Expressive dimensions of pain catastrophizing: An observational study in adolescents with chronic pain

Investigated was the relationship between pain catastrophizing and pain intensity in adolescents suffering from chronic pain (n = 38) and the extent to which they expressed communicative pain and pain-related protective behaviours. Adolescents were observed on video performing a 2-Min Walk Test (2MWT). Behaviours were coded on videotape. The adolescents’ verbalizations about the 2MWT were also rated by their parents. Analyses revealed that higher levels of catastrophic thinking about pain were associated with higher levels of facial pain expressions and verbalizations about their pain experience, beyond the effects of age, gender, pain duration and pain intensity. Pain-related protective behaviours did not vary with the adolescents’ level of pain catastrophizing, but varied with pain intensity. The findings corroborate the functional distinctiveness of different types of pain behaviours. The results are discussed in terms of the processes linking (1) catastrophizing to communicative pain behaviours and (2) pain to pain-related protective behaviours.     

Social modulation of facial pain display in high-catastrophizing children: an observational study in schoolchildren and their parents

The present study examined existing communal and operant accounts of children’s pain behavior by looking at the impact of parental presence and parental attention upon children’s pain expression as a function of child pain catastrophizing. Participants were 38 school children and 1 of their parents. Children completed a cold pressor pain task (CPT) twice, first when told that no one was observing (alone condition) and subsequently when told that they were being observed by their parent (parent-present condition). A 3-minute parent-child interaction occurred between the 2 CPT immersions, allowing measurement of parental attention to their child’s pain (ie, parental pain-attending talk vs non-pain-attending talk). Findings showed that child pain catastrophizing moderated the impact of parental presence upon facial displays of pain. Specifically, low-catastrophizing children expressed more pain in the presence of their parent, whereas high-catastrophizing children showed equally pronounced pain expression when alone or in the presence of a parent. Furthermore, children’s catastrophizing moderated the impact of parental attention upon facial displays and self-reports of pain; higher levels of parental nonpain talk were associated with increased facial expression and self-reports of pain among high-catastrophizing children; for low-catastrophizing children, facial and self-report of pain was independent of parental attention to pain. The findings are discussed in terms of possible mechanisms that may drive and maintain pain expression in high-catastrophizing children, as well as potential limitations of traditional theories in explaining pediatric pain expression.     

Parents who catastrophize about their child's pain prioritize attempts to control pain

How parents respond to their child in pain is critically important to how both parent and child attempt to cope with pain. We examined the influence of parental catastrophic thinking about child pain on their prioritization for pain control. Using a vignette methodology, parents reported, in response to different pain scenarios, on their imagined motivation for 2 competing goals: to control their child's pain (ie, pain control) or to encourage their child's participation in daily activities (ie, activity engagement). The effects of parent gender, pain intensity, and duration on parental goal priority were also explored. Findings indicated that higher levels of parental catastrophic thoughts were associated with the parents prioritizing child pain control over activity engagement. This effect was significantly moderated by pain duration. Specifically, pain control was more of a priority for those high in catastrophic thinking when the pain was more acute. In contrast, parental catastrophic thoughts had no effect on the pain control strategy favored by parents in situations with longer-lasting pain. Furthermore, independently of parental catastrophic thoughts, heightened priority for pain control was observed in highly intense and chronic pain situations. Moreover, in highly intense pain, priority for pain control was stronger for mothers compared with fathers. Theoretical and clinical implications and directions for future research are discussed.     

Experiencing Pain in the Presence of Others: A Structured Experimental Investigation of Older Adults

The role of various forms of social support (including the mere presence of another person) in pain has been studied in children and younger adults, but parallel studies involving older persons have not been conducted. In this investigation, older adults (N = 100) took part in a series of experimental pain tasks in each of the following conditions: alone, in the presence of a stranger, and in the presence of a family member. Indices of pain (threshold, tolerance, intensity, unpleasantness, facial expressions) and facial expressions of emotion were analyzed. Facial expressions of pain and happiness were more prominent when a family member was present. In the presence of a stranger, pain was reported as less unpleasant and facial expressions of fear were more frequent. In examining sex differences, male participants reported higher pain tolerance and female participants displayed more prominent facial expressions of pain. Moreover, facial expressions of neutral states and happiness were more frequent among female participants, whereas facial expressions of anger were more frequent among male participants. Results show that the presence of others influences the experience and expression of pain in older persons.

MR imaging in the triage of pregnant patients with acute abdominal and pelvic pain

Purpose  To retrospectively assess the performance of MR imaging in the evaluation and triage of pregnant patients presenting with acute abdominal or pelvic pain. Method and materials  MRI studies of pregnant patients who were referred for acute abdominal pain between 2001 and 2007 were included. MR images were retrospectively reviewed and compared with surgical and pathologic findings and clinical follow-up data. Analysis of imaging findings included evaluation of the visceral organs, bowel and mesentery, appendix (for presence of appendicitis), ovaries (detection and adnexal masses were evaluated), focal inflammation, presence of abscesses, and any other abnormal findings. Results  A total of 118 pregnant patients were included. MR findings were inconclusive in 2 patients and were positive for acute appendicitis in 11 patients (n = 9 confirmed by surgery, n = 2 improved without surgery). One patient with inconclusive MR had surgically confirmed appendicitis; the other patient with inconclusive MR had surgically confirmed adnexal torsion. Other surgical/interventional diagnoses suggested by MR imaging were adnexal torsion (n = 4), abscess (n = 4), acute cholecystitis (n = 1), and gastric volvulus (n = 1). Two patients with MR diagnosis of torsion improved without surgery. One patient with MR diagnosis of abscess had biliary cystadenoma at surgery. The rest of the MR diagnoses above were confirmed surgically or interventionally. MR imaging was normal in 67 patients and demonstrated medically treatable etiology in 28 patients: adnexal lesions (n = 9), urinary pathology (n = 6), cholelithiasis (n = 4), degenerating fibroid (n = 3), DVT (n = 2), hernia (n = 1), colitis (n = 1), thick terminal ileum (n = 1), rectus hematoma (n = 1). Three of these patients had negative surgical exploration and one had adnexal mass excision during pregnancy. Other patients were discharged with medical treatment. The sensitivity, specificity, accuracy, positive predictive values (ppv), and negative predictive values (npv) of MR imaging for acute appendicitis, and surgical/ interventional diagnoses were 90.0% vs. 88.9%, 98.1% vs. 95.0%, 97.5% vs. 94.1%, 81.8% vs. 76.2%, 99.1% vs. 97.9%, respectively. Conclusion  MR imaging is an excellent modality for diagnosis of acute appendicitis and exclusion of diseases requiring surgical/interventional treatment. Therefore MR imaging is useful for triage of pregnant patients with acute abdominal and pelvic pain.     

Parental catastrophizing about child's pain and its relationship with activity restriction: the mediating role of parental distress

Recent research has demonstrated that parental behaviors have an important impact upon child and adolescent pain outcomes. At present, however, we do not know which parents engage in particular behaviors and why. In 2 studies, the impact of parental catastrophizing about their child’s pain upon parental tendency to stop their child’s pain-inducing activity was investigated. Further, the mediating role of parental distress was explored. In study 1, a sample of schoolchildren (n = 62; M = 12.48 years; SD = 1.72) took part in a cold-pressor task. In study 2, a clinical sample of adolescents with chronic pain (n = 36; M = 15.68 years; SD = 1.85) performed a 2-min walking task designed as a pain-inducing activity. In both studies, the accompanying parent was asked to watch their child performing the pain task. Findings revealed, for both studies, that parents with a high level of catastrophic thinking about their child’s pain experienced more distress and a greater behavioral tendency of wanting to stop their child’s pain-inducing activity. Further, parental feelings of distress mediated the relationship between parental catastrophic thinking and parents’ tendency to restrict their child’s activity. The findings are discussed in light of an affective-motivational conceptualization of pain and pain behavior.     

An investigation to determine the association between neck pain and upper limb disability for patients with non-specific neck pain: a secondary analysis

This study investigated the relationship between neck pain and upper limb disability in patients with non-specific neck pain (n = 151) recruited from physiotherapy departments in the United Kingdom. Baseline neck pain/disability was measured using the Northwick Park Neck Pain Questionnaire (NPQ). Baseline upper limb disability was measured using the Disabilities of Arm, Shoulder, Hand questionnaire (DASH). A range of baseline psychosocial variables were measured as potential confounding variables. Pairwise analysis revealed a positive correlation between NPQ score and DASH score (Pearsons’ r = 0.799, p < 0.001). After adjusting for potential confounding variables, stepwise linear regression indicated that increasing upper limb disability was predicted by two baseline variables: higher NPQ scores (B = 0.743) and lower pain self efficacy (PSE) scores (B = −0.489) {R² = 0.713; n = 100, p < 0.001}. This study provides preliminary evidence that patients with severe neck pain/disability also report severe upper limb disability. The relationship between neck pain/disability and upper limb disability was mediated by PSE. Clinically, the presence of severe neck pain or low PSE should direct clinicians towards an assessment of upper limb function. In these cases upper limb disability may need to be addressed as part of the neck management process.     

Chronic pain reconsidered

Chronic pain has been traditionally defined by pain duration, but this approach has limited empirical support and does not account for chronic pain’s multi-dimensionality. This study compared duration-based and prospective approaches to defining chronic pain in terms of their ability to predict future pain course and outcomes for primary care patients with three common pain conditions: back pain (n = 971), headache (n = 1078), or orofacial pain (n = 455). At baseline, their chronic pain was classified retrospectively based on Pain Days in the prior six months and prospectively with a prognostic Risk Score identifying patients with “possible” or “probable” chronic pain. The 0–28 Risk Score was based on pain intensity, pain-related activity limitations, depressive symptoms, number of pain sites, and Pain Days. Pain and behavioral outcomes were assessed at six-month follow-up, and long-term opioid use was assessed two to five years after baseline. Risk Score consistently predicted clinically significant pain at six months better than did Pain Days alone (area under the curve of 0.74–0.78 for Risk Score vs. 0.63–0.73 for Pain Days). Risk Score was a stronger predictor of future SF-36 Physical Function, pain-related worry, unemployment, and long-term opioid use than Pain Days alone. Thus, for these three common pain conditions, a prognostic Risk Score had better predictive validity for pain outcomes than did pain duration alone. However, chronic pain appears to be a continuum rather than a distinct class, because long-term pain outcomes are highly variable and inherently uncertain.     

Sensory characteristics of chronic non-specific low back pain: A subgroup investigation

It has been proposed that patients with chronic non-specific low back pain (CNSLBP) can be broadly classified based on clinical features that represent either predominantly a mechanical pain (MP) or non-mechanical pain (NMP) profile. The aim of this study was to establish if patients with CNSLBP who report features of NMP demonstrate differences in pain thresholds compared to those who report MP characteristics and pain-free controls. This study was a cross-sectional design investigating whether pressure pain threshold (PPT) and/or cold pain threshold (CPT) at three anatomical locations differed between patients with mechanical CNSLBP (n = 17) versus non-mechanical CNSLBP (n = 19 and healthy controls (n = 19) whilst controlling for confounders. The results of this study provide evidence of increased CPT at the wrist in the NMP profile group compared to both the MP profile and control subjects, when controlling for gender, sleep and depression (NMP versus MP group Odds Ratio (OR): 18.4, 95% confidence interval (CI): 2.5–133.1, p = 0.004). There was no evidence of lowered PPT at any site after adjustment for confounding factors. Those with an MP profile had similar pain thresholds to pain-free controls, whereas the NMP profile group demonstrated elevated CPT's consistent with central amplification of pain. These findings may represent different pain mechanisms associated with these patient profiles and may have implications for targeted management.     

Characterization of patients with acute chest pain using cardiac magnetic resonance imaging

Aims  The purpose of this study was to evaluate whether CMRI provides characteristic findings in patients with acute chest pain suffering from ST-elevation-myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI), acute myocarditis or Tako-tsubo cardiomyopathy. Patients and methods  230 consecutive patients with acute chest pain underwent cardiac catheterization followed by CMRI within median 5 days. Patients were classified to suffer from STEMI (n = 102), NSTEMI (n = 89), acute myocarditis (n = 27), or Tako-tsubo cardiomyopathy (n = 12) on the synopsis of all clinical data. Wall motion abnormalities, late enhancement (LE), persistent microvascular obstruction as well ventricular volumes and functions were assessed by CMRI. Results  Right and left ventricular volumes were significantly different between the groups and values were highest in patients with acute myocarditis. Wall motion abnormalities were observed in 100% of STEMI, 75% of NSTEMI, 67% of acute myocarditis and 100% of Tako-tsubo patients. There was a characteristic pattern of abnormal wall motion focused on midventricular-apical segments in patients with Tako-tsubo cardiomyopathy, depending on the culprit vessel in patients with STEMI/NSTEMI and with a random distribution in patients with acute myocarditis. LE was mainly subendocardial or transmural in patients with STEMI (93.2%) or NSTEMI (62.9%). LE was diffuse, intramural or subepicardial in patients with acute myocarditis. No LE was observed in patients with Tako-tsubo cardiomyopathy. Persistent microvascular obstruction was only visualized in patients with STEMI (33%) or NSTEMI (6%). Conclusions  Cardiac magnetic resonance imaging provides characteristic patterns of LE, persistent microvascular obstruction and wall motion abnormalities that allow a differentiation between patients with acute chest pain from coronary and non-coronary origin. Supported in part by an unrestricted grant of Philips Medical Systems Best, The Netherlands, and Hamburg, Germany. For paper handling: jochen.woehrle@uniklinik-ulm.de     

Effects of a pain education program on nurses' pain knowledge, attitudes and pain assessment practices in China

The purpose of this study was to develop, implement, and evaluate the impact of a Pain Education Program (PEP) for nurses in China. The effects of PEP were measured in a quasi-experimental design. A total of 196 nurses who met the inclusion criteria from five nursing units in two teaching hospitals participated in the study. Randomization took place at the hospital level to select experimental and control groups. The research intervention was the PEP, which had two components: (1) to educate nurses about pain management and (2) to implement daily pain assessment by using the Changhai Pain Scale. The duration of PEP was five weeks and intervention methods included focused education, group activity, and individual instruction. After the baseline data were collected, PEP was implemented in the experimental group. The control group (n = 90) received no intervention, and the experimental group (n = 106) received six hours of focused education training. During the fourth and fifth weeks of the training program, the researcher and the faculty instructed nurses in five nursing units on how to use the Changhai Pain Scale to assess patients’ pain levels and demonstrated how to document pain condition in the nursing records. Nurses in both groups filled out a set of questionnaires, which included a background information form and the Nurses’ Knowledge and Attitude Survey form, before the PEP (T1), at one month after the PEP (T2), and at three months after the PEP (T3). Nurses in the experimental group who received the PEP had a significant improvement in their pain knowledge and attitudes. Their scores on the Nurses’ Knowledge and Attitude Survey increased from 15.67 at T1 to 26.13 at T2 and 35.14 at T3. The scores of nurses in the control group were unchanged (from 15.20 at T1 to 14.29 at T2 and 14.93 at T3, P > 0.05). In addition, experimental group nurses had an improvement in pain assessment. The percentage of nurses who correctly used the Changhai Pain Scale to assess patients’ pain intensity increased significantly after the PEP, and the increased usage of the assessment tool between experimental and control groups also shows a statistical difference in trend (χ²=93.281, P < 0.001). The PEP has been demonstrated to be effective in improving nurses’ pain knowledge, attitudes, and assessment.     

Association between knee pain location and abnormal imaging or arthroscopic findings: A systematic review

BackgroundAssessment of pain location is an essential component of the differential diagnosis of knee pain because pain location is thought to indicate pathology. Previous studies have questioned whether abnormal imaging findings are related to the presence of pain, but none has systematically reviewed the association between knee pain location and the location of abnormal imaging or arthroscopic findings.ObjectiveTo systematically review the association between the location of knee pain and the location of abnormal imaging or arthroscopic findings.MethodsDatabases were searched up to November 2021 for articles in English that investigated the association between pain location reported using pain mapping and the location of abnormal imaging or arthroscopic findings. Risk of bias was assessed with the modified Newcastle-Ottawa scale. Results were sub-grouped by pathology and data analysis was performed as appropriate.ResultsAmong 7730 articles identified, 10 (n = 2034 participants) met the inclusion criteria. Three sub-pathologies were evaluated: patellar tendinopathy (n = 2), knee osteoarthritis (n = 7), and degenerative meniscal tears (n = 1). The primary analysis found poor sensitivity and specificity of patellar tendon hypoechogenic areas and local patellar tendon pain in adult (n = 55) and adolescent athletes (n = 114). The location of pain and the location of abnormal imaging findings was associated in 2 studies of knee osteoarthritis (n = 166). Five articles reported no relationship (n = 1563). No association was reported between the location of pain and the location of arthroscopic findings in degenerative meniscus tears (n = 193). All articles included were rated at low risk of bias.ConclusionSensitivity and specificity of the presence of patellar tendon hypoechogenic areas and localised patellar tendon pain was poor. Pain location was not associated with the location of abnormal imaging findings in knee osteoarthritis or to abnormal arthroscopic findings in degenerative meniscus tears.     

A comparison of anatomical pain sites from a tertiary care sample: Evidence of disconnect between functional and perceived disability specific to lower back pain

Heterogeneity has been identified within chronic musculoskeletal pain (CMP) patient samples; however, investigations have typically focused on psychological constructs or coping (e.g., pain‐related anxiety, catastrophizing) in this regard. Furthermore, studies to date have included either samples presenting with a specific anatomical site (e.g., only lower back pain) or a mix of anatomical sites (e.g., lower back, shoulder, or leg pain) as the primary pain complaint, without making comparisons based on the anatomical site of reported pain. For example, patients with chronic lower back pain (CLBP) may differ from those with chronic upper or lower extremity pain (ULEP) in presentation, recovery trajectory, and psychological variables. The current investigation explored whether systematic differences existed between patients participating in a multidisciplinary reconditioning third‐party‐payer program who have CLBP relative to patients with ULEP. Patients included those with CLBP (n=23; 35% women) or ULEP (e.g., arm, shoulder, leg, knee; n=28; 29% women). The ULEP group began and finished the program with more pain‐related anxiety, more catastrophic thoughts, and more fearful cognitions than the CLBP group. There were no significant correlations between functional deficit and perceived levels of disability or associations between group and return to work status; however, there was an unexpected significant interaction between group and perceived disability. Specifically, CLBP patients reported increasing perceived disability despite improvements in functional deficit, whereas ULEP patients did not. These findings suggest a disconnect between perceived disability and function that may be specific to lower back pain. Implications and directions for future research are discussed.     

Factors impacting on doctors’ management of acute low back pain: A systematic review

The aim of this review was to determine the factors that impact on doctors’ management of patients with acute low back pain. A methodological assessment of databases (Medline, EMBASE, Psychinfo, BIOSIS, CINAHL, and the Cochrane Central Register of Controlled Trials) identified papers which were screened for inclusion criteria by two independent reviewers. Data were extracted from accepted papers, and the internal validity and strength of the evidence were determined using valid and reliable scales.The search generated a total of 28 papers [quantitative (n = 27), qualitative (n = 1) methodologies]. Themes were identified from the accepted papers: education (n = 18), knowledge of clinical guidelines and impact on management (n = 7), and doctors’ demographics (n = 4). There was consistent evidence that doctors did not adhere to clinical guidelines when performing a spinal assessment. There was inconsistent evidence that education increased adherence with acute LBP guideline recommendations in terms of referral rates to physiotherapy, for investigations, to secondary care and for maintaining patients at work. Strategies to address the factors impacting on doctors’ management of acute LBP are required; these would lead to improvement in patient outcomes and reduce healthcare costs.     

A prospective comparison of post-surgical behavioral pain scales in preschoolers highlighting the risk of false evaluations

Four behavioral rating scales (BRS) (CHEOPS, CHIPPS, FLACC and OPS) assessing postoperative pain in children aged 1–7 years were studied to compare their psychometric properties, sensitivity and specificity. One hundred and fifty children included in this prospective longitudinal study were videotaped to analyze retrospectively peri-operative behaviors. Pain and anxiety were evaluated by children or by their parents prospectively. At the end of the study, four observers rated the peri-operative videos using the four BRS. Because self-reporting cannot be used for all the children, facial expression of pain was analyzed from the videos to create a Facial Action Summary Score (FASS) which was considered as a reference for the study of validity of the four BRS. Internal validities were excellent but external validities were mixed. The FLACC seems to be better adapted to assess post-surgical pain in children between 1 and 7 years old. Nevertheless, it was significantly correlated with anxiety measures. Moreover, the analysis of sensitivity and specificity using both self-reporting of pain and FASS showed that some children were still under-evaluated. The multivariate analysis underlines silence as a high risk factor of misevaluating postoperative pain. In conclusion, this study highlights the difficulty of discriminating pain intensity from anxiety when using the four BRS and that postoperatively, nearly one child in 10 was misevaluated.     

Adverse drug reactions of statins in children and adolescents: a descriptive analysis from VigiBase,the WHO global database of individual case safety reports

In adults, statins safety profile is well known. However, literature data on their adverse drug reactions (ADRs) remain scarce in children in real-life setting. In order to better characterize ADRs related to ‘real-life’ use of statins in children, we reviewed statin-related ADRs recorded in the World Health Organization (WHO) global database of individual case safety reports (ICSRs), VigiBase. Methods. Individual case safety reports (ICSRs) in children (2–11 years) and adolescents (12–17 years) associated with statins from January 1, 1987, to July 18, 2017, were extracted from VigiBase. Characteristics of ICSRs, type of ADRs according to MedDRA classification (SOC and PT), and ICSR seriousness were described using SAS 9.4. A total of 311 ICSRs were identified for 8 statins with 712 ADRs. Musculoskeletal disorders (n = 85, 27.3%) were the first registered ADRs followed by general disorders (n = 67, 21.5%; mainly asthenia and pain). More than 1 out of 5 ADRs were ‘injury, poisoning and procedural complications’ (n = 67), mainly accidental or intentional exposures (n = 44, 14.1%), overdoses (n = 14, 4.5%), or off-label use (n = 11, 3.5%). Overall, 133 (42.8%) reports were ‘serious’, including 11 deaths. Deaths mainly involved adolescents with intentional overdose and completed suicide with other associated drugs in 75% of reports. Our study identified rare but serious safety issues (rhabdomyolysis, myalgia, and hepatocellular injury). These ADRs can impact quality of life or lead to life-threatening complications in children. Our results should be supplemented with other data sources. Spontaneous statin ADR reports in children to pharmacovigilance networks must be promoted.     

Does baseline EEG activity differ in the transition to or from a chronic pain state? A longitudinal study

Background and Aim

Identifying EEG brain markers might yield better mechanistic insights into how chronic pain develops and could be treated. An existing longitudinal EEG study gave us the opportunity to determine whether the development of pain is accompanied by less alpha power—ie, a “relaxed” brain state—and vice versa.

Methods

Five-minute resting EEG with the eyes open was measured 2 times in 95 subjects at T0 (baseline) and T1 (6 months later). Based on the Short-Form Health Survey and Brief Pain Inventory questionnaire, subjects were divided into 4 groups: staying pain-free (n = 44), developing chronic pain (n = 8), becoming pain-free (n = 15), and ongoing chronic pain (n = 28). The EEG data of 14 electrodes were analyzed by multilevel regression.

Results

The group that developed chronic pain demonstrated less power in the lower-frequency bands over time during the resting state EEG, whereas the transition to a pain-free state had the opposite pattern. Thus, the a priori hypothesis was confirmed.

Conclusions

Transitions in pain states are linked to a change in baseline EEG activity. Future research is needed to replicate these results in a larger study sample and in targeted clinical populations. Furthermore, these results might be beneficial in optimizing neurofeedback algorithms for the treatment of chronic pain.     

Habituation and sensitization to heat and cold pain in women with fibromyalgia and healthy controls

The purpose of this study was to examine differences in habituation to heat and cold pain in women with fibromyalgia (FM; n = 33) and in women who were healthy controls (HC; n = 44). Quantitative sensory testing (QST) was used to assess pain thresholds during five consecutive trials of ascending heat and descending cold stimulation. Anxiety, depression, fatigue, and pain during the previous week were assessed using self-report measures. The overall hypotheses were that there would be differences between groups in pain thresholds and in the rate of habituation to heat and cold pain stimuli. Multilevel modeling was used to test the hypotheses. There were large overall differences in pain thresholds, with the FM group showing greater sensitivity to heat and cold pain stimuli compared with the HC group. While habituation occurred in both of the groups for heat pain, the HC group had stronger habituation across trials than the FM group. Conversely, while the HC group habituated to cold pain stimuli, the FM group showed sensitization and had decreased cold pain thresholds across trials (they felt cold pain at higher temperatures). In addition, anxiety, depression, fatigue, and pain were related to decreased heat and cold pain thresholds in the overall sample. However, when group was controlled, none of these variables were related to thresholds or rates of habituation or sensitization. The differences between women with FM and healthy women in habituation and sensitization may have important implications for the etiology, diagnosis, and treatment of FM and other chronic pain conditions.     

Latency to facial expression change following noxious stimulation in infants is dependent on postmenstrual age

Change in facial expression over a fixed time after a noxious stimulus is the key measure used to calculate pain scores in preterm and newborn infants. We hypothesised that the latency of facial motor responses would be longer in the youngest premature infants and that behavioural scoring methods of pain may need to take this into account. One hundred and seventy-two clinically required heel lances were performed in 95 infants from 25 to 44 weeks postmenstrual age (PMA). Sixty-four percentage of the heel lances evoked a change in facial expression. Change in facial expression was observed in infants across the whole age range from 25 weeks PMA and the latency to the facial expression response ranged from 1 to 17 s. Latency to facial expression change was dependent on the infants’ PMA at the time of the heel lance. Infants below 32 weeks PMA had a significantly longer latency to change in facial expression than older infants (54% increase in infants below 32 weeks; p < 0.001). Sleep state and presence of brain damage (IVH grades 1–4) did not significantly increase the latency (p > 0.05 for each variable). Intravenous morphine at the time of the heel lance significantly increased the latency to facial expression response (p < 0.001) but the analysis shows that latency is highly dependent on PMA independent of morphine administration. These findings highlight developmental changes underlying infant behaviour that are critically important if pain scores are to be correctly interpreted.