Physical pain among Indigenous Peoples in Canada: a scoping review

PURPOSE

Pain is a multifaceted experience shaped by various factors including context of pain, previous life events, and ongoing ethnocultural circumstances. Moreover, the definition of pain is inconsistent across cultures. Western medicine views physical pain (e.g., associated with a bone fracture) and nonphysical mental pain (e.g., depression) as two distinct conditions. Indigenous perspectives are often more wholistic, encompassing mental, spiritual, emotional, and physical hurt. The subjective nature of pain invites ample opportunity for discrimination in both its assessment and management. As such, it is important to consider Indigenous perspectives of pain in research and clinical practice. To investigate which aspects of Indigenous pain knowledge are currently considered by Western research, we conducted a scoping review of the literature on pain in Indigenous Peoples of Canada.

SOURCE

In June 2021, we searched nine databases and downloaded 8,220 papers after removal of duplicates. Two independent reviewers screened abstracts and full-text articles.

PRINCIPLE FINDINGS

Seventy-seven papers were included in the analysis. Using grounded theory, five themes emerged: pain measures/scales (n = 7), interventions (n = 13), pharmaceuticals (n = 17), pain expression/experiences (n = 45), and pain conditions (n = 70).

CONCLUSION

This scoping review shows that there is a paucity of research on pain measurement in Indigenous Peoples of Canada. This finding is concerning in light of numerous studies reporting that Indigenous Peoples experience their pain as ignored, minimized, or disbelieved. Furthermore, a clear disconnect emerged between pain expression in Indigenous Peoples and assessment in medical professionals. We hope that this scoping review will serve to translate current knowledge to other non-Indigenous academics and to initiate meaningful collaboration with Indigenous partners. Future research led by Indigenous academics and community partners is critically needed to better address pain needs in Canada.

Parental Pain Catastrophizing, Communication Ability, and Post-surgical Pain Outcomes Following Intrathecal Baclofen Implant Surgery for Patients With Cerebral Palsy

There is strong evidence that psychosocial variables, including pain catastrophizing, influence parental and child ratings of pain, pain expression, and long-term outcomes among children with chronic pain. The role of these factors among children who have communication deficits due to cerebral palsy (CP) and other intellectual and developmental disabilities is currently unclear. In this study, parental pain catastrophizing was assessed before intrathecal baclofen (ITB) pump implantation for spasticity management in 40 children and adolescents with CP, aged 4 to 24 years. Pain was assessed before and after surgery with two methods: a parent-reported pain interference scale, and behavioral pain signs during a standardized range of motion exam. Linear mixed models with clinical/demographic factors and scores from the Pain Catastrophizing Scale for Parents (PCS-P), and child spoken language ability as predictors and the pain variables as the outcomes were implemented. On average, both pain outcomes improved after surgery. Only child spoken language ability predicted change in behavioral reactivity scores, with children with phrase speech showing an increase in reactivity at follow-up compared to pre-surgery levels, on average. A significant interaction between PCS-P scores and spoken language ability on change in pain interference scores over time showed that dyads with children with phrase speech whose parents reported high PCS-P scores reported the least improvement in pain interference at follow-up. Due to the preliminary nature of the study, future work is needed to investigate the parental behaviors that mediate the relationships between parental catastrophizing and pain outcomes in this population.

What is pain: Are cognitive and social features core components?

Pain is a universal experience, but it has been challenging to adequately define. The revised definition of pain recently published by the International Association for the Study of Pain addressed important shortcomings of the previous version; however, it remains narrow in its focus on sensory and emotional features of pain, failing to capture the substantial roles of cognitive and social core components of the experience and their importance to advances in pain management. This paper reviews evidence and theoretical models for the significant role social and cognitive factors play in pain experience and we argue that without explicit recognition of these core components in the definition, significant nuances are lost at a cost to understanding and clinical management of pain. A focus on sensory and emotional features perpetuates biomedical interventions and research, whereas recognition of cognitive and social features supports a multidimensional model of pain, advances in interdisciplinary care, and the benefits of cognitive behavioral therapy and self‐management interventions. We also explore the six Key Notes that accompany the new definition of pain, discuss their application to the understanding of pain in childhood, and, in doing so, further explore social and cognitive implications. Considerations are also described for assessment and treatment of pain in pediatric populations.

A child in pain: A psychologist’s perspective on changing priorities in scientific understanding and clinical care

My research and clinical career followed a trajectory of increasing appreciation for the importance of social factors as determinants of pain experience and expression. The social contexts of children’s lives determine whether infants and children are exposed to pain, how socialization in family and ethnocultural contexts lead to pain as a social experience, comprised of thoughts and feelings as well as sensory input, how others shape pain experience and expression, less so for automatic/reflexive features than purposeful representations, and how other's appraisals of children’s pain reflect the observer's unique background and capacities for intervening in the child’s interests. A greater understanding of the social dimensions of pain, as reflected in the social communication model of pain, would support innovation of psychological and social interventions.

Automated Pain Assessment using Electrodermal Activity Data and Machine Learning

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.

Pain in Child Health from 2002 to 2015: The early years of an international research training initiative

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.

Towards Automated Pain Detection in Children using Facial and Electrodermal Activity

Accurately determining pain levels in children is difficult, even for trained professionals and parents. Facial activity and electro- dermal activity (EDA) provide rich information about pain, and both have been used in automated pain detection. In this paper, we discuss preliminary steps towards fusing models trained on video and EDA features respectively. We compare fusion models using original video features and those using transferred video features which are less sensitive to environmental changes. We demonstrate the benefit of the fusion and the transferred video features with a special test case involving domain adaptation and improved performance relative to using EDA and video features alone.

Automated Pain Detection in Facial Videos of Children using Human-Assisted Transfer Learning

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.

Youth and Parent Appraisals of Participation in a Study of Spontaneous and Induced Pediatric Clinical Pain

The current study examined youths' and their parents' perceptions concerning participation in an investigation of spontaneous and induced pain during recovery from laparoscopic appendectomy. Youth (age range 5-17 years) and their parents independently completed surveys about their study participation. On a 0 (very negative) -to-10 (very positive) scale, both parents 9.4(1.3) [mean(SD)] and youth 7.9(2.4) rated their experience as positive. Among youth, experience ratings did not differ by pain severity and survey responses did not differ by age. Most youth (83%) reported they would tell another youth to participate. Ethical issues regarding instigation of pain in youth for research purposes are examined.

The relationship of prenatal maternal depression or anxiety to maternal caregiving behavior and infant behavior self-regulation during infant heel lance: an ethological time-based study of behavior

BACKGROUND

Sensitive and responsive maternal caregiving behavior strengthens infant self-regulatory capacities (HL), but this regulatory role may be diminished in some mothers with second-trimester prenatal exposure to depression and/ or anxiety (MDA). This study examined maternal and infant behavior during infant heel lance (HL) when mothers had or did not have MDA. Ethological methods and micro-analytic approaches capable of distinguishing and comparing time-based patterning in maternal and infant behavior were used to clarify biological mechanisms, such as MDA, that may underlie observed behavior. Aims were to examine group differences in caregiving behavior between mothers with and without MDA 5 min Pre-HL and 5 min Post-H, and relationships between MDA, maternal caregiving behavior and infant pain behavior self-regulation, concurrently.

METHODS

At second trimester, mothers were assessed for symptoms of mild-severe depression or anxiety. Mothers whose scores exceeded predetermined cut-off scores on one or more of the mental health measures were allocated to the MDA-exposure group, those below to the non-MDA-exposure group. Reliable observers, blinded to MDA status and study phases, coded video records of the caregiving behavior of each study mother for the full duration of the 5 min Pre-HL and 5 min Post-HL study phases. Group differences and associations between mean measures of maternal mental health scores, time-based measures of maternal behavior, and time-based measures of infant pain behavior regulation (previously coded) were concurrently analyzed using comparative and correlational statistics.

RESULTS

MDA-exposed mothers spent significantly more time not embracing, engaging or responding to infant cues than maternal controls Pre-HL and Post-HL. MDA was associated with atypical maternal caregiving behavior, which in turn was related to atypical infant pain behavior self-regulation during and after the HL.

CONCLUSION

Our findings have implication for practice. We recommend inclusion of mothers with MDA and their infants in interventions that strengthen the early mother-infant interaction and mother's regulatory caregiving role. MDA and maternal caregiving behavior must be considered in future infant pain studies to examine if they confound effectiveness of mother driven caregiving interventions for neonatal pain. We highlight the importance of examining maternal mental health throughout the perinatal and postnatal trajectory, and particularly the newborn period.

Automated Assessment of Children's Postoperative Pain Using Computer Vision

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.

Contextual factors associated with pain response of preterm infants to heel-stick procedures

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 non-pharmacological 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.

Pediatric analgesic clinical trial designs, measures, and extrapolation: report of an FDA scientific workshop

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.

A biopsychosocial formulation of pain communication

We present a detailed framework for understanding the numerous and complicated interactions among psychological and social determinants of pain through examination of the process of pain communication. The focus is on an improved understanding of immediate dyadic transactions during painful events in the context of broader social phenomena. Fine-grain consideration of social transactions during pain leads to an appreciation of sociobehavioral events affecting both suffering persons as well as caregivers. Our examination considers knowledge from a variety of perspectives, including clinical health psychology, social and developmental processes, evolutionary psychology, communication studies, and behavioral neuroscience.

Contextual factors influencing pain response to heelstick procedures in preterm infants: what do we know? A systematic review

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.

Perceiving pain in others: automatic and controlled mechanisms

Recent developments in clinical, cognitive, and behavioral sciences as well as in social neuroscience can provide new perspectives on our understanding of different forms of pain expression and the social reactions of observers to various types of pain expression. Studies indicate that pain expression is governed by both automatic (unintentional, reflexive) and controlled (intentional, purposive) neuroregulatory systems. Reciprocal mechanisms in observers responsible for automatic (unintentional, reflexive) and controlled (intentional, reflective) reactions also are important. Observers appear more likely to display immediate "visceral" emotional reactions to unintentional, reflexive expression, whereas controlled expression characterized by purposive behavior appears more likely to elicit reflection on the nature and origins of the person's pain. This review summarizes research within the context of a theoretical model for understanding how pain is perceived in others.

PERSPECTIVE

People attempting to understand another person's pain may have access to the person's spontaneous behavioral reaction as well as verbal report and other purposive communications. The former instigates reflexive and emotional reactions, whereas the latter tends to be perceived as confounding expression of experience with response to situational demands.

The communication of pain in paediatric dentistry

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.

Understanding caregiver judgments of infant pain: contrasts of parents, nurses and pediatricians

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.

Recognition and discrimination of prototypical dynamic expressions of pain and emotions

Facial expressions of pain and emotions provide powerful social signals, which impart information about a person's state. Unfortunately, research on pain and emotion expression has been conducted largely in parallel with few bridges allowing for direct comparison of the expressive displays and their impact on observers. Moreover, although facial expressions are highly dynamic, previous research has relied mainly on static photographs. Here we directly compare the recognition and discrimination of dynamic facial expressions of pain and basic emotions by naive observers. One-second film clips were recorded in eight actors displaying neutral facial expressions and expressions of pain and the basic emotions of anger, disgust, fear, happiness, sadness and surprise. Results based on the Facial Action Coding System (FACS) confirmed the distinct (and prototypical) configuration of pain and basic emotion expressions reported in previous studies. Volunteers' evaluations of those dynamic expressions on intensity, arousal and valence demonstrate the high sensitivity and specificity of the observers' judgement. Additional rating data further suggest that, for comparable expression intensity, pain is perceived as more arousing and more unpleasant. This study strongly supports the claim that the facial expression of pain is distinct from the expression of basic emotions. This set of dynamic facial expressions provides unique material to explore the psychological and neurobiological processes underlying the perception of pain expression, its impact on the observer, and its role in the regulation of social behaviour.

Expressive dimensions of pain catastrophizing: a comparative analysis of school children and children with clinical pain

We investigated the role of the child's pain catastrophizing in explaining (1) children's self-reported tendency to verbally share their pain experience with others and (2) different dimensions of pain expression, as described by the mother and the father, including non-verbal and verbal communicative pain behaviour and protective pain behaviour. Participants were school children, children with chronic or recurrent pain, and their parents. The results showed that: (1) Pain catastrophizing was associated with children's greater self-acknowledged tendency to verbally share their pain experience with others. (2) Mothers and fathers perceived highly catastrophizing children to be more communicative about their pain. (3) The role of pain catastrophizing in the child's verbal sharing of pain experiences and in explaining expressive behaviour as rated by parents did not differ between the school children and children with recurrent and chronic pain. (4) Nevertheless, findings indicated marked differences between school children and the clinical sample. Children of the clinical sample experienced more severe pain, more pain catastrophizing, more protective pain behaviour, but less verbal communications about their pain. These results further corroborate the position that catastrophic thoughts about pain have interpersonal consequences. Findings are discussed in terms of the possible functions and effects upon others of pain catastrophizing and associated categories of pain behaviour.

An Interdisciplinary Expert Consensus Statement on Assessment of Pain in Older Persons

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.

Genuine, suppressed and faked facial expressions of pain in children

Children's efforts to hide or exaggerate facial expressions of pain were compared to their genuine expressions using the cold pressor task. Fifty healthy 8- to 12-year-olds (25 boys, 25 girls) submerged their hands in cold and warm water and were instructed about what to show on their faces. Cold 10 degrees C water was used for the genuine and suppressed conditions and warm 30 degrees C water was used for the faked condition. Facial activity was videotaped and coded using the Facial Action Coding System to provide objective, detailed accounts of facial expressions in each condition, as well as during a baseline condition. Parents were subsequently asked to correctly identify each of the four conditions by viewing each video clip twice. Faked expressions of pain in children were found to show more frequent and more intense facial actions compared to their genuine pain expression, indicating that children had some understanding but were not fully successful in faking expressions of pain. Children's suppressed expressions, however, showed no differences from baseline facial actions, indicating that they were able to successfully suppress their expressions of pain. Parents correctly identified the four conditions significantly more frequently than would be expected by chance. They were generally quite successful at detecting faked pain, but experienced difficulty differentiating among the other conditions. The results indicate that children are capable of controlling their facial expressions of pain when instructed to do so, but are better able to hide their pain than to fake it.

Judgments of Infant Pain: The Impact of Caregiver Identity and Infant Age

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.

Brain responses to dynamic facial expressions of pain

The facial expression of pain is a prominent non-verbal pain behaviour, unique and distinct from the expression of basic emotions. Yet, little is known about the neurobiological basis for the communication of pain. Here, subjects performed a sex-discrimination task while we investigated neural responses to implicit processing of dynamic visual stimuli of male or female faces displaying pain or angry expressions, matched on expression intensity and compared to neutral expression. Stimuli were presented in a mixed blocked/event-related design while blood oxygenation level dependent (BOLD) signal was acquired using whole-brain functional magnetic resonance imaging (fMRI) at 1.5 Tesla. Comparable sustained responses to pain and angry faces were found in the superior temporal sulcus (STS). Stronger transient activation was also observed to male expression of pain (Vs neutral and anger) in high-order visual areas (STS and fusiform face area) and in emotion-related areas including the amygdala (highest peak t-value=10.8), perigenual anterior cingulate cortex (ACC), and SI. Male pain compared to anger expression also activated the ventromedial prefrontal cortex, SII/posterior insula and anterior insula. This is consistent with the hypothesis that the implicit processing of male pain expression triggers an emotional reaction characterized by a threat-related response. Unexpectedly, several areas responsive to male expression, including the amygdala, perigenual ACC, and somatosensory areas, showed a decrease in activation to female pain faces (Vs neutral). This sharp contrast in the response to male and female faces suggests potential differences in the socio-functional role of pain expression in males and females.

The role of developmental factors in predicting young children's use of a self-report scale for pain

Accurate pain assessment is the foundation for effective pain management in children. At present, there is no clear consensus regarding the age at which young children are able to appropriately use self-report scales for pain. This study examined young children's ability to use the Faces Pain Scale-Revised; (FPS-R; [Hicks CL, von Baeyer CL, Spafford PA, van Korlaar I, Goodenough B. The Faces Pain Scale-Revised: toward a common metric in pediatric pain measurement. Pain 2001; 93: 173-83]) for pain in response to vignettes and investigated the role of developmental factors in predicting their ability to use the scale. One hundred and twelve healthy children (3-6 years old) were assessed for their ability to accurately use a common faces scale to rate pain in hypothetical vignettes depicting pain scenarios common in childhood. Accuracy was determined by considering whether children's judgements of pain severity matched the pain severity depicted in the various vignettes. Children were also administered measures of numerical reasoning, language, and overall cognitive development. Results indicated that 5- and 6-year-old children were significantly more accurate in their use of the FPS-R in response to the vignettes than 4-year-old children, who in turn were significantly more accurate than 3-year-old children. However, over half of the 6-year-olds demonstrated difficulties using the FPS-R in response to the vignettes. Child age was the only significant predictor of children's ability to use the scale in response to the vignettes. Thus, a substantial number of young children experienced difficulties using the FPS-R when rating pain in hypothetical vignettes, although the ability to use the scale did improve with age.

“Ow!”: Spontaneous Verbal Pain Expression Among Young Children During Immunization

OBJECTIVES

Although self-reports are a commonly used means of assessing pain in clinical settings, little is understood about the nature of children's spontaneous verbal expressions of pain. The purpose of this study was to describe verbalizations of pain among children receiving a preschool immunization and to examine how pain verbalizations correspond to children's facial expressions and self-reports of pain intensity.

METHODS

Fifty-eight children between the ages of 4 years 8 months and 6 years 3 months (67% female) were videotaped while receiving their routine preschool immunization. Global ratings of facial expression and detailed transcription and coding of pain verbalizations were undertaken. Children provided self-reports of pain using a 7-point faces pain scale.

RESULTS

Fifty-three percent of children used verbalizations spontaneously to express their pain. The modal verbalization was the interjection "Ow!," which expressed negative affect and was specific to the experience of pain. Older children were less likely to use verbalizations to express their pain. Children who used verbalizations to express pain displayed greater facial reactions to pain and rated their pain experience as being more intense than children who did not use words to express their pain.

DISCUSSION

Results indicate that many young children do not spontaneously use verbalizations to express pain from immunization. When 5-year-olds use verbalizations to express pain, the verbalizations are most often brief statements that express negative affect and directly pertain to pain. Knowledge of how children verbalize pain may lead to an improved ability to assess and manage pediatric pain.

Faces Scales for the Measurement of Postoperative Pain Intensity in Children Following Minor Surgery

OBJECTIVES

Faces scales are commonly used to obtain self-reports of pain intensity from children. Previous research using hypothetical vignettes and pain following venepuncture has found differences in children's pain ratings as a function of the type of faces scale used. The purpose of the present study was to determine whether scales beginning with a smiling rather than neutral "no pain" face would produce higher ratings in the assessment of postoperative pain intensity in children and to compare ratings using different faces scales to those reported with an additional independent measure of pain intensity.

METHODS

Participants were 78 children between the ages of 5 and 13 years undergoing surgery, one of their parents, and their postoperative care nurse. Following surgery, children were asked to provide a rating of their current pain intensity using a set of 5 successively administered faces scales and the Colored Analog Scale (CAS). Parents and nurses provided independent ratings using the same measures.

RESULTS

Results showed that parents and nurses rated significantly more pain when using scales with a smiling rather than a neutral "no pain" face. This pattern was not as clear for the children's ratings, although their highest ratings were provided when using a smiling "no pain" faces scale. Children's and nurses' ratings on the CAS were generally more similar to their ratings using scales with neutral "no pain" faces, whereas parents' CAS ratings tended to fall in between ratings provided on the smiling and neutral "no pain" faces scales. Scale preference, age and sex differences in pain ratings, and child-parent-nurse agreement in pain ratings are also examined.

DISCUSSION

Children's and parents' ratings of postoperative pain intensity are influenced by the presence of a smiling "no pain" face at the beginning of faces scales, with such scales producing significantly higher ratings than scales with neutral "no pain" faces. Ratings on the independent CAS measure were more comparable to those provided on faces scales with neutral "no pain" faces. Nurses are also susceptible to the influencing effect of a smiling face at the beginning of a faces scale.

A normative analysis of the development of pain-related vocabulary in children

Effective verbalization of pain requires progressive cognitive development and acquisition of social communication skills. Use of self-report in pediatric pain assessment assumes children have acquired a capacity to understand and use common words to describe pain. The current investigation documented the language most commonly used by young children to describe pain and the age of onset of use of these words. Two complementary research methodologies were employed. Study 1 used the CHILDES database, an aggregated transcript database of multiple research studies examining spontaneous speech development across childhood. Transcripts of 14 randomly selected studies, yielding a total of 245 child participants ranging in age from 1 to 9 years, were searched for seven English primary pain word-stems: 'ache', 'boo-boo', 'hurt', 'ouch', 'ow', 'pain', and 'sore'. Study 2 surveyed 111 parents of children aged 3 to 6 years old concerning words the children commonly used for pain. Parents rated their children's frequency and age of first use of the seven pain word-stems. Both studies indicated that the most frequently used word-stems were 'hurt', 'ouch', and 'ow'. These words first emerged in children's vocabularies as early as 18 months of age. The word-stem 'pain' was used relatively infrequently and gradually emerged in children's vocabularies. The findings indicate that young children rely on a select number of words to describe pain, with these words appearing in children's vocabularies at an early age. These results have implications for developmentally appropriate pain assessment in young children.

Detecting Deception in Facial Expressions of Pain

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.

Parental judgements of infant pain: importance of perceived cognitive abilities, behavioural cues and contextual cues

BACKGROUND

Despite blatant indications, such as behavioural and contextual cues, infant pain is often undermanaged by adult caretakers. The belief that infants are limited in their abilities to comprehend the meaning of an experience or recall that experience has been used to minimize or deny the need for intervention in this vulnerable population.

OBJECTIVES

This investigation explored parental beliefs regarding the impact of infant cognitive capabilities, behavioural cues and contextual cues to their pain judgments. Particular interest was focused on their beliefs regarding the general cognitive capabilities of infants of different ages.

METHODS

Forty-nine parents viewed videotapes of healthy infants, aged two, four, six, 12 and 18 months, receiving routine immunization injections and provided judgements of the severity of pain on a 100 mm Visual Analogue Scale. Upon completion of their pain judgements for each of the five age groups (two infants per age group; 10 infants total), parents completed questionnaires regarding their beliefs about the capabilities of infants in that age group and then reported the importance of the various cues utilized to formulate their pain judgements.

RESULTS

Parents attributed substantial pain to infants in all age groups, almost twice the amount they hypothesized an adult undergoing a similar injection would experience. The cues rated as most important for judgements were similar for infants of varying ages. Overall, facial expressions, sounds and body movements were consistently reported to be most important. Parents acknowledged the development of memory and understanding of pain throughout infancy. However, these beliefs were not deemed by parents as important to their pain ratings, nor were their importance ratings directly related to the pain ratings.

CONCLUSION

Parents judged that infants undergoing a routine immunization were experiencing clinically significant levels of pain. However, despite generally acknowledging a developing trajectory for memory and understanding across the five age groups, parents did not indicate that a child's ability to remember and understand pain were essential features of their pain judgements. The results indicated that memory and understanding did not influence parental judgements of infant pain demonstrating the validity of the parents' self-assessments.

Expression of Pain in Children With Autism

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.

Time-contingent schedules for postoperative analgesia: a review of the literature

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.

Challenges of judging pain in vulnerable infants

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.

Detecting deception in pain expressions: the structure of genuine and deceptive facial displays

Clinicians tend to assign greater weight to non-verbal expression than to patients' self-report when judging the location and severity of pain. Judgments can misrepresent the actual experience because patients can successfully alter their pain expressions. The present research provides a basis for discriminating genuine and deceptive pain expressions by expanding detailed accounts of facial expressions to include previously unexamined variables, including study of temporal patterns and contiguity of facial actions as well as the occurrence of specific deception cues. Low back patients' facial expressions (n=40) were videotaped at rest and while undergoing a painful straight leg raise with instructions to: (1) genuinely express their pain, or (2) pretend that it did not hurt. As well, they were asked to fake pain without moving. The Facial Action Coding System was used to describe and quantify facial activity. The different types of expression were compared on the frequency, type, intensity, temporal pattern and contiguity of facial actions, as well as on the frequency of specific deception cues. Findings confirmed the difficulty of discriminating the facial expressions, but indicated that faked pain expressions show a greater number of pain-related and non-pain-related actions, have a longer peak intensity and overall duration, and the facial actions observed tend to be less temporally contiguous than are those in genuine pain expressions. The differences between masked pain and neutral expressions were subtle, with a greater frequency of mouth opening and residual eyebrow movement in masked pain expressions. Thus, there is an empirical basis for discriminating genuine and deceptive facial displays.