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1.  A Novel Tool for the Assessment of Pain: Validation in Low Back Pain 
PLoS Medicine  2009;6(4):e1000047.
Joachim Scholz and colleagues develop and validate an assessment tool that distinguishes between radicular and axial low back pain.
Adequate pain assessment is critical for evaluating the efficacy of analgesic treatment in clinical practice and during the development of new therapies. Yet the currently used scores of global pain intensity fail to reflect the diversity of pain manifestations and the complexity of underlying biological mechanisms. We have developed a tool for a standardized assessment of pain-related symptoms and signs that differentiates pain phenotypes independent of etiology.
Methods and Findings
Using a structured interview (16 questions) and a standardized bedside examination (23 tests), we prospectively assessed symptoms and signs in 130 patients with peripheral neuropathic pain caused by diabetic polyneuropathy, postherpetic neuralgia, or radicular low back pain (LBP), and in 57 patients with non-neuropathic (axial) LBP. A hierarchical cluster analysis revealed distinct association patterns of symptoms and signs (pain subtypes) that characterized six subgroups of patients with neuropathic pain and two subgroups of patients with non-neuropathic pain. Using a classification tree analysis, we identified the most discriminatory assessment items for the identification of pain subtypes. We combined these six interview questions and ten physical tests in a pain assessment tool that we named Standardized Evaluation of Pain (StEP). We validated StEP for the distinction between radicular and axial LBP in an independent group of 137 patients. StEP identified patients with radicular pain with high sensitivity (92%; 95% confidence interval [CI] 83%–97%) and specificity (97%; 95% CI 89%–100%). The diagnostic accuracy of StEP exceeded that of a dedicated screening tool for neuropathic pain and spinal magnetic resonance imaging. In addition, we were able to reproduce subtypes of radicular and axial LBP, underscoring the utility of StEP for discerning distinct constellations of symptoms and signs.
We present a novel method of identifying pain subtypes that we believe reflect underlying pain mechanisms. We demonstrate that this new approach to pain assessment helps separate radicular from axial back pain. Beyond diagnostic utility, a standardized differentiation of pain subtypes that is independent of disease etiology may offer a unique opportunity to improve targeted analgesic treatment.
Editors' Summary
Pain, although unpleasant, is essential for survival. Whenever the body is damaged, nerve cells detecting the injury send an electrical message via the spinal cord to the brain and, as a result, action is taken to prevent further damage. Usually pain is short-lived, but sometimes it continues for weeks, months, or years. Long-lasting (chronic) pain can be caused by an ongoing, often inflammatory condition (for example, arthritis) or by damage to the nervous system itself—experts call this “neuropathic” pain. Damage to the brain or spinal cord causes central neuropathic pain; damage to the nerves that convey information from distant parts of the body to the spinal cord causes peripheral neuropathic pain. One example of peripheral neuropathic pain is “radicular” low back pain (also called sciatica). This is pain that radiates from the back into the legs. By contrast, axial back pain (the most common type of low back pain) is confined to the lower back and is non-neuropathic.
Why Was This Study Done?
Chronic pain is very common—nearly 10% of American adults have frequent back pain, for example—and there are many treatments for it, including rest, regulated exercise (physical therapy), pain-killing drugs (analgesics), and surgery. However, the best treatment for any individual depends on the exact nature of their pain, so it is important to assess their pain carefully before starting treatment. This is usually done by scoring overall pain intensity, but this assessment does not reflect the characteristics of the pain (for example, whether it occurs spontaneously or in response to external stimuli) or the complex biological processes involved in pain generation. An assessment designed to take such factors into account might improve treatment outcomes and could be useful in the development of new therapies. In this study, the researchers develop and test a new, standardized tool for the assessment of chronic pain that, by examining many symptoms and signs, aims to distinguish between pain subtypes.
What Did the Researchers Do and Find?
One hundred thirty patients with several types of peripheral neuropathic pain and 57 patients with non-neuropathic (axial) low back pain completed a structured interview of 16 questions and a standardized bedside examination of 23 tests. Patients were asked, for example, to choose words that described their pain from a list provided by the researchers and to grade the intensity of particular aspects of their pain from zero (no pain) to ten (the maximum imaginable pain). Bedside tests included measurements of responses to light touch, pinprick, and vibration—chronic pain often alters responses to harmless stimuli. Using “hierarchical cluster analysis,” the researchers identified six subgroups of patients with neuropathic pain and two subgroups of patients with non-neuropathic pain based on the patterns of symptoms and signs revealed by the interviews and physical tests. They then used “classification tree analysis” to identify the six questions and ten physical tests that discriminated best between pain subtypes and combined these items into a tool for a Standardized Evaluation of Pain (StEP). Finally, the researchers asked whether StEP, which took 10–15 minutes, could identify patients with radicular back pain and discriminate them from those with axial back pain in an independent group of 137 patients with chronic low back pain. StEP, they report, accurately diagnosed these two conditions and was well accepted by the patients.
What Do These Findings Mean?
These findings indicate that a standardized assessment of pain-related signs and symptoms can provide a simple, quick diagnostic procedure that distinguishes between radicular (neuropathic) and axial (non-neuropathic) low back pain. This distinction is crucial because these types of back pain are best treated in different ways. In addition, the findings suggest that it might be possible to identify additional pain subtypes using StEP. Because these subtypes may represent conditions in which different pain mechanisms are acting, classifying patients in this way might eventually enable physicians to tailor treatments for chronic pain to the specific needs of individual patients rather than, as at present, largely guessing which of the available treatments is likely to work best.
Additional Information
Please access these Web sites via the online version of this summary at
This study is further discussed in a PLoS Medicine Perspective by Giorgio Cruccu and and Andrea Truini
The US National Institute of Neurological Disorders and Stroke provides a primer on pain in English and Spanish
In its 2006 report on the health status of the US, the National Center for Health Statistics provides a special feature on the epidemiology of pain, including back pain
The Pain Treatment Topics Web site is a resource, sponsored partly by associations and manufacturers, that provides information on all aspects of pain and its treatment for health care professionals and their patients
Medline Plus provides a brief description of pain and of back pain and links to further information on both topics (in English and Spanish)
The MedlinePlus Medical Encyclopedia also has a page on low back pain (in English and Spanish)
PMCID: PMC2661253  PMID: 19360087
2.  Mechanical and Heat Hyperalgesia Highly Predict Clinical Pain Intensity in Patients With Chronic Musculoskeletal Pain Syndromes 
Multiple abnormalities in pain processing have been reported in patients with chronic musculoskeletal pain syndromes. These changes include mechanical and thermal hyperalgesia, decreased thresholds to mechanical and thermal stimuli (allodynia), and central sensitization, all of which are fundamental to the generation of clinical pain. Therefore, we hypothesized that quantitative sensory tests may provide useful predictors of clinical pain intensity of such patients. Our previous studies of fibromyalgia (FM) patients have shown statistically significant correlations of quantitative sensory test results with clinical pain intensity, including mechanical spatial summation, number of pain areas, wind-up, and wind-up aftersensations. Although these tests predicted up to 59% of the variance in FM clinical pain intensity, their expense and technical complexities limited widespread use in clinical practice and trials. Thus, we developed practical tests of primary (mechanical) and secondary (heat) hyperalgesia that also strongly predict clinical pain intensity in patients with chronic musculoskeletal pain disorders. Thirty-six individuals with FM, 24 with local musculoskeletal pain, and 23 normal controls underwent testing of mechanical and heat hyperalgesia at the shoulders and hands. All subjects rated experimental pains using an electronic visual analog scale. Using either heat or pressure pain ratings as well as tender point counts and negative affect as predictors, up to 49.4% of the patients' variance of clinical pain intensity could be estimated. Results of this study emphasize the important contributions of peripheral and central factors to both local and widespread chronic pain. Overall, measures of mechanical and heat hyperalgesia in combination with tender point and negative affect provided powerful predictors of clinical pain intensity in chronic musculoskeletal pain patients that can be readily used in clinical practice and trials.
Simple tests of mechanical and heat hyperalgesia can predict large proportions of the variance in clinical pain intensity of chronic musculoskeletal pain patients and thus are feasible to be included in clinical practice and clinical trials.
PMCID: PMC3581857  PMID: 22739051
Mechanical; heat; hyperalgesia; tonic; fibromyalgia; back pain; chronic pain
3.  Fear of Pain, Pain Catastrophizing, and Acute Pain Perception: Relative Prediction and Timing of Assessment 
Pain-related fear and catastrophizing are important variables of consideration in an individual’s pain experience. Methodological limitations of previous studies limit strong conclusions regarding these relationships. In this follow-up study, we examined the relationships between fear of pain, pain catastrophizing, and experimental pain perception. One hundred healthy volunteers completed the Fear of Pain Questionnaire (FPQ-III), Pain Catastrophizing Scale (PCS), and Coping Strategies Questionnaire-Catastrophizing scale (CSQ-CAT) before undergoing the cold pressor test (CPT). The CSQ-CAT and PCS were completed again following the CPT, with participants instructed to complete these measures based on their experience during the procedure. Measures of pain threshold, tolerance, and intensity were collected and served as dependent variables in separate regression models. Sex, pain catastrophizing, and pain-related fear were included as predictor variables. Results of regression analyses indicated that after controlling for sex, pain-related fear was a consistently stronger predictor of pain in comparison to catastrophizing. These results were consistent when separate measures (CSQ-CAT vs. PCS) and time points (pre-task vs. “in-vivo”) of catastrophizing were used. These findings largely corroborate those from our previous study and are suggestive of the absolute and relative importance of pain-related fear in the experimental pain experience.
Although pain-related fear has received less attention in the experimental literature than pain catastrophizing, results of the current study are consistent with clinical reports highlighting this variable as an important aspect of the experience of pain.
PMCID: PMC2568976  PMID: 18486557
fear; catastrophizing; assessment; pain; experimental
4.  Sex, Gender, and Pain: A Review of Recent Clinical and Experimental Findings 
Sex-related influences on pain and analgesia have become a topic of tremendous scientific and clinical interest, especially in the last 10 to 15 years. Members of our research group published reviews of this literature more than a decade ago, and the intervening time period has witnessed robust growth in research regarding sex, gender, and pain. Therefore, it seems timely to revisit this literature. Abundant evidence from recent epidemiologic studies clearly demonstrates that women are at substantially greater risk for many clinical pain conditions, and there is some suggestion that postoperative and procedural pain may be more severe among women than men. Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances. The evidence regarding sex differences in laboratory measures of endogenous pain modulation is mixed, as are findings from studies using functional brain imaging to ascertain sex differences in pain-related cerebral activation. Also inconsistent are findings regarding sex differences in responses to pharmacologic and non-pharmacologic pain treatments. The article concludes with a discussion of potential biopsychosocial mechanisms that may underlie sex differences in pain, and considerations for future research are discussed.
This article reviews the recent literature regarding sex, gender, and pain. The growing body of evidence that has accumulated in the past 10 to 15 years continues to indicate substantial sex differences in clinical and experimental pain responses, and some evidence suggests that pain treatment responses may differ for women versus men.
PMCID: PMC2677686  PMID: 19411059
5.  Ethnic Differences in Diffuse Noxious Inhibitory Controls (DNIC) 
Substantial evidence indicates that the experience of both clinical and experimental pain differs among ethnic groups. Specifically, African Americans generally report higher levels of clinical pain and greater sensitivity to experimentally induced pain; however, little research has examined the origins of these differences. Differences in central pain-inhibitory mechanisms may contribute to this disparity. Diffuse noxious inhibitory controls (DNIC), or counterirritation, is a phenomenon thought to reflect descending inhibition of pain signals. The current study assessed DNIC in 57 healthy young adults from two different ethnic groups: African Americans and non-Hispanic whites. Repeated assessments of the nociceptive flexion reflex (NFR) as well as ratings of electrical pain were obtained prior to, during and after an ischemic arm pain procedure (as well as a sham procedure). The DNIC condition (i.e. ischemic arm pain) produced substantial reductions in pain ratings as well as electrophysiologic measures of the NFR for all participants when compared with the sham condition (p < .001). The DNIC condition produced significantly greater reductions in verbal pain ratings among non-Hispanic whites when compared with African Americans (p = .02), while ethnic groups showed comparable reductions in NFR. The findings of this study suggest differences in endogenous pain inhibition between African Americans and non-Hispanic whites and that additional research to determine the mechanisms underlying these effects is warranted.
This study adds to a growing literature examining ethnic differences in experimental pain perception. Our data suggest that these variations may be influenced by differences in descending inhibition.
PMCID: PMC2597628  PMID: 18482870
Experimental Pain; Diffuse Noxious Inhibitory Controls; DNIC; Nociceptive Flexion Reflex; NFR: Ethnic Differences
6.  Pain Related Fear and Catastrophizing Predict Pain Intensity and Disability Independently Using an Induced Muscle Injury Model 
The Journal of Pain  2012;13(4):370-378.
Timing of assessment of psychological construct is controversial and results differ based on the model of pain induction. Previous studies have not used an exercise induced injury model to investigate timing of psychological assessment. Exercise induced injury models may be appropriate for these investigations because they approximate clinical pain conditions better than other experimental stimuli. In this study we examined the changes of psychological constructs over time and determined whether timing of assessment affected the construct’s association with reports of pain intensity and disability. One-hundred twenty-six healthy volunteers completed the Fear of Pain Questionnaire (FPQ-III), Pain Catastrophizing Scale (PCS), and Tampa Scale of Kinesiophobia (TSK) prior to inducing muscle injury to the shoulder. The PCS and TSK were measured again 48 and 96 hours post-injury induction. Pain intensity and disability were collected at 48 and 96 hours and served as dependent variables in separate regression models. Results indicated that the FPQ-III had the strongest prediction of pain intensity from baseline to 96 hours. After baseline the PCS and TSK were stronger predictors of pain intensity and disability, respectively. These data provide support for the use of psychological constructs in predicting outcomes from shoulder pain. However, they deviate from the current theoretical model indicating that fear of pain is a consequence of injury and instead suggests that fear of pain before injury may influence reports of pain intensity.
The current study provides evidence that fear of pain can be assessed prior to injury. Furthermore, it supports that after injury pain catastrophizing and kinesiophobia are independently associated with pain and disability. Overall these data suggest that timing of psychological assessment may be an important consideration in clinical environments.
PMCID: PMC3321109  PMID: 22424914
Fear; catastrophizing; assessment; pain; disability
7.  The association of sleep and pain: An update and a path forward 
Ample evidence suggests that sleep and pain are related. However, many questions remain about the direction of causality in their association, as well as mechanisms that may account for their association. The prevailing view has generally been that they are reciprocally related. The present review critically examines the recent prospective and experimental literature (2005-present) in an attempt to update the field on emergent themes pertaining to the directionality and mechanisms of the association of sleep and pain. A key trend emerging from population-based longitudinal studies is that sleep impairments reliably predict new incidents and exacerbations of chronic pain. Microlongitudinal studies employing deep subjective and objective assessments of pain and sleep support the notion that sleep impairments are a stronger, more reliable predictor of pain than pain is of sleep impairments. Recent experimental studies suggest that sleep disturbance may impair key processes that contribute to the development and maintenance of chronic pain, including endogenous pain inhibition and joint pain. Several biopsychosocial targets for future mechanistic research on sleep and pain are discussed, including dopamine and opioid systems, positive and negative affect, and sociodemographic factors.
This critical review examines the recent prospective and experimental research (2005-present) on the association of sleep and pain in an attempt to identify trends suggestive of directionality and potential mechanisms. An update on this literature is needed to guide future clinical efforts to develop and augment treatments for chronic sleep disturbance and chronic pain.
PMCID: PMC4046588  PMID: 24290442
Chronic pain; sleep; insomnia; longitudinal; sleep deprivation
8.  Psychological and Sensory Predictors of Experimental Thermal Pain: A Multifactorial Model 
Although large interindividual differences in pain exist, the underlying factors that contribute to these variations remain poorly understood. Consequently, being able to accurately explain variability in pain ratings in terms of its contributing factors could provide insights into developing a better understanding of individual differences in pain experience. In the present investigation, we show that a significant portion of the variability in experimental heat pain ratings may be predicted using simple quantitative sensory testing and a series of psychological questionnaires including State Trait and Anxiety Inventory (STAI), Center for Epidemiologic Studies – Depression Scale (CES-D), and Positive and Negative Affect Schedule – Expanded form (PANAS-X). A factor analysis was used to reduce individual predictors into sets of composite predictive factors. A multifactorial model that was generated from these factors can reliably predict a significant amount of the variability in heat pain sensitivity ratings (r2 = 0.537, p=0.027). Moreover, individual variables including heat pain thresholds and self-assessment of pain sensitivity were found to be poor predictors of heat pain sensitivity. Taken together, these results suggest that a variety of factors underlie individual differences in pain experience, and that a reliable model for predicting pain should be constructed from a combination of these factors.
The present study provides a way to predict subjects’ experimental heat pain sensitivity using a multifactorial model generated from a combination of sensory and psychological factors. Future application of such a model in the studies of clinical pain could potentially improve the quality of care provided for patients in pain.
PMCID: PMC2954262  PMID: 20570569
pain prediction; psychological factors; model; heat pain; psychophysics
9.  Race and Histories of Mood Disorders Modulate Experimental Pain Tolerance in Women 
Thirty-two African American and 23 non-Hispanic White women were compared for experimental pain threshold and tolerance to thermal, ischemic, and cold pressor pain. Approximately half of each group had prior mood disorders (17 African Americans, 13 non-Hispanic Whites), though all were free of current mood disturbance. Women with prior mood disorders were less sensitive to ischemic pain than women with no prior mood disorders (p<.05), while African Americans were more sensitive to ischemic pain than non-Hispanic Whites, though only at pain tolerance (p<.001). For cold pressor pain, the effects of race were only seen in women with prior mood disorders, since African Americans with prior mood disorders were more sensitive than non-Hispanic Whites with prior mood disorders (p<.05). These results indicate that experimental pain sensitivity in women is influenced by both race and histories of mood disorders.
We examined the association of race and histories of mood disorders with experimental pain sensitivity in an exclusively female sample. Our findings for racial differences in pain sensitivity may have implications for greater clinical pain in African American women. Persistent disturbance in pain modulatory mechanisms in women with a history of mood disorders may also have implications for the development of subsequent mood disturbances.
PMCID: PMC2174960  PMID: 17644044
Mood disorders; Race; Pain Tolerance
10.  Pain-QuILT: Clinical Feasibility of a Web-Based Visual Pain Assessment Tool in Adults With Chronic Pain 
Chronic pain is a prevalent and debilitating problem. Accurate and timely pain assessment is critical to pain management. In particular, pain needs to be consistently tracked over time in order to gauge the effectiveness of different treatments. In current clinical practice, paper-based questionnaires are the norm for pain assessment. However, these methods are not conducive to capturing or tracking the complex sensations of chronic pain. Pain-QuILT (previously called the Iconic Pain Assessment Tool) is a Web-based tool for the visual self-report and tracking of pain (quality, intensity, location, tracker) in the form of time-stamped records. It has been iteratively developed and evaluated in adolescents and adults with chronic pain, including usability testing and content validation. Clinical feasibility is an important stepping-stone toward widespread implementation of a new tool. Our group has demonstrated Pain-QuILT clinical feasibility in the context of a pediatric chronic pain clinic. We sought to extend these findings by evaluating Pain-QuILT clinical feasibility from the perspective of adults with chronic pain, in comparison with standard paper-based methods (McGill Pain Questionnaire [MPQ] and Brief Pain Inventory [BPI]).
The goal of our study was to assess Pain-QuILT for (1) ease of use, (2) time for completion, (3) patient preferences, and (4) to explore the patterns of self-reported pain across the Pain-QuILT, MPQ, and BPI.
Participants were recruited during a scheduled follow-up visit at a hospital-affiliated pain management and physical rehabilitation clinic in southwestern Ontario. Participants self-reported their current pain using the Pain-QuILT, MPQ, and BPI (randomized order). A semistructured interview format was used to capture participant preferences for pain self-report.
The sample consisted of 50 adults (54% female, 27/50) with a mean age of 50 years. Pain-QuILT was rated as significantly easier to use than both the MPQ and BPI (P<.01) and was also associated with the fewest difficulties in completion. On average, the time to complete each tool was less than 5 minutes. A majority of participants (58%, 29/50) preferred Pain-QuILT for reporting their pain over alternate methods (16%, 8/50 for MPQ; 14%, 7/50 for BPI; 12%, 6/50 for “other”). The most commonly chosen pain descriptors on MPQ were matched with Pain-QuILT across 91% of categories. There was a moderate-to-high correlation between Pain-QuILT and BPI scores for pain intensity (r=.70, P<.01).
The results of this clinical feasibility study in adults with chronic pain are consistent with our previously published pediatric findings. Specifically, data indicate that Pain-QuILT is (1) easy to use, (2) quick to complete, (3) preferred by a majority of patients, and (4) correlated as expected with validated pain measures. As a digital, patient-friendly method of assessing and tracking pain, we conclude that Pain-QuILT has potential to add significant value as one standard component of chronic pain management.
PMCID: PMC4034112  PMID: 24819478
chronic pain; assessment tool; Internet; clinical feasibility
11.  Pain Beliefs and Readiness to Change Among Adolescents With Chronic Musculoskeletal Pain and Their Parents Before an Initial Pain Clinic Evaluation 
The Clinical journal of pain  2014;30(1):10.1097/AJP.0b013e31828518e9.
To understand relationships between pain-related beliefs and readiness to change among treatment-seeking adolescents with chronic musculoskeletal pain and their parents.
A total of 102 adolescent-parent dyads were recruited at the time of initial evaluation at a multidisciplinary pain management clinic. Dyads completed self-report measures to assess pain, catastrophizing, endorsement of a biopsychosocial perspective of pain, and readiness to change/motivation to adopt a self-management approach to pain coping.
Agreement between adolescent-parent dyad reports of pain catastrophizing and readiness to change was found; however, adolescents were less likely to view pain as “affected by feelings and emotions” than parents. The hypothesis that greater pain catastrophizing would be correlated with less readiness to change was partially supported. Adolescent and parents who reported lower levels of endorsement of a biopsychosocial perspective were less willing to adopt a self-management approach to pain coping. Endorsement of a biopsychosocial perspective of pain aligned with readiness to change stages more consistently for parents.
This study documents initial relationships among pain catastrophizing, biopsychosocial perspectives of pain, and readiness to engage in a self-management approach to pain coping for adolescents with chronic pain and their parents. Although agreement exists between dyads regarding catastrophizing and readiness to change, differences were noted in biopsychosocial perspective and dominant readiness to change stage before an initial pain clinic encounter. Findings are considered in terms of future research to advance knowledge regarding the role these factors may play in treatment adherence and outcomes.
PMCID: PMC3742695  PMID: 23446077
pain catastrophizing; biopsychosocial; PSOCQ-A; PSOCQ-P; pain management
12.  Depression Shows Divergent Effects on Evoked and Spontaneous Pain Behaviors in Rats 
Although it has been accepted that depression and pain are common comorbidities, their interaction is not fully understood. The present study was aimed to investigate the effects of depression on both evoked pain behavior (thermal induced nociception and hyperalgesia) and spontaneous pain behavior (formalin pain) in rats. An unpredictable chronic mild stress (UCMS) paradigm was employed to develop a classical depression. The emotional behaviors were assessed by sucrose preference test, open field test, and elevated plus-maze test. The results showed that the depressed rats always exhibited stronger tolerance to noxious thermal stimulation under both normal and complete Freund’s adjuvant (CFA)-induced chronic pain conditions, when compared to non-depressed animals. Interestingly, the spontaneous nociceptive behaviors induced by formalin injection were significantly enhanced in rats exposed to UCMS in comparison to those without UCMS. Systemic administration of antidepressant fluoxetine significantly restored the nociceptive behaviors to normal level in depressed animals. An additional finding was that the inflammatory rats tended to display depressive-like behaviors without being exposed to UCMS. These results demonstrated that depression can have different effects on stimulus-evoked pain and spontaneous pain, with alleviation in the former while aggravation in the latter.
Perspective: The present study provides evidence that depression can have divergent effects on stimulus-evoked and spontaneous pain by confirming that rats exposed to chronic mild stress tend to exhibit decreased pain sensitivity to experimental stimuli but increased intensity of ongoing pain. This may contribute to further understanding of the perplexing relationship between clinical depression and chronic pain.
PMCID: PMC2835830  PMID: 20096641
depression; fluoxetine; pain; thermal hyperalgesia; unpredictable chronic mild stress
13.  Therapy of acute wounds with water-filtered infrared-A (wIRA) 
Water-filtered infrared-A (wIRA) as a special form of heat radiation with a high tissue penetration and with a low thermal load to the skin surface acts both by thermal and thermic as well as by non-thermal and non-thermic effects. wIRA produces a therapeutically usable field of heat in the tissue and increases tissue temperature, tissue oxygen partial pressure, and tissue perfusion. These three factors are decisive for a sufficient tissue supply with energy and oxygen and consequently as well for wound healing and infection defense.
wIRA can considerably alleviate the pain (with remarkably less need for analgesics) and diminish an elevated wound exudation and inflammation and can show positive immunomodulatory effects. wIRA can advance wound healing or improve an impaired wound healing both in acute and in chronic wounds including infected wounds. Even the normal wound healing process can be improved.
A prospective, randomized, controlled, double-blind study with 111 patients after major abdominal surgery at the University Hospital Heidelberg, Germany, showed with 20 minutes irradiation twice a day (starting on the second postoperative day) in the group with wIRA and visible light VIS (wIRA(+VIS), approximately 75% wIRA, 25% VIS) compared to a control group with only VIS a significant and relevant pain reduction combined with a markedly decreased required dose of analgesics: during 230 single irradiations with wIRA(+VIS) the pain decreased without any exception (median of decrease of pain on postoperative days 2-6 was 13.4 on a 100 mm visual analog scale VAS 0-100), while pain remained unchanged in the control group (p<0.001). The required dose of analgesics was 57-70% lower in the subgroups with wIRA(+VIS) compared to the control subgroups with only VIS (median 598 versus 1398 ml ropivacaine, p<0.001, for peridural catheter analgesia; 31 versus 102 mg piritramide, p=0.001, for patient-controlled analgesia; 3.4 versus 10.2 g metamizole, p=0.005, for intravenous and oral analgesia). During irradiation with wIRA(+VIS) the subcutaneous oxygen partial pressure rose markedly by approximately 30% and the subcutaneous temperature by approximately 2.7°C (both in a tissue depth of 2 cm), whereas both remained unchanged in the control group: after irradiation the median of the subcutaneous oxygen partial pressure was 41.6 (with wIRA) versus 30.2 mm Hg in the control group (p<0.001), the median of the subcutaneous temperature was 38.9 versus 36.4°C (p<0.001). The overall evaluation of the effect of irradiation, including wound healing, pain and cosmesis, assessed on a VAS (0-100 with 50 as indifferent point of no effect) by the surgeon (median 79.0 versus 46.8, p<0.001) or the patient (79.0 versus 50.2, p<0.001) was markedly better in the group with wIRA compared to the control group. This was also true for single aspects: Wound healing assessed on a VAS by the surgeon (median 88.6 versus 78.5, p<0.001) or the patient (median 85.8 versus 81.0, p=0.040, trend) and cosmetic result assessed on a VAS by the surgeon (median 84.5 versus 76.5, p<0.001) or the patient (median 86.7 versus 73.6, p=0.001). In addition there was a trend in favor of the wIRA group to a lower rate of total wound infections (3 of 46, approximately 7%, versus 7 of 48, approximately 15%, p=0.208) including late infections after discharge, caused by the different rate of late infections after discharge: 0 of 46 in the wIRA group and 4 of 48 in the control group. And there was a trend towards a shorter postoperative hospital stay: 9 days in the wIRA group versus 11 days in the control group (p=0.037). The principal finding of this study was that postoperative irradiation with wIRA can improve even a normal wound healing process.
A prospective, randomized, controlled, double-blind study with 45 severely burned children at the Children’s Hospital Park Schönfeld, Kassel, Germany, showed with 30 minutes irradiation once a day (starting on the first day, day of burn as day 1) in the group with wIRA and visible light VIS (wIRA(+VIS), approximately 75% wIRA, 25% VIS) compared to a control group with only VIS a markedly faster reduction of wound size. On the fifth day (after 4 days with irradiation) decision was taken, whether surgical debridement of necrotic tissue was necessary because of deeper (second degree, type b) burns (11 of 21 in the group with wIRA, 14 of 24 in the control group) or non-surgical treatment was possible (second degree, type a, burns). The patients treated conservatively were kept within the study and irradiated till complete reepithelialization. The patients in the group with wIRA showed a markedly faster reduction of wound area: a median reduction of wound size of 50% was reached already after 7 days compared to 9 days in the control group, a median reduction of wound size of 90% was already achieved after 9 days compared to 13 days in the control group. In addition the group with wIRA showed superior results till 3 months after the burn in terms of the overall surgical assessment of the wound, cosmesis, and assessment of effects of irradiation compared to the control group.
In a prospective, randomized, controlled study with 12 volunteers at the University Medical Center Charité, Berlin, Germany, within each volunteer 4 experimental superficial wounds (5 mm diameter) as an acute wound model were generated by suction cup technique, removing the roof of the blister with a scalpel and a sterile forceps (day 1). 4 different treatments were used and investigated during 10 days: no therapy, only wIRA(+VIS) (approximately 75% wIRA, 25% VIS; 30 minutes irradiation once a day), only dexpanthenol (= D-panthenol) cream once a day, wIRA(+VIS) and dexpanthenol cream once a day. Healing of the small experimental wounds was from a clinical point of view excellent with all 4 treatments. Therefore there were only small differences between the treatments with slight advantages of the combination wIRA(+VIS) and dexpanthenol cream and of dexpanthenol cream alone concerning relative change of wound size and assessment of feeling of the wound area. However laser scanning microscopy with a scoring system revealed differences between the 4 treatments concerning the formation of the stratum corneum (from first layer of corneocytes to full formation) especially on the days 5-7: fastest formation of the stratum corneum was seen in wounds treated with wIRA(+VIS) and dexpanthenol cream, second was wIRA(+VIS) alone, third dexpanthenol cream alone and last were untreated wounds. Bacterial counts of the wounds (taken every 2 days) showed, that wIRA(+VIS) and the combination of wIRA(+VIS) with dexpanthenol cream were able to inhibit the colonisation with physiological skin flora up to day 5 when compared with the two other groups (untreated group and group with dexpanthenol cream alone). At any investigated time, the amount of colonisation under therapy with wIRA(+VIS) alone was lower (interpreted as more suppressed) compared with the group with wIRA(+VIS) and dexpanthenol cream.
During rehabilitation after hip and knee endoprosthetic operations the resorption of wound seromas and wound hematomas was both clinically and sonographically faster and pain was reduced by irradiation with wIRA(+VIS).
wIRA can be used successfully for persistent postoperative pain e.g. after thoracotomy.
As perspectives for wIRA it seems clinically prudent to use wIRA both pre- and postoperatively, e.g. in abdominal and thoracic operations. wIRA can be used preoperatively (e.g. during 1-2 weeks) to precondition donor and recipient sites of skin flaps, transplants or partial-thickness skin grafts, and postoperatively to improve wound healing and to decrease pain, inflammation and infections at all mentioned sites. wIRA can be used to support routine pre- or intraoperative antibiotic administration or it might even be discussed to replace this under certain conditions by wIRA.
PMCID: PMC2831241  PMID: 20204084
water-filtered infrared-A (wIRA); wound healing; acute wounds; prospective, randomized, controlled, double-blind studies; reduction of pain; problem wounds; wound infections; infection defense; wound exudation; inflammation; thermal and non-thermal effects; thermic and non-thermic effects; energy supply; oxygen supply; tissue oxygen partial pressure; tissue temperature; tissue blood flow; visual analog scales (VAS); quality of life
14.  Parent and child anxiety sensitivity: Relationship to children’s experimental pain responsivity 
Anxiety sensitivity (AS) or fear of anxiety sensations has been linked to childhood learning history for somatic symptoms, suggesting that parental AS may impact children’s responses to pain. Using structural equation modeling (SEM), we tested a conceptual model in which parent AS predicted child AS, which in turn predicted a hypothesized latent construct consisting of children’s pain intensity ratings for three laboratory pain tasks (cold pressor, thermal heat and pressure). This conceptual model was tested in 211 non-clinical parent-child pairs (104 girls, mean age = 12.4 years; 178 mothers). Our model was supported in girls only indicating that the sex of the child moderated the hypothesized relationships. Thus, parent AS was related to child laboratory pain intensity via its contribution to child AS in girls but not in boys. In girls, 42% of the effect of parent AS on laboratory pain intensity was explained via child AS. In boys, there was no clear link between parent AS and child AS, although child AS was predictive of experimental pain intensity across sex. Our results are consistent with the notion that parent AS may operate via healthy girls’ own fear of anxiety symptoms to influence their responses to laboratory pain stimuli.
Perspective-The present study highlights sex differences in the links among parent and child anxiety sensitivity (AS; fear of anxiety sensations) and children’s experimental pain responses. Among girls, childhood learning history related to somatic symptoms may be a particularly salient factor in the development of AS and pain responsivity.
PMCID: PMC1540407  PMID: 16632321
anxiety sensitivity; laboratory pain; children; adolescents; parent; sex differences
15.  Hyperalgesia in Heroin Dependent Patients and the Effects of Opioid Substitution Therapy 
The Journal of Pain  2012;13(4):401-409.
Evidence suggests that patients on opiate maintenance therapy for the treatment of addiction present with opioid-induced hyperalgesia (OIH). This study compared the experimental (cold-pressor, electrical stimulation) pain responses of 82 treatment-seeking heroin-dependent adults randomized to methadone (METH, n = 11) or buprenorphine (BUP, n = 64) therapy, with matched drug free controls (n = 21). Heroin-dependent participants were evaluated at baseline (treatment entry), medication (METH or BUP) stabilization (4-8 weeks), and chronic administration (12-18 weeks), at trough (just prior to dosing) and peak (3 hours after dosing) plasma levels. Collection of the control group’s pain responses occurred twice during a single session, three hours apart. Baseline comparisons indicate that heroin-dependent individuals demonstrate significantly shorter latencies to threshold and tolerance for cold-pressor pain than the control group. Across pain stimuli and time points, little change in pain responses were found over time, the exception being cold pressor pain tolerance, for which hyperalgesia significantly increased at trough METH/BUP levels in both groups as they stabilized in treatment. We conclude that heroin-dependent individuals are hyperalgesic, and that once stabilized in treatment, are not different in pain responses regardless of treatment agent. The effects of non-pharmacologic therapy and previous heroin use may explain increased hyperalgesia found with treatment.
To better understand the clinical phenomenon of OIH, this article describes experimental pain responses of heroin-dependent participants both prior to and over the course of maintenance therapy with methadone or buprenorphine. Hyperalgesia is present with illicit and treatment opioid use, and does not appear to appreciably improve over the course of treatment.
PMCID: PMC3334366  PMID: 22424799
opioid-induced hyperalgesia; methadone; heroin; buprenorphine; pain
16.  Sex Differences in How Social Networks and Relationship Quality Influence Experimental Pain Sensitivity 
PLoS ONE  2013;8(11):e78663.
This is the first study to examine how both structural and functional components of individuals’ social networks may moderate the association between biological sex and experimental pain sensitivity. One hundred and fifty-two healthy adults (mean age = 22yrs., 53% males) were measured for cold pressor task (CPT) pain sensitivity (i.e., intensity ratings) and core aspects of social networks (e.g., proportion of friends vs. family, affection, affirmation, and aid). Results showed consistent sex differences in how social network structures and intimate relationship functioning modulated pain sensitivity. Females showed higher pain sensitivity when their social networks consisted of a higher proportion of intimate types of relationship partners (e.g., kin vs. non kin), when they had known their network partners for a longer period of time, and when they reported higher levels of logistical support from their significant other (e.g., romantic partner). Conversely, males showed distinct patterns in the opposite direction, including an association between higher levels of logistical support from one’s significant other and lower CPT pain intensity. These findings show for the first time that the direction of sex differences in exogenous pain sensitivity is likely dependent on fundamental components of the individual’s social environment. The utility of a social-signaling perspective of pain behaviors for examining, comparing, and interpreting individual and group differences in experimental and clinical pain reports is discussed.
PMCID: PMC3818490  PMID: 24223836
17.  Pain management in patients with dementia 
There are an estimated 35 million people with dementia across the world, of whom 50% experience regular pain. Despite this, current assessment and treatment of pain in this patient group are inadequate. In addition to the discomfort and distress caused by pain, it is frequently the underlying cause of behavioral symptoms, which can lead to inappropriate treatment with antipsychotic medications. Pain also contributes to further complications in treatment and care. This review explores four key perspectives of pain management in dementia and makes recommendations for practice and research. The first perspective discussed is the considerable uncertainty within the literature on the impact of dementia neuropathology on pain perception and processing in Alzheimer’s disease and other dementias, where white matter lesions and brain atrophy appear to influence the neurobiology of pain. The second perspective considers the assessment of pain in dementia. This is challenging, particularly because of the limited capacity of self-report by these individuals, which means that assessment relies in large part on observational methods. A number of tools are available but the psychometric quality and clinical utility of these are uncertain. The evidence for efficient treatment (the third perspective) with analgesics is also limited, with few statistically well-powered trials. The most promising evidence supports the use of stepped treatment approaches, and indicates the benefit of pain and behavioral interventions on both these important symptoms. The fourth perspective debates further difficulties in pain management due to the lack of sufficient training and education for health care professionals at all levels, where evidence-based guidance is urgently needed. To address the current inadequate management of pain in dementia, a comprehensive approach is needed. This would include an accurate, validated assessment tool that is sensitive to different types of pain and therapeutic effects, supported by better training and support for care staff across all settings.
PMCID: PMC3817007  PMID: 24204133
pain assessment; Alzheimer’s disease; cognitive impairment; behavior
18.  Comparing the clinical-effectiveness and cost-effectiveness of an internet-delivered Acceptance and Commitment Therapy (ACT) intervention with a waiting list control among adults with chronic pain: study protocol for a randomised controlled trial 
BMJ Open  2014;4(7):e005092.
Internet-delivered psychological interventions among people with chronic pain have the potential to overcome environmental and economic barriers to the provision of evidence-based psychological treatment in the Irish health service context. While the use of internet-delivered cognitive–behavioural therapy programmes has been consistently shown to have small-to-moderate effects in the management of chronic pain, there is a paucity in the research regarding the effectiveness of an internet-delivered Acceptance and Commitment Therapy (ACT) programme among people with chronic pain. The current study will compare the clinical-effectiveness and cost-effectiveness of an online ACT intervention with a waitlist control condition in terms of the management of pain-related functional interference among people with chronic pain.
Methods and analysis
Participants with non-malignant pain that persists for at least 3 months will be randomised to one of two study conditions. The experimental group will undergo an eight-session internet-delivered ACT programme over an 8-week period. The control group will be a waiting list group and will be offered the ACT intervention after the 3-month follow-up period. Participants will be assessed preintervention, postintervention and at a 3-month follow-up. The primary outcome will be pain-related functional interference. Secondary outcomes will include: pain intensity, depression, global impression of change, acceptance of chronic pain and quality of life. A qualitative evaluation of the perspectives of the participants regarding the ACT intervention will be completed after the trial.
Ethics and dissemination
The study will be performed in agreement with the Declaration of Helsinki and is approved by the National University of Ireland Galway Research Ethics Committee (12/05/05). The results of the trial will be published according to the CONSORT statement and will be presented at conferences and reported in peer-reviewed journals.
Trial registration number
PMCID: PMC4091504  PMID: 24993763
Pain Management
19.  Genetic Contributions to Clinical Pain and Analgesia: Avoiding Pitfalls in Genetic Research 
Understanding the genetic basis of human variations in pain is critical to elucidating the molecular basis of pain sensitivity, variable responses to analgesic drugs, and, ultimately, to individualized treatment of pain and improved public health. With the help of recently accumulated knowledge and advanced technologies, pain researchers hope to gain insight into genetic mechanisms of pain and eventually apply this knowledge to pain treatment.
We critically reviewed the published literature to examine the strength of evidence supporting genetic influences on clinical and human experimental pain. Based on this evidence and the experience of false associations that have occurred in other related disciplines, we provide recommendations for avoiding pitfalls in pain genetic research.
PMCID: PMC2999357  PMID: 19559388
Genetic association study; single nucleotide polymorphism; haplotype; population stratification; multiple test correction
20.  Psychologic Influence on Experimental Pain Sensitivity and Clinical Pain Intensity for Patients with Shoulder Pain 
Pain-related fear and pain catastrophizing are two central psychologic factors in fear-avoidance models. Our previous studies in healthy subjects indicated that pain-related fear, but not pain catastrophizing, was associated with cold pressor pain outcomes. The current study extends previous work by investigating pain-related fear and pain catastrophizing in a group of subjects with shoulder pain, and included concurrent measures of experimental and clinical pain. Fifty nine consecutive subjects seeking operative treatment of shoulder pain were enrolled in this study (24 females, mean age = 50.4, sd = 14.9). Subjects completed validated measures of pain-related fear, pain catastrophizing, and clinical pain intensity and then underwent a cold pressor task to determine experimental pain sensitivity. Multivariate regression models used sex, age, pain-related fear, and pain catastrophizing to predict experimental pain sensitivity and clinical pain intensity. Results indicated that only pain-related fear uniquely contributed to variance in experimental pain sensitivity (beta = −.42, p < .01). In contrast, sex (beta = −.29, p = .02) and pain catastrophizing (beta = .43, p < .01) uniquely contributed to variance in clinical pain intensity. These data provide additional support for application of fear-avoidance models to subjects with shoulder pain. Our results also suggest that pain-related fear and pain catastrophizing may influence different components of the pain experience, providing preliminary support for recent theoretical conceptualizations of the role of pain catastrophizing.
PMCID: PMC2672100  PMID: 19070551
Chronic pain; biopsychosocial; pain-related fear; pain catastrophizing; quantitative sensory testing; fear-avoidance model
21.  Sex Differences in Muscle Pain: Self-care Behaviors and Effects on Daily Activities 
Women have a higher prevalence of fibromyalgia and myofascial pain than men, but sex differences in muscle pain are inconsistently detected. We examined sex differences in ratings and effects of recalled and experimentally-induced muscle pain. In Study 1 (N = 188), participants completed a questionnaire about recalled muscle pain. In Study 2 (N = 55), participants’ described muscle pain from an exercise stimulus across three days by telephone. Muscle pain ratings, self-care behaviors for muscle pain, and effects of muscle pain on activities were measured. No significant sex differences were found except that women tended to view exercise as more effective for decreasing muscle pain than men (F1, 187 = 5.43, p = .02, η2 = .03), fewer women performed exercise for induced muscle pain than men, and women’s activity interference was significantly higher than men’s at the third day post-exercise (F2, 42 = 6.54, p= .01, η2 = .14). These findings support the absence of meaningful sex differences in muscle pain ratings. However, additional investigations are needed that consider the daily activities completed by people and the prevalence and incidence of performing a wide range of self-care behaviors for pain.
Perspective: These studies support that sex differences are not present in recalled and experimentally-induced muscle pain ratings. Therefore, we must be cautious about generalizing the musculoskeletal pain literature to muscle pain. Additional research is needed to interpret potential sex differences in self-care behaviors for muscle pain and activity interference from muscle pain.
PMCID: PMC2290003  PMID: 18088556
Gender; delayed-onset muscle soreness; self-management
22.  Contributions of myofascial pain in diagnosis and treatment of shoulder pain. A randomized control trial 
Rotator cuff tendinopathy and subacromial impingement syndrome present complex patomechanical situations, frequent difficulties in clinical diagnosis and lack of effectiveness in treatment. Based on clinical experience, we have therefore considered the existence of another pathological entity as the possible origin of pain and dysfunction. The hypothesis of this study is to relate subacromial impingement syndrome (SIS) with myofascial pain syndrome (MPS), since myofascial trigger points (MTrPs) cause pain, functional limitation, lack of coordination and alterations in quality of movement, even prior to a tendinopathy. MTrPs can coexist with any degenerative subacromial condition. If they are not taken into consideration, they could perpetuate and aggravate the problem, hindering diagnosis and making the applied treatments ineffective.
The aims and methods of this study are related with providing evidence of the relationship that may exist between this condition and MPS in the diagnosis and treatment of rotator cuff tendonitis and/or SIS.
A descriptive transversal study will be made to find the correlation between the diagnosis of SIS and rotator cuff tendonitis, positive provocation test responses, the existence of active MTrPs and the results obtained with ultrasonography (US) and Magnetic Renonance Imaging (MRI). A randomized double blinded clinical trial will be carried out in experimental conditions: A Protocolized treatment based on active and passive joint repositioning, stabilization exercises, stretching of the periarticular shoulder muscles and postural reeducation. B. The previously described protocolized treatment, with the addition of dry needling applied to active MTrPs with the purpose of isolating the efficacy of dry needling in treatment.
This study aims to provide a new vision of shoulder pain, from the perspective of MPS. This syndrome can, by itself, account for shoulder pain and dysfunction, although it can coexist with real conditions involving the tendons.
Trail Registration
ISRCTN Number: 30907460
PMCID: PMC2724401  PMID: 19630975
23.  Pain Catastrophizing and Salivary Cortisol Responses to Laboratory Pain Testing in Temporomandibular Disorder and Healthy Participants 
Pain catastrophizing is an important variable in the context of acute and chronic pain. The neurophysiological correlates of pain catastrophizing, however, have not been rigorously evaluated. We examined the relationship between trait pain catastrophizing and morning salivary cortisol levels before and following a 45-minute laboratory pain testing session in healthy, pain-free (n=22) and temporomandibular disorder (TMD) participants (n=39). We also examined whether TMD patients evidenced generalized hyperalgesia and hypercortisolism. Pain catastrophizing was associated with a flattened morning salivary cortisol profile in the context of pain testing, irrespective of pain status. Cortisol profiles did not differ between healthy and TMD participants. TMD was associated with mechanical hyperalgesia only at the masseter. These data are the first to show an association between pain catastrophizing and elevated salivary cortisol profiles in the context of standardized experimental pain testing. These findings in both healthy individuals and those with chronic orofacial pain suggest that aberrant adrenocortical responses to pain may serve as a neurophysiologic pathway by which pain catastrophizing enhances vulnerability for development of chronic pain and maintains and/or exaggerates existing pain and associated morbidity.
Neurophysiological mechanisms by which pain catastrophizing is related to acute and chronic pain recently have come under empirical study. Understanding of these mechanisms has the unique potential to shed light on key central nervous system factors that mediate catastrophizing-pain relations and therapeutic benefits associated with changes in catastrophizing and related cognitive processes.
PMCID: PMC2821973  PMID: 19853521
pain catastrophizing; pain threshold; temporomandibular disorders; HPA; pressure pain; thermal pain
24.  Partners' Empathy Increases Pain Ratings: Effects of Perceived Empathy and Attachment Style on Pain Report and Display 
The Journal of Pain  2014;15(9):934-944.
Pain can be influenced by its social context. We aimed to examine under controlled experimental conditions how empathy from a partner and personal attachment style affect pain report, tolerance, and facial expressions of pain. Fifty-four participants, divided into secure, anxious, and avoidant attachment style groups, underwent a cold pressor task with their partners present. We manipulated how much empathy the participants perceived that their partners had for them. We observed a significant main effect of perceived empathy on pain report, with greater pain reported in the high perceived empathy condition. No such effects were found for pain tolerance or facial display. We also found a significant interaction of empathy with attachment style group, with the avoidant group reporting and displaying less pain than the secure and the anxious groups in the high perceived empathy condition. No such findings were observed in the low empathy condition. These results suggest that empathy from one's partner may influence pain report beyond behavioral reactions. In addition, the amount of pain report and expression that people show in high empathy conditions depends on their attachment style.
Believing that one's partner feels high empathy for one's pain may lead individuals to rate the intensity of pain as higher. Individual differences in attachment style moderate this empathy effect.
•The role of empathy and attachment style on pain was studied experimentally.•Empathy from one's partner may influence pain report and behavioral reactions.•Perceived high empathy from a partner may lead to higher pain ratings.•Individual differences in attachment style moderate this empathy effect.•Individual differences in attachment style also moderate facial display of pain.
PMCID: PMC4162650  PMID: 24953886
Social support; social presence; empathy; partner; attachment
25.  Patient versus parental perceptions about pain and disability in children and adolescents with a variety of chronic pain conditions 
Cross-informant variance is often observed in patient self-reports versus parent proxy reports of pediatric chronic pain and disability.
To assess the relationship and merit of the child versus parent perspective.
A total of 99 patients (eight to 17 years of age [mean 13.2 years]; 71% female, 81% Caucasian) and parents completed the Pediatric Pain Questionnaire and Functional Disability Inventory at their initial clinic visit. Patients’ and parents’ pain intensity and disability scores were analyzed using an intraclass correlation coefficient (ICC), Wilcoxon signed-rank test, Bland-Altman plot and Spearman’s correlation coefficient. The association between clinical/demographic variables and differences in patient/parent pain intensity and disability scores was assessed using multivariable regression.
There was significant agreement between patients’ self-reports and parents’ proxy reports of their child’s pain intensity (ICC=0.52; P<0.001) and disability (ICC=0.57; P=0.004) at the individual level. There were no significant group differences in patient versus parent-proxy pain intensity scores (P=0.40) and disability scores (P=0.54). The difference between patient and parent-proxy pain intensity was associated with patients’ self-reported pain intensity (P<0.001). The difference between patient and parent-proxy disability was associated with patient’s self-reported pain disability (P<0.001). Bland-Altman plots revealed major inter-rater variation in the Pediatric Pain Questionnaire and Functional Disability Inventory across their score ranges. A significant relationship (r=0.38; P<0.001) was observed between patients’ self-reported pain intensity and disability.
While equal merit should ideally be given to pediatric chronic pain patients’ self-reports and their parents’ proxy reports of pain intensity and disability, it would appear that, as needed, pediatric patients or parents can offer a clinically valid, single clinical perspective.
PMCID: PMC3938337  PMID: 24147272
Adolescents; Children; Chronic pain; Disability; Functional capacity; Pain intensity; Parent-child; Pediatrics

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