Conditioned pain modulation (CPM) refers to the diminution of perceived pain intensity for a test stimulus following application of a conditioning stimulus to a remote area of the body, and is thought to reflect the descending inhibition of nociceptive signals. Studying CPM in children may inform interventions to enhance central pain inhibition within a developmental framework. We assessed CPM in 133 healthy children (mean age = 13 years; 52.6% girls) and tested the effects of sex and age. Participants were exposed to four trials of a pressure test stimulus before, during, and after the application of a cold water conditioning stimulus. CPM was documented by a reduction in pressure pain ratings during cold water administration. Older children (12–17 years) exhibited greater CPM than younger (8–11 years) children. No sex differences in CPM were found. Lower heart rate variability (HRV) at baseline and after pain induction was associated with less CPM controlling for child age. The findings of greater CPM in the older age cohort suggest a developmental improvement in central pain inhibitory mechanisms. The results highlight the need to examine developmental and contributory factors in central pain inhibitory mechanisms in children to guide effective, age appropriate, pain interventions.
diffuse noxious inhibitory controls; experimental pain; descending modulation; endogenous inhibition; pediatric pain
Studies in adults have demonstrated a relationship between lowered heart rate variability (HRV) and poor health. However, less is known about the role of autonomic arousal in children’s well-being. The aim of the current study was to examine resting HRV in children with chronic pain compared to healthy control children and, further, to examine children’s HRV following a series of acute experimental pain tasks in both groups. Participants included 104 healthy control children and 48 children with chronic pain aged 8–17 years. The laboratory session involved a 5-minute baseline electrocardiogram followed by four pain induction tasks: evoked pressure, cold pressor, focal pressure, and a conditioned pain modulation task. After the tasks were complete, a 5-minute post-task electrocardiogram recording was taken. Spectral analysis was used to capture high-frequency normalized power and the ratio of low-to-high frequency band power, signifying cardiac vagal tone and sympathetic balance, respectively. Results revealed that children with chronic pain had significantly lower resting HRV (signified by low high-frequency normalized power and high ratio of low-to-high frequency band power) compared to healthy children; moreover, a significant interaction between groups and time revealed that children with chronic pain displayed a static HRV response to the pain session compared to healthy children, whose HRV was reduced concomitant with the pain session. These findings suggest that children with chronic pain may have a sustained stress response with minimal variability in response to new acute pain stressors.
laboratory pain; pediatric pain; cold pressor; experimental pain; childhood pain; stress task
Parental behaviors, emotions, and cognitions are known to influence children’s response to pain. However, prior work has not tested the association between maternal psychological factors and children’s responses to a conditioned pain modulation (CPM) task. CPM refers to the reduction in perceived pain intensity for a test stimulus following application of a conditioning stimulus to a remote area of the body, and is thought to reflect the descending inhibition of nociceptive signals.
The present study examined sex differences in the association between maternal anxiety about pain and children’s CPM responses in 133 healthy children aged 8–17 years. Maternal pain anxiety was assessed using the Pain Anxiety Symptoms Scale-20. In addition to the magnitude of CPM, children’s anticipatory anxiety and pain-related fear of the CPM task were measured.
Sequential multiple linear regression revealed that even after controlling for child age and general maternal psychological distress, greater maternal pain anxiety was significantly related to greater CPM anticipatory anxiety and pain-related fear in girls, and to less CPM (ie, less pain inhibition) in boys.
The findings indicate sex-specific relationships between maternal pain anxiety and children’s responses to a CPM task over and above that accounted for by the age of the child and the mother’s general psychological distress.
diffuse noxious inhibitory controls; pediatric pain; mother-child relationship; cold pressor; pressure pain; laboratory pain
Extant research comparing laboratory pain responses of children with chronic pain with healthy controls is mixed, with some studies indicating lower pain responsivity for controls and others showing no differences. Few studies have included different pain modalities or assessment protocols.
To compare pain responses among 26 children (18 girls) with chronic pain and matched controls (mean age 14.8 years), to laboratory tasks involving thermal heat, pressure and cold pain. Responses to cold pain were assessed using two different protocols: an initial trial of unspecified duration and a second trial of specified duration.
Four trials of pressure pain and of thermal heat pain stimuli, all of unspecified duration, were administered, as well as the two cold pain trials. Heart rate and blood pressure were assessed at baseline and after completion of the pain tasks.
Pain tolerance and pain intensity did not differ between children with chronic pain and controls for the unspecified trials. For the specified cold pressor trial, 92% of children with chronic pain completed the entire trial compared with only 61.5% of controls. Children with chronic pain exhibited a trend toward higher baseline and postsession heart rate and reported more anxiety and depression symptoms compared with control children.
Contextual factors related to the fixed trial may have exerted a greater influence on pain tolerance in children with chronic pain relative to controls. Children with chronic pain demonstrated a tendency toward increased arousal in anticipation of and following pain induction compared with controls.
Acute pain; Cold pressor task; Laboratory pain; Pain intensity; Pressure pain; Thermal heat pain
Adult studies have demonstrated that increased resting blood pressure (BP) levels correlate with decreased pain sensitivity. However, few studies have examined the relationship between BP and experimental pain sensitivity among children.
This study investigated the association between resting BP levels and experimental pain tolerance, intensity, and unpleasantness in healthy children. We also explored whether these BP–pain relationships were age and gender dependent.
Participants underwent separate 4-trial blocks of cutaneous pressure and thermal pain stimuli, and 1 trial of a cold pain stimulus in counterbalanced order.
A total of 235 healthy children (49.6% female; mean age 12.7 [2.9] years; age range 8–18 years) participated. The study revealed specific gender-based BP–pain relationships. Girls with higher resting systolic BP levels were found to have lower thermal intensity ratings than girls with lower resting systolic BP levels; this relationship was stronger among adolescent girls than among younger girls. Among young girls (8–11 years), those with higher resting diastolic BP (DBP) levels were found to have lower cold intensity and unpleasantness as well as lower thermal intensity ratings than did young girls with lower resting DBP levels; these DBP–pain response relationships were not seen among adolescent girls.
Age, rather than resting BP, was predictive of laboratory pain ratings in boys. The findings suggest that the relationship between BP and experimental pain is age and gender dependent. These aspects of cardiovascular relationships to pain in males and females need further attention to understand their clinical importance.
blood pressure; children; gender differences; laboratory pain
Rheumatoid arthritis (RA) is a chronic disease characterized by inflammation of joints and associated fatigue, deteriorated range of motion, and impaired psychosocial functioning. Young adults with RA are at a particular risk for compromised health-related quality of life, and there is a need for safe, effective complementary treatment in addition to traditional medical approaches. The aim of the present study was to use face-to-face participant interviews, conducted before and after an Iyengar yoga (IY) program, to examine mechanisms through which yoga may be beneficial to young adults with RA.
This pilot study utilized a single-arm design where all participants received the intervention. Classes were taught twice per week (1.5 hours each) for 6 weeks by an IY teacher qualified in therapeutics. Interview themes included participants’ baseline expectations about yoga and viewpoints as to how their functioning had been impacted by the IY intervention were examined. Five young adults with RA aged 24–31 years (mean = 28; 80% female) completed the yoga intervention. Participants consistently reported that yoga helped with energy, relaxation and mood and they discussed perceived mechanisms for how yoga impacted well-being. Mechanisms included physical changes such as range of motion and physiological awareness, and psychospiritual developments such as acceptance, coping, self-efficacy and mindfulness. Though the study is limited, participants’ responses provide compelling evidence that IY for RA patients is an intervention worthy of further exploration. The mechanisms and outcomes reported by participants support a biopsychosocial model, which proposes that yoga benefits patients through both physiological and psychospiritual changes.
Iyengar yoga; Rheumatoid arthritis; Qualitative data
Children, adolescents, and young adults do not typically feature in clinics, studies, and mainstream notions of chronic pain. Yet many young people experience debilitating pain for extended periods of time. Chronic pain in these formative years may be especially important to treat in order for young patients to maintain life tasks and to prevent protracted disability. The Pediatric Pain Program at the University of California, Los Angeles, is a multidisciplinary treatment program designed for young people with chronic pain and their families. We offer both conventional and complementary medicine to treat the whole individual. This article describes the work undertaken in the clinic and our newly developed Yoga for Youth Research Program. The clinical and research programs fill a critical need to provide service to youth with chronic pain and to scientifically study one of the more popular complementary treatments we offer, Iyengar yoga.
chronic pain; complementary medicine; pediatrics; yoga
Few studies have focused on identifying predictors of medical consultation for pain in healthy children and adolescents.
This investigation sought to identify parent and child laboratory and non-laboratory predictors of pediatric healthcare utilization for pain problems.
Participants were 210 healthy children and adolescents (102 girls), aged 8–17 years who took part in a laboratory pain session.
Three months after the laboratory session, participants were contacted by telephone to ascertain whether they had experienced pain and whether they had seen a healthcare professional for pain. Zero-order correlations among sociodemographics, child laboratory pain responses, parent physical/mental health status and medical consultation for pain were conducted to identify relevant correlates of pediatric healthcare utilization; these correlates were subjected to multivariate analyses.
Bivariate analyses indicated that higher anticipated pain and bother for the cold pressor task, as well as poorer parent physical health status, were associated with pediatric medical consultation for pain, but only among girls. Sequential logistic regression analyses controlling for child age indicated that only parent physical health status, not the laboratory indicators, significantly predicted healthcare consultation for pain among girls. No parent or child correlates of care-seeking for pain emerged for boys.
The findings suggest that parents’ perceived physical health plays a role in determining whether medical care is sought for pain complaints in healthy girls. These results suggest that interventions to assist parents in managing their own physical health problems may lead to reductions in medical consultation for girls’ pain.
pediatric health care; parent health status; parent-child relationship; experimental pain; acute pain
This study employed a mixed-method design to test sex-specific parent-child pain associations. Subjects were 179 chronic pain patients aged 11–19 years (mean = 14.34; 72% female) presenting for treatment at a multidisciplinary, tertiary clinic. Mothers and children completed questionnaires prior to their clinic visit, including measures of children’s pain, functioning and psychological characteristics. Mothers also reported on their own pain and psychological functioning. Interviews were conducted with a sub-sample of 34 mothers and children prior to the clinic visit and analyzed using a grounded theory approach. The quantitative data suggest stronger mother-daughter than mother-son pain relationships. The qualitative data suggest that girls’ pain and pain-related disability is related to an overly enmeshed mother-daughter relationship and the presence of maternal models of pain, while boys’ pain and disability is linked to male pain models and criticism and to maternal worry and solicitousness. Boys and girls appear to have developmentally incongruous levels of autonomy and conformity to maternal expectations. The mixed-method data suggest distinct trajectories through which mother and father involvement may be linked to chronic pain in adolescent boys and girls.
Sex differences; parent-child relationships; chronic pain
Little is known about how sociodemographic factors relate to children’s chronic pain. This paper describes the pain, health, and sociodemographic characteristics of a cohort of children presenting to an urban tertiary chronic pain clinic and documents the role of age, sex and minority status on pain-related characteristics. A multidisciplinary, tertiary clinic specializing in pediatric chronic pain. Two hundred and nineteen patients and their parents were given questionnaire packets to fill out prior to their intake appointment which included demographic information, clinical information, Child Health Questionnaire – Parent Report, Functional Disability Index – Parent Report, Child Somatization Index – Parent Report, and a Pain Intensity Scale. Additional clinical information was obtained from patients’ medical records via chart review. This clinical sample exhibited compromised functioning in a number of domains, including school attendance, bodily pain, and health compared to normative data. Patients also exhibited high levels of functional disability. Minority children evidenced decreased sleep, increased somatization, higher levels of functional disability, and increased pain intensity compared to Caucasians. Caucasians were more likely to endorse headaches than minorities, and girls were more likely than boys to present with fibromyalgia. Younger children reported better functioning than did teens. The results indicate that sociodemographic factors are significantly associated with several pain-related characteristics in children with chronic pain. Further research must address potential mechanisms of these relationships and applications for treatment.
Chronic pain; pediatric; clinical cohort; ethnic differences
Although sex differences in anxiety sensitivity or the specific tendency to fear anxiety-related sensations have been reported in adults with clinical pain, there is a dearth of relevant research among children. This study examined sex differences in anxiety sensitivity across unselected samples of 187 children with chronic pain (71.7% girls; mean age = 14.5) and 202 non-clinical children (52% girls; mean age = 13.6). Girls in the chronic pain and non-clinical samples reported elevated anxiety sensitivity relative to boys irrespective of clinical status. Girls with chronic pain also reported heightened fears of the physical consequences of anxiety compared to non-clinical girls but there were no such differences for psychological or social concerns. Among boys, anxiety sensitivity did not differ between the chronic pain and non-clinical groups. Future longitudinal research may examine whether specific fears of anxiety-related somatic sensations constitutes a sex-based vulnerability factor in the development of chronic pain.
chronic pain; children; anxiety sensitivity; anxiety; sex differences
Rheumatoid arthritis is a chronic, disabling disease that can compromise mobility, daily functioning, and health-related quality of life, especially in older adolescents and young adults. In this project, we will compare a standardized Iyengar yoga program for young people with rheumatoid arthritis to a standard care wait-list control condition.
Seventy rheumatoid arthritis patients aged 16-35 years will be randomized into either the 6-week Iyengar yoga program (12 - 1.5 hour sessions twice weekly) or the 6-week wait-list control condition. A 20% attrition rate is anticipated. The wait-list group will receive the yoga program following completion of the first arm of the study. We will collect data quantitatively, using questionnaires and markers of disease activity, and qualitatively using semi-structured interviews. Assessments include standardized measures of general and arthritis-specific function, pain, mood, and health-related quality of life, as well as qualitative interviews, blood pressure/resting heart rate measurements, a medical exam and the assessment of pro-inflammatory cytokines. Data will be collected three times: before treatment, post-treatment, and two months following the treatment.
Results from this study will provide critical data on non-pharmacologic methods for enhancing function in rheumatoid arthritis patients. In particular, results will shed light on the feasibility and potential efficacy of a novel intervention for rheumatoid arthritis symptoms, paving the way for a larger clinical trial.
Irritable bowel syndrome affects as many as 14% of high school-aged students. Symptoms include discomfort in the abdomen, along with diarrhea and/or constipation and other gastroenterological symptoms that can significantly impact quality of life and daily functioning. Emotional stress appears to exacerbate irritable bowel syndrome symptoms suggesting that mind-body interventions reducing arousal may prove beneficial. For many sufferers, symptoms can be traced to childhood and adolescence, making the early manifestation of irritable bowel syndrome important to understand. The current study will focus on young people aged 14-26 years with irritable bowel syndrome. The study will test the potential benefits of Iyengar yoga on clinical symptoms, psychospiritual functioning and visceral sensitivity. Yoga is thought to bring physical, psychological and spiritual benefits to practitioners and has been associated with reduced stress and pain. Through its focus on restoration and use of props, Iyengar yoga is especially designed to decrease arousal and promote psychospiritual resources in physically compromised individuals. An extensive and standardized teacher-training program support Iyengar yoga's reliability and safety. It is hypothesized that yoga will be feasible with less than 20% attrition; and the yoga group will demonstrate significantly improved outcomes compared to controls, with physiological and psychospiritual mechanisms contributing to improvements.
Sixty irritable bowel syndrome patients aged 14-26 will be randomly assigned to a standardized 6-week twice weekly Iyengar yoga group-based program or a wait-list usual care control group. The groups will be compared on the primary clinical outcomes of irritable bowel syndrome symptoms, quality of life and global improvement at post-treatment and 2-month follow-up. Secondary outcomes will include visceral pain sensitivity assessed with a standardized laboratory task (water load task), functional disability and psychospiritual variables including catastrophizing, self-efficacy, mood, acceptance and mindfulness. Mechanisms of action involved in the proposed beneficial effects of yoga upon clinical outcomes will be explored, and include the mediating effects of visceral sensitivity, increased psychospiritual resources, regulated autonomic nervous system responses and regulated hormonal stress response assessed via salivary cortisol.
This study examined the relationships among anxiety sensitivity (AS), catastrophizing, somatization, and pain in 240 non-clinical children (121 girls; mean age = 12.7 years). Children with pain problems (n = 81; 33.8%) reported greater AS and catastrophizing (p’s < .01) relative to children without pain problems. AS but not catastrophizing was significantly associated with current pain. However, both AS and catastrophizing were significantly associated with somatization. AS and catastrophizing represent related but partially distinct cognitive constructs that may be targeted by interventions aimed at alleviating pain and somatization in children.
Children; pain; somatization; catastrophizing; anxiety sensitivity
Prior research has demonstrated links between psychosocial factors, including negative life events (NLE) and pain in children. The present study examined sex differences in the relationship between mother-reported NLE, child NLE, mother somatization and children’s laboratory pain responses for heat, cold and pressure pain tasks. We predicted that maternal NLE would be moderately associated with girls’ pain responses, but would not be associated with boys’ pain responses.
Participants were 176 non-clinical children (89 boys) aged 8–18 years (mean = 12.2, SD = 2.7) and their mothers. Mothers and children completed questionnaires assessing their perceptions of NLE experienced in the previous 12 months.
Contrary to predictions, maternal NLE were related to pain responses in both boys and girls, although in opposite directions. Thus, increased maternal stress was associated with increased pain responses in girls but with decreased pain responses in boys. In addition, the impact of maternal NLE was only apparent for heat and pain tasks, indicating differential effects for various types of pain.
The current findings underscore the importance of family variables in understanding sex differences in children’s pain. Future research is needed to examine the mechanisms within the parent-child relationship that contribute to sex-differentiated pain outcomes, particularly under conditions of exacerbated parental stress.
negative life events; children’s laboratory pain; sex differences
Chronic or recurrent pain is a widespread health issue that affects a large proportion of the population, including adults and children. Family factors in the development of pain have received increasing attention of late as research has shown that pain tends to run in families, A burgeoning literature has also demonstrated the influence of parental factors in children’s responses to chronic and laboratory pain. This review attempts to integrate: first,) the literature documenting an association between parent and child pain both within the clinical chronic pain and laboratory pain literatures; and second,) research accounting for likely mechanisms explaining the parent-child pain association. To this end, we present a conceptual model that incorporates a number of parent and child specific characteristics, such as parental responses, coping and gender role socialization as well as broader socio-demographic factors such as parent and child age and sex, family functioning, socioeconomic status, and race/ethnicity. It is anticipated that consideration of such variables will lead to needed research exploring the mechanisms of parent-child pain relationships, and to interventions designed to prevent and ameliorate child pain sensitivity when it correlates with poor adaptation to pain.
children; pain; family; parents
Previous research has established links between parent and child pain. However, little is known about sex-specific parent-child pain relationships in a nonclinical population. A sample of 186 children aged eight to 18 years (49% female) provided information on maternal and self bodily pain, assessed by asking children about the presence and location of bodily pain experienced. Children also completed three laboratory pain tasks and reported on cold pressor pain intensity, pressure pain intensity and heat pain intensity. The presence of child-reported maternal pain was consistently correlated with daughters’ bodily and laboratory pain, but not with sons’ pain in bivariate analyses. Multivariate analyses controlling for child age and maternal psychological distress indicated that children of mothers with bodily pain reported more total bodily pain sites as well as greater pressure and cold pain intensity, relative to children of mothers without bodily pain. For cold pain intensity, these results differed for boys versus girls, in that daughters reporting maternal pain evidenced significantly higher cold pain intensity compared with daughters not reporting maternal pain. No such differences were found for boys. The findings suggest that children’s perceptions of maternal pain may play a role in influencing children’s own experience of pain, and that maternal pain models may affect boys and girls differently.
Children; Pain; Sex differences; Social learning
Previous research has established links between parent and child pain. Yet little is known about sex-specific parent-child pain relationships in a non-clinical population. A sample of 186 children aged 8–18 years (49% female) provided information on maternal and self bodily-pain, assessed by asking children about the presence and location of bodily pain experienced. Children also completed three laboratory pain tasks and reported on cold pressor pain intensity, pressure pain intensity and heat pain intensity. The presence of child-reported maternal pain was consistently correlated with daughters’ bodily and laboratory pain, but not with sons’ pain in bivariate analyses. Multivariate analyses controlling for child age and maternal psychological distress indicated that children of mothers with bodily pain reported more total bodily pain sites as well as greater pressure and cold pain intensity, relative to children of mothers without bodily pain. For cold pain intensity, these results differed for boys vs. girls, in that daughters reporting maternal pain evidenced significantly higher cold pain intensity compared to daughters not reporting maternal pain. No such differences were found for boys. The findings suggest that children’s perceptions of maternal pain may play a role in influencing children’s own experience of pain and that maternal pain models may affect boys and girls differently.
pain; sex differences; social learning; children
There is increasing concern regarding the number of painful medical procedures that infants must undergo and the potential risks of alleviating infant pain with conventional pharmacologic agents. This article is Part I of a two-part series that aims to provide an overview of the literature on complementary and alternative (CAM) approaches for pain and distress related to medical procedures among infants up to six weeks of age. The focus of this article is a review of the empirical literature on sucrose with or without non-nutritive sucking (NNS) for procedural pain in infancy. Computerized databases were searched for relevant studies including prior reviews and primary trials. The most robust evidence was found for the analgesic effects of sucrose with or without NNS on minor procedural pain in healthy full-term infants. Despite some methodological weaknesses, the literature to date supports the use of sucrose, NNS and other sweetened solutions for the management of procedural pain in infancy.
infant; neonate; nonnutritive sucking; procedural pain; sucrose
This article is the second in a two-part series reviewing the empirical evidence for complementary and alternative medicine (CAM) approaches for the management of pain related to medical procedures in infants up to 6 weeks of age. Part I of this series investigated the effects of sucrose with or without non-nutritive sucking (NNS). The present article examines other CAM interventions for procedural pain including music-based interventions, olfactory stimulation, kangaroo care and swaddling. Computerized databases were searched for relevant studies including prior reviews and primary trials. Preliminary support was revealed for the analgesic effects of the CAM modalities reviewed. However, the overall quality of the evidence for these approaches remains relatively weak. Additional well-designed trials incorporating rigorous methodology are required. Such investigations will assist in the development of evidence-based guidelines on the use of CAM interventions either alone or in concert with conventional approaches to provide safe, reliable analgesia for infant procedural pain.