The assessment of anxiety and fear in persons with chronic pain: a comparison of instruments

Association between seated trunk control and cortical sensorimotor white matter brain changes in patients with chronic low back pain

Trunk control involves integration of sensorimotor information in the brain. Individuals with chronic low back pain (cLBP) have impaired trunk control and show differences in brain structure and function in sensorimotor areas compared with healthy controls (HC). However, the relationship between brain structure and trunk control in this group is not well understood. This cross-sectional study aimed to compare seated trunk control and sensorimotor white matter (WM) structure in people with cLBP and HC and explore relationships between WM properties and trunk control in each group. Thirty-two people with cLBP and 35 HC were tested sitting on an unstable chair to isolate trunk control; performance was measured using the 95% confidence ellipse area (CEA95) of center-of-pressure tracing. A WM network between cortical sensorimotor regions of interest was derived using probabilistic tractography. WM microstructure and anatomical connectivity between cortical sensorimotor regions were assessed. A mixed-model ANOVA showed that people with cLBP had worse trunk control than HC (F = 12.96; p < .001; ηp2 = .091). There were no differences in WM microstructure or anatomical connectivity between groups (p = 0.564 to 0.940). In the cLBP group, WM microstructure was moderately correlated (|r| = .456 to .565; p ≤ .009) with trunk control. Additionally, the cLBP group demonstrated stronger relationships between anatomical connectivity and trunk control (|r| = .377 to .618 p < .034) compared to the HC group. Unique to the cLBP group, WM connectivity between right somatosensory and left motor areas highlights the importance of interhemispheric information exchange for trunk control. Parietal areas associated with attention and spatial reference frames were also relevant to trunk control. These findings suggest that people with cLBP adopt a more cortically driven sensorimotor integration strategy for trunk control. Future research should replicate these findings and identify interventions to effectively modulate this strategy.

Experiential Avoidance as a Factor in Generalized Psychological Vulnerability: In the Relationship Between Chronic Pain and Pain Anxiety With Pain Disability

BACKGROUND

Pain is a major socio-psychological problem worldwide. Chronic pain has a negative effect on areas of psychological functioning such as depression, anxiety, and perceived stress.

AIM

The present study investigated the mediating role of experiential avoidance in the relationship between chronic pain and pain anxiety with pain disability.

METHODS

Participants were treatment-seeking patients (N = 361) at an outpatient pain clinic in Shiraz (Fars, Iran). The Multidimensional Pain Inventory (MPI), Pain Anxiety Symptom Scale (PASS-20), Pain Disability Questionnaire (PDQ), and Acceptance and Action Questionnaire-II (AAQ-II) were used to measure multidimensional pain, anxiety, pain disability, experiential avoidance, and pain severity.

RESULTS

The results of the correlation revealed that a significant relationship exists between multidimensional pain and pain anxiety, pain disability, and experiential avoidance. Experiential avoidance mediated the associations from multidimensional pain and pain disability significantly. Also, experiential avoidance moderated associations between pain anxiety and pain disability significantly. In general, Structural Equation Modeling (SEM) showed that experiential avoidance mediated the relationship between multidimensional pain and pain anxiety with pain disability.

CONCLUSION

In general, the results revealed that experiential avoidance can mediate the relationship among pain, pain anxiety, and pain disability as a maladaptive regulation strategy. The results obtained from this study seem to introduce experiential avoidance as a vulnerability factor effectively.

Patients' expectancy scale of acupuncture: Development and clinical performance test

PURPOSE

This study aims to develop and validate a concise tool for evaluating acupuncture expectancy that is easy to understand and conforms to acupuncture characteristics.

MATERIALS AND METHODS

A draft was created using the Delphi consensus method. Reliability, validity, discrimination, and feasibility tests were conducted at the item and scale levels.

RESULTS

The scale themes were defined as disease-related, treatment-related, process-related, and outcome-related. After two rounds of Delphi surveys with good experts' reliability (authority coefficients of experts were 0.86 and 0.87 in the two rounds) and agreement (Kendall's concordance coefficient of the participants were 0.33 and 0.15 in the two rounds, P < 0.05), 11 items (the mean score for item importance, full mark ratios, and coefficient of variation of items were ≥3.5, ≥25%, and ≤0.30, respectively) were included in the draft. A total of 145 individuals were recruited to test the draft. Reliability was assessed by Cronbach's α coefficient (0.90), split-half reliability coefficient (0.89), and test-retest reliability (Pearson's coefficient = 0.74, P < 0.05). Content validity was assessed by the content validity index (Item-CVI ≥ 0.78 and Scale-CVI/Ave = 0.92), and a confirmatory factor analysis was performed to assess the construct validity. The discrimination of scale items was evaluated by the critical ratio (CR > 3.00) and the homogeneity test (item-total correlations >0.40). Feasibility was assessed through the acceptance rate (recovery rate = 98.60%, response rate = 100%), completion rate (100%), and completion time (4.99 ± 6.80 min).

CONCLUSION

The patients' expectancy scale of acupuncture (PESA) consists of 11 items with four themes, disease-related, treatment-related, process-related, and outcome-related. It has great reliability, validity, discrimination, and feasibility and has the potential to evaluate acupuncture expectancy in clinical trials.

Measuring State and Trait Anxiety: An Application of Multidimensional Item Response Theory

The State-Trait Inventory for Cognitive and Somatic Anxiety (STICSA) is a widely used measure of state and trait anxiety. Within the Classical Testing Theory model, consistent findings provide support for its multidimensional factor structure, discriminant, convergent, and nomological validity, as well as age and gender invariance, across healthy and clinical samples. Nevertheless, some issues regarding STICSA dimensionality and item-scale composition remain unresolved (e.g., both bifactor and two-factor models were found to fit data equally well). The goal of this study was to investigate the STICSA's dimensionality within the Item Response Theory, and to assess the tenability of the bifactor model as a plausible model over the multidimensional model. The sample consisted of 3338 Italian participants (58.21% females; 41.79% males) with an average age of 35.65 years (range: 18-99; SD = 20.25). Both bifactor and two-correlated dimensions of the STICSA scales were confirmed to fit data by applying the multidimensional Item Response Theory (mIRT). While the bifactor model showed better fit indices, the multidimensional model was more accurate and precise (0.86-0.88) in estimating state and trait latent anxiety. A further comparison between multidimensional item parameters revealed that the multidimensional and bifactor models were equivalent. Findings showed that the STICSA is an accurate and precise instrument for measuring somatic and cognitive symptomatology dimensions within state and trait anxiety. The use of the state/trait total score requires special attention from the clinicians and researchers to avoid bias in the psychodiagnostic assessment.

Pain-Related Cognitive Processes, Pain Interference, and Alexithymia in Patients With Primary Headaches

Objectives This study aims to investigate the effects of pain-related cognitive processes (PRCPs) and emotional state on pain-related disability (PRD) and pain interference (difficulty in performing daily routines, difficulty in engaging in social activities [the enjoyment of life], and the impact on work and/or school performance) in patients with primary headaches (PHs). Methodology PRCPs were evaluated with the Pain Anxiety Symptom Scale-20 (PASS-20), Pain Catastrophizing Scale (PCS), and Pain Belief Questionnaire (PBQ). Anxiety, depression, and alexithymia were investigated to assess the emotional state. PRD was assessed by Headache Impact Test-6 (HIT-6). Health-related quality of life (HRQoL) was evaluated under three headings: daily activities (with Short Form-36 [SF-36] Question [Q] 22), social activities (with Graded Chronic Pain Scale-Revised [GCPS-R] Q 4), as well as the working ability (with GCPS-R Q 5). Two separate models were constructed to identify the factors influencing PRD and HRQoL in PHP: M1 to reveal the factors affecting PRD and M2 to determine the independent factors affecting pain interference. In both models, correlation analysis was applied first and the significant data were then evaluated with regression analysis. Results A total of 364 participants (74 healthy controls [HCs] and 290 PHPs) completed the study. In M1, the following domains were significantly associated with PRD: cognitive anxiety (β = 0.098; 95% confidence interval [CI] = 0.001-0.405; P = 0.049); helplessness (β = 0.107; 95% CI = 0.018-0.356; P = 0.031); alexithymia (β = 0.077; 95% CI = 0.005-0.116; P = 0.033); depression (β = 0.083; 95% CI = 0.014-0.011; P = 0.025). In M2, factors associated with impairment in daily activities for PHP were as follows: duration of pain, pain intensity, alexithymia, escape-avoidance response, psychological anxiety, anxiety, and poor sleep quality (R = 0.770; R² = 0.588). The independent factors affecting social activities for PHP were pain intensity and pain-related anxiety (R = 0.90; R² = 0.81). Independent risk factors that affected the ability to work for PHP were pain intensity, cognitive anxiety, escape-avoidance response, and pain anxiety (R = 0.90; R² = 0.81). Conclusions This study highlights the importance of cognitive and emotional processes that help increase our understanding of the patient with PHs. This understanding may help to reduce disability and improve the quality of life in this population by helping to guide multidisciplinary treatment goals.

Fear of pain as a predictor of concurrent and downstream PTSD symptoms

BACKGROUND

Pain anxiety has been associated with more severe posttraumatic stress disorder (PTSD) symptoms. However, the unique role of individual domains of pain anxiety has yet to be explored in the prediction of PTSD severity. This study examined whether specific pain anxiety domains (i.e., cognitive anxiety, escape/avoidance, fear of pain, and physiological anxiety) predict both concurrent and downstream PTSD symptoms above and beyond other PTSD risk factors.

METHOD

Participants were 63 survivors of traumatic events with moderate to high baseline pain treated in the emergency department and assessed for PTSD symptoms and pain anxiety at 3- and 12-months.

RESULTS

Three-month pain anxiety domains of fear of pain and physiological anxiety (inversely related) significantly predicted concurrent 3-month PTSD symptoms above and beyond other established PTSD risk factors (i.e., sex, age, pain, and trauma type). However, only 3-month fear of pain significantly predicted 12-month PTSD symptoms.

CONCLUSIONS

Findings highlight the relevance of specific pain anxiety domains in concurrent and future PTSD symptoms and suggest the importance of evaluating pain anxiety among patients with PTSD. Interventions focused on increasing willingness to experience and tolerate fear of pain may help mitigate this risk, thereby improving outcomes for individuals with acute PTSD symptoms.

When pain becomes uncontrollable: an experimental analysis of the impact of instructions on pain-control attempts

ABSTRACT

Under some conditions, people persist in their attempts to control their pain even when no such control is possible. Theory suggests that such pain-control attempts arise from actual pain experiences. Across 3 experiments we examined how (1) losing control over pain and (2) instructions concerning pain, moderated pain-control attempts. In each experiment, participants completed a learning task. Before the task, one group of participants received instructions outlining a strategy through which they could control pain, whereas another group had to develop such a strategy through trial-and-error learning. During the first half of the task, the pain-control instructions allowed participants to successfully control pain, whereas during the second half of the task, this was no longer the case. Instead, participants lost control over pain because of an unannounced change in the learning task. Results indicated that when participants lost control over pain, they generally stuck to the previously effective pain-control strategy, and that this tendency was larger if they received instructions from others than when they developed a strategy by themselves. These findings suggest that when pain is no longer controllable, very persistent pain-control attempts might be the result of adherence to previously effective pain-control instructions.

Online questionnaire, clinical and biomechanical measurements for outcome prediction of plantar heel pain: feasibility for a cohort study

BACKGROUND

Plantar heel pain (PHP) accounts for 11-15% of foot symptoms requiring professional care in adults. Recovery is variable, with no robust prognostic guides for sufferers, clinicians or researchers. Therefore, we aimed to determine the validity, reliability and feasibility of questionnaire, clinical and biomechanical measures selected to generate a prognostic model in a subsequent cohort study.

METHODS

Thirty-six people (19 females & 17 males; 20-63 years) were recruited with equal numbers in each of three groups: people with PHP (PwPHP), other foot pain (PwOP) and healthy (H) controls. Eighteen people performed a questionnaire battery twice in a randomised order to determine online and face-to-face agreement. The remaining 18 completed the online questionnaire once, plus clinical measurements including strength and range of motion, mid-foot mobility, palpation and ultrasound assessment of plantar fascia. Nine of the same people underwent biomechanical assessment in the form of a graded loaded challenge augmenting walking with added external weight and amended step length on two occasions. Outcome measures were (1) feasibility of the data collection procedure, measurement time and other feedback; (2) establishing equivalence to usual procedures for the questionnaire battery; known-group validity for clinical and imaging measures; and initial validation and reliability of biomechanical measures.

RESULTS

There were no systematic differences between online and face-to-face administration of questionnaires (p-values all > .05) nor an administration order effect (d = - 0.31-0.25). Questionnaire reliability was good or excellent (ICC2,1_absolute)(ICC 0.86-0.99), except for two subscales. Full completion of the survey took 29 ± 14 min. Clinically, PwPHP had significantly less ankle-dorsiflexion and hip internal-rotation compared to healthy controls [mean (±SD) for PwPHP-PwOP-H = 14°(±6)-18°(±8)-28°(±10); 43°(±4)- 45°(±9)-57°(±12) respectively; p < .02 for both]. Plantar fascia thickness was significantly higher in PwPHP (3.6(0.4) mm vs 2.9(0.4) mm, p = .01) than the other groups. The graded loading challenge demonstrated progressively increasing ground reaction forces.

CONCLUSION

Online questionnaire administration was valid therefore facilitating large cohort recruitment and being relevant to remote service evaluation and research. The physical and ultrasound examination revealed the expected differences between groups, while the graded loaded challenge progressively increases load and warrants future research. Clinician and researchers can be confident about these methodological approaches and the cohort study, from which useful clinical tools should result, is feasible.

LEVEL OF EVIDENCE

IV.

Identifying mechanisms that link pain to smoking relapse during a quit attempt

OBJECTIVE

Emerging evidence suggests that adults with chronic pain have poor smoking cessation outcomes, but the exact mechanisms are less understood. This study examined whether depression, anxiety, stress, and then, positive outcome expectancy for smoking mediated the association between pain and smoking relapse during a quit attempt.

METHODS

This study is a secondary data analysis of a three-armed randomized clinical trial that compared in-person and smartphone-based smoking cessation interventions. Participants (N = 81) self-reported the amount of bodily pain they experienced in the past 4 weeks at baseline. Depression, anxiety, stress, and positive outcome expectancy for smoking were measured daily, via a smartphone app, throughout the first week of the quit attempt, and were aggregated to the week level for analyses. Biochemically verified smoking abstinence was assessed 4 weeks postquit date.

RESULTS

Sequential mediation analyses showed that pain was indirectly associated with smoking relapse through greater feelings of stress and then higher expectations that smoking would improve mood (B = 0.22 [95% CI = 0.03, 0.65]). The pathways for depression and anxiety were not significant mediators of pain and smoking relapse.

CONCLUSION

Findings from this study indicate that pain is indirectly associated with smoking relapse through feelings of stress and then positive outcome expectancy for smoking. Smoking cessation treatment for adults who experience high levels of bodily pain should include psychoeducation that teaches adaptive coping responses, such as mindfulness, to manage stress, and challenge expectations about the ability of smoking to improve mood. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Pain anxiety and rehabilitation outcomes after acquired brain injury

Purpose: The purpose of this study was to examine pain anxiety after acquired brain injury (ABI) and its relationship to rehabilitation outcomes.Materials and Method: Participants consisted of 89 adults with an ABI participating in outpatient rehabilitation therapy. They completed a battery of neuropsychological tests at baseline along with surveys of mood, health-related self-efficacy, and pain anxiety. Separately, occupational therapists assessed basic and instrumental activities of daily living (ADLs) as well as therapy engagement across treatment after the sixth session.Results: Individuals who reported high pain anxiety had fewer years of formal education, lower self-efficacy, and more emotional distress than those with low pain anxiety. Although Blacks were about half (56%) of the study sample, they comprised the majority (73.1%) of individuals in the high pain anxiety group. Pain anxiety was negatively related to therapy engagement. Moderation analysis using linear regression indicated that pain anxiety moderated the influence of self-efficacy on basic ADLs.Conclusions: Pain anxiety, particularly when high, is negatively associated with rehabilitation outcomes for individuals with ABI. Among those with high pain anxiety, health-related self-efficacy is an important resilience characteristic to improve functional outcomes. In rehabilitation therapy, pain anxiety provides a novel intervention target to enhance ABI recovery.

Behavioral, Physiological and EEG Activities Associated with Conditioned Fear as Sensors for Fear and Anxiety

Anxiety disorders impose substantial costs upon public health and productivity in the USA and worldwide. At present, these conditions are quantified by self-report questionnaires that only apply to behaviors that are accessible to consciousness, or by the timing of responses to fear- and anxiety-related words that are indirect since they do not produce fear, e.g., Dot Probe Test and emotional Stroop. We now review the conditioned responses (CRs) to fear produced by a neutral stimulus (conditioned stimulus CS+) when it cues a painful laser unconditioned stimulus (US). These CRs include autonomic (Skin Conductance Response) and ratings of the CS+ unpleasantness, ability to command attention, and the recognition of the association of CS+ with US (expectancy). These CRs are directly related to fear, and some measure behaviors that are minimally accessible to consciousness e.g., economic scales. Fear-related CRs include non-phase-locked phase changes in oscillatory EEG power defined by frequency and time post-stimulus over baseline, and changes in phase-locked visual and laser evoked responses both of which include late potentials reflecting attention or expectancy, like the P300, or contingent negative variation. Increases (ERS) and decreases (ERD) in oscillatory power post-stimulus may be generalizable given their consistency across healthy subjects. ERS and ERD are related to the ratings above as well as to anxious personalities and clinical anxiety and can resolve activity over short time intervals like those for some moods and emotions. These results could be incorporated into an objective instrumented test that measures EEG and CRs of autonomic activity and psychological ratings related to conditioned fear, some of which are subliminal. As in the case of instrumented tests of vigilance, these results could be useful for the direct, objective measurement of multiple aspects of the risk, diagnosis, and monitoring of therapies for anxiety disorders and anxious personalities.

Breaking the cycle of smoking and pain: do pain-related anxiety and pain reduction expectancies sabotage attempts to quit smoking and can smoking cessation improve pain and pain-related disability outcomes?

Contemporary models of smoking and pain suggest a reciprocal and self-perpetuating cycle, wherein smoking reduces pain in the short term but indirectly exacerbates pain in the long term. In a sample of participants engaged in an active smoking-cessation attempt, this investigation assessed a) whether specific smoking risk factors (i.e., smoking expectancies for pain reduction, pain-related anxiety) acted as barriers to cessation, and b) whether breaking the smoking-pain cycle through successful smoking abstinence impacted pain and pain-related disability outcomes for participants with pain. Participants comprised 168 smokers (44.4% with pain) who engaged in an online smoking-cessation program. Pain-related anxiety, but not smoking expectancies, accounted for a significant proportion of variance of smoking dependence from pre- to post-intervention. Results suggest that pain-related anxiety is a risk factor for maintained smoking dependence for all smokers regardless of pain status. Participants with pain who successfully quit smoking experienced statistically and clinically meaningful decreases in pain and pain-related disability from pre- to post-intervention. Exploratory post hoc analyses indicated that individuals who signed-up for the smoking cessation program but failed to begin a quit-attempt had significantly higher pain disability, depression, and anxiety scores than participants who commenced a quit-attempt. Theoretical and practical implications are discussed.

Test-Retest and Inter-Examiner Reliability of a Novel Bedside Quantitative Sensory Testing Battery in Postherpetic Neuralgia Patients

In health and disease, the somatosensory system has been interrogated with standardized research techniques, collectively referred to as quantitative sensory testing (QST). In neuropathic pain, QST has been used to characterize multiple sensory derangements. However, the use of QST outside the lab has been limited by several factors, including a lack of standardization, variability in procedural technique, and duration of testing that would be unacceptable for clinic. To address these shortcomings, the Neuropathic Pain Research Consortium designed an easy and low-cost "bedside" QST procedure. To test the hypothesis that this procedure would be clinically reliable over time and across different examiners, a multisite, blinded study was performed in subjects with postherpetic neuralgia. Generally, agreement between 2 examiners and over 2 study visits with 1 examiner was high. Additionally, intraclass correlation coefficients and Kappa statistics calculated showed that the battery of QST tests included were highly reliable. Interestingly, mechanical modalities (light brush, pinprick, pressure, and vibration) showed the highest reliability. The least reliable modalities were cool (room temperature) and warmth (38°C). These data demonstrate that the Neuropathic Pain Research Consortium beside QST protocol is reliable across examiner and over time, providing a validated QST tool for use in clinical practice and clinical trials. PERSPECTIVE: This blinded, multicenter trial in 32 patients with postherpetic neuralgia demonstrates bedside QST is reliable and suitable as a clinical trial outcome. The novel bedside battery could be used in clinical trials or in clinical practice over time given the reliability data presented in this article.

The Fear of Pain Questionnaire: psychometric properties of a Brazilian version for adolescents and its relationship with brain-derived neurotrophic factor (BDNF)

Objectives

The primary aim was to assess the psychometric properties (including internal consistency, construct validity, criterion validity, criterion-group validity and responsiveness) of the Fear of Pain Questionnaire (FOPQ) for adolescents (FOPQ-A) and parents (FOPQ-P) translated to Brazilian Portuguese (BrP). The secondary aim was to analyze the factor structures and their ability to identify subjects with chronic pain conditions and identify the relationship of the BrP FOPQ-A with saliva brain-derived neurotrophic-factor (BDNF).

Methods

A cross-sectional study was conducted with 286 adolescents aged 11 to 18 (257 healthy adolescents [157 females] and 29 adolescents with chronic pain [16 females]). Parents and adolescents completed the BrP-FOPQ. A team of experts translated the FOPQ according to international guidelines. Convergent validity and factor analysis were performed. Later, a subsample (n=146) was used to correlate the BrP-FOPQ-A with saliva BDNF.

Results

The BrP-FOPQ for adolescents and parents presented strong psychometric properties (Cronbach’s α equal to 0.92 and 0.91, respectively). BrP-FOPQ-A confirmatory factor analysis yielded a two-factor structure while the factorial analyses of BrP-FOPQ-P demonstrated that the best solution was a three-structure factorial. The BrP-FOPQ-P scores in healthy adolescents and those in chronic pain conditions was 34.13 (16.71) vs 43.14 (18.08), respectively. A generalized mixed model demonstrated that the scores in the BrP-FOPQ-A are higher in those with chronic pain conditions compared to healthy subjects (29.20 [12.77] vs 33.80 [10.76], respectively; Wald χ²= 17.80; df=1, P<0.0001). The model revealed that the BDNF was positively correlated with the score of BrP-FOPQ-A and subjects with chronic pain showed higher levels of BDNF.

Conclusion

The BrP-FOPQ scores for adolescents and parents were found to be psychometrically robust and reliable instruments, with primary evidence of validity. Higher scores on the BrP-FOPQ-A were correlated positively with saliva BDNF and permitted the identification of subjects with chronic pain conditions.

Pain-Related Fear-Dissociable Neural Sources of Different Fear Constructs

Fear of pain demonstrates significant prognostic value regarding the development of persistent musculoskeletal pain and disability. Its assessment often relies on self-report measures of pain-related fear by a variety of questionnaires. However, based either on “fear of movement/(re)injury/kinesiophobia,” “fear avoidance beliefs,” or “pain anxiety,” pain-related fear constructs plausibly differ while it is unclear how specific the questionnaires are in assessing these different constructs. Furthermore, the relationship of pain-related fear to other anxiety measures such as state or trait anxiety remains ambiguous. Advances in neuroimaging such as machine learning on brain activity patterns recorded by functional magnetic resonance imaging might help to dissect commonalities or differences across pain-related fear constructs. We applied a pattern regression approach in 20 human patients with nonspecific chronic low back pain to reveal predictive relationships between fear-related neural pattern information and different pain-related fear questionnaires. More specifically, the applied multiple kernel learning approach allowed the generation of models to predict the questionnaire scores based on a hierarchical ranking of fear-related neural patterns induced by viewing videos of activities potentially harmful for the back. We sought to find evidence for or against overlapping pain-related fear constructs by comparing the questionnaire prediction models according to their predictive abilities and associated neural contributors. By demonstrating evidence of nonoverlapping neural predictors within fear-processing regions, the results underpin the diversity of pain-related fear constructs. This neuroscientific approach might ultimately help to further understand and dissect psychological pain-related fear constructs.

The Fear-Avoidance Components Scale (FACS): Responsiveness to Functional Restoration Treatment in a Chronic Musculoskeletal Pain Disorder (CMPD) Population

OBJECTIVES

To assess the clinical validity and factor structure of the Fear-Avoidance Components Scale (FACS), a new fear-avoidance measure.

MATERIALS AND METHODS

In this study, 426 chronic musculoskeletal pain disorder patients were admitted to a Functional Restoration Program (FRP). They were categorized into 5 FACS severity levels, from subclinical to extreme, at admission, and again at discharge. Associations with objective lifting performance and other patient-reported psychosocial measures were determined at admission and discharge, and objective work outcomes for this predominantly disabled cohort, were assessed 1 year later.

RESULTS

Those patients in the severe and extreme FACS severity groups at admission were more likely to "drop out" of treatment than those in the lower severity groups (P=0.05). At both admission and discharge, the FACS severity groups were highly and inversely correlated with objective lifting performance and patient-reported fear-avoidance-related psychosocial variables, including kinesiophobia, pain intensity, depressive symptoms, perceived disability, perceived injustice, and insomnia (Ps<0.001). All variables showed improvement at FRP discharge. Patients in the extreme FACS severity group at discharge were less likely to return to, or retain, work 1 year later (P≤0.02). A factor analysis identified a 2-factor solution.

DISCUSSION

Strong associations were found among FACS scores and other patient-reported psychosocial and objective lifting performance variables at both admission and discharge. High discharge-FACS scores were associated with worse work outcomes 1 year after discharge. The FACS seems to be a valid and clinically useful measure for predicting attendance, physical performance, distress, and relevant work outcomes in FRP treatment of chronic musculoskeletal pain disorder patients.

Machine-learning-derived classifier predicts absence of persistent pain after breast cancer surgery with high accuracy

Background

Prevention of persistent pain following breast cancer surgery, via early identification of patients at high risk, is a clinical need. Supervised machine-learning was used to identify parameters that predict persistence of significant pain.

Methods

Over 500 demographic, clinical and psychological parameters were acquired up to 6 months after surgery from 1,000 women (aged 28–75 years) who were treated for breast cancer. Pain was assessed using an 11-point numerical rating scale before surgery and at months 1, 6, 12, 24, and 36. The ratings at months 12, 24, and 36 were used to allocate patents to either “persisting pain” or “non-persisting pain” groups. Unsupervised machine learning was applied to map the parameters to these diagnoses.

Results

A symbolic rule-based classifier tool was created that comprised 21 single or aggregated parameters, including demographic features, psychological and pain-related parameters, forming a questionnaire with “yes/no” items (decision rules). If at least 10 of the 21 rules applied, persisting pain was predicted at a cross-validated accuracy of 86% and a negative predictive value of approximately 95%.

Conclusions

The present machine-learned analysis showed that, even with a large set of parameters acquired from a large cohort, early identification of these patients is only partly successful. This indicates that more parameters are needed for accurate prediction of persisting pain. However, with the current parameters it is possible, with a certainty of almost 95%, to exclude the possibility of persistent pain developing in a woman being treated for breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s10549-018-4841-8) contains supplementary material, which is available to authorized users.

Fear of Pain Questionnaire-9: Brief assessment of pain-related fear and anxiety

BACKGROUND

Fear and anxiety are important considerations in both acute and chronic pain. Effectively and efficiently measuring fear and anxiety associated with pain in healthcare settings is critical for identifying vulnerable patients. The length and administration time of current measures of pain-related fear and anxiety inhibit their routine use, as screening tools and otherwise, suggesting the need for a shorter, more efficient instrument.

METHODS

A 9-item shortened version of the Fear of Pain Questionnaire - III (FPQ-III), the Fear of Pain Questionnaire-9 (FPQ-9), was developed based upon statistical analyses of archival data from 275 outpatients with chronic pain and 275 undergraduates. Additionally, new data were collected from 100 outpatients with chronic pain and 190 undergraduates to directly compare the standard and short forms. Exploratory and confirmatory factor analyses, and other psychometric analyses, were conducted to examine and establish the FPQ-9 as a reliable and valid instrument.

RESULTS

The original three-factor structure of the FPQ-III was retained in the shortened version; a confirmatory factor analysis produced good model fit (RMSEA = 0.00, CFI = 1.00, TLI = 1.00, SRMR = 0.03). Results suggested a high degree of correlation between the original FPQ-III and the new FPQ-9 (r = 0.77, p < 0.001). Measures of internal consistency for FPQ-9 subscales were high; correlations with other pain and anxiety instruments suggested concurrent, convergent and divergent validity.

CONCLUSIONS

The FPQ-9 is a psychometrically sound alternative to longer instruments assessing fear and anxiety associated with pain, for use in both clinical and research situations that only allow brief screening.

SIGNIFICANCE

The FPQ-9 has considerable potential for dissemination and utility for routine, brief screening, given its length (completion time ~2 min; scoring time ~1 min), reading level and psychometric properties.

The effects of slow-paced versus mechanically assisted breathing on autonomic function in fibromyalgia patients

Paced breathing has shown efficacy in fibromyalgia (FM), but the mechanisms associated with symptom change are largely unknown. We investigated whether changes in respiratory rate (RR) alone resulted in autonomic changes during normal, paced, and mechanically assisted breathing in untrained FM patients and controls. Participants included 20 FM patients and 14 controls matched for age and body mass index. During a single visit, participants completed three 15-minute breathing sessions: 1) normal breathing, 2) slow-paced breathing, and 3) mechanically assisted breathing (continuous positive airway pressure) while supine. Continuous blood pressure and electrocardiogram were recorded, and measures of heart rate variability (HRV) and spontaneous baroreceptor sensitivity (sBRS) were calculated. During normal breathing, FM patients had higher heart rate (HR), but lower HRV and sBRS variables compared to controls with no difference in RR. Compared to the paced breathing condition, FM patients had significantly lower HR with higher HRV and sBRS variables during mechanically assisted breathing, despite no significant change in RR. Mechanically assisted breathing provided greater benefits in autonomic function than paced breathing in untrained FM patients. Future research will be needed to elucidate the central pathways involved in these autonomic changes and whether training in paced breathing can eventually replicate the results seen in mechanically assisted patients.

A Preliminary Genome-Wide Association Study of Pain-Related Fear: Implications for Orofacial Pain

Background

Acute and chronic orofacial pain can significantly impact overall health and functioning. Associations between fear of pain and the experience of orofacial pain are well-documented, and environmental, behavioral, and cognitive components of fear of pain have been elucidated. Little is known, however, regarding the specific genes contributing to fear of pain.

Methods

A genome-wide association study (GWAS; N = 990) was performed to identify plausible genes that may predispose individuals to various levels of fear of pain. The total score and three subscales (fear of minor, severe, and medical/dental pain) of the Fear of Pain Questionnaire-9 (FPQ-9) were modeled in a variance components modeling framework to test for genetic association with 8.5 M genetic variants across the genome, while adjusting for sex, age, education, and income.

Results

Three genetic loci were significantly associated with fear of minor pain (8q24.13, 8p21.2, and 6q26; p < 5 × 10⁻⁸ for all) near the genes TMEM65, NEFM, NEFL, AGPAT4, and PARK2. Other suggestive loci were found for the fear of pain total score and each of the FPQ-9 subscales.

Conclusions

Multiple genes were identified as possible candidates contributing to fear of pain. The findings may have implications for understanding and treating chronic orofacial pain.

Cognitive Impairment in Patients with Chronic Neuropathic or Radicular Pain: An Interaction of Pain and Age

A growing body of empirical research has confirmed an association between chronic pain and cognitive dysfunction. The aim of the present study was to determine whether cognitive function is affected in patients with a diagnosis of chronic neuropathic or radicular pain relative to healthy control participants matched by age, gender, and years of education. We also examined the interaction of pain with age in terms of cognitive performance. Some limitations of previous clinical research investigating the effects of chronic pain on cognitive function include differences in the pain and cognitive scale materials used, and the heterogeneity of patient participants, both in terms of their demographics and pathological conditions. To address these potential confounds, we have used a relatively homogenous patient group and included both experimental and statistical controls. We have also specifically investigated the interaction effect of pain and age on cognitive performance. Patients (n = 38) and controls (n = 38) were administered a battery of cognitive tests measuring IQ, spatial and verbal memory, attention, and executive function. Educational level, depressive symptoms, and state anxiety were assessed as were medication usage, caffeine, and nicotine consumption to control for possible confounding effects. Both the level of depressive symptoms and the state anxiety score were higher in chronic pain patients than in matched control participants. Chronic pain patients had a lower estimated IQ than controls, and showed impairments on measures of spatial and verbal memory. Attentional responding was altered in the patient group, possibly indicative of impaired inhibitory control. There were significant interactions between chronic pain condition and age on a number of cognitive outcome variables, such that older patients with chronic pain were more impaired than both age-matched controls and younger patients with chronic pain. Chronic pain did not appear to predict performance on the Wisconsin Card Sorting Task, which was used a measure of executive function. This study supports and extends previous research indicating that chronic pain is associated with impaired memory and attention.

Perspective: Compared to healthy control participants, patients with chronic neuropathic or radicular pain showed cognitive deficits which were most pronounced in older pain patients.

Fear of Pain Mediates the Association between MC1R Genotype and Dental Fear

Fear of pain is experienced in acute and chronic pain populations, as well as in the general population, and it affects numerous aspects of the orofacial pain experience, including pain intensity, pain-related disability, and pain behavior (e.g., avoidance). A related but separate construct-dental fear-is also experienced in the general population, and it influences dental treatment-seeking behavior and oral and systemic health. Minimal work has addressed the role of genetics in the etiologies of fear of pain and dental fear. Limited available data suggest that variants of the melanocortin 1 receptor (MC1R) gene may predict greater levels of dental fear. The MC1R gene also may be etiologically important for fear of pain. This study aimed to replicate the finding that MC1R variant status predicts dental fear and to determine, for the first time, whether MC1R variant status predicts fear of pain. Participants were 817 Caucasian participants (62.5% female; mean ± SD age: 34.7 ± 8.7 y) taking part in a cross-sectional project that identified determinants of oral diseases at the community, family, and individual levels. Participants were genotyped for single-nucleotide polymorphisms on MC1R and completed self-report measures of fear of pain and dental fear. Presence of MC1R variant alleles predicted higher levels of dental fear and fear of pain. Importantly, fear of pain mediated the relation between MC1R variant status and dental fear (B = 1.60, 95% confidence interval: 0.281 to 3.056). MC1R variants may influence orofacial pain perception and, in turn, predispose individuals to develop fears about pain. Such fears influence the pain experience and associated pain behaviors, as well as fears about dental treatment. This study provides support for genetic contributions to the development/maintenance of fear of pain and dental fear, and it offers directions for future research to identify potential targets for intervention in the treatment of fear of pain and dental fear.

Effect of investigator observation on gait parameters in individuals with and without chronic low back pain

Despite the ubiquity of gait assessment in clinic and research, it is unclear how observation impacts gait, particularly in persons with chronic pain and psychological stress. We compared temporal spatial gait patterns in people with and without chronic low back pain (CLBP) when they were aware and unaware of being observed. This was a repeated-measures, deception study in 55 healthy persons (32.0±12.4 yr, 24.2±2.7kg/m²) and persons with CLBP (51.9±17.9 yr, 27.8±4.4kg/m²). Participants performed one condition in which they were unaware of observation (UNW), and three conditions under investigator observation: (1) aware of observation (AWA), (2) investigators watching cadence, (3) investigators watching step length. Participants walked across an 8.4m gait mat, while temporal spatial parameters of gait were collected. The Medical Outcomes Short Form (SF-12), Beck Depression Inventory (BDI), State Trait Anxiety Inventory (STAI), and Oswestry Disability Index (ODI) were completed. Significant condition by group interactions were found for velocity and step length (p<0.05). Main effects of study condition existed for all gait variables except for step width. Main effects of group (healthy, LBP) were significant for all variables except for step width (p<0.05). Regression analyses revealed that after accounting for age, sex, and SF-12 mental component score, BDI scores predict velocity changes during walking from the UNW to AWA conditions. These findings show that people change their gait patterns when being observed. Gait analyses may require additional trials before data can reliably be interpreted and used for clinical decision-making.

Psychometric Properties of an Arabic Pain Anxiety Symptoms Scale-20 (PASS-20) in Healthy Volunteers and Patients Attending a Physiotherapy Clinic

PURPOSE

The aim of this study was to cross-culturally adapt the PASS-20 questionnaire for use in Libya.

METHODS

Participants were 71 patients (42 women) attending the physiotherapy clinic, Ibn Sina Hospital, Sirt, Libya for management of persistent pain and 137 healthy unpaid undergraduate students (52 women) from the University of Sirt, Libya. The English PASS-20 was translated into Arabic. Patients completed the Arabic PASS-20 and the Arabic Pain Rating Scales on two occasions separated by a 14-day interval. Healthy participants completed the Arabic PASS-20 on one occasion.

RESULTS

The internal consistency (ICC) for pain patient and healthy participant samples yielded a good reliability for the total score, cognitive anxiety, fear of pain, and physiological anxiety. The test-retest reliability of the Arabic PASS-20 score showed high reliability for the total score (ICC = 0.93, p < 0.001), escape/avoidance (ICC = 0.93, p < 0.001), fear of pain (ICC = 0.94, p < 0.001), and physiological anxiety subscales (ICC = 0.96, p < 0.001) and good reliability for the cognitive anxiety (ICC = 0.85, p < 0.001). Inspection of the Promax rotation showed that each factor comprised of five items were consistent with the theoretical constructs of the original PASS-20 subscales.

CONCLUSION

The Arabic PASS-20 retained internal consistency and reliability with the original English version and can be used to measure pain anxiety symptoms in both pain and healthy individual samples in Libya.

Telehealth Versus In-Person Acceptance and Commitment Therapy for Chronic Pain: A Randomized Noninferiority Trial

The purpose of this randomized noninferiority trial was to compare video teleconferencing (VTC) versus in-person (IP) delivery of an 8-week acceptance and commitment therapy (ACT) intervention among veterans with chronic pain (N = 128) at post-treatment and at 6-month follow-up. The primary outcome was the pain interference subscale of the Brief Pain Inventory. Secondary outcomes included measures of pain severity, mental and physical health-related quality of life, pain acceptance, activity level, depression, pain-related anxiety, and sleep quality. In intent to treat analyses using mixed linear effects modeling, both groups exhibited significant improvements on primary and secondary outcomes, with the exception of sleep quality. Further, improvements in activity level at 6-month follow-up were significantly greater in the IP group. The noninferiority hypothesis was supported for the primary outcome and several secondary outcomes. Treatment satisfaction was similar between groups; however, significantly more participants withdrew during treatment in the VTC group compared with the IP group, which was moderated by activity level at baseline. These findings generally suggest that ACT delivered via VTC can be as effective and acceptable as IP delivery for chronic pain. Future studies should examine the optimal delivery of ACT for patients with chronic pain who report low levels of activity. This trial was registered at ClinicalTrials.gov (NCT01055639).

PERSPECTIVE

This study suggests that ACT for chronic pain can be implemented via VTC with reductions in pain interference comparable with IP delivery. This article contains potentially important information for clinicians using telehealth technology to deliver psychosocial interventions to individuals with chronic pain.

A meta-analysis of fear-avoidance and pain intensity: The paradox of chronic pain

Background

The fear-avoidance model of chronic pain has established avoidance as a predictor of negative outcomes in chronic pain patients. Avoidance, or deliberate attempts to suppress or prevent unwanted experiences (e.g., pain), has been studied extensively, with multiple reviews implicating this behavior as a predictor of disability, physical disuse, and depression. Despite hundreds of studies examining the associations between different components of this model (i.e., catastrophizing, fear, avoidance, depression), the association between fear-avoidance and pain intensity has remained unclear. The present study seeks to clarify this association across samples.

Method

The present analyses synthesize the literature (articles from PsycInfo, PubMed, and ProQuest) to determine if fear-avoidance and pain intensity are consistently correlated across studies, samples, and measures. Eligible studies measured pain intensity and fear-avoidance cross-sectionally in chronic pain patients. The search resulted in 118 studies eligible for inclusion. A random-effects model was used to estimate the weighted mean effect size. Comprehensive Meta-Analysis software was used for all analyses. Moderation analyses elucidate the variables that affect the strength of this association. Meta-regression and meta-ANOVA analyses were conducted to examine moderating variables. Moderator variables include demographic characteristics, pain characteristics, study characteristics, and national cultural characteristics (using Hofstede’s cultural dimensions). Publication bias was examined using the funnel plot and the p-curve.

Results

Results indicate a small-to-moderate positive association between fear-avoidance and pain intensity. The results were stable across characteristics of the sample, including mean age, gender distribution, marital status, and duration of pain. Moderation analyses indicate that the measures utilized and cultural differences affect the strength of this association. Weaker effect sizes were observed for studies that utilized measures of experiential avoidance when compared to studies that utilized pain-specific fear-avoidance measures. Studies that utilized multiple measures of fear-avoidance had stronger effect sizes than studies that utilized a single measure of fear-avoidance. Three of Hofstede’s cultural dimensions moderated the association, including Power Distance Index, Individualism versus Collectivism, and Indulgence versus Restraint.

Conclusions

The present meta-analysis synthesizes the results from studies examining the association between fear-avoidance and pain intensity among individuals with chronic pain. The positive association indicates that those with increased fear-avoidance have higher pain intensity, and those with higher pain intensity have increased fear-avoidance. Findings indicate that cultural differences and measurement instruments are important to consider in understanding the variables that affect this association. The significant cultural variations may indicate that it is important to consider the function of avoidance behavior in different cultures in an effort to better understand each patient’s cultural beliefs, as well as how these beliefs are related to pain and associated coping strategies.

Implications

The results from the current meta-analysis can be used to inform interventions for patients with chronic pain. In particular, those with more intense pain or increased fear-avoidance should be targeted for prevention and intervention work. Within the intervention itself, avoidance should be undermined and established as an ineffective strategy to manage pain in an effort to prevent disability, depression, and physical deconditioning.

Resting blood pressure differentially predicts time course in a tonic pain experiment

Resting blood pressure (BP) shows a negative relationship with pain sensitivity (BP-related hypoalgesia). In chronic pain conditions, this relationship is inverted. The precise mechanisms responsible for the inversion are unknown. Using a tonic pain protocol, we report findings closely resembling this inversion in healthy participants. Resting BP and state measures of anxiety and mood were assessed from 33 participants (21 female). Participants then immersed their dominant hand in painfully hot water (47 °C) for five trials of 1-min duration, with 30-s intertrial intervals. Throughout the trials, participants continually registered their pain. After a 35-min intermission, the trial sequence was repeated. A disassociation of the negative relationship of resting systolic BP (as per Trial 1) was found using hierarchical linear modeling (p < .001, R(2)  = .07). The disassociation unfolds over each consecutive trial, with an increasingly positive relationship. In Sequence 2, the initially negative relationship is almost completely absent. Furthermore, the association of BP and pain was found to be moderated by anxiety, such that only persons with low anxiety exhibited BP hypoalgesia. Our findings expand the existing literature by incorporating anxiety as a moderator of BP hypoalgesia. Furthermore, the protocol emulates the changing relationship between BP and pain observed in chronic pain patients. The protocol has potential as a model for chronic pain; however, future research should determine if similar physiological systems are involved. The finding holds potential diagnostic or prognostic relevance for certain clinical pain conditions, especially those involving dysfunction of the descending modulation of pain.

The Development of a Technology-Based Hierarchy to Assess Chronic Low Back Pain and Pain-Related Anxiety From a Fear-Avoidance Model

Previous studies have not examined the assessment of chronic low back pain (CLBP) and pain-related anxiety from a fear avoidance model through the use of motion-capture software and virtual human technologies. The aim of this study was to develop and assess the psychometric properties of an interactive, technologically based hierarchy that can be used to assess patients with pain and pain-related anxiety. We enrolled 30 licensed physical therapists and 30 participants with CLBP. Participants rated 21 video clips of a 3-D animated character (avatar) engaging in activities that are typically feared by patients with CLBP. The results of the study indicate that physical therapists found the virtual hierarchy clips acceptable and depicted realistic patient experiences. Most participants with CLBP reported at least 1 video clip as being sufficiently anxiety-provoking for use clinically. Therefore, this study suggests a hierarchy of fears can be created out of 21 virtual patient video clips paving the way for future clinical use in patients with CLBP.

PERSPECTIVE

This report describes the development of a computer-based virtual patient system for the assessment of back pain-related fear and anxiety. Results show that people with back pain as well as physical therapists found the avatar to be realistic, and the depictions of behavior anxiety- and fear-provoking.

Psychosocial Adjustment of People with Chronic Pain: A Conceptual Framework of Risk and Resistance Factors

The purposes of this review article are to gather existing evidence on the contributing factors in affecting the psychosocial adjustment among people with chronic pain, and to promote a comprehensive conceptual framework in this topic by adapting Wallander and colleagues' (1989) Risk and Resistance Model of Adjustment. Our intention is to promote future empirical research that will validate this working conceptual framework and will provide and clinical guidelines for rehabilitation professionals who work with people with chronic pain.

The German PASS-20 in patients with low back pain: new aspects of convergent, divergent, and criterion-related validity

BACKGROUND

The PASS-20 (McCracken and Dhingra, Pain Res Manag 7:45-50, 2002) is a shortened version of the Pain Anxiety Symptoms Scale (PASS), a self-report measure of pain anxiety. The PASS-20 demonstrates good psychometric characteristics but has not yet been validated in a German population.

PURPOSE

The aims of the present study were to (1) examine the factor structure and psychometric characteristics of the German PASS-20; (2) investigate its construct validity with respect to depression, fear-avoidance, and endurance; and (3) determine its criterion-related validity with a special emphasis on pain, disability, and quality of life.

METHOD

A principal component analysis was performed on a sample (N = 195) of patients with acute, subacute, and chronic low back pain. Reliability was examined with Cronbach's α. Validity was assessed by correlating the PASS-20 to measures of depression, anxiety, disability, quality of life, and avoidance-endurance-related behavioral pain responses.

RESULTS

The original four-factor structure proposed for the PASS-20 was replicated using the original subscale labels. The reliability of the total score and the subscales was satisfactory to excellent, and both convergent and divergent validity were moderate to high in the expected directions, showing positive correlations with anxiety, fear, depression, and fear-avoidance and negative correlations with endurance and quality of life. The PASS-20 showed unique predictive ability and advantages over the Tampa Scale of Kinesiophobia.

CONCLUSIONS

The results for the German PASS-20 support the original factor structure and provide evidence of satisfactory psychometric characteristics and usefulness in patients with low back pain.

The Fear-avoidance Components Scale (FACS): Development and Psychometric Evaluation of a New Measure of Pain-related Fear Avoidance

Pain-related fear avoidance (FA), a common problem for patients with painful medical conditions, involves pain-related catastrophizing cognitions, hypervigilance, and avoidance behaviors, which can ultimately lead to decreased functioning, depression, and disability. Several patient-reported instruments have been developed to measure FA, but they have been criticized for limited construct validity, inadequate item specificity, lack of cutoff scores, and missing important FA components. The Fear-Avoidance Components Scale (FACS) is a new patient-reported measure designed to comprehensively evaluate FA in patients with painful medical conditions. It combines important components of FA found in prior FA scales, while trying to correct some of their deficiencies, within a framework of the most current FA model. Psychometric evaluation of the FACS found high internal consistency (α = 0.92) and high test/retest reliability (r = 0.90-0.94, P < 0.01). FACS scores differentiated between 2 separate chronic pain patient samples and a nonpatient comparison group. When clinically relevant severity levels were created, FACS severity scores were highly associated with FA-related patient-reported psychosocial and objective lifting performance variables. These results suggest that the FACS is a psychometrically strong and reliable measure that can help healthcare providers assess FA-related barriers to function and recovery.

The effect of changing movement and posture using motion-sensor biofeedback, versus guidelines-based care, on the clinical outcomes of people with sub-acute or chronic low back pain-a multicentre, cluster-randomised, placebo-controlled, pilot trial

Background

The aims of this pilot trial were to (i) test the hypothesis that modifying patterns of painful lumbo-pelvic movement using motion-sensor biofeedback in people with low back pain would lead to reduced pain and activity limitation compared with guidelines-based care, and (ii) facilitate sample size calculations for a fully powered trial.

Methods

A multicentre (8 clinics), cluster-randomised, placebo-controlled pilot trial compared two groups of patients seeking medical or physiotherapy primary care for sub-acute and chronic back pain. It was powered for longitudinal analysis, but not for adjusted single-time point comparisons. The intervention group (n = 58) received modification of movement patterns augmented by motion-sensor movement biofeedback (ViMove, dorsaVi.com) plus guidelines-based medical or physiotherapy care. The control group (n = 54) received a placebo (wearing the motion-sensors without biofeedback) plus guidelines-based medical or physiotherapy care.

Primary outcomes were self-reported pain intensity (VAS) and activity limitation (Roland Morris Disability Questionnaire (RMDQ), Patient Specific Functional Scale (PSFS)), all on 0–100 scales. Both groups received 6–8 treatment sessions. Outcomes were measured seven times during 10-weeks of treatment and at 12, 26 and 52 week follow-up, with 17.0 % dropout. Patients were not informed of group allocation or the study hypothesis.

Results

Across one-year, there were significant between-group differences favouring the intervention group [generalized linear model coefficient (95 % CI): group effect RMDQ −7.1 (95 % CI–12.6;–1.6), PSFS −10.3 (−16.6; −3.9), QVAS −7.7 (−13.0; −2.4); and group by time effect differences (per 100 days) RMDQ −3.5 (−5.2; −2.2), PSFS −4.7 (−7.0; −2.5), QVAS −4.8 (−6.1; −3.5)], all p < 0.001. Risk ratios between groups of probability of improving by >30 % at 12-months = RMDQ 2.4 (95 % CI 1.5; 4.1), PSFS 2.5 (1.5; 4.0), QVAS 3.3 (1.8; 5.9).

The only device-related side-effects involved transient skin irritation from tape used to mount motion sensors.

Conclusions

Individualised movement retraining using motion-sensor biofeedback resulted in significant and sustained improvements in pain and activity limitation that persisted after treatment finished. This pilot trial also refined the procedures and sample size requirements for a fully powered RCT.

This trial (Australian New Zealand Clinical Trials Registry NCT01572779) was equally funded by dorsaVi P/L and the Victorian State Government.

Words putting pain in motion: the generalization of pain-related fear within an artificial stimulus category

Patients with chronic pain are often fearful of movements that never featured in painful episodes. This study examined whether a neutral movement's conceptual relationship with pain-relevant stimuli could precipitate pain-related fear; a process known as symbolic generalization. As a secondary objective, we also compared experiential and verbal fear learning in the generalization of pain-related fear. We conducted an experimental study with 80 healthy participants who were recruited through an online experimental management system (M age = 23.04 years, SD = 6.80 years). First, two artificial categories were established wherein nonsense words and joystick arm movements were equivalent. Using a between-groups design, nonsense words from one category were paired with either an electrocutaneous stimulus (pain-US) or threatening information, while nonsense words from the other category were paired with no pain-US or safety information. During a final testing phase, participants were prompted to perform specific joystick arm movements that were never followed by a pain-US, although they were informed that it could occur. The results showed that movements equivalent to the pain-relevant nonsense words evoked heightened pain-related fear as measured by pain-US expectancy, fear of pain, and unpleasantness ratings. Also, experience with the pain-US evinced stronger acquisition and generalization compared to experience with threatening information. The clinical importance and theoretical implications of these findings are discussed.

Fear of movement/(Re)injury in low back pain: confirmatory validation of a German version of the Tampa Scale for Kinesiophobia

BACKGROUND

The Tampa Scale for Kinesiophobia (TSK), an instrument for measuring fear of movement/(re)injury, has been confirmed as an important predictor for the persistence of pain-related disability. The aims of this study were to evaluate the psychometric properties of a German version of the TSK (TSK-GV), examining aspects of content validity with special focus on fear-avoidance and endurance, and to confirm criterion-related validity in patients with low back pain (LBP).

METHODS

A total of 191 patients with LBP were included in this study. Several models with different factor structures from published studies were compared in a confirmatory factor analysis. Internal consistencies of the TSK-GV and its subscales were examined, and correlations with related self-report measures were calculated.

RESULTS

The internal consistency of the TSK-GV was α = 0.73. A two-factor model with 11 items was found to be the best fit for our data. The two factors were labelled Somatic Focus (SF) and Activity Avoidance (AA). The total score, SF and AA revealed moderate to high correlations with other fear-avoidance variables.

CONCLUSIONS

The TSK-GV is a reliable and valid measure for assessing the fear of movement/(re)injury.