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Over the last decade, the content, delivery and media of pain education have been adjusted in line with scientific discovery in pain and educational sciences, and in line with consumer perspectives. This paper describes a decade-long process of exploring consumer perspectives on pain science education concepts to inform clinician-derived educational updates (undertaken by the authors). Data were collected as part of a quality audit via a series of online surveys in which consent (non-specific) was obtained from consumers for their data to be used in published research. Consumers who presented for care for a persistent pain condition and were treated with a pain science education informed approach were invited to provide anonymous feedback about their current health status and pain journey experience 6, 12 or 18 months after initial assessment. Two-hundred eighteen consumers reported improvement in health status at follow-up. Results of the surveys from three cohorts of consumers that reported improvement were used to generate iterative versions of ‘Key Learning Statements’. Early iteration of these Key Learning Statements was used to inform the development of Target Concepts and associated community-targeted pain education resources for use in public health and health professional workforce capacity building initiatives. Perspective This paper reflects an explicit interest in the insights of people who have been challenged by persistent pain and then recovered, to improve pain care. Identifying pain science concepts that consumers valued learning provided valuable information to inform resources for clinical interactions and community-targeted pain education campaigns. Refereed/Peer-reviewed

Background context : Low back pain is a major cause of morbidity and disability worldwide and is responsible for vast societal impact. Rates of surgical intervention for lumbar spine disorders continue to rise but poor outcomes remain common. Understanding how the social determinants of health (SDH) influence spinal surgical outcomes stands to inform appropriately tailored care practices and lead to better patient outcomes. Purpose : To determine the relationships between the SDH and pain, opioid use, disability and work absenteeism following lumbar spine surgery. Study design : Systematic review and narrative synthesis. Methods : We searched Embase, the Cochrane Library, Medline, and Web of Science from inception to 21/4/2020. Studies eligible for inclusion involved participants receiving lumbar spine surgery and investigated the relationship between at least one SDH and post-surgical pain, opioid use, disability or work absenteeism. We evaluated the risk of bias of included studies and used the PROGRESS-Plus framework to organise a narrative synthesis of findings. Results : Relevant data was extracted from twenty-three studies involving 30,987 adults from 12 countries. 107 relationships between the SDH and post-surgical outcomes were evaluated, 67 in multivariate analyses. Education was investigated in 23 analyses (14 studies): 70% revealed significant independent relationships between lower education and poorer outcomes. Socioeconomic status was investigated in nine analyses (four studies): 67% revealed independent relationships between lower socioeconomic status and poorer outcomes. Gender was investigated in 40 analyses (22 studies): indications that male versus female sex was associated with poorer outcomes were equivocal. Place of residence, race/ethnicity, and social capital were infrequently investigated. Conclusions : Low educational attainment and low income status are clear independent contributors to poorer outcomes following lumbar spine surgery. Occupational factors and work context are likely to be influential. Further research is critical to guide best-practice spinal surgery through a health equity lens. Study registration : PROSPERO registration number CRD42015015778

The purpose of the current study was to determine whether auditory prepulse inhibition (PPI) and/or prepulse facilitation (PPF) were altered in people with fibromyalgia (FM) when compared with controls. Eyeblink responses were recorded from 29 females with FM and 27 controls, while they listened to 3 blocks of auditory stimuli that delivered pulses with either PPI or PPF. Using a linear mixed model, our main findings were that there was a GROUP*CONDITION interaction (F4, 1084 = 4.01, P= .0031) indicating that the difference in amplitude between FM group and control group changed depending on the condition (PPI or PPF). Post hoc tests revealed no differences between the groups in response to PPI. The FM group showed a greater reactivity of response to the PPF conditioned stimulus than the control group did (t(39.7) = 2.03, P= .0494). Augmentation of PPF, as demonstrated by the FM group is thought to be linked to alterations in information processing mediated by an autonomically driven general orienting process. Activities that decrease autonomic drive or rebalance autonomic and parasympathetic tone such as vagal stimulation might be pursued as effective interventions for people with FM. Perspective This article presents evidence of preservation of neural circuitry that underpins response suppression and evidence of neural circuit disturbance mediated by autonomic drive-in people with FM. These results are important because intact circuitry underpins the effectiveness of therapies and may be harnessed, and rebalancing autonomic drive may be indicated.

Refereed/Peer-reviewed

Objectives: Hamstring injuries in athletes can lead to significant time away from competition as a result of persistent posterior thigh pain. These cases are often difficult to treat as the state of the tissues alone cannot explain symptoms. In non-athletic populations with persistent pain, disruptions to tactile, proprioceptive, and spatial cortical representations exist, which has led to promising brain-based treatments.Here, we explored whether athletes with persistent posterior thigh pain also display impairments in these cortical representations.Design: Cross-sectional study.Methods: Fourteen male professional athletes with persistent posterior thigh pain (‘Patients’) and 14pain-free age, sport, body mass index and level-matched controls (‘Controls’) participated. The tactile cortical representation was assessed using two-point discrimination (TPD) threshold and accuracy of tactile localisation; the proprioceptive cortical representation was assessed using a left/right judgement task; spatial processing was assessed using an auditory detection task. Results: TPD thresholds were similar for Patients and Controls (p = 0.70). Patients were less accurate at localising tactile stimuli delivered to their affected leg, slower to make left/right judgements when the lower limb image corresponded to the side of their affected leg, and less accurate at detecting auditory stimuli delivered near their affected leg, when compared to their healthy leg or to the leg of Controls(p < 0.01 for all). Conclusions: Leg-specific tactile, proprioceptive, and spatial processing deficits exist in athletes with persistent posterior thigh pain. That these processing deficits exist despite rehabilitation and normal tissue healing time suggests they may play a role in the persistence of posterior thigh pain. Refereed/Peer-reviewed

Resume Les douleurs musculosquelettiques chroniques font reference aux douleurs osseuses, articulaires et tissulaires qui persistent depuis plus de 3 mois. Dans ces affections, il est communement admis que les dysfonctions secondaires ou les consequences de la douleur persistante–peur du mouvement, catastrophisme, anxiete ou sensibilisation du systeme nerveux–semblent les principales causes de la douleur et de l’incapacite fonctionnelle. En cas de douleurs persistantes, les exercices constituent une modalite de traitement fondamentale. Leur objectif principal est souvent l’amelioration de la fonction physique ; peu d’attention est portee aux troubles secondaires. Les interventions basees sur les exercices et qui s’interessent aux troubles secondaires sont en accord avec les pratiques contemporaines destinees a la reeducation de la douleur. Elles presentent un potentiel plus important pour ameliorer les resultats des patients que des exercices seuls. Une approche biopsychosociale, qui valide et tienne compte de la contribution des facteurs biologiques, psychologiques et sociaux de la douleur et de l’incapacite fonctionnelle, est actuellement consideree comme l’approche la plus efficace en cas de douleur chronique. Elle est aussi consideree comme plus efficace que des exercices ou de la kinesitherapie utilises isolement. Cette mise au point clinique aborde les elements-cles d’une approche biopsychosociale qui prend en compte les besoins du patient et les competences du clinicien pour la prescription d’exercices en cas de douleurs musculosquelettiques chroniques. Il existe un consensus pour preconiser des exercices supervises, individualises, bases sur les caracteristiques, les objectifs et les preferences du patient. Celui-ci devrait percevoir ces exercices comme des activites sans danger et non menacants afin d’eviter qu’il etablisse des associations nefastes entre les activites physiques et la douleur. Des etudes portant sur des exercices aerobies et de resistance ont apporte une caution scientifique a l’interet de prescrire des exercices en cas de douleurs musculosquelettiques chroniques. Cependant, certaines incertitudes demeurent quant a meilleure facon d’appliquer les resultats de ces etudes. Cette mise au point s’appuie sur une synthese de la litterature scientifique pour apporter des conseils bases sur l’evidence dans le domaine de l’exercice et de la reeducation en cas de douleurs musculosquelettiques chroniques. Niveau de preuve NA.

Purpose: To understand the process of change at an individual level, this study used a single-case experimental design to evaluate how change in potential mediators related to change in disability over time, during an exposure-based behavioural intervention in four people with chronic low back pain and high pain-related fear. A second aim was to evaluate whether the change (sequential or simultaneous) in mediators and disability occurred at the same timepoint for all individuals. Results: For all participants, visual and statistical analyses indicated that changes in disability and proposed mediators were clearly related to the commencement of Cognitive Functional Therapy. This was supported by standard outcome assessments at pre-post timepoints. Cross-lag correlation analysis determined that, for all participants, most of the proposed mediators (pain intensity, pain controllability, and fear) were most strongly associated with disability at lag zero, suggesting that mediators changed concomitantly and not before disability. Importantly, these changes occurred at different rates and patterns for different individuals, highlighting the individual temporal variability of change. Conclusion: This study demonstrated the interplay of factors associated with treatment response, highlighting ‘how change unfolded’ uniquely for each individual. The findings that factors underpinning treatment response and the outcome changed simultaneously, challenge the traditional understanding of therapeutic change. Refereed/Peer-reviewed

Background Left/right judgement (LRJ) of body parts is commonly used to assess the ability to perform implicit motor imagery and the integrity of brain-grounded maps of the body. Clinically, LRJ are often undertaken using a mobile tablet, but the concurrent validity and reliability of this approach has not yet been established. Objectives To evaluate the concurrent validity and test-retest reliability of a mobile tablet for assessing LRJ. Method Participants completed LRJ for 50 hand images (Experiment 1), and 40 back, foot, or neck images (Experiment 2) using a mobile tablet and desktop computer in random order. Participants in Experiment 2 performed a repeat test the following day to assess test-retest reliability. Accuracy and response time (RT) were recorded. Results Twenty participants aged 55.3 (±6.7) years in Experiment 1, and 37 participants aged 38.2 (±12.3) years in Experiment 2, were recruited. Concurrent validity of the mobile tablet was good to excellent for hand judgements (ICC 3,1 = 0.836 for RT; ICC = 0.909 for accuracy), and was good for back, foot, and neck judgements (ICC = 0.781 for accuracy; ICC = 0.880 for RT). Test-retest reliability of the mobile tablet was good to excellent (ICC = 0.824 for accuracy; ICC = 0.903 for RT). Conclusions The mobile tablet demonstrated good to excellent concurrent validity with the desktop computer in two separate samples. The mobile tablet also demonstrated good to excellent test-retest reliability. The mobile tablet for LRJ is a valid alternative to the original desktop version.

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.

Objective: Interhemispheric inhibition is an important cortical mechanism to support motor control. Altered interhemispheric inhibition has been the target of neuromodulation interventions. This systematic review investigated the evidence for altered interhemispheric inhibition in adults with unilateral neurological conditions: stroke, amyotrophic lateral sclerosis, cerebral palsy, complex regional pain syndrome, traumatic brain injury, and cerebral palsy Methods: We pre-registered the protocol and followed PRISMA guidelines. Five databases were systematically searched to identify studies reporting interhemispheric inhibition measures in unilateral neurological conditions and healthy controls. Data were grouped according to the measure (ipsilateral silent period and dual-coil), stimulated hemisphere, and stage of the condition (subacute and chronic). Results: 1372 studies were identified, of which 14 were included (n = 226 adults with stroke and 161 age-matched controls). Ipsilateral silent period-duration was longer in people with stroke than in controls (stimulation of dominant hemisphere) regardless of stroke stage. Motor evoked potential was less suppressed in people with sub-acute stroke (stimulation of the unaffected hemisphere) than controls (stimulation of dominant hemisphere) and this reversed in chronic stroke. Conclusion: Detection of altered interhemispheric inhibition appears to be dependent on the measure of interhemispheric inhibition and the stage of recovery Significance: Rebalancing interhemispheric inhibition using neuromodulation is considered a promising line of treatment for stroke rehabilitation. Our results did not find compelling evidence to support consistent alterations in interhemispheric inhibition in adults with stroke. Refereed/Peer-reviewed

No abstract available Refereed/Peer-reviewed

Prominent clinical models of chronic pain propose a fundamental role of classical conditioning in the development of pain-related disability. If classical conditioning is key to this process, then people with chronic pain may show a different response to pain-related conditioned stimuli than healthy control subjects. We set out to determine whether this is the case by undertaking a comprehensive and systematic review of the literature. To identify studies comparing classical conditioning between people with chronic pain and healthy control subjects, the databases MEDLINE, PsychINFO, PsychARTICLES, Scopus, and CINAHL were searched using key words and medical subject headings consistent with ‘classical conditioning’ and ‘pain.’ Articles were included when: 1) pain-free control and chronic pain groups were included, and 2) a differential classical conditioning design was used. The systematic search revealed 7 studies investigating differences in classical conditioning between people with chronic pain and healthy control participants. The included studies involved a total of 129 people with chronic pain (fibromyalgia syndrome, spinal pain, hand pain, irritable bowel syndrome), and 104 healthy control participants. Outcomes included indices of pain-related conditioning such as unconditioned stimulus (US) expectancy and contingency awareness, self-report and physiological measures of pain-related fear, evaluative judgements of conditioned stimulus pleasantness, and muscular and cortical responses. Because of variability in outcomes, meta-analyses included a maximum of 4 studies. People with chronic pain tended to show reduced differential learning and flatter generalization gradients with respect to US expectancy and fear-potentiated eyeblink startle responses. Some studies showed a propensity for greater muscular responses and perceptions of unpleasantness in response to pain-associated cues, relative to control cues. Perspective The review revealed preliminary evidence that people with chronic pain may exhibit less differential US expectancy and fear learning. This characteristic may contribute to widespread fear-avoidance behavior. The assumption that altered classical conditioning may be a predisposing or maintaining factor for chronic pain remains to be verified.

© 2016 Elsevier Ireland Ltd Objective Professional appearance is easily modifiable, and might alter the effects of a clinical encounter. We aimed to determine whether professional attire influences a patient's perception of treatment credibility. Methods We performed a single-blind randomized controlled study on 128 patients with acute non-specific low back pain who were about to receive treatment in primary care. The treating clinician was randomly allocated to wear formal attire (experimental condition) or casual attire (control condition) to the consultation. Clinicians provided a standardized briefing on the rationale behind the patient's forthcoming treatment. Treatment credibility (Credibility and Expectancy Questionnaire) was assessed immediately after this briefing. Results All patients received the experimental or control condition as allocated and provided complete primary outcome data. Formal attire had no effect on perceived treatment credibility (Mean difference between groups 1.2 [95%CI-1.1 to 3.5]). Age was the only significant predictor of treatment credibility; older patients rated treatment credibility higher (Beta = 0.16 [95%CI 0.08 to 0.24]). Conclusion In a trial setting, whether or not a clinician is formally dressed has no effect on perceptions of treatment credibility in patients with acute low back pain. Practice implication Clinicians should dress comfortably without fear of losing credibility.

A classical conditioning framework is often used for clinical reasoning about pain that persists after tissue healing. However, experimental studies demonstrating classically conditioned pain in humans are lacking. The current study tested whether non-nociceptive somatosensory stimuli can come to modulate pain threshold after being paired with painful nociceptive stimuli in healthy humans. We used a differential simultaneous conditioning paradigm in which one non-painful vibrotactile conditioned stimulus (CS+) was simultaneously paired with an unconditioned painful laser stimulus (US), while another vibrotactile stimulus (CS-) was paired with a non-painful laser stimulus. After acquisition, at-pain-threshold laser stimuli were delivered simultaneously with a CS+ or CS- vibrotactile stimulus. The primary outcome was the percentage of at-threshold laser stimuli that were reported as painful. The results were as expected: after conditioning, at-threshold laser trials paired with the CS+ were reported as painful more often, as more intense, and as more unpleasant than those paired with the CS-. This study provides new evidence that pain thresholds can be modulated via classical conditioning, even when the stimulus used to test the threshold can not be anticipated. As such, it lays a critical foundation for further investigations of classical conditioning as a possible driver of persistent pain. publisher: Elsevier articletitle: Pain by Association? Experimental Modulation of Human Pain Thresholds Using Classical Conditioning journaltitle: The Journal of Pain articlelink: http://dx.doi.org/10.1016/j.jpain.2016.06.012 content_type: article copyright: © 2016 by the American Pain Society ispartof: The Journal of Pain vol:17 issue:10 pages:1105-1115 ispartof: location:United States status: published

Models of Care (MoCs) for injured workers in the compensation environment recommend adoption of biopsychosocial management approaches. Still, widespread dominance of biomedical constructs at the system, organisational and individual levels of the compensation system prevails, contributing to suboptimal management practices and outcomes for injured workers. Efforts to implement contemporary MoCs in the compensation environment show some promise in improving outcomes. Areas of promise at the organisational level, particularly in the workplace, and at the system level are discussed. Implementation of a contemporary understanding of pain biology as part of the biopsychosocial approach in the management of the person with pain and associated disability has been effective in the non-compensable environment. The implications of this for the compensable environment are explored. Resultant helpful and unhelpful perspectives and behaviours are presented as a blueprint for areas of potential change in development and implementation of MoCs in a compensable environment. Refereed/Peer-reviewed

Background: Anecdotally, clinical presentations in which pain seems to be elicited by non-noxious stimuli are often explained using a classical conditioning framework. We were primarily interested in whether (a) clinicians think that pain can be a classically conditioned response to a non-noxious stimulus, and (b) clinicians think that there is evidence to support that idea.Method: Practising healthcare clinicians participated anonymously in an online survey. The information collected included descriptive demographics, clinical experience, personal experience of chronic pain, beliefs about pain, and beliefs about classical conditioning and pain. Responses to the pre-requisite question – whether pain can occur without nociception – were compared to a historical data set from 2004.Results: 1090 people from 57 countries and eight distinct types of health profession completed the survey. 86% stated that pain can occur without nociception; 96% of those believed that pain can be a classically conditioned response to a non-noxious stimulus; 98% of those believed that there is evidence to support that statement. The 2004 data showed that 44% of participants distinguished between pain and nociception.Conclusions: This broad sample overwhelmingly endorsed the ideas that clinicians think that pain can be a classically conditioned response to a non-noxious stimulus and think that there is evidence to support that idea, revealing a discrepancy between beliefs in the clinical community and the scientific evidence. The distinction between nociception and pain has become more accepted by the clinical community over the last 10 years. Refereed/Peer-reviewed

Background: Implicit motor imagery performance is altered in a variety of chronic pain conditions, but it is not known whether this is the case in shoulder pain.Objectives: The aim of this study was to assess implicit motor imagery performance, using a valid and reliable shoulder left/right judgement task in people with shoulder pain.Design: Cross-sectional observational study.Methods: Participants with (n ¼ 369) and without (n ¼ 747) shoulder pain completed the shoulder left/right judgement task (LRJT). Response times (RT), accuracy were determined. Age, gender, hand dominance, current pain intensity, Shoulder Pain and Disability Index (SPADI) and pain duration recorded. Planned analysis included ANOVAs for current pain, RT and accuracy.Results: Gender and hand dominance distribution were similar between groups (p > 0.5). The shoulder pain participants were older, mean age (SD); 47(14)years, than the control group; 41(14)years, p < 0.01. Participants with shoulder pain were slower, mean RT(SD); 1809(746)ms than the controls; 1701(749)ms; p ¼ 0.02, but no different in accuracy, mean % (SD); 93.2(8.5)% to controls; 94.1(9.4)%; p ¼ 0.13. The differences in RT were resolved when age was entered as a covariate (p ¼0.83). Regression of the data from the shoulder pain group only found that current pain was positively related to RT (B ¼ 43.97) and negatively to accuracy (B ¼-0.70).Conclusions: Participants with shoulder pain do not demonstrate poorer implicit motor imagery performance than people who are pain-free. However, more intense shoulder pain is associated with poorer implicit motor imagery performance. We recommend further research utilising the LRJT in well-defined clinically homogenous groups, with verified pain severity, functional disability, and chronicity. Refereed/Peer-reviewed

Background: Individual experimental data suggest that visual input during tactile stimulation enhances tactile appreciation – whether this finding is replicated across studies and across body sites is unknown. Objective: To determine the available evidence as to whether non-informative vision of the body has an effect on tactile acuity. Methods: Studies that assessed tactile acuity with vision of the body, compared to vision of a neutral object or vision occluded, were systematically identified and reviewed. Seven relevant electronic databases were searched from their inception to April 2014. Risk of bias was assessed using adapted criteria from the Cochrane Handbook. Effect sizes were calculated using mean differences in a random effects model. Results: Ten studies were included. All were randomized, within subject, controlled trials published in English (total n=232 participants), with low to moderate risk of bias. Despite the diversity of protocols and outcome measures used, eight of the studies reported improvements in tactile acuity when vision of the relevant body part (predominantly the hand) was available. Meta-analysis revealed statistically significant findings from grating orientation tests (p=0.002, SMD 3.31, 95% CI 1.24–5.39), demonstrating a positive effect of vision of the body. No significant effect was found for other sensory tests or for other body parts, such as the back, and statistical heterogeneity was high. Conclusions: This review provides confirmatory evidence for a visual enhancement effect for tactile acuity for body parts where vision has a plausible functional linkage – further studies are required to elaborate on the mechanisms for multi-modal processing of sensory stimuli. Refereed/Peer-reviewed

Reduced pain perception during painful stimulation to another body region (ie, conditioned pain modulation [CPM]) is considered important for pain modulation and development of pain disorders. The various methods used to study CPM limit comparison of findings. We investigated the influence of key methodologic variations on CPM and the properties of CPM when the back is used for the test stimulus or the conditioning stimulus (CS). Two different test stimuli (pressure pain threshold and pain response to suprathreshold heat [Pain-45, ie, pain rated at 45 on a 0-100 numeric rating scale]) were assessed before and during application of a noxious or non-noxious (sham) CS. Eight blocks of trials varied the anatomic location (back and forearms) and arrangement (body side) of the stimuli. Pressure pain threshold (as the test stimulus) increased during application of noxious, but not non-noxious, CS when stimuli were applied to opposite body sides or heterotopic sites on one body side. Inconsistent with pain-induced CPM, Pain-45 decreased during both noxious and non-noxious CS. These findings indicate that 1) pressure pain threshold can be more confidently interpreted with respect to CPM evoked by a painful stimulus than Pain-45, 2) the back and forearm are equally effective as sites for stimuli, and 3) stimuli arrangement does not influence CPM, except for identical anatomic regions on the same body side. Perspective: This study indicates that pressure pain threshold as the test stimulus provides a more valid measure of pain-induced CPM than pain response to a suprathreshold heat stimulus. Induction and magnitude of CPM is independent of stimuli arrangement, as long as ipsilateral homotopic sites are avoided. These findings clarify methods to study CPM. (C) 2015 by the American Pain Society Refereed/Peer-reviewed

A widely held belief within the clinical community is that chronic pain is associated with cognitive impairment, despite the absence of a definitive systematic review or meta-analysis on the topic. The current systematic review and meta-analysis aimed to establish the current evidence concerning the difference in executive function between people with chronic pain and healthy controls. Six databases were searched for citations related to executive function and chronic pain from inception to June 24, 2013. Two reviewers independently assessed studies for eligibility and extracted relevant data according to the Cochrane Collaboration and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Twenty five studies were included in the review and twenty two studies in the meta-analysis. A small to moderate impairment in executive function performance was found in people with chronic pain across cognitive components, although all studies had a high risk of bias. The current evidence suggests impairment of executive function in people with chronic pain, however, important caveats exist. First, executive function involves many cognitive components and there is no standard test for it. Second, moderators of executive function, such as medication and sleep, were seldom controlled for in studies of executive function performance. Refereed/Peer-reviewed

This article has been made available through the Brunel Open Access Publishing Fund. Impaired tactile acuity in people with chronic pain conditions has been suggested to reflect altered cortical representation of the painful body part, and treatments that aim to improve tactile acuity in these conditions have shown clinical benefit. Whether abnormalities in tactile acuity are a consistent feature of chronic pain remains largely unknown. The aim of this review was to systematically evaluate the literature and use meta-analysis to establish whether tactile acuity is altered in people with chronic non-neuropathic pain. We systematically searched the literature for studies that investigated tactile acuity in people with chronic non-neuropathic pain and compared it to an appropriate control group. Sixteen studies, reporting data from 5 chronic pain conditions, were included. Data were available for 18 chronic pain populations (n = 484) and 15 control populations (n = 378). Our results suggest that tactile acuity is diminished in arthritis, complex regional pain syndrome, and chronic low back pain but not in burning mouth syndrome. The strength of the available evidence is weakened by somewhat inconsistent results and the high risk of bias observed in all of the included studies. Perspective: This systematic review synthesizes the evidence for tactile acuity deficits in people with chronic non-neuropathic pain. The findings suggest that tactile acuity deficits may be characteristic of chronic pain. That tactile acuity training may be of benefit to chronic pain disorders suggests that clinical trials of this possibility appear warranted.

Dysfunction in the central nervous systemis thought to underlie themovement disorders that commonly occur in complex regional pain syndrome (CRPS), with much of the literature focusing on reorganization of the primary motor cortex (M1). Presumed changes in the M1 representation of the CRPS-affected body part have contributed to new CRPS treatments, which are increasingly being integrated in the clinic. We systematically investigated the evidence for altered M1 function in CRPS. We adhered to rigorous systematic review procedure in our search strategy, risk-of-bias appraisal, and data extraction. Eighteen studies comprising 14 unique data sets were included. The included studies used several neuroimaging techniques, whose outcomeswe grouped intoM1 cortical excitability, spatial representation, reactivity, and glucose metabolism, and conducted meta-analyses where possible. Risk of bias across studies was high, mainly due tomissing data and unblinded assessment of outcomes. No definitive conclusions can be drawn regarding M1 spatial representation, reactivity, or glucose metabolism in CRPS. There is limited evidence for bilateralM1 disinhibition in CRPS of the upper limb. Perspective: Despite widely held assumptions of primary motor cortex dysfunction in complex regional pain syndrome, there is only evidence to support bilateral disinhibition, and there is high risk of bias across the literature. Refereed/Peer-reviewed

That complex regional pain syndrome (CRPS) is associated with functional reorganization in the primary somatosensory cortex (S1) is widely accepted and seldom questioned. Despite more than a decade of research, there has been no systematic review of the CRPS literature concerning the changes in S1 function, and therefore the extent of these changes is unclear. Here we conduct a systematic review and meta-analysis to quantify the spatial and temporal aspects of S1 function in CRPS. A comprehensive search strategy identified functional neuroimaging studies of S1 in CRPS. We adhered to a rigorous systematic review protocol when extracting data and appraising risk of bias. Outcomes were grouped into spatial representation; activation levels, including disinhibition; peak latency of activation; and glucose metabolism. Meta-analysis was conducted where possible. Fifteen studies were included, all investigating upper-extremity CRPS. In patients with CRPS, the S1 spatial representation of the affected hand is smaller than that of the unaffected hand and that of non-CRPS controls; however, this evidence comes from only a few studies. There is no difference in activation, disinhibition, or latency of peripherally evoked S1 responses in CRPS. The risk of bias was high across studies, mainly from unclear sampling methods and unblinded analysis of outcomes. Perspective: The evidence for a difference in function of the primary somatosensory cortex in CRPS compared with controls is clouded by high risk of bias and conflicting results, but reduced representation size seems consistent. Refereed/Peer-reviewed

This is the post-print version of the final paper published in The Journal of Pain. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 The American Pain Society. Graded motor imagery (GMI) is becoming increasingly used in the treatment of chronic pain conditions. The objective of this systematic review was to synthesize all evidence concerning the effects of GMI and its constituent components on chronic pain. Systematic searches were conducted in 10 electronic databases. All randomized controlled trials (RCTs) of GMI, left/right judgment training, motor imagery, and mirror therapy used as a treatment for chronic pain were included. Methodological quality was assessed using the Cochrane risk of bias tool. Six RCTs met our inclusion criteria, and the methodological quality was generally low. No effect was seen for left/right judgment training, and conflicting results were found for motor imagery used as stand-alone techniques, but positive effects were observed for both mirror therapy and GMI. A meta-analysis of GMI versus usual physiotherapy care favored GMI in reducing pain (2 studies, n = 63; effect size, 1.06 [95% confidence interval, .41, 1.71]; heterogeneity, I2 = 15%). Our results suggest that GMI and mirror therapy alone may be effective, although this conclusion is based on limited evidence. Further rigorous studies are needed to investigate the effects of GMI and its components on a wider chronic pain population. NHMRC

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]50.86) but group use only for the anxiety (PSI50.74) and stress (PSI50.82) subscales. A DASS-21 aggregate score of ‘‘negative affect’’ lacked fit to the Rasch model (c25191.48, 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. Refereed/Peer-reviewed

Threatening stimuli are thought to bias spatial attention toward the location from which the threat is presented. Although this effect is well-established in the visual domain, little is known regarding whether tactile attention is similarly affected by threatening pictures. We hypothesised that tactile attention might be more affected by cues implying physical threat to a person's bodily tissues than by cues implying general threat. In the present study, participants made temporal order judgments (TOJs) concerning which of a pair of tactile (or auditory) stimuli, one presented to either hand, at a range of inter-stimulus intervals, had been presented first. A picture (showing physical threat, general threat, or no threat) was presented in front of one or the other hand shortly before the tactile stimuli. The results revealed that tactile attention was biased toward the side on which the picture was presented, and that this effect was significantly larger for physical threat pictures than for general threat or neutral pictures. By contrast, the bias in auditory attention toward the side of the picture was significantly larger for general threat pictures than for physical threat pictures or neutral pictures. These findings therefore demonstrate a modality-specific effect of physically threatening cues on the processing of tactile stimuli, and of generally threatening cues on auditory information processing. These results demonstrate that the processing of tactile information from the body part closest to the threatening stimulus is prioritized over tactile information from elsewhere on the body.

QUESTION: Does faulty proprioceptive input disrupt the internal model of the body that the brain uses to control movement? DESIGN: Randomised, within-participant experimental study. PARTICIPANTS: Twenty- two (13 F) healthy adults. INTERVENTION: Participants performed a motor imagery task that involved making left/right judgements of pictured right and left hands in 16 different postures under five conditions involving stimuli being applied to the experimental (L) hand. The five conditions were: vibration (of the wrist extensor tendons to elicit the illusion of wrist flexion), sham (vibration of the ulna styloid), active flexion, passive flexion, and control (no stimulus). OUTCOME MEASURES: Accuracy and response time of the control (R) hand in making left/right judgements of the pictures. RESULTS: Response time during vibration was longer for those who reported the illusion of wrist flexion (n = 18) than for those who did not (p < 0.01) whereas accuracy was unaffected (p = 0.71). In those who reported the illusion, accuracy was unaffected by condition, hand or picture (p > 0.21). Response time during vibration was 910 ms longer (95% CI 730 to 1090) for pictures of the experimental (L) hand (mean 2731 ms, 95% CI 2543 to 2918) than it was for pictures of the control (R) hand (mean 1822 ms, 95% CI 1634 to 2009), and approximately 580 ms longer (95% CI 380 to 785) for pictures of either hand during any other condition (p < 0.025). CONCLUSION: Faulty proprioceptive input disrupted this motor imagery task, which suggests it can disrupt the model of the limb that the brain uses for movement.

The way people with chronic low back pain think about pain can affect the way they move. This case report concerns a patient with chronic disabling low back pain who underwent functional magnetic resonance imaging scans during performance of a voluntary trunk muscle task under three conditions: directly after training in the task and, after one week of practice, before and after a 2.5 hour pain physiology education session. Before education there was widespread brain activity during performance of the task, including activity in cortical regions known to be involved in pain, although the task was not painful. After education widespread activity was absent so that there was no brain activation outside of the primary somatosensory cortex. The results suggest that pain physiology education markedly altered brain activity during performance of the task. The data offer a possible mechanism for difficulty in acquisition of trunk muscle training in people with pain and suggest that the change in activity associated with education may reflect reduced threat value of the task.

Many authors report changes in the control of the trunk muscles in people with low back pain (LBP). Although there is considerable disagreement regarding the nature of these changes, we have consistently found differential effects on the deep intrinsic and superficial muscles of the lumbopelvic region. Two issues require consideration; first, the potential mechanisms for these changes in control, and secondly, the effect or outcome of changes in control for lumbopelvic function. Recent data indicate that experimentally induced pain may replicate some of the changes identified in people with LBP. While this does not exclude the possibility that changes in control of the trunk muscles may lead to pain, it does argue that, at least in some cases, pain may cause the changes in control. There are many possible mechanisms, including changes in excitability in the motor pathway, changes in the sensory system, and factors associated with the attention demanding, stressful and fearful aspects of pain. A new hypothesis is presented regarding the outcome from differential effects of pain on the elements of the motor system. Taken together these data argue for strategies of prevention and rehabilitation of LBP.

Central nervous system performance is disrupted by pain and by the threat of pain. It is not known whether disruption caused by the threat of pain is dependent on the likelihood of pain occurring. We hypothesised that when a painful stimulus is possible but unpredictable central nervous system performance is reduced, but when the pain is predictable and unavoidable it is not. Sixteen healthy subjects performed a reaction time task during predictable and unpredictable conditions (100% and 50% probability of pain, respectively). Group data showed increased reaction time with the threat of pain by 50 ms (95% CI 16 to 83 ms) for the predictable condition and 46 ms (95% CI 12 to 80 ms) for the unpredictable condition (p lt 0.01 for both), but there was no difference between predictable and unpredictable conditions (p = 0.41). However, individual data showed that there was a differential effect in 75% of subjects (p lt 0.05 for all) and that there was a greater effect of predictable pain for some subjects and a greater effect of unpredictable pain for others. Reaction time was related to reported anxiety (r = 0.49, p = 0.02 for both conditions). The predictability of a painful stimulus may have a differential effect on central nervous system performance within individuals, but anxiety about the impending pain appears to be important in determining this effect.

A recent study has found that activity in multisensory brain areas, namely the premotor cortex, intraparietal cortex and the putamen, mirrors the vividness of ownership over a mannequin, induced by the body-swap illusion. Refereed/Peer-reviewed