The cross-cultural adaptation, validity, and reliability of the Spanish version of the Fremantle Back Awareness Questionnaire.

Introduction: In chronic low back pain (CLBP), disturbed body image has been highlighted as a contributor to the condition and a potential target for treatment. The Fremantle Back Awareness Questionnaire (FreBAQ) allows its assessment. Following international guidelines for the cross-cultural translation of questionnaires, we aimed to translate the FreBAQ into Spanish (FreBAQ-S) and validate the new questionnaire in a sample of Spanish-speaking people with CLBP. Methods: Two hundred and sixty-four adults with CLBP (91 males) and 128 healthy controls (34 males) completed an online form including the FreBAQ-S and questionnaires related to the pain experience. All participants were Spanish and no gender identities differing from biological sex were reported. A week later, 113 CLBP participants and 45 healthy controls (41 and 13 males, respectively), re-answered the FreBAQ-S to evaluate test-retest reliability. Confirmatory factor and multigroup analysis assessed the scale consistency on the patient sample. Discriminant and convergent validity were explored by between-group differences and the relationship with clinical characteristics. Reliability relied on Cronbach's alpha estimates and test-retest (intraclass correlation coefficient, standard error of measurement, minimal detectable change). Results and discussion: Confirmatory factor analysis showed a one-factor structure of the questionnaire, without supporting evidence for item deletion (CFI = 0.97; TLI = 0.96; RMSEA = 0.06; SRMR = 0.07; SRMRu = 0.064). Multigroup analyses do not support mean invariance between groups regarding health condition or sex. The FreBAQ-S demonstrated good discriminant and convergent validity, internal consistency (α = 0.82), and test-retest reliability (ICC = 0.78; SE = 3.41; MDC = 5.12). The FreBAQ-S is a valid and reliable tool to assess back awareness in clinical and non-clinical samples.

It's safe to move! A protocol for a randomised controlled trial investigating the effect of a video designed to increase people's confidence becoming more active despite back pain.

INTRODUCTION: Social media provide promising contemporary platforms for sharing public health information with a broad audience. Before implementation, testing social media campaigns that are intended to engage audiences and initiate behaviour change is necessary. This trial aims to investigate the effectiveness of a public health campaign to increase people's confidence in becoming more active despite low back pain in comparison with no intervention. METHODS AND ANALYSIS: This is an online randomised controlled trial with two intervention groups and one control group in a 1:1:1 allocation. People over 18 years of age and fluent in English will be recruited via social media advertising. We developed a social media-based public health campaign to support recommendations for managing low back pain. The interventions are two videos. Participants in the control group will be asked questions about low back pain but will not view either video intervention. The primary outcome will be item 10 of the Pain Self-Efficacy Questionnaire, which asks participants to rate how confident they would feel to gradually become more active despite pain ranging from 0 (not at all confident) to 6 (completely confident). This outcome will be measured immediately in all participant groups. We will compare group mean of the three arms of the trial using univariate analyses of variance. ETHICS AND DISSEMINATION: This trial has been prospectively registered with the Australian New Zealand Clinical Trials Registry. We obtained ethical approval from our institutions Human Research Ethics Committee before data collection. We will publish the results in a peer-reviewed medical journal and on institution websites. TRIAL REGISTRATION NUMBER: Australian New Zealand Clinical Trials Registry (ACTRN12622000466741).

Knee-related disability was largely influenced by cognitive factors and disturbed body perception in knee osteoarthritis.

The aim of this study was to explore the existence of subgroups in a cohort of people with knee osteoarthritis (OA) based upon data from multiple pain-related variables and to profile identified clusters according to levels of pain intensity and knee-related disability. Three hundred and three people with knee OA were recruited. Latent profile analysis was used to confirm the optimal number of knee OA subgroups. Body mass index, radiographic knee OA severity, pain catastrophizing, pain related self-efficacy, and knee specific self-perception, were incorporated into the model. Cluster, demographic and clinical variables were compared between the resulting classes. Four distinct classes were identified. Cluster 1 (28.7%) represented early radiographic OA, and moderate pain intensity, disability and cognitive and perceptual dysfunction. Cluster 2 (18.8%) showed advanced radiographic OA, and moderate pain intensity, disability and cognitive and perceptual dysfunction. Cluster 3 (34.3%) represented various levels of radiographic OA, and the lowest pain intensity, disability and cognitive and perceptual dysfunction. Cluster 4 (18.1%) represented various levels of radiographic OA, the highest disability and cognitive and perceptual dysfunction. Considering cognitive factors and disturbed body perception may help to explain the phenomenon of the discrepancy between the knee-related disability and the severity of radiographic knee OA.

Development and validation of a shoulder-specific body-perception questionnaire in people with persistent shoulder pain.

BACKGROUND: There is evidence that people with persistent shoulder pain exhibit findings consistent with the presence of sensorimotor dysfunction. Sensorimotor impairments can manifest in a variety of ways, and further developing our understanding of sensorimotor dysfunction in shoulder pain may improve current models of care. The Fremantle Back Awareness Questionnaire (FreBAQ) has been developed to assess disturbed body perception specific to the back. The purpose of the present study was to develop a shoulder-specific self-perception questionnaire and evaluate the questionnaire in people with persistent shoulder pain. METHODS: The Fremantle Shoulder Awareness Questionnaire (FreSHAQ-J) was developed by modifying the FreBAQ. One hundred and twelve consecutive people with persistent shoulder pain completed the FreSHAQ-J. Thirty participants completed the FreSHAQ-J again two-weeks later to assess test-retest reliability. Rasch analysis was used to assess the psychometric properties of the FreSHAQ-J. Associations between FreSHAQ-J total score and clinical status was explored using correlational analysis. RESULTS: The FreSHAQ-J has acceptable category order, unidimensionality, no misfitting items, and excellent test-retest reliability. The FreSHAQ-J was moderately correlated with disability and pain catastrophization. CONCLUSIONS: The FreSHAQ-J fits the Rasch measurement model well and is suitable for use with people with shoulder pain. Given the relationship between the FreSHAQ-J score and clinical status, change in body perception may be worth assessing when managing patients with shoulder pain.

Identifying participants with knee osteoarthritis likely to benefit from physical therapy education and exercise: A hypothesis-generating study.

BACKGROUND: The purpose of this investigation was to undertake a hypothesis-generating study to identify candidate variables that characterize people with knee osteoarthritis who are most likely to experience a positive response to exercise. METHODS: One hundred and fifty participants with knee osteoarthritis participated in this observational, longitudinal study. All participants received a standard exercise intervention that consisted of 20-min sessions two to three times a week for three months. The classification and regression tree methodology (CART) was used to develop prediction of positive clinical outcome. Positive pain and disability outcomes (dependent variables) were defined as an improvement in pain intensity by >50% or an improvement of five or more on the Oxford knee score, respectively. The predictor variables considered included age, sex, body mass index, knee osteoarthritis severity (Kellgren/Lawrence grade), pain duration, use of medication, range of knee motion, pain catastrophizing, self-efficacy and knee self-perception. RESULTS: Fifty-five participants (36.6%) were classified as responders for pain intensity and 36.6% were classified as responders for disability. The CART model identified impairments in knee self-perception and knee osteoarthritis severity as the discriminators for pain intensity reduction following exercise. No variables predicted reduction of disability level following exercise. CONCLUSIONS: Such findings suggest that both body perception and osteoarthritis severity may play a role in treatment outcome with exercise. It also raises the possibility that those with higher levels of disrupted body perception may need additional treatment targeted at restoring body perception prior to undertaking exercise. SIGNIFICANCE: Regardless age, sex, body mass index, pain duration, use of medication, knee range of motion, pain catastrophizing and self-efficacy, participants with knee osteoarthritis who report low levels of body perception disruption (a FreKAQ score ≦ 17) and minimal structural changes (KL grade I) demonstrate significantly better outcomes from exercise therapy than other participants.

Embodying the illusion of a strong, fit back in people with chronic low back pain. A pilot proof-of-concept study.

OBJECTIVE: This proof-of-concept pilot study aimed to investigate if a visual illusion that altered the size and muscularity of the back could be embodied and alter perception of the back. METHODS: The back visual illusions were created using the MIRAGE multisensory illusion system. Participants watched real-time footage of a modified version of their own back from behind. Participants undertook one experimental condition, in which the image portrayed a muscled, fit-looking back (Strong), and two control conditions (Reshaped and Normal) during a lifting task. Embodiment, back perception as well as pain intensity and beliefs about the back during lifting were assessed. RESULTS: Two participants with low back pain were recruited for this study: one with altered body perception and negative back beliefs (Participant A) and one with normal perception and beliefs (Participant B). Participant A embodied the Strong condition and pain and fear were less and both perceived strength and confidence were more than for the Normal or the Reshaped condition. Participant B did not embody the Strong condition and reported similar levels of pain, fear strength and confidence across all three conditions. DISCUSSION: An illusion that makes the back look strong successfully induced embodiment of a visually modified back during a lifting task in a low back pain patient with altered body perception. Both participants tolerated the illusion, there were no adverse effects, and we gained preliminary evidence that the approach may have therapeutic potential.

Safety and feasibility of transcranial direct current stimulation (tDCS) combined with sensorimotor retraining in chronic low back pain: a protocol for a pilot randomised controlled trial.

INTRODUCTION: Chronic low back pain (LBP) is a common and costly health problem yet current treatments demonstrate at best, small effects. The concurrent application of treatments with synergistic clinical and mechanistic effects may improve outcomes in chronic LBP. This pilot trial aims to (1) determine the feasibility, safety and perceived patient response to a combined transcranial direct current stimulation (tDCS) and sensorimotor retraining intervention in chronic LBP and (2) provide data to support a sample size calculation for a fully powered trial should trends of effectiveness be present. METHODS AND ANALYSIS: A pilot randomised, assessor and participant-blind, sham-controlled trial will be conducted. Eighty participants with chronic LBP will be randomly allocated to receive either (1) active tDCS + sensorimotor retraining or (2) sham tDCS + sensorimotor retraining. tDCS (active or sham) will be applied to the primary motor cortex for 20 min immediately prior to 60 min of supervised sensorimotor retraining twice per week for 10 weeks. Participants in both groups will complete home exercises three times per week. Feasibility, safety, pain, disability and pain system function will be assessed immediately before and after the 10-week intervention. Analysis of feasibility and safety will be performed using descriptive statistics. Statistical analyses will be conducted based on intention-to-treat and per protocol and will be used to determine trends for effectiveness. ETHICS AND DISSEMINATION: Ethical approval has been gained from the institutional human research ethics committee (H10184). Written informed consent will be provided by all participants. Results from this pilot study will be submitted for publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: ACTRN12616000624482.

Disrupted Self-Perception in People With Chronic Low Back Pain. Further Evaluation of the Fremantle Back Awareness Questionnaire.

UNLABELLED: Several lines of evidence suggest that body perception is altered in people with chronic back pain. Maladaptive perceptual awareness of the back might contribute to the pain experience as well as serve as a target for treatment. The Fremantle Back Awareness Questionnaire (FreBAQ) is a simple questionnaire recently developed to assess back-specific altered self-perception. The aims of this study were to present the outcomes of a comprehensive evaluation of the questionnaire's psychometric properties and explore the potential relationships between body perception, nociceptive sensitivity, distress, and beliefs about back pain and the contribution these factors might play in explaining pain and disability. Two hundred fifty-one people with chronic back pain completed the questionnaire as well as a battery of clinical tests. The Rasch model was used to explore the questionnaires' psychometric properties and correlation and multiple linear regression analyses were used to explore the relationship between altered body perception and clinical status. The FreBAQ appears unidimensional with no redundant items, has minimal ceiling and floor effects, acceptable internal consistency, was functional on the category rating scale, and was not biased by demographic or clinical variables. FreBAQ scores were correlated with sensitivity, distress, and beliefs and were uniquely associated with pain and disability. PERSPECTIVE: Several lines of evidence suggest that body perception might be disturbed in people with chronic low back pain, possibly contributing to the condition and offering a potential target for treatment. The FreBAQ was developed as a quick and simple way of measuring back-specific body perception in people with chronic low back pain. The questionnaire appears to be a psychometrically sound way of assessing altered self-perception. The level of altered self-perception is positively correlated with pain intensity and disability as well as showing associations with psychological distress, pain catastrophization, fear avoidance beliefs, and lumbar pressure pain threshold. In this sample, it appears that altered self-perception might be a more important determinant of clinical severity than psychological distress, pain catastrophization, fear avoidance beliefs, or lumbar pressure pain threshold.

Interdisciplinary Management of Complex Regional Pain Syndrome of the Face.

BACKGROUND AND PURPOSE: Orofacial pain disorders are relatively uncommon and pose a substantial diagnostic challenge. This case report documents the diagnosis and management of hemifacial pain in a patient who was referred to an interdisciplinary pain medicine unit. The purpose of this case report is twofold. First, it presents complex regional pain syndrome (CRPS) as a potential differential diagnosis in cases of facial pain. Second, it describes the successful adaption of contemporary management approaches for distal-extremity CRPS to treat people with CRPS of the facial region. CASE DESCRIPTION: The patient had hemifacial pain and concomitant motor and autonomic symptoms after a small laceration of the eyelid. Extensive specialist medical evaluations were undertaken to exclude an underlying structural pathology. After detailed clinical assessments by a physical therapist, pain physician, and clinical psychologist, a diagnosis of CRPS involving the face was made. OUTCOMES: The patient's pain was largely unresponsive to pharmacological agents. A modified graded motor imagery program, together with desensitization and discrimination training, was commenced by the physical therapist and clinical psychologist. A positive clinical response was indicated by a decrease in allodynia, normalization of motor control, and regained function in activities of daily living. DISCUSSION: Complex regional pain syndrome is an infrequently reported differential diagnosis that can be considered in patients with persistent facial pain. This case report highlights how careful examination and clinical decision making led to the use of an innovative therapeutic strategy to manage a challenging condition.

Disturbed body perception, reduced sleep, and kinesiophobia in subjects with pregnancy-related persistent lumbopelvic pain and moderate levels of disability: An exploratory study.

BACKGROUND: For a small but significant group, pregnancy-related lumbopelvic pain may become persistent. While multiple factors may contribute to disability in this group, previous studies have not investigated sleep impairments, body perception or mindfulness as potential factors associated with disability post-partum. OBJECTIVES: To compare women experiencing no pain post-pregnancy with those experiencing pregnancy-related persistent lumbopelvic pain (either low- or high-level disability) across multiple biopsychosocial domains. DESIGN: Cross-sectional. METHODS: Participants completed questionnaires for thorough profiling of factors thought to be important in pregnancy-related lumbopelvic pain. Specific measures were the Urinary Distress Inventory, Medical Outcomes Study Sleep Scale, Back Beliefs Questionnaire, Tampa Scale for Kinesiophobia, Depression Anxiety Stress Scale, Coping Strategies Questionnaire, Pain Catastrophising Scale, The Fremantle Back Awareness Questionnaire and the Mindful Attention Awareness Scale. Women where categorised into three groups; pain free (n = 26), mild disability (n = 12) and moderate disability (n = 12) (based on Oswestry Disability Index scores). Non-parametric group comparisons were used to compare groups across the profiling variables. RESULTS: Differences were identified for kinesiophobia (p = 0.03), body perception (p = 0.02), sleep quantity (p < 0.01) and sleep adequacy (p = 0.02). Generally subjects in the moderate disability group had more negative findings for these variables. CONCLUSION: Disturbances in body-perception, sleep and elevated kinesiophobia were found in pregnancy-related lumbopelvic pain subjects with moderate disability, factors previously linked to persistent low back pain. The cross-sectional nature of this study does not allow for identification of directional pathways between factors. The results support the consideration of these factors in the assessment and management of pregnancy-related lumbopelvic pain.

Moving in an environment of induced sensorimotor incongruence does not influence pain sensitivity in healthy volunteers: a randomised within-subject experiment.

OBJECTIVES: It has been proposed that in the same way that conflict between vestibular and visual inputs leads to motion sickness, conflict between motor commands and sensory information associated with these commands may contribute to some chronic pain states. Attempts to test this hypothesis by artificially inducing a state of sensorimotor incongruence and assessing self-reported pain have yielded equivocal results. To help clarify the effect sensorimotor incongruence has on pain we investigated the effect of moving in an environment of induced incongruence on pressure pain thresholds (PPT) and the pain experienced immediately on completion of PPT testing. METHODS: Thirty-five healthy subjects performed synchronous and asynchronous upper-limb movements with and without mirror visual feedback in random order. We measured PPT over the elbow and the pain evoked by testing. Generalised linear mixed-models were performed for each outcome. Condition (four levels) and baseline values for each outcome were within-subject factors. RESULTS: There was no effect of condition on PPT (p = 0.887) or pressure-evoked pain (p = 0.771). A sensitivity analysis using only the first PPT measure after each condition confirmed the result (p = 0.867). DISCUSSION: Inducing a state of movement related sensorimotor incongruence in the upper-limb of healthy volunteers does not influence PPT, nor the pain evoked by testing. We found no evidence that sensorimotor incongruence upregulates the nociceptive system in healthy volunteers.

Assessing self-perception in patients with chronic low back pain: development of a back-specific body-perception questionnaire.

BACKGROUND: There is considerable interest in the role that disturbance of body-perception may play in long standing pain problems such as chronic low back pain (CLBP), both as a contributor to the clinical condition and as a potential target for treatment. In some chronic pain conditions body-perception has been investigated using self-report questionnaires. There is currently no questionnaire for assessing body-perception in people with CLBP. OBJECTIVE: To describe the development of a back-specific body-perception questionnaire and examine the psychometrics of this new scale. METHODS: Based on available evidence a back-specific body-perception questionnaire was developed. Fifty-one people with CLBP and an equal number of healthy controls completed the questionnaire; a subset of the patient population completed the questionnaire again one-week later. Scale-consistency and test-retest reliability were investigated on the patient sample. Validity was investigated by comparing responses between patients and controls as well as exploring the relationship between the questionnaire and important clinical characteristics. RESULTS: All but one of the patients endorsed items on the questionnaire, which suggests that distorted body-perception may exist in this population. The internal-consistency and test-retest reliability of the scale appear acceptable. The discriminative validity of the questionnaire is supported by the marked differences in the questionnaire responses between patients and healthy controls and the construct validity by the significant association between the questionnaire score and important clinical variables. CONCLUSION: Symptoms of body-perception distortion were endorsed by most CLBP patients, while these symptoms are very infrequent amongst healthy controls. Our results suggest the questionnaire has reasonable psychometric properties.

Lumbar tactile acuity is near identical between sides in healthy pain-free participants.

A growing body of literature suggests that alterations in brain structure and function are a feature of chronic back pain. Tactile acuity is considered a clinical signature of primary somatosensory representation and offers a simple measure of cortical reorganisation. Clinical interpretation of test scores from an individual patient is hampered by variance in published normative values and less than ideal inter-rater reliability. These problems might be mitigated in people with unilateral back pain by using the patient as their own control and comparing tactile acuity at the painful site to performance at the corresponding position on the non-painful side. The first step in exploring this approach is to quantify the normal side-to-side difference in healthy populations. We pooled data from three previous studies that measured lumbar tactile acuity bilaterally in healthy controls using similar protocols. We calculated the mean and variance of the absolute error between sides, the standard error of measurement and the reliable change index (RCI). The mean difference between sides was 3.2 mm (±5.2) when assessed vertically and 1.9 mm (±3.2) when assessed horizontally. The standard error of measurement was 4.2 mm when assessed vertically and 2.7 mm when assessed horizontally. The RCI suggests that differences of greater than 13 mm when assessed horizontally and 17 mm when assessed vertically equate to 95% confidence that a difference truly exists. Several assumptions related to the application of this approach need to be investigated further.

Illusory touch temporarily improves sensation in areas of chronic numbness: a brief communication.

BACKGROUND: Creating the visual illusion of touch can improve tactile perception in healthy subjects. OBJECTIVE: We were interested in seeing if creating the illusion of touch in an insensate area could improve sensation in that area. METHODS: Fourteen people with chronic numbness participated in a randomized crossover experiment. The 4 conditions were the following: (a) stimulation over the unaffected limb with mirror visual feedback (experimental condition), (b) stimulation over the affected limb with mirror visual feedback, (c) stimulation over the unaffected limb without mirror visual feedback, and (d) stimulation over the affected limb without mirror visual feedback. Participants were assessed before and after each condition using the Ten-Test and mechanical detection thresholds. Data were analyzed using linear mixed models. RESULT: Only the experimental condition produced a change in the Ten-Test (mean difference = -1.1; 95% confidence interval = -1.8 to -0.4; P = .003), corresponding to a 24% improvement in sensation. No differences were observed for any condition in mechanical detection thresholds. CONCLUSION: Creating the illusion of touch may improve sensory function in areas of chronic numbness. This preliminary finding adds to the growing body of evidence supporting the use of techniques that directly target cortical function in people with peripheral nerve injury.

Acupuncture applied as a sensory discrimination training tool decreases movement-related pain in patients with chronic low back pain more than acupuncture alone: a randomised cross-over experiment.

BACKGROUND: High-quality clinical evidence suggests that although acupuncture appears superior to usual care in the management of chronic low back pain, there is little meaningful difference between true and sham acupuncture. This suggests that the benefits of acupuncture are mediated by the placebo response. An alternative explanation is that sham acupuncture is an active treatment and shares a mechanism of action with traditionally applied acupuncture. One plausible candidate for this mechanism is improvement in self-perception mediated through the sensory discrimination-like qualities of acupuncture. We aimed to compare the effects of acupuncture with a sensory discrimination training component to acupuncture without. METHODS: 25 people with chronic low back pain were enroled in a randomised cross-over experiment. We compared the effect of acupuncture delivered when sensory discrimination is optimised to acupuncture delivered when it is not, on movement-related back pain immediately after each intervention. RESULTS: We found that the average pain intensity after participants had received acupuncture with sensory discrimination training (2.8±2.5) was less than when they received acupuncture without sensory discrimination training (3.6±2.0). This difference was statistically significant (after adjustment; mean difference=-0.8, 95% CI -1.4 to -0.3; p=0.011). CONCLUSIONS: Our findings are consistent with the idea that acupuncture may offer specific benefit that is not dependent on precisely where the needles are inserted so much as that the patient attends to where they are inserted. If so, the location of the needles might be better focused on the painful area and the need for penetration of the skin may be mitigated.

Seeing it helps: movement-related back pain is reduced by visualization of the back during movement.

OBJECTIVES: The aim of this study was to determine whether visualization of the back influenced parameters of movement-related pain in people with chronic nonspecific low back pain. METHODS: We used a randomized cross-over experiment in which 25 participants performed repeated lumbar spine movements under 2 conditions. In the visual feedback condition, patients were able to visualize their back as it moved by the use of mirrors. In the control condition, the mirror was covered so no visualization of the back was possible. RESULTS: The average postmovement pain intensity after participants had moved with visual feedback was less (35.5 ± 22.8 mm) than when they moved without visual feedback (44.7 ± 26.0 mm). This difference was statistically significant (mean difference=9.3, 95% confidence interval: 2.8-15.7 F(1,22)=8.82, P=0.007). The average time to ease after participants had moved with visual feedback was shorter (44.5 s ± 53.8) than when they moved without visual feedback (94.4 s ± 80.7). This difference was also statistically significantly (mean difference=49.9, 95% confidence interval: 19.3-80.6, F(1,22)=8.82, P=0.003). DISCUSSION: Patients with chronic nonspecific low back pain reported less increase in pain and faster resolution of pain when moving in an environment that enabled them to visualize their back. This is consistent with emerging research on the use of mirror visual feedback in other long-standing pain problems and suggests that similar lines of inquiry may be worth pursuing in the chronic nonspecific low back pain population.

Rasch analysis supports the use of the depression, anxiety, and stress scales to measure mood in groups but not in individuals with chronic low back pain.

OBJECTIVE: Chronic pain is a common problem that is associated with mood disorders such as depression. The Depression, Anxiety, and Stress Scales (DASS-21) questionnaire is commonly used to help measure disordered mood. In this study, we used Rasch analysis to analyze the clinimetric properties of the DASS-21 in a chronic low back pain sample. STUDY DESIGN AND SETTING: A Rasch analysis was conducted on data collected as a part of a randomized hospital-based placebo-controlled trial. DASS-21 questionnaires were completed by the 154 enrolled participants. RESULTS: The DASS-21 subscales fit the Rasch model. No differential item functioning was detected for age, gender, pain severity, or disability. Reliability for individual use was supported for the depression subscale (Person Separation Index [PSI]=0.86) but group use only for the anxiety (PSI=0.74) and stress (PSI=0.82) subscales. A DASS-21 aggregate score of "negative affect" lacked fit to the Rasch model (χ(2)=191.48, P<0.001). CONCLUSION: This is the first study that used Rasch analysis to demonstrate that the DASS-21 subscales demonstrate adequate measurement properties for research involving groups with chronic pain. Only the DASS-21 depression subscale demonstrated adequate reliability for use with individuals with chronic pain. The use of a single DASS-21 aggregate score as a measure of "negative affect" was not supported.

Cortical changes in chronic low back pain: current state of the art and implications for clinical practice.

There is increasing evidence that chronic pain problems are characterised by alterations in brain structure and function. Chronic back pain is no exception. There is a growing sentiment, with accompanying theory, that these brain changes contribute to chronic back pain, although empirical support is lacking. This paper reviews the structural and functional changes of the brain that have been observed in people with chronic back pain. We cast light on the clinical implications of these changes and the possibilities for new treatments but we also advise caution against concluding their efficacy in the absence of solid evidence to this effect.