Volume 9, Issue 1

Background and aims We explore the relationship between behaviour and cognition in chronic pain by applying Action Identification Theory (AIT). AIT holds that every action may be construed in several ways. High level construals confer greater meaning than lower level construals. When an action is interrupted a lower level, more concrete identity with reduced meaning is elicited. We hypothesized that interference of activity by chronic pain affects the meaning ascribed to activity and thus a person’s overall sense of meaning in life. Methods In Study 1, a measure of Action Identification in Pain (AIP) is developed. In Study 2, the AIP was administered to 47 chronic pain patients who also completed the Meaningful Life Measure and measures of pain interference, depression, acceptance and optimism. Results High levels of action identification were positively correlated with meaning in life and high levels of interference were negatively correlated with meaning in life. Contrary to expectation interference and action identification were not associated. Further analyses showed that inclusion of depression, acceptance and optimism eliminated the effect of pain interference but only optimism abolished the effect of action identification. Conclusion Chronic pain patients holding higher levels of action identification report a greater sense of meaning in life. Meaning in life is also associated with the amount of interference of behavioural activity. The anticipated relationship between action identification and interference was not observed. The present evidence suggests that interference and action identification contribute independently to a person’s sense of meaning in life.

Background and aims Stress has been pointed out as an important influential factor in the development and maintaining of the fibromyalgia syndrome (FMS) . Since stress may worsen the pain experience, the development of individual strategies for coping with stress is essential to reduce the impact of FMS on daily life. The aim of the study was to investigate whether a group based stress management cognitive behaviour therapy (CBT) programme could influence self-reported stress, wellbeing and life control, as well as self-reported pain behaviour in female FMS patients. Methods 48 female FMS patient were randomized into a cognitive behaviour therapy treatment group ( n = 24) and a waitlist control group ( n = 24) . When the 6 months waitlist period was over the control group received the same CBT programme. This allowed two analytical approaches, one based on the randomized controlled trial design and one based on a before-and-after design to improve the statistical power of the study. Four psychometric instruments were used: The West Haven-Yale Multidimensional Pain Inventory (three parts, MPI-1 to MPI-3), the Maastricht Questionnaire, the Everyday Life Stress, and the Montgomery-Åsberg Depression rating scale – self-reported. Primary outcome was the MPI-1 dimension ‘life control’, secondary outcomes were the MPI-1 dimensions ‘interference’, ‘affective distress’ and ‘support from spouses or significant others’, the various MPI-2 dimensions, the ‘general activity level’ in the MPI-3 dimension, and ‘vital exhaustion’, ‘stress behaviour’, and ‘depression’. The only tertiary outcome was the MPI-1 dimension ‘pain severity’. Results In the RCT design the West Haven-Yale Multidimensional Pain Inventory dimensions ‘life control’, ‘interference from pain’, ‘affective distress’, ‘support from spouses or significant others’, and ‘distracting responses’ and ratings for depression improved in the treatment group as compared with the control group. In the before-and after design these improvements were maintained and enhanced during 1-year follow-up, and so was the ‘vital exhaustion’ and ‘stress behaviour’. ‘Pain severity’ was rated higher after the intervention. Conclusions Cognitive behaviour therapy improved the life control in a female population with FMS. Coping behaviour in response to chronic pain was improved at the same time and in spite of higher subjective ratings of pain. Positive effects were seen on depression, vital exhaustion and stress behaviour. The effects of therapy were maintained and enhanced during the follow up period. It appears that women with FMS after the CBT treatment, according to this protocol obtained tools leading to better acceptance of their disorder. Implications FMS is a disorder with great therapeutic challenges. Total abolishment of pain symptoms is extremely difficult or impossible to achieve. Thus, the development of individual strategies for coping with pain is essential to reduce its impact on daily life. Since stress may worsen the pain experience, coping with stress might be a promising route to accomplishing that goal. In evaluations of interventions for pain it is important to monitor the effect on behaviour responses to pain and not only ratings of pain itself.

Objective Insomnia is the most commonly diagnosed comorbidity disorder among patients with chronic pain. This circumstance requests brief and valid instruments for screening insomnia in epidemiological studies. The main object of this study was to assess the psychometric properties and factor structure of the Swedish version of the Insomnia Severity Index (ISI). The ISI is a short instrument designed to measure clinical insomnia and one of the most common used scales both in clinical and research practice. However there is no study in Sweden that guarantees neither its factor structure nor its feasibility in chronic pain patients. We further examined the measurement invariance property of the ISI across the two sexes. Methods The ISI was administered to 836 (269 men and 567 women) chronic pain patients from the Swedish Quality Registry for Pain Rehabilitation. This study used demographic data, the Hospital Anxiety and Depression Scale (HADS), the Mental Summary Component (MSC) of the Health Survey (SF-36) and the item 7 from Multidimensional Pain Inventory (MPI). The sample was divided into two random halves: exploratory factor analysis (EFA) was performed in the first sample (N1 = 334, 40%) and confirmatory factor analysis (CFA) in the second half of the sample (N2 = 502, 60%). The measurement and structural invariance of the proposed structure (4-item version) between the two sexes as well as reliability and validity indexes were further assessed. Results Exploratory factor analysis using the principal axis factoring method generated one global factor structure for the ISI, explaining 63.1% of the total variance. The one factor solution was stable between the two sexes. Principal component analysis was also applied and indicated almost identical results. The structure was further assessed by CFA, resulting in an adequate fit only after omitting three items. The difference on structural and measurement invariance in the loadings by participants’ sex was not significant (Δ χ 2 = 10.6; df = 3; p = .69 and Δ χ 2 = 2.86; df = 3; p = 41 respectively). The shorter version four-item Insomnia Severity Index (ISI-4) was analysed further. The Chronbach’s alpha for the global ISI-4 score was 0.88. The construct validity of the ISI-4 was also supported by the, Hospital Anxiety and Depression Scale, the Mental Summary Component of quality of life and quality of sleep data. Pain intensity was significantly associated with the ISI-4 score (beta = .29, p < 001) whereas no significant correlation between four-item Insomnia Severity Index score and age was observed ( p > 05). Conclusions and implications Although short, the four-item Insomnia Severity Index (ISI-4) version seemed to effectively assess insomnia in chronic pain patients. An important clinical implication is that the four-item Swedish Insomnia Severity Index can be used in chronic pain cohorts when screening for insomnia problems. Its measurement and structural invariance property across the two sexes shows that the ISI-4 is a valid measure of the insomnia across groups of chronic patients. Our results also suggest its utility both in pain clinical practice and research purposes.

Background and aims Investigation of the multidimensional correlates of pressure pain threshold (PPT) requires the study of large cohorts, and thus the use of multiple raters, for sufficient statistical power. Although PPT testing has previously been shown to be reliable, the reliability of multiple raters and investigation for systematic bias between raters has not been reported. The aim of this study was to evaluate the intrarater and interrater reliability of PPT measurement by handheld algometer at the wrist, leg, cervical spine and lumbar spine. Additionally the study aimed to calculate sample sizes required for parallel and cross-over studies for various effect sizes accounting for measurement error. Methods Five research assistants (RAs) each tested 20 pain free subjects at the wrist, leg, cervical and lumbar spine. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and systematic bias were calculated. Results Both intrarater reliability (ICC = 0.81–0.99) and interrater reliability (ICC = 0.92–0.95) were excellent and intrarater SEM ranged from 79 to 100 kPa. There was systematic bias detected at three sites with no single rater tending to consistently rate higher or lower than others across all sites. Conclusion The excellent ICCs observed in this study support the utility of using multiple RAs in large cohort studies using standardised protocols, with the caveat that an absence of any confounding of study estimates by rater is checked, due to systematic rater bias identified in this study. Implications Thorough training of raters using PPT results in excellent interrater reliability. Clinical trials using PPT as an outcome measure should utilise a priori sample size calculations.

ABSTRACT Background and aims Pain is known to be a subjective experience yet the majority of pain related research does not address the lived experience of the condition. Difficult to diagnose, Complex Regional Pain Syndrome (CRPS) is often poorly managed. The aim of this paper was to identify and synthesise the currently available literature on experiences of living with chronic pain in order to understand where and how CRPS research may be best situated in the future. Methods A narrative review was performed and ProQuest, EBSCO, Informit, Scopus/Science Direct and Web of Science, Medline, CINHAL and Google Scholar were searched in order to identify the literature from 1998 until 2015. 301 papers were identified of which 197 described the lived experience of chronic pain conditions. 12 papers were examined closely to determine the experience of living with CRPS or a similar chronic pain condition that does not have a definite pain origin such as cancer or endometriosis. Results Known understandings of pain were identified and a model was developed depicting the lived experience of chronic pain starting with loss of the former healthy, pain free self and culminating in acceptance of the condition. Major themes identified were disbelief/invisibility of pain, loss, coping with a non-compliant/constant painful body, self-management and alleviating pain/treatment. The review also found that there is no peer-reviewed published literature on the lived experience of CRPS. Conclusions Little is known about the lived experience of CRPS. There appears to be a clear indication that research needs to be conducted into CRPS from a lived experience perspective in order to provide information to patients, the general public, health practitioners and policy makers of previously unknown characteristics of this condition which may improve health outcomes for this patient cohort. It has been identified that patients and their families should be active participants in education of health practitioners and in providing information to inform the development of National Pain Strategies currently being devised throughout the world. Implications Research into the lived experience of chronic pain conditions, and CRPS in particular, can help to provide information to enhance understanding enabling national pain strategies and future treatment guidelines strategies to be devised appropriately.

Background and aims The clinical management of chronic neuropathic pain remains a global health challenge. Current treatments are either ineffective, or associated with unwanted side-effects. The development of effective, safe therapies requires the identification of novel therapeutic targets using clinically relevant animal models of neuropathic pain. Peroxisome proliferator activated receptor alpha (PPARα), is a member of the nuclear hormone family of transcription factors, which is widely distributed in the peripheral and central nervous systems. Pharmacological studies report antinociceptive effects of PPARα agonists following systemic administration in rodent models of neuropathic pain, however the neuronal mechanisms and sites of action mediating these effects are unclear. The aim of this study was to investigate the effects of systemic administration of the synthetic PPARα agonist, WY-14643 on mechanically-evoked responses of spinal cord dorsal horn wide dynamic range (WDR) neurones in the spinal nerve ligated (SNL) model of neuropathic pain in rats. In addition, comparative molecular analysis of mRNA coding for PPARα and PPARα protein expression in the spinal cord of sham-operated and neuropathic rats was performed. Methods Lumbar L5–L6 spinal nerve ligation was performed in male Sprague–Dawley rats (110–130 g) under isoflurane anaesthesia. Sham controls underwent similar surgical conditions, but without ligation of the L5–L6 spinal nerves. Hindpaw withdrawal thresholds were measured on the day of surgery -day 0, and on days- 2, 4, 7, 10 and 14 post-surgery. At day 14 extracellular single-unit recordings of spinal (WDR) dorsal horn neurons were performed in both sham and SNL neuropathic rats under anaesthesia. The effects of intraperitoneal (i.p.) administration of WY-14643 (15 and 30 mg/kg) or vehicle on evoked responses of WDR neurons to punctate mechanical stimulation of the peripheral receptive field of varying bending force (8–60 g) were recorded. In a separate cohort of SNL and sham neuropathic rats, the expression of mRNA coding for PPARα and protein expression in the ipsilateral and contralateral spinal cord was determined using quantitative real time polymerase chain reaction (qRT-PCR) and western blotting techniques respectively. Results WY-14643 (15 and 30mg/kg i.p.) rapidly attenuated mechanically evoked (8, 10 and 15g) responses of spinal WDR neurones in SNL, but not sham-operated rats. Molecular analysis revealed significantly increased PPARα protein, but not mRNA, expression in the ipsilateral spinal cord of SNL, compared to the contralateral side in SNL rats. There were no changes in PPARα mRNA or protein expression in the sham controls. Conclusion The observation that levels of PPARα protein were increased in ipsilateral spinal cord of neuropathic rats supports a contribution of spinal sites of action mediating the effects of systemic WY-14643. Our data suggests that the inhibitory effects of a PPARα agonist on spinal neuronal responses may account, at least in part, for their analgesic effects of in neuropathic pain. Implication Selective activation of PPARα in the spinal cord may be therapeutically relevant for the treatment of neuropathic pain.

Graphical Abstract Abstract Background and aims Assessment of pain in children with cognitive impairment (CI) including cerebral palsy (CP) is difficult. Several pain assessment tools have been developed and validated for use in children with CI. The revised Face, Legs, Activity, Cry and Consolability score (r-FLACC) includes core behaviours of children with CI and adds an open-ended descriptor for individualisation (5 items assigned 0–2 points, total range 0–10). Other pain assessment tools including individual pain behaviours are the Individualised Numeric Rating Scale (INRS) and the Paediatric Pain Profile (PPP). Both the Noncommunicating Childrens’s Pain Checklist – Postoperative version (NCCPC-PV) and the Echelle Douleur Enfant San Salvador (DESS) are developed from core pain behaviours for children with CI but have no possibility for individualisation. For successful clinical application a pain assessment tool should not only be reliable and valid, but also clinically feasible. The aim of this study was to select the most valid and feasible pain assessment tool for children with CI and translate that tool into Danish. Methods A literature review on studies on pain, pain assessment tools, feasibility and CI was performed. Studies were evaluated with focus on children with CI not able to self-report pain and the r-FLACC was chosen for translation. A10 step translation process guideline was used from the Translation and Cultural Adaptation Group, which describes preparation, forward translation, reconciliation, back translation, back translation review, harmonization, cognitive debriefing, review of cognitive debriefing, finalisation, proofreading, and final report. Results Studies show that the r-FLACC is superior regarding clinical feasibility. The r-FLACC is a useful tool for assessing pain in children with CI due to its ease to use in a clinical setting and its use of both core and individual pain behaviours. In the back translation review discrepancies of words between the original and the back-translated English versions were assessed and in three of nine discrepancies a word was changed. In the cognitive debriefing no issues were found regarding understandability, interpretation or cultural relevance of the translation. No other language translations of the r-FLACC score have been published; hence the harmonisation step with a comparison of the English back translations was not possible. Conclusions The r-FLACC is assessed to have the most preferable profile with use of core pain behaviours, flexibility regarding individualisation, good psychometric properties, and high clinical feasibility; hence suited for use in Danish children with CP. A Danish version of the r-FLACC score now exits and may be used in a clinical setting for the assessment of pain. Implications It is important for health-care professionals to be able to assess pain in hospitalized children with CP who are not able to self-report. The r-FLACC score is clinically feasible and has the potential for becoming the gold standard of pain assessments in children with CP. A standardised approach to pain assessment may lead to an increased focus on pain and help improve the treatment of pain in children with CP in Denmark.

Graphical Abstract Abstract Background and aims Pain in children with cerebral palsy (CP) is difficult to assess and is therefore not sufficiently recognized and treated. Children with severe cognitive impairments have an increased risk of neglected postoperative, procedural and chronic pain resulting in decreased quality of life. The r-FLACC (revised Face, Legs, Activity, Cry and Consol ability) pain score is an internationally acclaimed tool for assessing pain in children with CP because of its ease to use and its use of core pain behaviours. In addition the r-FLACC pain score may be superior to other pain assessment tools since it includes an open- ended descriptor for incorporation of individual pain behaviours. The COSMIN group has set up three quality domains, which describe the quality of Health-Related Patient-Reported Outcomes (HR-PROs). These are reliability (internal consistency, reliability and measurement error), validity (content validity, construct validity and criterion validity) and responsiveness. The r-FLACC score has only been assessed for reliability and validity in the original English version by the developers of the score. The aim of this study is to assess reliability and validity of the r-FLACC pain score for use in Danish children with CP. Methods Twenty-seven children aged 3–15 years old with CP were included after orthopaedic surgery. Two methods for assessment of postoperative pain were used. Pain intensity was assessed by r-FLACC, with a 2 min standardized video recording of the child, and the Observational Visual Analogue Score (VAS-OBS) assessed by the parents. The COSMIN checklist was used as a guideline in the reliability and validity testing of the r-FLACC score. Results Reliability was supported by three measurement properties. Internal consistency was excellent with a Cronbachs alpha of 0.9023 and 0.9758 (two raters). A factor analysis of the subgroups in the r-FLACC score showed unidimensionality. A test-retest showed excellent intra-rater reliability with an intraclass correlation (ICC) of 0.97530. Inter-rater reliability was acceptable with an ICC of 0.74576. Validity was supported by three measurement properties. Content validity was tested by the originators of the r-FLACC. Construct validity was supported by a significant increase in r-FLACC scores following surgery ( n = 17; difference 2.23; p = 0.0397). Criterion validity was acceptable with Pearson’s correlation coefficients of 0.76 and 0.59 when comparing r-FLACC scores and VAS-OBS scores. Conclusions and implications This study benefits from a systematical approach to the validation and reliability parameters by using the COSMIN checklist as a guideline. It is evident that the r-FLACC pain score maintains its psychometric properties after translation. In conclusion, the r-FLACC pain score is valid and reliable in assessing postoperative pain in children with CP not able to self-report pain. With the r-FLACC pain score clinicians have a valid tool for assessing postoperative pain, hence increasing the quality of pain management in children with CP. In addition the validated r-FLACC score has the potential for use in interventional research regarding pain management in this vulnerable group of patients. Future perspectives include validation of the r-FLACC score for procedural and chronic everyday pain and implementation into daily practice.

Background and purpose Recurrent vulvar pain is a common and debilitating condition which has received remarkably little attention in pain research. For instance, little is known about how these women cope with sexual activities, and there are no structured assessment tools. The purpose of this study was to explore coping strategies in this group, with a view to develop a measure to assess how women with vulvar pain cope with sexual activities. Methods The current study is based on a subsample from a longitudinal study about vulvar pain in a student sample consisting of women between 18 and 35 years old ( N = 964). Only data from the ones reporting recurrent vulvar pain during the last six months ( N = 289) were used in the analyses. First, the CHAMP Sexual Pain Coping Scale (CSPCS) was created, with the aim of assessing how women with vulvar pain cope with sexual activities. The scale was inspired by previous research on women with vulvar pain as well as well-known coping strategies in other pain populations. Second, the psychometric properties of the scale were explored by analyzing the factor structure and internal reliability. Third, validity features were examined in terms of criterion validity and construct validity. Results The analyses supported a three-factor solution, embracing the strategies endurance, avoidance and alternative coping. The internal reliability of the subscales turned out to be good, and the criterion validity was supported for all three subscales. The construct validity was clearly supported for the endurance and the avoidance subscales, but not for the alternative coping subscale. Conclusions The findings support the CSPCS as an instrument for assessing how women with vulvar pain cope with sexual activities. The strategies endurance, avoidance and alternative coping correspond with findings from earlier research. Endurance reflects a tendency to engage in and continue with sexual activities despite pain, while attempting to minimize or suppress thoughts of pain. Avoidance, on the other hand, involves efforts to stay away from sexual activities, in particular vaginal penetration, because of fear of pain. Alternative coping refers to endeavours to find alternative sexual activities that do not necessarily involve vaginal penetration. Even though this first study indicates that the CSPCS may be psychometrically sound, more studies are needed to confirm the psychometric properties and clinical application of this instrument. In particular, the construct validity of the alternative coping subscale needs to be further evaluated. Implications A valid instrument for assessing strategies for coping with sexual activities in this population has important clinical implications, since it provides a method that may enhance assessment procedures, be used in research, and stimulate the development of treatment.

Background and aims Quantitative sensory testing of thermal perception (QTT) is a valuable method in clinical and experimental assessment of the function of small nerve fibres. Previous studies have indicated existence of spatial summation for warmth, cool and heat pain stimulation, but study designs and assessment methods have not always been mutually consistent. The aims of this study were, first , to examine spatial summation of QTT by differently sized contact thermodes, and, second , to evaluate if these differences are significant from a clinical and scientific perspective. Methods Sixteen healthy subjects were included. Warmth detection (WDT), cool detection (CDT) and heat pain (HPT) thresholds were assessed in random order, with the stimulation areas of the contact thermodes of 3.0, 6.3 and 12.5 cm 2 , blinded to the subjects. Assessments were made bilaterally at volar part of the distal arm and medial part of the lower leg. Data analyses were by a mixed model with random effect for subject and fixed-effects for the variables, site (arm/leg), thermode area (ln thermode area) and side (dominant/non-dominant), in addition to conventional pairwise non-parametric comparisons. Results Data from 2 subjects were excluded. In the remaining 14 subjects only 4 subjects were able to identify the correct sequence of thermode sizes. The model demonstrated highly statistical significant relationships regarding main effects: thermode area ( P < 0.0001) and stimulation site ( P < 0.0001; except for CDT P = 0.011). The only significant interaction was between thermode area*site ( P = 0.005) for CDT. The study demonstrated in 17 of 18 possible comparisons between thermode size and stimulation site, a significant spatial summation for WDT, CDT and HPT. Conclusion This randomized, single-blind study of thermal thresholds demonstrated spatial summation and that considerable deviations may occur if values obtained with differing thermode sizes are used uncritically. Implications Data from the present study enable interpolation of thermal thresholds with differing thermode sizes, facilitating comparisons across studies.