The Fear-Avoidance Model of Musculoskeletal Pain: Current State of Scientific Evidence

Exposure to movement in chronic back pain: Evidence of successful generalization across a reaching task

According to the fear-avoidance model, kinesiophobia (pain-related fear) is an important factor in the development of chronic pain and disability through the maintenance of maladaptive avoidance behaviors. Using a paradigm that required repeated exposure to a reaching task, the current study investigated generalization of pain and harm expectancy corrections (i.e., the tendency to bring expectations in line with experience) in chronic low back pain sufferers with high versus low levels of kinesiophobia. Sixty participants were asked to consecutively perform four adaptations of a reaching task, each introducing an element of increased intensity. Expected and experienced pain and harm ratings were collected during the two trials comprising each movement. Individuals with high levels of kinesiophobia reported greater pain and harm ratings during the movements. Further, highly kinesiophobic female, but not male, participants demonstrated greater overprediction of harm relative to low kinesiophobic counterparts during the first reaching trial. Finally, in contrast to previous investigations, highly kinesiophobic participants showed successful generalization of pain expectancy corrections across movement tasks. Possible clinical implications of the findings are noted.

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.

Effects of attention on the control of locomotion in individuals with chronic low back pain

Background

People who suffer from low back pain (LBP) exhibit an abnormal gait pattern, characterized by shorter stride length, greater step width, and an impaired thorax-pelvis coordination which may undermine functional walking. As a result, gait in LBP may require stronger cognitive regulation compared to pain free subjects thereby affecting the degree of automaticity of gait control. Conversely, because chronic pain has a strong attentional component, diverting attention away from the pain might facilitate a more efficient walking pattern.

Methods

Twelve individuals with LBP and fourteen controls participated. Subjects walked on a treadmill at comfortable speed, under varying conditions of attentional load: (a) no secondary task, (b) naming the colors of squares on a screen, (c) naming the colors of color words ("color Stroop task"), and (d) naming the colors of words depicting motor activities. Markers were attached to the thorax, pelvis and feet. Motion was recorded using a three-camera SIMI system with a sample frequency of 100 Hz. To examine the effects of health status and attention on gait, mean and variability of stride parameters were calculated. The coordination between thoracic and pelvic rotations was quantified through the mean and variability of the relative phase between those oscillations.

Results

LBP sufferers had a lower walking speed, and consequently a smaller stride length and lower mean thorax-pelvis relative phase. Stride length variability was significantly lower in the LBP group but no significant effect of attention was observed. In both groups gait adaptations were found under performance of an attention demanding task, but significantly more so in individuals with LBP as indicated by an interaction effect on relative phase variability.

Conclusion

Gait in LBP sufferers was characterized by less variable upper body movements. The diminished flexibility in trunk coordination was aggravated under the influence of an attention demanding task. This provides further evidence that individuals with LBP tighten their gait control, and this suggests a stronger cognitive regulation of gait coordination in LBP. These changes in gait coordination reduce the capability to deal with unexpected perturbations, and are therefore maladaptive.

Assessing fear in patients with cervical pain: development and validation of the Pictorial Fear of Activity Scale-Cervical (PFActS-C)

The fear avoidance model (FAM) postulates that fear of pain or reinjury is a risk factor for persistent pain and disability, because it leads to the avoidance of physical activity. Research on the FAM has not yielded consistent results, which may be attributed to the model itself, but could also be a product of the way fear of movement is assessed. Studies of the FAM have measured fear using verbal scales consisting of items that are often vague and have only an indirect relationship with fear. This study reports on the development of a Pictorial Fear of Activity Scale-Cervical (PFActS-C). The instrument consists of a set of photographs depicting movements in which four factors that determine biomechanical demands on the neck are systematically varied--Direction of Movement, Arm Position, Weight Bearing, and Extremity of Movement. Patients (n=355) who had been involved in motor vehicle collisions with minimal symptoms (n=143) and moderate to severe symptoms (n=212) rated their fear of engaging in a set of activities depicted in the PFActS-C. Based on a principle components analysis, a 19 item measure was developed. Internal consistency (alpha=.98), stability over time (n=44, IntraClass Correlation=.72), and construct validity were all good to excellent. The results indicate that the PFActS-C may be a useful tool for assessing fear of movement in patients with cervical pain. Research is needed to confirm the factor structure of the PFActS-C and to assess the generalizability of the results to other samples with neck pain.

Nocebo hyperalgesia: how anxiety is turned into pain

PURPOSE OF REVIEW

Nocebo hyperalgesia is a phenomenon that is opposite to placebo analgesia and whereby expectation of pain increase plays a crucial role. In recent times, both the neuroanatomical and the neurochemical bases of the nocebo effect and of nocebo-related effects have begun to be explored. Here, we highlight recent advances in our understanding of the neurobiology of the nocebo hyperalgesic effect.

RECENT FINDINGS

A typical nocebo hyperalgesic response occurs following the administration of an inert substance which the subject believes to be a hyperalgesic agent (negative placebo or nocebo). It has been shown that the subject's negative expectations of pain worsening induce anticipatory anxiety about the impending pain increase and this triggers the activation of cholecystokinin that, in turn, facilitates pain transmission. Accordingly, cholecystokinin antagonists have been found to prevent this anxiety-induced hyperalgesia. Brain-imaging studies have shown that the perceived intensity of a painful stimulus following negative expectations of pain increase is higher than in the absence of negative expectations and this is associated with changes in activation of specific brain regions.

SUMMARY

Since pain appears to be amplified by anxiety through the activation of cholecystokininergic systems, new therapeutic strategies, such as new cholecystokinin antagonists, can be envisaged whenever pain has an important anxiety component.

Chronic nonmalignant pain: a challenge for patients and clinicians

Chronic pain is widely regarded as a condition that is triggered by various factors, including physical, socio-cultural and psychological deficiencies (that is, maladaptive beliefs). These factors are important in the development and maintenance of this unpleasant experience, which consequently requires a biopsychosocial treatment approach. Pain is a multifaceted sense, the perception of which is personal. Pain also depends on various circumstances, and therefore represents a challenge for the patient, as well for the treating physicians. Patients who suffer from long-lasting pain with a predominantly psychosocial component should be referred to specialized pain clinics for further diagnostic assessment and possible allocation to multidisciplinary pain programs. High-quality randomized controlled trials indicate that multidisciplinary pain programs represent the best therapeutic option for the management of patients with complaints associated with complex chronic pain. The prevalence and the costs--both direct and indirect--that are attributed to chronic pain are increasing; however, not enough is being done to sufficiently and effectively treat chronic pain. There is, therefore, a need for well-designed, interdisciplinary, internationally comparable, and widely distributed pain programs, both in outpatient and inpatient settings, to contribute to the prevention of some future pain diseases.

Predictors of psychological distress and well-being in women with chronic musculoskeletal pain: two sides of the same coin?

OBJECTIVE

To date, few results on well-being in chronic-pain patients have been published, while several studies in patients without pain have indicated that well-being may not be equivalent to absence of psychological distress. The aim of the present study was to investigate the relationship between psychological distress and well-being and to identify the predictors of each in patients with chronic nonmalignant pain.

METHODS

Sixty-nine women with chronic multiregional musculoskeletal pain, 41 of whom met American College of Rheumatology criteria for fibromyalgia, completed questionnaires on pain, fatigue, stiffness, physical disability (Fibromyalgia Impact Questionnaire), psychological distress [Multidimensional Affect and Pain Survey (MAPS), Symptom Check List-90 (SCL-90), State-Trait Anxiety Inventory Form Y2 (STAI-Y2)], and hedonic and eudaimonic well-being (MAPS).

RESULTS

Patients reported increased amounts of psychological distress (STAI-Y2 and SCL-90) compared to healthy people. Multiple regression analysis of patient data demonstrated that higher psychological distress was related to higher age, more intense pain, a higher positive tender point count, and more physical disability. Well-being (both hedonic and eudaimonic aspects) decreased with higher disability, but was independent of age, pain intensity, and number of positive tender points. Bivariate correlations showed that psychological distress was moderately related to eudaimonic well-being and strongly related to positive affect, an aspect of hedonic well-being.

CONCLUSION

In patients with chronic musculoskeletal pain, self-reports of well-being and low psychological distress only partially overlap with each other and are differently related to major patient symptoms, supporting the relevance of the concept of well-being to chronic-pain research and a need for further studies in this field.

Investigation of elevated fear-avoidance beliefs for patients with low back pain: a secondary analysis involving patients enrolled in physical therapy clinical trials

STUDY DESIGN

Secondary analysis.

OBJECTIVE

To investigate the Fear-Avoidance Beliefs Questionnaire (FABQ) for its ability to predict 6-month outcomes for patients with low back pain (LBP) participating in physical therapy clinical trials.

BACKGROUND

Consistent evidence suggests that fear-avoidance beliefs are predictive of short-term outcomes for patients with LBP. However, proposed cut-off scores have not been widely investigated for longer-term outcomes in samples of patients receiving physical therapy.

METHODS AND MEASURES

Subjects (n = 160) were participants in 2 separate randomized trials that used standard methodology and investigated the efficacy of physical therapy interventions for LBP. Subjects completed baseline measures of pain, disability, fear-avoidance beliefs, and physical impairment. They completed 4 weeks of randomly assigned physical therapy and were reassessed at 6 months with standard examination techniques. The accuracy of previously proposed cut-offs for elevated FABQ scores were determined by independent t tests and chi-square analysis on raw 6-month Oswestry Disability Questionnaire (ODQ) scores, 6-month ODQ change scores, and minimally clinical important difference (MCID) in ODQ scores (6 points). Next, a hierarchical regression model determined which FABQ scale better predicted 6-month ODQ scores after controlling for previously reported prognostic factors and relevant treatment parameters. Last, receiver operating characteristic curve analyses were planned to generate a range of FABQ cut-off scores that predicted 6-month MCID in the ODQ.

RESULTS

The previously reported cut-off score for the FABQ physical activity scale (>14) resulted in 111 (69.4%) of 160 patients being classified as having elevated baseline scores, while the previously reported cut-off score for the FABQ work scale (>29) resulted in 19 (11.9%) of 160 patients being classified as having elevated baseline scores. Patients with elevated FABQ physical activity scale scores (>14) had no significant differences in 6-month ODQ outcomes. Patients with elevated FABQ work scale (>29) scores reported higher 6-month ODQ scores and were more likely to have reported no improvement in ODQ score. The final regression model explained 24.4% of the variance in 6-month ODQ scores, with only manipulation and exercise and the FABQ work scale as unique predictors. Fifteen of the subjects (12.7%) had a 6-month change in ODQ that indicated no improvement. The area under the receiver operating characteristic curve for the FABQ physical activity scale predicting this outcome was 0.562 (95% CI: 0.415-0.710) and for the FABQ work scale was 0.694 (95% CI: 0.542-0.846). Cut-off scores were explored for the FABQ work scale only, with positive likelihood ratios that ranged from 1.19 to 5.15 and negative likelihood ratios that ranged from 0.30 to 0.83.

CONCLUSIONS

The FABQ work scale was the better predictor of self-report of disability in this sample of patients participating in physical therapy clinical trials. Future studies are necessary to further test and refine the FABQ work scale as a screening tool alone, and in combination with other examination findings.

Chronic non-specific low back pain - sub-groups or a single mechanism?

BACKGROUND

Low back pain is a substantial health problem and has subsequently attracted a considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions for chronic non-specific low back pain indicate limited effectiveness for most commonly applied interventions and approaches.

DISCUSSION

Many clinicians challenge the results of clinical trials as they feel that this lack of effectiveness is at odds with their clinical experience of managing patients with back pain. A common explanation for this discrepancy is the perceived heterogeneity of patients with chronic non-specific low back pain. It is felt that the effects of treatment may be diluted by the application of a single intervention to a complex, heterogeneous group with diverse treatment needs. This argument presupposes that current treatment is effective when applied to the correct patient. An alternative perspective is that the clinical trials are correct and current treatments have limited efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important that the sub-grouping paradigm is closely examined. This paper argues that there are numerous problems with the sub-grouping approach and that it may not be an important reason for the disappointing results of clinical trials. We propose instead that current treatment may be ineffective because it has been misdirected. Recent evidence that demonstrates changes within the brain in chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of cortical reorganisation and degeneration. This perspective offers interesting insights into the chronic low back pain experience and suggests alternative models of intervention.

SUMMARY

The disappointing results of clinical research are commonly explained by the failure of researchers to adequately attend to sub-grouping of the chronic non-specific low back pain population. Alternatively, current approaches may be ineffective and clinicians and researchers may need to radically rethink the nature of the problem and how it should best be managed.

Translation and validation study of the Iranian versions of the Neck Disability Index and the Neck Pain and Disability Scale

STUDY DESIGN

Cultural translation and psychometric testing.

OBJECTIVE

To translate and validate the Iranian versions of the Neck Disability Index (NDI-IR) and the Neck Pain and Disability Scale (NPDS-IR).

SUMMARY OF BACKGROUND DATA

The widely used the NDI and the NPDS scales have not been translated and validated for Persian-speaking patients with neck pain. This was to provide a validated instrument to measure functional status in patients with neck pain in Iran.

METHODS

The translation and cultural adaptation of the original questionnaires were carried out in accordance with the published guidelines. One hundred and eighty-five patients with neck pain were participated in the study. Patients were asked to complete a questionnaire booklet including the NDI-IR, the NPDS-IR, the Iranian SF-36, and a visual analog scale (VAS) of pain. To carry out the test-retest reliability, 30 randomly selected patients with neck pain were asked to complete the questionnaire booklet 48 hours later for the second time.

RESULTS

Cronbach alpha coefficient for the NDI-IR was 0.88 and for the 4 subscales of the NPDS-IR was found to be satisfactory (ranging from 0.74 to 0.94). The NDI-IR and the NPDS-IR subscales showed excellent test-retest reliability (intraclass correlation coefficient ranged from 0.90 to 0.97; P < 0.01). The correlation between the NDI-IR and the NPDS-IR subscales and functional scales of the SF-36 showed desirable results, indicating a good convergent validity (Pearson correlation coefficients ranged from -0.31 to -0.70). The correlation between the NDI-IR and the VAS was 0.71 and between the NPDS-IR subscales and the VAS ranged from 0.63 to 0.79 (P < 0.01).

CONCLUSION

The Iranian versions of the NDI and NPDS are reliable and valid instruments to measure functional status in Persian-speaking patients with neck pain in Iran. They are simple and easy to use and now can be applied in clinical settings and future outcome studies in Iran and other Persian speaking communities.

Measuring perceived harmfulness of physical activities in patients with chronic low back pain: the Photograph Series of Daily Activities--short electronic version

Cognitive-behavioral models of chronic low back pain (CLBP) predict that dysfunctional assumptions about the harmfulness of activities may maintain pain-related fear and disability levels. The Photograph Series of Daily Activities (PHODA) is an instrument to determine the perceived harmfulness of daily activities in patients with CLBP. This study examined the psychometric properties of a short electronic version of the PHODA (PHODA-SeV). The results show that the PHODA-SeV measures a single factor and has a high internal consistency. The test-retest reliability and stability of the PHODA-SeV over a 2-week time interval are good, with discrepancies between 2 measurements over 20 points suggesting true change. The construct validity is supported by the finding that both self-reported pain severity and fear of movement/(re)injury were uniquely related to the PHODA-SeV. Validity is further corroborated by the finding that patients who have received exposure in vivo, that aimed to systematically reduce the perceived harmfulness of activities, had significantly lower PHODA-SeV scores after treatment than patients receiving graded activity that did not address these assumptions. The findings support the PHODA-SeV as a valid and reliable measure of the perceived harmfulness of activities in patients with CLBP. Preliminary normative data of the PHODA-SeV are presented.

PERSPECTIVE

This article describes a pictorial measurement tool (PHODA-SeV) for the assessment of the perceived harmfulness of activities in patients with chronic low back pain. The PHODA-SeV has good psychometric properties and can be used to elaborate on the contribution of beliefs about harmful consequences of activities to pain and disability.