The journal of pain : official journal of the American Pain Society
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The past few decades have witnessed a huge leap forward in our understanding of the mechanistic underpinnings of pain, in normal states where it helps protect from injury, and also in pathological states where pain evolves from a symptom reflecting tissue injury to become the disease itself. However, despite these scientific advances, chronic pain remains extremely challenging to manage clinically. Although the number of potential treatment targets has grown substantially and a strong case has been made for a mechanism-based and individualized approach to pain therapy, arguably clinicians are not much more advanced now than 20 years ago, in their capacity to either diagnose or effectively treat their patients. The gulf between pain research and pain management is as wide as ever. We are still currently unable to apply an evidence-based approach to chronic pain management that reflects mechanistic understanding, and instead, clinical practice remains an empirical and often unsatisfactory journey for patients, whose individual response to treatment cannot be predicted. In this article we take a common and difficult to treat pain condition, chronic low back pain, and use its presentation in clinical practice as a framework to highlight what is known about pathophysiological pain mechanisms and how we could potentially detect these to drive rational treatment choice. We discuss how present methods of assessment and management still fall well short, however, of any mechanism-based or precision medicine approach. Nevertheless, substantial improvements in chronic pain management could be possible if a more strategic and coordinated approach were to evolve, one designed to identify the specific mechanisms driving the presenting pain phenotype. We present an analysis of such an approach, highlighting the major problems in identifying mechanisms in patients, and develop a framework for a pain diagnostic ladder that may prove useful in the future, consisting of successive identification of 3 steps: pain state, pain mechanism, and molecular target. Such an approach could serve as the foundation for a new era of individualized/precision pain medicine. The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION)-American Pain Society (APS) Pain Taxonomy (AAPT) includes pain mechanisms as 1 of the 5 dimensions that need to be considered when making a diagnostic classification. The diagnostic ladder proposed in this article is consistent with and an extension of the AAPT. ⋯ We discuss how identifying the specific mechanisms that operate in the nervous system to produce chronic pain in individual patients could provide the basis for a targeted and rational precision medicine approach to controlling pain, using chronic low back pain as our example.
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Multicenter Study
Parent and Child Catastrophizing in Pediatric Sickle Cell Disease.
Pain catastrophizing is poorly understood in children and adolescents with sickle cell disease (SCD) and their parents. The objectives of this study were twofold: 1) to evaluate the interplay between parent and child pain catastrophizing and its effect on disability among youth with SCD, and 2) to evaluate whether child pain catastrophizing served as a mechanism that explained the relation between pain and functional disability within the context of varying levels of parent pain catastrophizing. One hundred youth (8-18 years old) with SCD and parents completed measures of pain characteristics (pain frequency and intensity), catastrophizing (Pain Catastrophizing Scale), and the outcome of functional disability (Functional Disability Inventory) in a cross-sectional study. Youth with low levels of catastrophizing showed high levels of disability in the presence of high levels of parent catastrophizing. Additionally, child pain catastrophizing was a significant mechanism that partially explained the effect of higher pain frequency and pain intensity on greater levels of disability, but only at low levels of parent pain catastrophizing. High levels of parent catastrophizing and incongruence between child and parent catastrophizing contributes to poorer functional outcomes in youth with SCD. ⋯ Youth with SCD and parents with high levels of catastrophic thinking about child pain or incongruent levels of catastrophizing are at increased risk for greater child disability. Clinicians treating youth with SCD should focus on targeting worried thinking about pain in patients and parents to facilitate improved function.
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Cognitive appraisals inform and shape individuals' pain experiences. As researchers examine mechanisms of cognitive-behavioral interventions for chronic pain, psychometrically sound measures based in cognitive theory are needed to directly assess pain beliefs. The Pain Beliefs Questionnaire (PBQ), a 32-item self-report measure informed by coping and appraisal theory, was designed to assess children's pain threat appraisals, problem-focused pain coping efficacy, and emotion-focused pain coping efficacy. The present study aimed to: 1) create a short form of the PBQ, and 2) evaluate the psychometric properties of the reduced measure in a large database of pediatric patients with functional abdominal pain (n = 871). Item reduction analyses identified an 18-item short form of the PBQ (PBQ-SF) that exhibited psychometric properties similar to the original measure. All 3 subscales of the PBQ-SF exhibited strong internal consistency (α levels ranged from .79 to .80) and adequate test-retest reliability at 2 weeks. Evidence for construct validity was provided by examining patterns of partial correlations for each subscale. The PBQ-SF represents a valid and reliable measure for evaluating children's pain beliefs. Future studies should investigate the treatment sensitivity of the PBQ-SF to evaluate its appropriateness for use in clinical trials. ⋯ This article presents the psychometric properties of a reduced 18-item version of a measure used to assess children's pain beliefs in a large sample of children with functional abdominal pain. This measure could help identify processes and individual differences underlying children's responses to psychological treatments for chronic pain.
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Negative interpretation bias, the tendency to appraise ambiguous situations in a negative or threatening way, has been suggested to be important for the development of adult chronic pain. To our knowledge, this is the first study to examine the role of a negative interpretation bias in adolescent pain. We first developed and piloted a novel task that measures the tendency for adolescents to interpret ambiguous situations as indicative of pain and bodily threat. Using this task in a separate community sample of adolescents (N = 115), we then found that adolescents who catastrophize about pain, as well as those who reported more pain issues in the preceding 3 months, were more likely to endorse negative interpretations, and less likely to endorse benign interpretations, of ambiguous situations. This interpretation pattern was not, however, specific for situations regarding pain and bodily threat, but generalized across social situations as well. We also found that a negative interpretation bias, specifically in ambiguous situations that could indicate pain and bodily threat, mediated the association between pain catastrophizing and recent pain experiences. Findings may support one potential cognitive mechanism explaining why adolescents who catastrophize about pain often report more pain. ⋯ This article presents a new adolescent measure of interpretation bias. We found that the tendency to interpret ambiguous situations as indicative of pain and bodily threat may be one potential cognitive mechanism explaining why adolescents who catastrophize about pain report more pain, thus indicating a potential novel intervention target.
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Multicenter Study
Disrupted self-perception in people with chronic low back pain. Further evaluation of The Fremantle Back Awareness Questionnaire.
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. ⋯ 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.