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Facial activity was examined as 60 female and 60 male chronic low back pain patients responded to a painful range of motion exercise during a scheduled physical examination. Subsequently, they were asked to fake the facial response to the movement inducing the most pain or to attempt to suppress evidence that they were experiencing pain when this same movement was again repeated. Facial behavior was measured using the Facial Action Coding System. Self-reports of pain also were provided. The genuine expression was consistent with that observed in previous research, but minor differences indicated that the facial display of pain reflects differences between sources of pain, social context in which pain is induced and individual differences among patients. Considerable voluntary control over the facial expression of pain was observed, although the faked expression was more an intensified caricature of the genuine expression, and an attempt to suppress the facial grimace of pain was not entirely successful as residual facial activity persisted. Self-reports were only moderately correlated with facial behavior.

Research in the field of pediatric pain has largely ignored the role of fathers in their children’s pain experiences. The first objective of the present study was to examine the effect of the presence of mothers versus fathers on children’s subjective ratings, facial expressions and physiological responses to acute pain. The second objective was to examine whether child and parent sex influence parents’ proxy ratings of their children’s pain. The final objective was to compare levels of agreement between mothers’ and fathers’ assessments of their children’s pain. Participants included 73 children (37 boys, 36 girls), four to 12 years of age, along with 32 fathers and 41 mothers. Children undertook the cold pressor pain task while observed by one of their parents. During the task, the children’s heart rates and facial expressions were recorded. Children provided self-reports and parents provided proxy reports of child pain intensity using the seven-point Faces Pain Scale. Neither child nor parent sex had a significant impact on children’s subjective reports, facial expressions or heart rates in response to acute pain. Fathers gave their sons higher pain ratings than their daughters, whereas mothers’ ratings of their sons’ and daughters’ pain did not differ. Kappa statistics andttests revealed that fathers tended to be more accurate judges of their children’s pain than mothers. Overall, this research highlights the importance of examining both parent and child sex differences in pediatric pain research.

Infants, children, and adolescents presenting with pain differ dramatically in physical, cognitive, emotional, behavioral, and social characteristics. This chapter presents an overview of basic concepts that should be understood in the delivery of developmentally appropriate care and addresses their relevance to pain assessment and management. The developmental issues concern variations in maturation and growth in perception and central processing of nociceptive information, and its expression in the actions of the child, as well as consideration of how pain affects different spheres of activity at different ages.

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.

El sufrimiento emocional es una de las caracteristicas intrinsecas mas indeseables de las experiencias dolorosas. Ademas de este malestar inevitable, al dolor a menudo le acompanan el temor y la ansiedad, y se observan otras cualidades emocionales de rechazo como depresion, rabia y aversion. La bibliografia creciente demuestra que el procesamiento se distribuye entre mecanismos espinales y cerebrales de motivacion afectiva, y caracteristicas discriminatorias sensoriales del dolor.

In het onderzoek naar pijn heeft men belangrijke voortgang geboekt nadat de iasp (International Association for the Study of Pain, Internationaal genootschap voor de bestudering van pijn) -commissie voor taxonomie pijn heeft gedefinieerd als ‘een vervelende zintuiglijke en emotionele ervaring, in verband met feitelijke of mogelijke weefselschade, of beschreven in termen van dergelijke schade’, Verder verklaarde de commissie dat ‘pijn altijd subjectief is.

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.

The biasing effect of pain sensitivity information and the impact of facial activity on observers' judgements of pain intensity of children with autism were examined. Observers received information that pain experience in children with autism is either the same as, more intense than, or less intense than children without autism. After viewing six video clips of children with autism undergoing venepuncture, observers estimated pain intensity using a visual analogue scale. Facial activity as coded by Chambers et al. (Child Facial Action Coding System Revised Manual, 1996) had a significant impact on observers' estimates of pain intensity; pain sensitivity information did not. These results have important implications for the assessment and management of pain in children with autism.

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.

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.

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.

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.

Human pain experience and expression evolved to serve a range of social functions, including warning others, eliciting care, and influencing interpersonal relationships, as well as to protect from physical danger. Study of the relatively specific, involuntary, and salient facial display of pain permits examination of these roles, extending our appreciation of pain beyond the prevalent narrow focus on somatosensory mechanisms.

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.

Self-report and observational measures of pain are examined from the perspective of a model of human communication. This model examines the experience of pain as affected by intrapersonal and contextual factors, the process whereby it is encoded into expressive behaviour, and the process of decoding by observers prior to their engaging in action. Self-report measures primarily capture expressive pain behaviour that is under the control of higher mental processes, whereas observational measures capture behaviour that is less subject to voluntary control and more automatic. Automatic expressive behaviours are subject to less purposeful distortion than are behaviours dependent upon higher mental processes. Consequently, observational measures can be used and have clinical utility as indices of pain when self-report is not available, for example, in infants, young children, people with intellectual disabilities or brain damage, and seniors with dementia. These measures are also useful when the credibility of self-report is questioned and even when credible self-report is available. However, automatic behaviours may be more difficult for observers to decode. The model outlined herein takes into account the role of various human developmental stages in pain experience and expression and in understanding the utility of self-report and observational measures. We conclude that both observational and self-report measures are essential in the assessment of pain because of the unique information that each type contributes.

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.

Publisher Summary This chapter describes pain from the perspectives of health psychology and culture. It discusses the concept of pain, impairment, and disability. Complex psychological mechanisms can be observed in both acute and chronic pain. The differences in individual behavioral response to painful events are because of variations in individual behavioral response. The potential for committing errors in the pain assessment process because of insensitivity to one's own or others' cultural norms is considerable. Cultural factors influence the purpose of perceiving pain in others. The chapter also discusses the three biological models of pain: specificity theory, the Pattern Theory, and the gate theory. The chapter also describes psychological parameters and cultural variations in the experience and expression of pain. Finally, a culturally competent model of care for the assessment and treatment of pain is illustrated. The culturally competent care model requires assessment and intervention methods that explore personal schemata for pain symptoms and the establishment of treatment goals that are based on the client's cultural experience and expression of pain.

Objective: To examine whether children with developmental delays respond to painful events differently than nondelayed children. Methods: Sixty families participated. Children between the ages of 2 and 6 years were observed at daycare centers while engaged in usual daily activities, such as free play. Spontaneous painful incidents and the child’s responses were recorded using an observational measure (Dalhousie Everyday Pain Scale) designed to capture pain behavior. Results: Children with developmental delays (n 24) displayed a less intense distress response to an equivocal pain event than nondelayed children (n 36). Children with developmental delays were more likely to display no reaction following a pain event, whereas children without delays cried more often. Further, children with developmental delays engaged in fewer help-seeking behaviors and were less likely to display a social response following a pain event than nondelayed children. Conclusions: Children with developmental delays appear to react in a different manner to pain events than nondelayed children do; we discuss a possible socio-communicative deficit.

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.

Faces scales have become the most popular approach to eliciting children's self-reports of pain, although different formats are available. The present study examined: (a) the potential for bias in children's self-reported ratings of clinical pain when using scales with smiling rather than neutral 'no pain' faces; (b) levels of agreement between child and parent reports of pain using different faces scales; and (c) preferences for scales by children and parents. Participants were 75 children between the ages of 5 and 12 years undergoing venepuncture, and their parents. Following venepuncture, children and parents independently rated the child's pain using five different randomly presented faces scales and indicated which of the scales they preferred and why. Children's ratings across scales were very highly correlated; however, they rated significantly more pain when using scales with a smiling rather than a neutral 'no pain' face. Girls reported significantly greater levels of pain than boys, regardless of scale type. There were no age differences in children's pain reports. Parents' ratings across scales were also highly correlated; however, parents also had higher pain ratings using scales with smiling 'no pain' faces. The level of agreement between child and parent reports of pain was low and did not vary as a function of the scale type used; parents overestimated their children's pain using all five scales. Children and parents preferred scales that they perceived to be happy and cartoon-like. The results of this study indicate that subtle variations in the format of faces scales do influence children's and parents' ratings of pain in clinical settings.

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 cognitive-behavioral theory of health anxiety predicts atypical responses in health anxious individuals when exposed to health related information. Systematic research is still needed to support the theory. This investigation examined 192 participants varying a subclinical levels of health anxiety, who were randomly given feedback on an ostensible diagnostic measure, indicating positive, negative or ambiguous risk for health complications. Responses to a cold pressor task were then measured. The results indicated that regardless of the type of feedback patients were given, health anxious individuals displayed the predicted cognitive (e.g. negatively interpreted information) and behavioral responses (e.g. increased reassurance seeking). Important and perhaps central cognitions to health anxiety were identified. Health anxious individuals regarded themselves to be at greater risk for disease overall, and attached greater accuracy to health related information. Extending the cognitive-behavioural theory, health anxiety was found to be associated with decreased usage of positive somatic monitoring of symptoms, suggesting health anxiety may be associated with a failure to engage in protective strategies. Health anxiety did not result in cognitive or behavioural avoidance of illness information. Clinical implications and future directions for research are described.

Age-related changes in the facial expression of pain during the first 18 months of life have important implications for our understanding of pain and pain assessment. We examined facial reactions video recorded during routine immunization injections in 75 infants stratified into 2-, 4-, 6-, 12-, and 18-month age groups. Two facial coding systems differing in the amount of detail extracted were applied to the records. In addition, parents completed a brief questionnaire that assessed child temperament and provided background information. Parents' efforts to soothe the children also were described. While there were consistencies in facial displays over the age groups, there also were differences on both measures of facial activity, indicating systematic variation in the nature and severity of distress. The least pain was expressed by the 4-month age group. Temperament was not related to the degree of pain expressed. Systematic variations in parental soothing behaviour indicated accommodation to the age of the child. Reasons for the differing patterns of facial activity are examined, with attention paid to the development of inhibitory mechanisms and the role of negative emotions such as anger and anxiety.

Accuracy and errors in judges' attempts to differentiate facial expressions that displayed genuine pain, no pain or were dissimulated (i.e., masked and exaggerated) were examined. Judges were informed that misrepresentations in the facial expressions were present and were asked to rate their confidence in classifying these expressions. Detailed, objective coding of the patients' facial reactions (e.g., brow lowering, mouth opening) were related to judges' decisions. Judges' classification decisions were better than chance, but there were many errors. Extreme expressions (i.e., no pain, and exaggerated expressions) were identified more accurately than genuine and masked expressions. Judges level of confidence was consistent with their level of accuracy. Judges consistently used rules of thumb based on specific facial cues when making judgments. Certain cues were effectively discriminative. Systematic training in the use of specific cues or the use of articulated decision rules may be helpful in improving judges' accuracy.

Our focus has been on the role of early cry as a commanding source of information about infant pain and distress that requires interpretation by an adult caregiver. Its inherent ambiguity may offer an adaptive advantage, as resolution requires adult presence and scrutiny of other behavioral, physical, and contextual factors.

Explored the facial and cry characteristics that adults use when judging an infant's pain. Sixteen women viewed videotaped reactions of 36 newborns subjected to noninvasive thigh rubs and vitamin K injections in the course of routine care and rated discomfort. The group mean interrater reliability was high. Detailed descriptions of the infants' facial reactions and cry sounds permitted specification of the determinants of distress judgments. Several facial variables (a brow bulge, eyes squeezed shut, and deepened nasolabial fold constellation, and taut tongue) accounted for 49% of the variance in ratings of affective discomfort after controlling for ratings of discomfort during a noninvasive event. In a separate analysis not including facial activity, several cry variables (formant frequency, latency to cry) also accounted for variance (38%) in ratings. When the facial and cry variables were considered together, cry variables added little to the prediction of ratings in comparison to facial variables. Cry would seem to command attention, but facial activity, rather than cry, can account for the major variations in adults' judgments of neonatal pain.

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.

The purpose of this study was to examine the behavioural responses of infants to pain stimuli across different developmental ages. Eighty infants were included in this cross-sectional design. Four subsamples of 20 infants each included: 1. (1) premature infants between 32 and 34 weeks gestational age undergoing heel-stick procedure; 2. (2) full-term infants receiving intramuscular vitamin K injection; 3. (3) 2-month-old infants receiving subcutaneous injection for immunisation against DPT; 4. (4) 4-month-old infants receiving subcutaneous injection for immunisation against DPT. Audio and video recordings were made for 15 sec from stimulus. Cry analysis was conducted on the first full expiratory cry by FFT with time and frequency measures. Facial action was coded using the Neonatal Facial Action Coding System (NFCS). Results from multivariate analysis showed that premature infants were different from older infants, that full-term newborns were different from others, but that 2- and 4-month-olds were similar. The specific variables contributing to the significance were higher pitched cries and more horizontal mouth stretch in the premature group and more taut tongue in the full-term newborns. The results imply that the premature infant has the basis for communicating pain via facial actions but that these are not well developed. The full-term newborn is better equipped to interact with his caretakers and express his distress through specific facial actions. The cries of the premature infant, however, have more of the characteristics that are arousing to the listener which serve to alert the caregiver of the state of distress from pain.

Correspondence: Dr Kenneth D Craig, University of British Columbia, 2136 West Mall, Vancouver, British Columbia V6T 1Z4. Telephone 604-822-3948, fax 604-822-6923, e-mail kcraig@psych.ubc.ca The intense focus on specific challenges in understanding and controlling pain brought by the International Association for the Study of Pain program of Global Years Against Pain continues in the current Global Year Against Musculoskeletal Pain. The theme “When Moving Hurts” captures the miseries that people confront when mobility is diminished by acute and chronic pain. In previous years, there has been a focus on the “Right to Pain Relief”, “Pain in Children”, “Pain in Older Persons”, “Pain in Women” and “Cancer Pain”. Pain Research & Management has taken pleasure in providing a vehicle whereby the Canadian Pain Society joins the international movement represented by other International Association for the Study of Pain Chapters and Federations in combatting some of the most debilitating and refractory problems. Focusing on specific challenges seems to energize the research and practitioner community. In successive years, it has not been difficult to secure excellent papers exploring different facets of understanding and managing the different challenges of pain. The present issue of Pain Research & Management features a comprehensive series of articles focusing on an evidence-based approach to whiplash injuries. All musculoskeletal disorders can pose serious challenges of pain and disability, with whiplashassociated disorders being one of the most serious public health problems. As this series of papers indicates, we are slowly making headway in understanding causes, assessment, treatment and intervention; however, much remains to be achieved in mastering the disabling pain resulting from musculoskeletal disorders.

The newborn emerges from the protective intrauterine environment well-equipped biologically to experience pain and display acute distress when tissue damage occurs. Pain will be a common experience for the infant and young child when physical development and socialization influences are occurring at a remarkable pace. Despite pain’s dramatic and traumatic nature, our understanding of pain in the newborn and young child only recently has received concerted attention, and there have been serious misconceptions held by many practitioners and scholars. There also has been a substantial lag between our rapidly developing understanding of pain in the very young child and applications of this knowledge base in clinical settings.

Correspondence: Dr Kenneth D Craig, University of British Columbia, 2136 West Mall, Vancouver, British Columbia V6T 1Z4. Telephone 604-822-3948, fax 604-822-6923, e-mail kcraig@psych.ubc.ca Current preoccupation with the magnitude, severity, misery and economic challenges of chronic pain has led to diverse demands. On one hand, the recognition that persisting high levels of suffering reflect inadequacies in our understanding of acute and chronic pain leads to calls for improved support of scientific investigation capable of penetrating the mysteries and advancing knowledge. At the same time, it is appreciated that striking advances in understanding pain over the past several decades have not been adequately translated into substantial reductions in the suffering and costs that are attached to pain. In consequence, demands for improved knowledge translation are accelerating. Is it possible that both the requirements of science and the community at large would benefit from greater attention to ensuring that advances in knowledge are indeed translated into applications that benefit people? That appears to be one of the many questions that arise from Henry’s provocative paper “The need for knowledge translation in chronic pain”, which is published in the present issue of Pain Research & Management. In the preceding editorial “Do we care about people with chronic pain?”, Lynch very effectively addressed the paper as a manifesto justifying and calling for a change in how pain is conceptualized if we are to transform the health service delivery system to better serve Canadians and those legions of others caught up in the epidemic of chronic pain. I am intrigued by the somewhat different but complementary question, ‘Are there prospects for Pain Research & Management serving as a vehicle that would permit scientists to demonstrate the implications and importance of their research for improving the lives of people who suffer excessive or unnecessary acute or chronic pain?’. As Henry observed, the Canadian Institutes of Health Research has as its mandate from the Parliament of Canada both the advancement and translation of knowledge into improved health for Canadians. All applicants to the Canadian Institutes of Health Research (and other national research councils) must justify their research in terms of application and provide plans demonstrating how they will disseminate research beyond academic and scientific circles. These requirements are often perceived as frustrating and irrelevant to the challenges of good science. Please consider this an invitation to scientists, whether interested in basic biological or behavioural science, clinical science, social and cultural determinants of health, or health service delivery, to use Pain Research & Management as a publication outlet for papers explaining and exploring translation of their research into improved health for Canadians. It is intriguing that a basic scientist, James Henry, distinguished by outstanding research in molecular mechanisms of pain, and Scientific Director of the Michael G DeGroote Institute for Pain Research and Care (McMaster University, Hamilton, Ontario), would seize the initiative to carefully and provocatively examine issues concerning population health and health service delivery. While scientists typically favour specialty journals for focused empirical papers, there is a great need for integrative, even speculative, reviews and theoretical analyses. There are many outstanding Canadian scientists who could accept this challenge. The title of our journal signals an interest in this type of integration. Readers of the Journal are broadly representative of research and pain management and would find the papers of great interest. It would be a pleasure to provide editorial review of papers of this type. Kenneth D Craig PhD Editor-in-Chief Pain Research & Management editorial

Evaluation of pain in neonates is difficult due to their limited means of communication. The aim was to determine whether behavioural reactions of cry and facial activity provoked by an invasive procedure could be discriminated from responses to non-invasive tactile events. Thirty-six healthy full-term infants (mean age 2.2 h) received 3 procedures in counterbalanced order: intramuscular injection, application of triple dye to the umbilical stub, and rubbing thigh with alcohol. Significant effects of procedure were found for total face activity and latency to face movement. A cluster of facial actions comprised of brow bulging, eyes squeezed shut, deepening of the naso-labial furrow and open mouth was associated most frequently with the invasive procedure. Comparisons between the 2 non-invasive procedures showed more facial activity to thigh swabbing and least to application of triple dye to the umbilical cord. Acoustic analysis of cry showed statistically significant differences across procedures only for latency to cry and cry duration for the group as a whole. However, babies who cried to two procedures showed higher pitch and greater intensity to the injection. There were no significant differences in melody, dysphonation, or jitter. Methodological difficulties for investigators in this area were examined, including criteria for the selection of cries for analysis, and the logical and statistical challenges of contrasting cries induced by different conditions when some babies do not always cry. It was concluded that facial expression, in combination with short latency to onset of cry and long duration of first cry cycle typifies reaction to acute invasive procedures.