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Pain assessment in children continues to challenge clinicians and researchers, as subjective experiences of pain require inference through observable behaviors, both involuntary and deliberate. The presented approach supplements the subjective self-report-based method by fusing electrodermal activity (EDA) recordings with video facial expressions to develop an objective pain assessment metric. Such an approach is specifically important for assessing pain in children who are not capable of providing accurate self-pain reports, requiring nonverbal pain assessment. We demonstrate the performance of our approach using data recorded from children in post-operative recovery following laparoscopic appendectomy. We examined separately and combined the usefulness of EDA and video facial expression data as predictors of children's self-reports of pain following surgery through recovery. Findings indicate that EDA and facial expression data independently provide above chance sensitivities and specificities, but their fusion for classifying clinically significant pain vs. clinically nonsignificant pain achieved substantial improvement, yielding 90.91% accuracy, with 100% sensitivity and 81.82% specificity. The multimodal measures capitalize upon different features of the complex pain response. Thus, this paper presents both evidence for the utility of a weighted maximum likelihood algorithm as a novel feature selection method for EDA and video facial expression data and an accurate and objective automated classification algorithm capable ofdiscriminating clinically significant pain from clinically nonsignificant pain in children.

Biomarkers are commonly used in clinical care and research as indicators of diseases and physiological states. Preferably, a biomarker should be readily accessible, low in cost, easy to interpret, highly specific, and sensitive to health and disease. Owing to the complexity of the pain system, no unidimensional reliable biomarker for pain has been identified that meets all of these criteria to date. In children, neurologically dependent developmental changes, maturation of physiological stress reactivity systems, and life experience add additional layers of complexity to the use of biomarkers of pain. Nevertheless, readily available and reliable biomarkers reflecting function of the pain system would greatly enhance timely and appropriate understanding and treatment of pain, especially in infants and children with communication, cognitive, and motor disabilities. This chapter examines currently available pain-related biomarkers, their use, and limitations.

Objective For people who experience social inequities and structural violence, pain and related care are inexorably linked to experiences of injustice and stigma. The purpose of this study was to examine in greater depth the experiences of pain and discrimination and stigma across diverse marginalized communities in order to recommend equity-oriented healthcare approaches. Methods This community-based qualitative study reports on four focus groups that included 36 people living with pain. All participants identified with one of three groups known to experience high levels of inequities and structural violence including an Indigenous group, a LGBTQ2S group, and two newcomer and refugee groups. Results Pain was entangled with and shaped by: social locations and identities, experiences of violence, trauma and related mental health issues, experiences of discrimination, stigma and dismissal, experiences of inadequate and ineffective health care, and the impacts of these intersecting experiences. Conclusions Equity-oriented responses to chronic pain would recognize pain not only as a biomedical issue but as a social justice issue. The EQUIP Framework is an approach to integrating trauma- and violence-informed care; culturally-safe care; and harm reduction in health care that may hold promise for being tailored to people experiencing pain and social marginalization.

Background: The 2018 Global Year for Excellence in Pain Education, an initiative of the International Association for the Study of Pain, brought worldwide attention to the need for education that crosses narrow disciplinary boundaries, addresses up-to-date research methods and findings, and encourages teamwork among trainees and mentors at different levels of training and with different perspectives. Aims: This commentary describes the development of Pain in Child Health (PICH), an interdisciplinary training program for researchers in pediatric pain at the undergraduate, graduate, and postdoctoral levels of training. Methods: Based on documentation of the structure, training processes, leadership, and membership of PICH, we outline its organization and its challenges and accomplishments over the first 12 years of its growth into a well-known international program. Results and Conclusions: Pain in Child Health began as a Strategic Training Initiative of the Canadian Institutes of Health Research in 2002 and developed into an international research training consortium featuring cross-site and cross-discipline mentorship and collaboration. PICH trainees and alumni have contributed extensively to the current scientific literature on children’s pain. PICH could serve as a possible model for training and mentorship in other specialized health research domains within and outside thestudy of pain.

Diverse behavioral cues have been proposed to be useful cues in infant pain assessment, but there is a paucity of evidence on the basis of formal psychometric evaluation to establish their validity for this purpose. We aimed to examine 2 widely used coding systems, the Neonatal Facial Coding System (NFCS) and the Modified Behavior Pain Scale (MBPS), by examining their factor structures with confirmatory factor analysis using a large archival data set. The results indicated that an item-reduced NFCS scale with 3 items produced a 1-factor pain model that maintained the good psychometric properties of the 7-item scale. In addition, it was found that MBPS also has challenging internal consistency, with items that are weakly correlated as well as highly redundant. One item of the MBPS may be able to capture the construct of pain equally well or potentially improve its psychometric properties. Redefinition of the MBPS with cry as a sole indicator was suggested. This analysis provides 2 new iterations of the NFCS and MBPS that improve construct validity and internal consistency. These shorter versions also improve the feasibility of both measures and increase their potential for clinical use because less time is required for their administration. Perspective This article presents new iterations of the NFCS and MBPS scales. These revised measures improve the internal consistency of the measures, feasibility of use of the tools in research settings, and the efficiency of the coding process. The revised tools could also improve the feasibility of coding within clinical settings.

Accurately determining pain levels in children is difficult, even for trained professionals and parents. Facial activity provides sensitive and specific information about pain, and computer vision algorithms have been developed to automatically detect Facial Action Units (AUs) defined by the Facial Action Coding System (FACS). Our prior work utilized information from computer vision, i.e., automatically detected facial AUs, to develop classifiers to distinguish between pain and no-pain conditions. However, application of pain/no-pain classifiers based on automated AU codings across different environmental domains results in diminished performance. In contrast, classifiers based on manually coded AUs demonstrate reduced environmentally-based variability in performance. In this paper, we train a machine learning model to recognize pain using AUs coded by a computer vision system embedded in a software package called iMotions. We also study the relationship between iMotions (automatically) and human (manually) coded AUs. We find that AUs coded automatically are different from those coded by a human trained in the FACS system, and that the human coder is less sensitive to environmental changes. To improve classification performance in the current work, we applied transfer learning by training another machine learning model to map automated AU codings to a subspace of manual AU codings to enable more robust pain recognition performance when only automatically coded AUs are available for the test data. With this transfer learning method, we improved the Area Under the ROC Curve (AUC) on independent data from new participants in our target domain from 0.67 to 0.72.

Objective pain assessment is required for appropriate pain management in the clinical setting. However, clinical gold standard pain assessment is based on subjective methods. Automated pain detection from physiological data may provide important objective information to better standardize pain assessment. Specifically, electrodermal activity (EDA) can identify features of stress and anxiety induced by varying pain levels. However, notable variability in EDA measurement exists and research to date has demonstrated sensitivity but lack of specificity in pain assessment. In this paper, we use timescale decomposition (TSD) to extract salient features from EDA signals to identify an accurate and automated EDA pain detection algorithm to sensitively and specifically distinguish pain from no-pain conditions.

BACKGROUND: Current pain assessment methods in youth are suboptimal and vulnerable to bias and underrecognition of clinical pain. Facial expressions are a sensitive, specific biomarker of the presence and severity of pain, and computer vision (CV) and machine-learning (ML) techniques enable reliable, valid measurement of pain-related facial expressions from video. We developed and evaluated a CVML approach to measure pain-related facial expressions for automated pain assessment in youth. METHODS: A CVML-based model for assessment of pediatric postoperative pain was developed from videos of 50 neurotypical youth 5 to 18 years old in both endogenous/ongoing and exogenous/transient pain conditions after laparoscopic appendectomy. Model accuracy was assessed for self-reported pain ratings in children and time since surgery, and compared with by-proxy parent and nurse estimates of observed pain in youth. RESULTS: Model detection of pain versus no-pain demonstrated good-to-excellent accuracy (Area under the receiver operating characteristic curve 0.84–0.94) in both ongoing and transient pain conditions. Model detection of pain severity demonstrated moderate-to-strong correlations (r = 0.65–0.86 within; r = 0.47–0.61 across subjects) for both pain conditions. The model performed equivalently to nurses but not as well as parents in detecting pain versus no-pain conditions, but performed equivalently to parents in estimating pain severity. Nurses were more likely than the model to underestimate youth self-reported pain ratings. Demographic factors did not affect model performance. CONCLUSIONS: CVML pain assessment models derived from automatic facial expression measurements demonstrated good-to-excellent accuracy in binary pain classifications, strong correlations with patient self-reported pain ratings, and parent-equivalent estimation of children’s pain levels over typical pain trajectories in youth after appendectomy.

OBJECTIVES Capacities for self-regulation that influence infant adaptation to noxious stimulation require investigation of changes in behavior over time. Prenatal exposure to maternal depression and anxiety (MDA) has been linked to altered infant pain reactivity; however, findings are inconclusive about MDA dynamic impacts on recovery. This study quantified the temporal profile of behavioral response and recovery to routine heel lance (HL) of infants with and without prenatal-MDA exposure. Aims were to examine whether MDA were associated with alterations in time-based measures of infant behavior and sequential patterning in pain expression. MATERIALS AND METHODS Videotaped facial, body, and cry behaviors of 21 full-term newborns were coded second-by-second for the duration of HL (baseline, HL, Post-HL) using validated behavioral coding systems. Mean heart rate and proportion of time infants spent exhibiting behavioral measures were compared between infant groups and over subphases of HL. Simple regressions, latency, and Yule-Q measures of effect size examined which behaviors were predicted by prenatal-MDA and magnitude of sequential association between first and subsequent behavior. RESULTS During HL, all infants reacted immediately and substantially on heart rate, facial, body, and cry measures. Facial reactivity was followed within 2 seconds by body and cry behavior. There were no group differences in magnitude of initial behavioral reactions, but during Post-HL, MDA-exposed infants spent more time crying in a weak/exhausted manner and displayed strained and erratic limb movement and immobility. CONCLUSIONS Temporal measures can further help in understanding of infant complex behavioral responses to pain. Delayed recovery in MDA-exposed infants suggested diminished capacities for self-regulation of noxious distress.

Background: Evidence indicates that medical and demographic contextual factors (cFs) impact pain responses in preterm neonates, but the existing evidence is very heterogeneous. Aim: To explore the effect of cFs on pain responses to heel-stick procedures of preterm infants. Methods: This study was a secondary analysis of data collected during a randomized controlled trial examining pain response to nonpharmacological interventions across repeated heel sticks. Five heel sticks across the first 14 days of life were videotaped. Pain response was rated with the Bernese Pain Scale for Neonates (BPSN) by four raters blinded to the heel-stick phases (baseline, heel stick, recovery). Demographic and medical cFs were extracted from medical charts. Mixed single and multiple regression analyses were performed controlling for the intervention group, site and heel-stick phase. Results: Apgar scores at 1 min were negatively associated with behavioural (p = 0.002) BPSN scores, while Apgar scores at 5 min after birth were positively associated with behavioural (p = 0.006) scores. Accumulated number of painful procedures (p = 0.002) and gender (p = 0.02) were positively associated with physiological scores while continuous positive airway pressure CPAP (p = 0.009) and mechanical ventilation (p = 0.005) were negatively associated. Conclusion: Higher exposure to painful procedures, male infants and having CPAP or mechanical ventilation were cFs associated with physiological response. The only variables significantly associated with behavioural BPSN scores were Apgar scores but these relationships were inconsistent.

Analgesic trials pose unique scientific, ethical, and practical challenges in pediatrics. Participants in a scientific workshop sponsored by the US Food and Drug Administration developed consensus on aspects of pediatric analgesic clinical trial design. The standard parallel-placebo analgesic trial design commonly used for adults has ethical and practical difficulties in pediatrics, due to the likelihood of subjects experiencing pain for extended periods of time. Immediate-rescue designs using opioid-sparing, rather than pain scores, as a primary outcome measure have been successfully used in pediatric analgesic efficacy trials. These designs maintain some of the scientific benefits of blinding, with some ethical and practical advantages over traditional designs. Preferred outcome measures were recommended for each age group. Acute pain trials are feasible for children undergoing surgery. Pharmacodynamic responses to opioids, local anesthetics, acetaminophen, and nonsteroidal antiinflammatory drugs appear substantially mature by age 2 years. There is currently no clear evidence for analgesic efficacy of acetaminophen or nonsteroidal antiinflammatory drugs in neonates or infants younger than 3 months of age. Small sample designs, including cross-over trials and N of 1 trials, for particular pediatric chronic pain conditions and for studies of pain and irritability in pediatric palliative care should be considered. Pediatric analgesic trials can be improved by using innovative study designs and outcome measures specific for children. Multicenter consortia will help to facilitate adequately powered pediatric analgesic trials.

AIM: In this paper the communication model of pain is reviewed and the information then applied to understanding the acute pain experience of children in dentistry, with attention directed to improving the process of pain assessment. BACKGROUND: Expression of pain in children is of great importance as it enables them to engage others who may provide care. The experience of pain, however, is inherently private and not directly accessible to others. Therefore, it requires judgment and skill on the part of observers if pain is to be assessed accurately. In addition, there are striking individual differences in how people react to pain, which makes the assessment of pain in others an even greater challenge. Craig and colleagues [2008] have proposed the use of the social communication model of pain that gives priority to understanding the numerous social factors that affect whether children are successful in communicating painful distress. CONCLUSION: When children’s pain is underestimated or a child’s self-report is not seen as credible, there is a considerable risk of failure to deliver needed dental care.

BACKGROUND: Research suggests that caregivers’ beliefs pertaining to infant pain and which infant pain cues are perceived to be important play an integral role in pediatric pain assessment and management.OBJECTIVES: Following a recent quasi-experimental study reporting on caregiver background and age differences in actual infant pain judgments, the present study clarified these findings by analyzing caregivers’ pain beliefs and the cues they use to make pain assessments, and by examining how the wording of belief questions influenced caregivers’ responses.METHODS: After making pain judgments based on video footage of infants between two and 18 months of age receiving immunizations, parents, nurses and pediatricians were required to respond to questionnaires regarding pain beliefs and importance of cues.RESULTS: Parents generally differed from pediatricians. Parents tended to have less optimal beliefs regarding medicating the youngest infants, were more influenced by question wording, and reported using many more cues when judging older infants than other caregiver groups. In terms of beliefs, influence of question wording and cue use, nurses tended to fall in between both groups; they displayed similarities to both parents and pediatricians.CONCLUSIONS: Paralleling the original findings on pain judgments, these findings suggest that parents differ from pediatricians in their pain beliefs and the cues they use to make pain judgments. Moreover, some similarities were found between parents and nurses, and between nurses and pediatricians. Finally, caution must be taken when interpreting research pertaining to beliefs about infant pain because question wording appears to influence interpretation.

This paper represents an expert-based consensus statement on pain assessment among older adults. It is intended to provide recommendations that will be useful for both researchers and clinicians. Contributors were identified based on literature prominence and with the aim of achieving a broad representation of disciplines. Recommendations are provided regarding the physical examination and the assessment of pain using self-report and observational methods (suitable for seniors with dementia). In addition, recommendations are provided regarding the assessment of the physical and emotional functioning of older adults experiencing pain. The literature underlying the consensus recommendations is reviewed. Multiple revisions led to final reviews of 2 complete drafts before consensus was reached.

Objective To examine whether caregiver judgments of infant pain would vary systematically with different infant caregiver groups and infant age. Methods A total of 123 caregivers (41 parents, 41 in patient nurses, 41 pediatricians) viewed videotapes of the vigorous behavioral responses of healthy infants (aged 2, 4, 6, 12, and 18 months) to a routine immunization injection and provided ratings of both the affective distress and pain intensity observed. Results A principal components analysis of affective and intensity ratings yielded a weighted pain summary score for each injection event. Older infants were attributed significantly more pain than younger infants, even though the vigor of the behavioral reactions was experimentally controlled across age groups. A profile analysis contrasting observer groups indicated that pediatricians attributed significantly lower levels of pain than parents, while nurses were intermediate to the other groups, not significantly differing from either group. These systematic differences in judgments were consistent across infant age groups. Conclusions The findings reveal systematic sources of significant variations in observer judgments of infant pain. Despite an absence of differences in the behavioral reactions of the children, both the type of caregiver and their knowledge of the child’s age systematically influenced attributions of pain to infants. This work suggests the important role of caregiver role variation and perceived developmental maturity as determinants of infant pain judgments and highlights potential areas of difficulty in controlling the unnecessary suffering of infants.

Clinicians tend to assign greater weight to nonverbal expression than to patient self-report when judging the location and severity of pain. However, patients can be successful at dissimulating facial expressions of pain, as posed expressions resemble genuine expressions in the frequency and intensity of pain-related facial actions. The present research examined individual differences in the ability to discriminate genuine and deceptive facial pain displays and whether different models of training in cues to deception would improve detection skills. Judges (60 male, 60 female) were randomly assigned to 1 of 4 experimental groups: 1) control; 2) corrective feedback; 3) deception training; and 4) deception training plus feedback. Judges were shown 4 videotaped facial expressions for each chronic pain patient: neutral expressions, genuine pain instigated by physiotherapy range of motion assessment, masked pain, and faked pain. For each condition, the participants rated pain intensity and unpleasantness, decided which category each of the 4 video clips represented, and described cues they used to arrive at decisions. There were significant individual differences in accuracy, with females more accurate than males, but accuracy was unrelated to past pain experience, empathy, or the number or type of facial cues used. Immediate corrective feedback led to significant improvements in participants' detection accuracy, whereas there was no support for the use of an information-based training program.

This study examined explanatory variables that could predict parent attitudes concerning the helpfulness of pain medication for their postoperative child. Predictor variables included beliefs underlying attitudes, prior medical experiences of the child and parent, and parental goals for pain relief. Data were provided by 236 parents of children undergoing day surgery and were analyzed using a multiple regression model. Although beliefs were significant predictors, parents' own experiences with surgery were stronger predictors of attitudes toward the helpfulness of pain medication for their children. Identifying parents' personal adverse experiences with surgery may assist in improving the care they provide to their child after surgery.

Objectives: Reduced pain sensitivity is widely reported to be a common feature of children with autism, yet this conclusion frequently has been based on anecdotal observations and questionable measures of pain. The aims of the study were to (1) characterize the behavioral response of children with autism experiencing a venepuncture using objective observational measures of pain and distress, (2) examine parents’ assessments of pain behavior in children with and without autism, including comparison of the relationship of parental reports with behavioral measures, and (3) compare the behavioral reactions and parental assessments of children with autism with children without autism undergoing venepuncture. Methods: Pain reactions to the invasive procedure of venepuncture were videotaped, systematically described and compared in 21 children with autism (3–7 years old) and 22 nonimpaired children, the latter providing a chronological age and gender equivalent comparison group. Parents provided observer reports of pain, and facial activity was used as an objective behavioral measure of pain. Results: The children with autism displayed a significant facial pain reaction in response to the venepuncture procedure. There was a lack of concordance between parental reports of pain and observed pain responses for the children with autism. Behavioral responses of the children with autism were generally similar to the comparison group, except the substantial facial pain reactivity instigated by the venepuncture in the children with autism exceeded that displayed by the nonimpaired comparison children. Parent reports of pain severity did not differ between the autism and comparison groups. The degree of concordance between parental report and observed pain responses was consistently better for the comparison group. Discussion: The findings demonstrate that children with autism display a significant behavioral reaction in response to a painful stimulus, and these findings are in sharp contrast to the prevailing beliefs of pain insensitivity described in the literature to date. The findings also raise questions about the appropriateness of parental global report as an assessment tool for pain in children with autism.

The purpose was to determine if a nursing intervention pre-operatively with post-operative follow up would improve levels of pain, and the extent of common symptoms such as nausea and constipation. Two hundred and twenty-two surgical day patients undergoing arthroscopic knee surgery, mammary reduction, hernia repair and anal surgery completed pain diaries post-operatively. Nurses telephoned the intervention group on post-operative days 1, 2 and 3 with advice and support. Results indicate that the telephone intervention decreased patients post-operative pain. Patients do not always understand oral or written information given at discharge and there is a need for specific follow-up advice and information.

The inevitability of pain during infancy and its potential for destructive impact impose a burden on caregiving adults. An armamentarium of effective pharmacological, behavioral and environmental interventions is available if pain were recognized and accurately assessed. Infants have limited behavioral repertoires that make identification of specific needs difficult, mothers and other caregivers prone to high levels of protection and redundant care. But more specific care can best suit infant requirements. Certain behaviors are sensitive to states of distress, including pain, for example, cry and disruption of usual activities such as sleep. Others appear more specific, for example, facial activity. This paper proposes that effective care is best delivered to infants and children if we recognize the complexities of the sociocommunication process; subjective states are encoded in behavioral activity and caregivers must be able to recognize the meaning of these actions. The paper delineates some features of the process whereby caregivers arrive at judgments of infant's needs and make decisions concerning interventions.

Summary Chronic pain is highly prevalent in the ageing population. Individuals with neurological disorders such as dementia are susceptible patient groups in which pain is frequently under-recognised, underestimated, and undertreated. Results from neurophysiological and neuroimaging studies showing that elderly adults are particularly susceptible to the negative effects of pain are of additional concern. The inability to successfully communicate pain in severe dementia is a major barrier to effective treatment. The systematic study of facial expressions through a computerised system has identified core features that are highly specific to the experience of pain, with potential future effects on assessment practices in people with dementia. Various observational–behavioural pain assessment instruments have been reported to be both reliable and valid in individuals with dementia. These techniques need to be interpreted in the context of observer bias, contextual variables, and the overall state of the individual's health and wellbeing.

The Pain in Child Health (PICH) consortium is a Strategic Training Initiative in Health Research funded by the Canadian Institutes of Health Research. The PICH represents a community of interdisciplinary researchers whose goal is to support the education of highly qualified personnel and to promote research on the prevention and relief of pediatric pain. The authors of this article report on the success of the PICH since its inception in 2002., BACKGROUND AND OBJECTIVES: Pain in Child Health (PICH) is a transdisciplinary, international research training consortium. PICH has been funded since 2002 as a Strategic Training Initiative in Health Research of the Canadian Institutes of Health Research, with contributions from other funding partners and the founding participation of five Canadian universities. The goal of PICH has been to create a community of scholars in pediatric pain to improve child health outcomes. METHODS: Quantitative analyses enumerated PICH faculty, trainees, training activities and scientific outputs. Interviews with PICH stakeholders were analyzed using qualitative methods capturing perceptions of the program’s strengths, limitations, and opportunities for development and sustainability. RESULTS: PICH has supported 218 trainee members from 2002 through 2013, from 14 countries and more than 16 disciplines. The faculty at the end of 2013 comprised nine co-principal investigators, 14 Canadian coinvestigators, and 28 Canadian and international collaborators. Trainee members published 697 peer-reviewed journal articles on pediatric pain through 2013, among other research dissemination activities including conference presentations and webinars. Networks have been established between new and established researchers across Canada and in 13 other countries. Perceptions from stakeholders commended PICH for its positive impact on the development of pediatric pain researchers. Stakeholders emphasized skills and abilities gained through PICH, the perceived impact of PICH training on this research field, and considerations for future training in developing researchers in pediatric pain. CONCLUSIONS: PICH has been successfully developing highly qualified health research personnel within a Canadian and international community of pediatric pain scholarship.

Assessing pain in young children requires astute judgment by observers. Multidimensional observational scales for pediatric pain contribute by providing behavioral cues believed to characterize pain in children; yet, few measurement items have undergone rigorous psychometric evaluation. This is the case with facial expression, which has been widely recognized as the most sensitive and specific nonverbal indicator of pain. The criteria for identifying facial expressions of pain differ substantially across scales and are frequently inconsistent with empirical descriptions.The present study compared observer ratings of children's (aged 1 to 6 y, inclusive) videotaped postoperative pain reactions using the facial activity items from 6 widely used pediatric pain assessment scales and an anatomically based and empirically validated measure, the Child Facial Coding System. We hypothesized that facial expression items that did not correspond to empirical descriptions would lead to less reliable and divergent pain estimates. Intercoder reliability, criterion validity (empirical and convergent), content validity, and face validity were examined.Findings supported hypotheses and indicated that variation in cues proposed for assessing facial expression led to widely ranging scores that could be insensitive to differences in children's pain intensity.The facial items varied considerably in coder judgment reliability as well as criterion (empirical and convergent), content, and face validity. Observational scales should provide behavioral cues that correspond to empirical descriptions of the facial expression of pain.

Objective: To identify the structure of facial reaction to procedural pain and to determine the subset of facial actions that best describe the response. Design: Observational. Setting: Five rural and five urban physicians’ offices. Patients: One hundred twenty-three children aged 4 to 5 years undergoing routine diphtheria, pertussis, tetanus, and polio immunization. Outcome Measures: The Child Facial Coding System, comprising 13 discrete facial actions, was used to code each second of five 10-second phases from videotape: baseline, preneedle, needle, postneedle, and posthandling. Parents and a technician provided visual analog scale ratings of children’s pain. Children provided a self-report using a Faces Pain Scale, and parents and nurses rated the children’s pain and anxiety using visual analog scales. Results: A “pain face” similar to that reported in adults emerged with the onset of pain. Principal component analyses revealed the frequency and intensity of facial action during the needle phase could be represented by components reflecting pain sensation, a “brave face,” and the children’s expectations for pain. Children’s Faces Pain Scale and adult visual analog scale ratings were best predicted by components reflecting pain sensation and expectations of high pain. Conclusions: These results provide a preliminary indication that the Child Facial Coding System can be reduced to components that reflect several aspects of children’s acute pain experience and predict self-reports and observer reports of children’s pain. Key Words: Facial action—Immunization—Pain—Pain assessment—Pediatric.

Objective To determine whether psychological measures would differentiate a group of patients with physician-diagnosed nonneurologic hand pain from patients with carpal tunnel syndrome (CTS). Many patients, who also displayed symptoms of psychological distress, were referred to an electrodiagnostic clinic with a diagnosis of possible CTS; they subsequently had normal nerve conduction studies. Design Sixty patients with hand pain were referred to either of two university clinics for electrophysiologic testing, were assigned to either the CTS or nonneurologic group, and were compared on a series of psychometric tests. Results The Beck Depression Inventory and McGill Pain Questionnaire showed that the physician-assigned nonneurologic patients have a greater degree of depression, use more affective adjectives, and choose more words on the McGill Pain Questionnaire than the physician-assigned CTS group. The nonneurologic group also scored higher on indices of self-reported disability on the Pain Disability Inventory in five of seven categories. Although the CTS group perceived more control over their pain, no differences were observed in the types of coping strategies used on the Coping Strategy Questionnaire. Finally, the nonneurologic group had more Workers' Compensation Board claims. Conclusion Evidence of important psychological issues in some patients with hand pain suggests a need for greater awareness among treating physicians.

To further understand acute pain response in children with a significant neurologic impairment (SNI), we undertook a descriptive hypothesis-generating study of the response to a routine vaccine among adolescents with SNI.Within-subject crossover design.Tertiary care facility for children and adolescents with SNI.Eight adolescents (mean age = 15 years).Mock and real vaccine injections.Quantitative measures of heart rate, videotaped facial action, Child Facial Coding System (CFCS), and Facial Action Coding System (FACS); observer ratings visual analog scale (VAS) were obtained before, during, and after a mock injection and routine annual influenza vaccine injection presented in a counterbalanced order.VAS scores were significantly higher during the injection phase than during the other time periods; however, there were no significant differences across study time periods when using the other outcome measures.Although the dampened behavioral and physiologic reactions to an acute noxious stimulus were similar to those of previous work with developmentally delayed children and frail elderly, it remains unclear what underlies the apparent reduced pain response in this setting. These findings have potentially important implications for the daily care of individuals with significant neurologic impairment and illustrate the compelling need tor further study of the unique character of the pain experience in this setting.

Objective: Parents are often the primary source of information regarding their children pain in both research and clinical practice. However, parent--child agreement on pain ratings has not been well established. The objective of the present study was to examine agreement between child- and parent-rated pain following minor surgery. Setting: Tertiary care children's hospital. Participants: A total of 110 children (56.4% male) aged 7-12 years undergoing surgery and their parents. Outcome Measures: Parents and children independently rated pain intensity by using a 7-point Faces Pain Scale on the day of the child's surgery and the following 2 days. Results: Correlations (both Pearson's and intraclass correlation coefficients) indicated a highly significant relationship between child and parent ratings. However, kappa statistics indicated only poor to fair agreement beyond chance. Parents tended to underestimate their children's pain on the day of surgery and the following day, but not on the second day following surgery. When children's and parents pain ratings for each of the 3 days were collapsed into a no-pain/low-pain group or a clinically significant pain group, kappa statistics indicated fair to good agreement, Parents demonstrated low levels of sensitivity in identifying when their children were experiencing clinically significant pain. Conclusions: Correlations between parent and child pain reports do not accurately represent the relationship between these ratings and in fact overestimate the strength of the relationship. Parents' underestimation of their child's pain may contribute to inadequate pain control.

This study examined the impact of evidence concerning the presence of 1) a biomedical basis for pain and 2) psychosocial influences on practitioner appraisals of patient pain experiences. Furthermore, the potential moderating role of patient pain behavior was examined. In an online study, 52 general practitioners and 46 physiotherapists viewed video sequences of 4 patients manifesting pain, with accompanying vignettes describing presence or absence of medical evidence and psychosocial influences. Participants estimated pain intensity, daily interference, sympathy felt, effectiveness of pain medication, self-efficacy, their likability, and suspicions of deception. Primary findings indicated lower perceived pain and daily interference, less sympathy, lower expectations of medication impact, and less self-efficacy when medical evidence was absent. The same results were found when psychosocial influences were present, but only when the patient displayed higher levels of pain behavior. Furthermore, absence of medical evidence was related to less positive evaluations of the patients and to higher beliefs in deception in both professions. The presence of psychosocial influences was related to less positive evaluations and higher beliefs in deception in both professions. In sum, a range of contextual factors influence health care practitioner responses to patient pain. Implications for caregiving behavior are discussed. Perspective The present study indicates that in the absence of clear medical evidence and in the presence of psychosocial influences, patient pain might be taken less seriously by health care practitioners. These findings are important to further understand the difficulties that relate to the clinical encounter between pain patients and health care practitioners.

Major efforts to develop objective measurement tools for neonatal pain assessment have been made. However, the challenge of measuring pain in neonates remains suggesting that contextual factors (cFs) might alter their responses to pain. Although the role of cFs is increasingly discussed as crucial for pain assessment, they are not well described in the literature and are rarely considered in the clinical setting despite their importance. Aim To systematically examine studies investigating the impact of cFs on pain response in preterm infants. Method A literature search was undertaken for the period from 1990 to 2009. Studies reporting the relation between one or more cFs and pain response in preterm infants during a heelstick procedure were considered for inclusion. Results Twenty-three studies satisfied inclusion criteria. The studies varied relative to their design, sample, analysis procedures, and variables examined. Six categories of cFs emerged: age, pain exposure, health status, therapeutic interventions, behavioral status, and demographic factors. The examined cFs varied in the strength of their association with pain response, although none were invariably related, as evidenced by contradictory findings. In some cases the inconsistencies appeared attributable to methodological limitations in studies. Behavioral and physiological pain responses were not always in agreement as would be expected. Conclusion This review supports the influence of some cFs on pain response. However, the results remain inconclusive which may be, in part, related to the heterogeneity of the studies. Contextual factors need further investigation for a better understanding of the magnitude of their effect on pain response.

Pain assessment conventionally has been viewed hierarchically with self-report as its "gold-standard." Recent attempts to improve pain management have focused on the importance of assessment, for example, the initiative to include pain as the "fifth vital sign." We question the focus in the conceptualization of pain assessment upon a "vital sign," not in terms of the importance of assessment, but in terms of the application of self-report as a mechanistic index akin to a biologic measure such as heart rate and blood pressure. We synthesize current inclusive models of pain and pain assessment and propose a more comprehensive conceptualization of pain assessment as a transaction based on an organismic interplay between the patient and clinician.

Facial expression is widely used as a measure of pain in infants; whether nonhuman animals display such pain expressions has never been systematically assessed. We developed the mouse grimace scale (MGS), a standardized behavioral coding system with high accuracy and reliability; assays involving noxious stimuli of moderate duration are accompanied by facial expressions of pain. This measure of spontaneously emitted pain may provide insight into the subjective pain experience of mice.

The management of pain reflects a history of myths and misconceptions often based on the "common sense" of the time. Evidence-based approaches to patient care are now strongly advocated. Recognizing that the accepted practice for administering postoperative analgesics has become the time-contingent or around-the-clock (ATC) regime, this article reviews the existing literature in search of empirical evidence supporting this practice. The review was conducted through MEDLINE, with the database limited to articles in the English language, involving human subjects, and published between 1960 and 2000. Database searches included each of the terms schedule, ATC, time, regime, administration, hour, dosing, qid, q6h, q4h, pro re nata, regular, and prn. Furthermore, common pain relieving drugs used in the postoperative period also were used as search words. Every database search was qualified by the terms post-operative or postoperative. The search showed sparse empirical work warranting endorsement of this dosing regimen. Although a great deal is known about specific drugs and dosage requirements, research is needed that clearly examines optimal scheduling regimens if we are to maximize patient care.

s The Journal of Pain S3 (108) Automated facial expression analysis can detect clinical pain in youth in the post-operative setting J Huang, K Craig, D Diaz, K Sikka, A Ahmed, L Terrones, G Littlewort, M Goodwin, and M Bartlett; University of California San Diego, La Jolla, CA Clinical pain assessment has relied on self-report and clinician observations. The former requires cognitive competence, social skills and candor and the latter requires clinician skill and substantial human resources. Failures to recognize pain and suboptimal pain assessment in youth have been documented, particularlywhenusing assessmentby proxy.Wepursued an alternative approachusing computer vision, pattern recognition and machine learning to provide automated, objectivepainassessment information in thepostoperative setting. Facial expressions have been recognized as sensitive and specific to pain and well-validated coding systems (FACS) are available. We utilized an automated FACS system (CERT) to measure facial expressions in clinical pain and no-pain situations to determine potential utility of CERT tomeasure clinical pain in children. Specifically, we video-recorded facial expressions within 24 hours of appendectomy in 40 otherwise healthy children and again after clinical resolution at a follow-up visit 20 (18,29) [median(interquartile range)] days later when no pain was reported. Measured youth were 13 (10,15) years old, 88% Hispanic, and 65% male. Recordings were analyzed using CERT, and mean measurements of facial actions associatedwith pain (AUs 4, 6, 7, 9, 10, 25, 43)were comparedwithin subjects over time using repeated-measure analyses. CERTwas able to detect differences in at-rest facial expressions during the immediate postoperative pain period (validated by self-reports of presence of pain) as compared to expressions measured during the no-pain period (AU4, P=0.006; AU7, P 18.61; p’s .335). The PDI and VAS showed mostly weak relationships with performances on sit-to-stand, stair climb and treadmill distance (r’s range: -.31 to .01; p’s >.06). Pain intensity during the functional tests (postminus pre-pain NRS) also showed weak relationships with performances on sit-to-stand, stair climb and treadmill distance (r’s range: -.23 to -.14; p’s >.10). Results suggest that self-reports of pain and disability may not correspond well with subjects’ actual capacities to perform simple everyday functions. Even the pain intensity increases evoked during the functional tests correlated weakly with performance, indicating that those reporting greatest pain increases during the functional tests did not differ on performance from those reporting small pain increases. Thus, having subjects perform simple functional tests that do not require complex apparatus could add greatly to the clinical picture portrayed by OA patients. Supported by a research grant from Forest Laboratories, Inc. (110) Withdrawn A04 Clinical Outcomes Measurement (111) Stanford-NIH Pain Registry: catalyzing the rate limited step of psychometrics withmodern patient-reported outcomes M Kao, K Cook, G Olson, T Pacht, B Darnall, S Weber, and S Mackey; Stanford School of Medicine, Palo Alto, CA Unlike passive biometric measurements, psychometric measures require active participation from subjects and are rate-limited by subject burden.We develop a comprehensive system of algorithms on the Stanford-NIH Pain Registry to support modern patient reported outcome (PRO) with item-response theory (IRT) and computerized adaptive testing (CAT). This system, called SNAPLCAT, is designed as amulti-feature computation engine for the NIH funded psychometric item banks NIH PROMIS and NIH Toolbox. Implemented on open sourceMEAN stackwith D3.js visualization, the system’s features include initialization (individualized or patient population priors), item selection (expected Kullback-Leibler, minimum expected posterior variance), advanced item selection (alpha-stratification, exposure control, content balancing, probabilistic constrained optimization), stopping rule (predicted standard error reduction, percentile width, hybrid), and estimation (expected a posteriori, maximum likelihood, maximum a posterior). Item banks and linkages are obtained from Northwestern Access Center and PROsetta Stone. Performance in 4,466 measurements in the Registry are analyzed. We find that basic CAT provided significant reduction in burden (mean number of items 6 SD, fold reduction): Anger (6.24+/-1.21, 4.6-fold vs BPAQ), Anxiety (4.93+/-0.97, 1.4-fold vs GAD-7), Depression (4.97+/-1.07, 1.8-fold vs PHQ-9), Fatigue (4.78+/-0.76, 8.4-fold vs FACIT-F), Physical Function (4.11+/-0.48, 4.9-fold vs HAQ-DI), Pain Interference (4.19+/-0.71, 1.7-fold vs BPI), Sleep Disturbance (4.95+/-1.41, 2.4-fold vs SDQ), Sleep-Related Impairment (4.54+/-1.24, 1.8-fold vs ESS). Altogether, the 132 classic instrument items may be alternatively assessed by 38.7 +/7.9 items, for 2.8 to 4.3 fold reduction in patient burden. In conclusion, using IRT and advanced CAT, the Stanford-NIH Pain Registry and SNAPL-CAT leverage the powers of NIH PROMIS and Toolbox, and enable big data psychometrics for the study of pain.

Objective: Prior research examining the utility of nonverbal measures of pain in persons with cognitive impairments has focused on acute procedurally-induced phasic pain (i.e., venipuncture and needle injections). The goal of the current project was to examine the utility of both self-report and nonverbal measures of pain in frail elders experiencing exacerbations of chronic musculoskeletal pain. These were assumed to be more representative of the day-to-day pain experience of elderly patients. Design: Participants were 58 frail elders, 29 of whom had been found to have significant cognitive impairments. All were filmed as they undertook a series of structured activities (e.g., walking and reclining), and pain was assessed using self-report. Trained coders identified the incidence of pain-related behaviors using the videotapes. The various pain measures (i.e., self-report and nonverbal indices) were compared across both patient groups and the several activities. Results: Consistent with our hypotheses, more pain was identified (using both self-report and nonverbal measures) when patients engaged in more physically demanding activities. Facial reactions varied as a function of patient cognitive status, with those participants who were cognitively impaired more responsive. Of the various nonverbal indices that we examined, guarded behavior appeared to be especially sensitive. The various pain indices were only modestly correlated with one another. Conclusions: This study supports the validity of self-report and behavioral measures of pain in frail elders with and without cognitive impairments. Each of the measures used contributed different information to pain assessment, suggesting that investigations of pain in elders with cognitive impairments should employ varying types of pain assessment tools.

The purposes of the study were threefold: (a) to determine whether a measurement system based on facial expression would be useful in the assessment of post-operative pain in young children; (b) to examine construct validity in terms of structure, consistency, and dynamics of the facial display; and (c) to evaluate concurrent validity in terms of associations with global judgments of the children's pain.One hundred children between the ages of 13 and 74 months were video-taped for a maximum of 1 hour after arrival in the postanesthesia care unit (PACU) at British Columbia's Children's Hospital.Videotapes were edited into 20-second blocks, randomly selected from each 2-minute time period taped during the hour following surgery, and coded for the presence or absence of 13 facial actions in the Child Facial Coding System (CFCS).Facial expressions were characterized primarily by the following constellation of actions: open lips, lowered brows, a deepened nasolabial furrow, mouth stretched wide in both horizontal and vertical directions, eyes squeezed shut or squinted, and raised cheeks. A principal components analysis indicated that these actions comprised a single factor, accounting for 55% of the variance in CFCS actions. Facial action summary scores were correlated with a visual analog rating of global pain, confirming that the CFCS has convergent validity. Facial action summary scores, i.e., pain displays, were at their lowest immediately after admittance to the PACU and just before the child's release from the PACU.The present study demonstrated that the CFCS serves as a valid measurement tool for persistent pain in children.

To determine morphine pharmacokinetics in premature neonates varying in postconceptional age (PCA) and evaluate behavioral pain response in relationship to serum morphine concentrations.Premature neonates (n = 48), stratified by weeks of PCA (group 1 = 24-27 weeks, group 2 = 28-31 weeks, group 3 = 32-35 weeks, and group 4 = 36-39 weeks) received morphine infusions. Blood samples were drawn at 48, 60, and 72 hours and at discontinuation of morphine, followed by 3 samples obtained during the next 24 hours. Newborns were videotaped during heel lances and restful states, with morphine at steady-state concentrations and without morphine. Pain was assessed by using the Neonatal Facial Coding System (NFCS). Statistical analysis included regression between NFCS score changes from baseline to painful procedure with and without morphine.Morphine clearance for groups 1, 2, 3, and 4 was calculated as 2.27 +/- 1.07, 3.21 +/- 1.57, 4.51 +/- 1.97, and 7.80 +/- 2.67 mL/kg/min, respectively, and correlated with PCA (r = 0.63, P.001). Pain measured by facial expression was diminished; however, it did not correlate with morphine concentrations.Morphine clearance in premature neonates is less than reported, increasing with PCA. Facial activity discloses morphine analgesia; however, it is unrelated to morphine concentrations.

This study examined trends in chronic pain (including chronic headache) research from 1986 to 1995. Medical and psychological citation databases were accessed to identify chronic pain publications and yearly trends. Data from the PsycLIT (psychological) database indicated significant growth over the time frame analyzed in both raw number of chronic pain publications and the percentage of articles devoted to chronic pain. Conversely, the Medline (medical) database showed a significant decline in the percentage of chronic pain articles over the time frame analyzed. Analyses revealed increases on the PsycLIT and Medline databases in the number of studies on elderly people, and the Medline database showed increases in the number of studies of chronic pain in children. Remarkably, there were significant increases on PsycLIT in the number of drug-therapy studies for chronic pain, but a significant decrease was evident in the number of drug therapy articles abstracted on Medline. Factors that may be associated with these research trends are discussed, and future probable trends are anticipated.

The impact of invasive procedures on preterm neonates has received little systematic attention. We examined facial activity, body movements, and physiological measures in 56 preterm and full-term newborns in response to heel lancing, along with comparison preparatory and recovery intervals. The measures were recorded in special care and full-term nurseries during routine blood sampling. Data analyses indicated that in all measurement categories reactions of greatest magnitude were to the lancing procedure. Neonates with gestational ages as short as 25–27 weeks displayed physiological responsivity to the heel lance, but only in the heart rate measure did this vary with gestational age. Bodily activity was diminished in preterm neonates in general, relative to full-term newborns. Facial activity increased with the gestational age of the infant. Specificity of the response to the heel lance was greatest on the facial activity measure. Identification of pain requires attention to gestational age in the preterm neonate.