measures based on their experience during the procedure. Measures of pain threshold, tolerance, and intensity were collected and served as dependent variables in separate regression models. Sex, pain catastrophizing, and pain-related fear were included as predictor variables. Results of regression analyses indicated that after controlling for sex, pain-related fear was a consistently stronger predictor of pain in comparison to catastrophizing. These results were consistent when separate measures (CSQ-CAT vs PCS) and time points (pretask vs “in vivo”) of catastrophizing were used. These findings largely corroborate those from our previous study and are suggestive of the absolute and relative importance of pain-related fear in the experimental pain experience.

Perspective

Although pain-related fear has received less attention in the experimental literature than pain catastrophizing, results of the current study are consistent with clinical reports highlighting this variable as an important aspect of the experience of pain.     

Fear of pain influences outcomes after exercise-induced delayed onset muscle soreness at the shoulder

OBJECTIVES: This study investigated whether anxiety, fear of pain, or pain catastrophizing were predictive of pain-related outcomes after induced delayed onset muscle soreness (DOMS) at the shoulder. METHODS: Healthy participants (19 males and 23 females) were eligible for participation if they had (a) no history of neck or shoulder pain, (b) no sensory or motor impairments of the upper-extremity, (c) not regularly participating in upper-extremity weight training, (d) not currently or regularly taking pain medication, and (e) no history of upper-extremity surgery. Participants completed self-report measures for fear of pain, pain catastrophizing, and anxiety. Then, participants underwent a standard fatigue protocol to induce DOMS in the shoulder external rotator muscles. Participants were reassessed 24 hours after DOMS induction on clinical and evoked pressure pain reports, muscle force production, self-report of upper-extremity disability, and kinesiophobia. Stepwise regression models considered sex, anxiety, pain intensity, fear of pain, and pain catastrophizing as outcome predictors. RESULTS: Fear of pain alone explained 16% (P=0.008) of the variance in clinical pain and 10% (P=0.047) evoked pressure pain intensity. Clinical pain intensity alone explained 11% (P<0.031) of the variance in muscle force production. Clinical pain intensity and fear of pain explained 50% (P<0.001) of the variance in upper-extremity disability, whereas fear of pain and sex accounted for 26% (P=0.005) of the variance in kinesiophobia. CONCLUSIONS: With the exception of muscle force production, fear of pain had a consistent influence on shoulder DOMS outcomes, even after controlling for pain intensity. This study suggests fear of pain may be a relevant psychologic factor to consider in clinical studies investigating the development and treatment of chronic shoulder pain.     

The joint contribution of physical pathology, pain-related fear and catastrophizing to chronic back pain disability

The present study examined the contribution of physical pathology, pain-related fear and catastrophizing cognitions to pain intensity and disability in 100 patients with non-specific low back pain. Self-report instruments were completed as part of the intake procedure of patients, while physical pathology was quantified from medical charts using the MEDICS procedure. Results of the multiple regression analyses, adjusted for relevant demographic variables, pain intensity and pain duration, indicated that physical pathology was associated with pain intensity, but not with self-reported physical disability. Disability showed the strongest association with pain intensity. However, pain-related fear and catastrophizing contributed 4-10% additional explained variance to the regression models for pain intensity and disability. Thus, this study confirms the relationship between biological and psychological variables in determining the severity of low back pain complaints, and underscores the necessity for a multidisciplinary approach to diagnostics and intervention.     

Pain-related fear in acute low back pain: the first two weeks of a new episode.

The overall aim of this study was to explore the natural course of pain-related fear during the early stage of a new low back pain episode, using a prospective case series design. Specific research questions addressed the existence of typical patterns in individual time series of pain-related fear and sequential relationships between the occurrence of pain-related fear, pain and pain catastrophizing. Forty-four general practice patients who consulted their physician with a new episode of non-specific low back pain were recruited. They completed diaries on pain-related fear, pain and pain catastrophizing for 14 days following the consultation. Follow-up questionnaires on disability were completed at 3 months and 12 months. Time series analyses produced subgroups of patients with descending, stable and rising levels of pain-related fear over the 2-week period. These groups differed on baseline characteristics and outcome at follow-up. A time-shift between the occurrence of pain-events and pain-related fear or pain catastrophizing could not be demonstrated.In summary, these results fit in with previous findings in chronic patients. A relevant subgroup of patients who might benefit from early intervention could be identified. These findings support the need for further research into fear mechanisms in acute low back pain.