Anxiety and stress can predict pain perception following a cognitive stress

Chronic neck and low back pain from personal experiences: a written narrative approach

Background: Chronic neck and low back pain are very common and have detrimental effects for people and society. In this study, we explore the experiences of individuals with neck and/or back pain using a written narrative methodology. Materials & methods: A total of 92 individuals explained their pain experience using written narratives. Narratives were analyzed through thematic analysis and text data mining. Results: Participants wrote about their experience in terms of pain characteristics, diagnosis process, pain consequences, coping strategies, pain triggers, well-being and future expectations. Text data mining allowed us to identify concurrent networks that were basically related with pain characteristics, management and triggers. Conclusion: Written narratives are useful to understand individuals' experiences from their point of view.

Nociception related biomolecules in the adult human saliva: A scoping review with additional quantitative focus on cortisol

Nociception related salivary biomolecules can be useful patients who are not able to self-report pain. We present the existing evidence on this topic using the PRISMA-ScR guidelines and a more focused analysis of cortisol change after cold pain induction using the direction of effect analysis combined with risk of bias analysis using ROBINS-I. Five data bases were searched systematically for articles on adults with acute pain secondary to disease, injury, or experimentally induced pain. Forty three articles met the inclusion criteria for the general review and 11 of these were included in the cortisol-cold pain analysis. Salivary melatonin, kallikreins, pro-inflammatory cytokines, soluable TNF-α receptor II, secretory IgA, testosterone, salivary α-amylase (sAA) and, most commonly, cortisol have been studied in relation to acute pain. There is greatest information about cortisol and sAA which both rise after cold pain when compared with other modalities. Where participants have been subjected to both pain and stress, stress is consistently a more reliable predictor of salivary biomarker change than pain. There remain considerable challenges in identifying biomarkers that can be used in clinical practice to guide the measurement of nociception and treatment of pain. Standardization of methodology and researchers' greater awareness of the factors that affect salivary biomolecule concentrations are needed to improve our understanding of this field towards creating a clinically relevant body of evidence.

The Biology of Chronic Pain and Its Implications for Pain Neuroscience Education: State of the Art

Pain is an individualized experience for the person suffering from chronic pain. Significant strides have been made in the last few decades in understanding various biological changes that coincide with chronic pain. This state-of-the-art overview looks at the current evidence related to the biology of chronic pain and the implications these findings have on the delivery of pain neuroscience education (PNE). The paper summarizes the various (epi)genetic, neural, endocrine, and immune factors discovered and explored in the scientific literature concerning chronic pain. Each of these biological factors has various implications for the content and delivery of PNE. We discuss the future directions these biological factors have for the clinical implementation of PNE by linking the importance of behavior change, optimizing the learning environment, and using an individualized multimodal treatment approach with PNE. In addition, future directions for research of PNE based on these biological factors are provided with importance placed on individualized patient-centered care and how PNE can be used with traditional modes of care and growing trends with other care methods. PNE was originally and continues to be rooted in understanding chronic pain biology and how that understanding can improve patient care and outcomes.

Stand by Me: Social Ties and Health in Real-Time

Sociological research has documented myriad associations between individuals' overall social connectedness and health, but rarely considers the shorter-term dynamics of social life that may underlie these associations. We examine how being with others ("social accompaniment") is associated with momentary experiences of symptoms, drawing smartphone-based ecological momentary assessments (N=12,720) collected from 342 older adults from the Chicago Health and Activity in Real Time study. We find that patterns of social accompaniment are distinct from global measures of social integration such as network size. Older adults who are in the company of a friend or neighbor are significantly less likely to experience momentary fatigue and stress, even after accounting for overall measures of social integration. These results suggest that social accompaniment has unique implications for short-term health outcomes. New theoretical perspectives and empirical analyses are needed to better understand the dynamic nature of everyday social accompaniment and its longer-term implications for well-being.

Physical activity restriction in the pandemic is associated with lower pain self-efficacy in the population with musculoskeletal pain: cross-sectional study

ABSTRACT During the COVID-19 pandemic, a lower level of physical activity was observed in the population, which may influence the level of pain self-efficacy in the population with musculoskeletal pain. In this context, this study sought to analyze whether there is an association between the time of physical activity practice and the level of pain self-efficacy in the population with pain during the COVID-19 pandemic in the state of São Paulo, controlled by biopsychosocial variables. This study was conducted via an online form with questions about sociodemographic aspects, weekly physical activity practice, stress and anxiety levels, pain intensity and pain self-efficacy (Pain Self-Efficacy Questionnaire - PSEQ-10). The analysis was determined by two models of multiple linear regression, with (Model A) and without (Model B) the control of data by psycho-emotional factors (anxiety and stress) in 150 subjects. An association was found between weekly physical activity practice time and pain self-efficacy level, Model A (p=0.0271, β=1.914) and Model B (p=0.0333, β=1.826). Pain intensity during the pandemic, body mass index (BMI) and sex, among the control variables, also were associated with the pain self-efficacy level. A higher time of physical activity practice was associated with a higher pain self-efficacy level in the population with musculoskeletal pain during the COVID-19 pandemic. Pain intensity during the pandemic, BMI and sex also were associated with pain self-efficacy level.

Restrição à atividade física na pandemia está associada com menor autoeficácia para dor na população com dor musculoesquelética: um estudo transversal

RESUMO Durante a pandemia de COVID-19, observou-se um menor nível de prática de atividade física pela população, o que pode influenciar o nível de autoeficácia para dor na população com dor musculoesquelética. Neste contexto, o objetivo deste estudo foi analisar se existe associação entre o tempo de prática de atividade física e o nível de autoeficácia para dor na população com dor musculoesquelética durante a pandemia de COVID-19 no estado de São Paulo, controlada por variáveis biopsicossociais. Realizou-se um estudo através de um formulário online com questões sobre aspectos sociodemográficos, tempo semanal de prática de atividade física, níveis de estresse e ansiedade, intensidade de dor e autoeficácia para dor (PSEQ-10 - Pain Self-Efficacy Questionnaire). A análise estatística ocorreu por meio de dois modelos de regressão linear múltipla, com (modelo A) e sem (modelo B) o controle dos dados por fatores psicoemocionais (ansiedade e estresse) em 150 pessoas. Foi encontrada associação entre o tempo de prática de atividade física semanal e o nível de autoeficácia para dor no modelo A (p=0,0271, β=1,914) e no modelo B (p=0,0333, β=1,826). Intensidade de dor durante a pandemia, índice de massa corporal (IMC) e sexo, dentre as variáveis de controle, também foram associadas ao nível de autoeficácia para dor. Maior tempo de prática de atividade física foi associado a maior nível de autoeficácia para dor na população com dor musculoesquelética durante a pandemia de COVID-19. Intensidade de dor durante a pandemia, IMC e sexo também foram associados ao nível de autoeficácia para dor.

Effects of Open-Label Placebos on State Anxiety and Glucocorticoid Stress Responses

Stress belongs to the most frequent negative feelings people are confronted with in daily life. Strategies against acute stress include, e.g., relaxation techniques or medications, but it is also known that placebos can successfully reduce negative emotional stress. While it is widely held that placebos require deception to provoke a response, recent studies demonstrate intriguing evidence that placebos may work even without concealment (e.g., against anxiety or pain). Most of these studies are based on self-report questionnaires and do not include physiological measures. Here we report results of a study examining whether placebos without deception reduce acute stress. A total of 53 healthy individuals received either placebos without deception or no pills before participating in a laboratory stress test (Maastricht Acute Stress Test, MAST). We recorded self-report stress measures and cortisol responses before and after the MAST. Results showed no significant differences between the placebo and the control group, but when comparing participants with high relative to low beliefs in the power of placebos we found significant lower anxiety and cortisol responses for the placebo believers. These results show that non-deceptive placebos may successfully reduce acute anxiety and stress, but only in participants who had a strong belief in placebos. We discuss the results by suggesting that open-label placebos might be a possible treatment to reduce stress at least for some individuals.

The Effect of Stress on Repeated Painful Stimuli with and Without Painful Conditioning

OBJECTIVES

Stress and pain have been interrelated in clinical widespread pain conditions. Studies indicate that acute experimental stress in healthy volunteers has a negative effect on the descending inhibitory pain control system and thus the ability to inhibit one painful stimulus with another (conditioned pain modulation [CPM]) although without effect on general pain sensitivity. CPM effects can be assessed immediately after the stress induction, whereas some physiological stress responses (e.g., cortisol release) are delayed and longer lasting. It is unclear whether CPM may relate to stress-induced increases in cortisol.

DESIGN

Twenty-five healthy men had CPM effects measured over a period of 10 minutes. Pain detection thresholds (PDTs) were assessed by repeated test stimuli with cuff algometry on one leg, with and without painful cuff pressure conditioning on the contralateral leg. CPM effects, assessed as the increase in PDT during conditioning stimulation compared with without, were measured before and after experimental stress and a control condition (Montreal Imaging Stress Task [MIST]). Saliva cortisol levels and self-perceived stress were collected.

RESULTS

Participants reported the MIST to be more stressful compared with the MIST control, but cortisol levels did not change significantly from baseline. In all sessions, PDT increased during conditioning (P = 0.001), although the MIST compared with the MIST control had no significant effect on PDT or CPM effects. A negative correlation between changes in cortisol and conditioned PDT was found when applying the MIST (P < 0.03).

CONCLUSIONS

No significant effect of stress was found on CPM compared with a matched control condition. Individual changes in experimental stress and in conditioned pain sensitivity may be linked with cortisol.

PROs in the wild: Assessing the validity of patient reported outcomes in an electronic registry

BACKGROUND AND OBJECTIVES

Collecting Patient-Reported Outcomes (PROs) is an important way to get first-hand information by patients on the outcome of treatments and surgical procedure they have undergone, and hence about the quality of the care provided. However, the quality of PRO data cannot be given for granted and cannot be traced back to the dimensions of timeliness and completeness only. While the reliability of these data can be guaranteed by adopting standard and validated questionnaires that are used across different health care facilities all over the world, these facilities must take responsibility to assess, monitor and ensure the validity of PROs that are collected from their patients. Validity is affected by biases that are hidden in the data collected. This contribution is then aimed at measuring bias in PRO data, for the impact that these data can have on clinical research and post-marketing surveillance.

METHODS

We considered the main biases that can affect PRO validity: Response bias, in terms of Acquiescence bias and Fatigue bias; and Non-Response bias. To assess Acquiescence bias, phone interviews and online surveys were compared, adjusted by age. To assess Fatigue bias, we proposed a specific item about session length and compared PROs scores stratifying according to the responses to this item. We also calculated the intra-patient agreement by conceiving an intra-interview test-retest. To assess Non-Response bias, we considered patients who participated after the saturation of the response-rate curve as proxy of potential non respondents and compared the outcomes in these two strata. All methods encompassed common statistical techniques and are cost-effective at any facility collecting PRO data.

RESULTS

Acquiescence bias resulted in significantly different scores between patients reached by either phone or email. In regard to Fatigue bias, stratification by perceived fatigue resulted in contrasting results. A relevant difference was found in intra-patient agreement and an increasing difference in average scores as a function of interview length (or completion time). In regard to Non-Response bias, we found non-significant differences both in scores and variance.

CONCLUSIONS

In this paper, we present a set of cost-effective techniques to assess the validity of retrospective PROs data and share some lessons learnt from their application at a large teaching hospital specialized in musculoskeletal disorders that collects PRO data in the follow-up phase of surgery performed therein. The main finding suggests that response bias can affect the PRO validity. Further research on the effectiveness of simple and cost-effective solutions is necessary to mitigate these biases and improve the validity of PRO data.

A Functional Near-Infrared Spectroscopy Study on the Cortical Haemodynamic Responses During the Maastricht Acute Stress Test

In order to better understand stress responses, neuroimaging studies have investigated the underlying neural correlates of stress. Amongst other brain regions, they highlight the involvement of the prefrontal cortex. The aim of the present study was to explore haemodynamic changes in the prefrontal cortex during the Maastricht Acute Stress Test (MAST) using mobile functional Near-Infrared Spectroscopy (fNIRS), examining the stress response in an ecological environment. The MAST includes a challenging mental arithmic task and a physically stressful ice-water task. In a between-subject design, participants either performed the MAST or a non-stress control condition. FNIRS data were recorded throughout the test. Additionally, subjective stress ratings, heart rate and salivary cortisol were evaluated, confirming a successful stress induction. The fNIRS data indicated significantly increased neural activity of brain regions of the dorsolateral prefrontal cortex (dlPFC) and the orbitofrontal cortex (OFC) in response to the MAST, compared to the control condition. Furthermore, the mental arithmetic task indicated an increase in neural activity in brain regions of the dlPFC and OFC; whereas the physically stressful hand immersion task indicated a lateral decrease of neural activity in the left dlPFC. The study highlights the potential use of mobile fNIRS in clinical and applied (stress) research.

Pain upon inserting a peripheral intravenous catheter: Size does not matter

BACKGROUND

Approximately 1.2 billion peripheral intravenous catheters are inserted across the world annually. It is known that intravenous cannulation may be a painful procedure, which affects cognitive abilities by increasing anxiety and discomfort.

AIM

We hypothesized that inserting a smaller sized peripheral intravenous catheter has a lower level of pain sensation compared to a larger sized catheter.

METHODS

This observational, cross-sectional study was conducted between May and October 2016, in which surgical patients, aged 18 years or older, were eligible to participate. Experienced anesthesiologists and nurse anesthetists routinely obtained peripheral intravenous access according to the standards of care. The primary outcome was pain (verbal numeric rating scale, 0-10) upon intravenous cannulation.

RESULTS

A total of 1063 patients were included and they were divided into four groups: group 1, 22 gauge (N = 29); group 2, 20 gauge (N = 447); group 3, 18 gauge (N = 531); and group 4, sized over 18 gauge (N = 56). Inserting an 18-gauged peripheral intravenous catheter resulted in the lowest pain score (3.2 ± 2.0). As a result of the multivariate linear analysis, five factors were significantly associated with pain upon inserting a peripheral intravenous catheter (sex, American Society of Anesthesiology classification, a patients risk profile on the A-DIVA scale, site of cannulation on the extremity, and whether or not the attempt was successful); however, the size of the inserted peripheral intravenous catheter had no significant relation to the primary outcome.

CONCLUSION

Inserting a smaller sized peripheral intravenous catheter did not result in a lower pain sensation. Moreover, to prevent pain upon inserting a peripheral intravenous catheter, an unsuccessful attempt must be avoided.

The Effect of Foot Reflexology on the Anxiety Levels of Women in Labor

OBJECTIVES

This research was conducted to analyze the effect of foot reflexology on the anxiety levels of women during labor.

DESIGN, SETTING AND SUBJECTS

The study was conducted as a semiexperimental study. It was conducted with 154 nulliparous pregnant women who applied to a maternity unit of a state hospital in the north-western part of Turkey to give birth.

INTERVENTIONS

Foot reflexology was applied once to the pregnant women in the experimental group when cervical dilation was 3-4 cm. The treatment was applied to the right foot and left foot reflex points for 15 min, for a total of 30 min. The data in the study were collected using the "Pregnant Women Introductory Information Form" and the "Spielberger State-trait Anxiety Inventory" (STAI TX-1). In evaluating the data, number, percentage, Chi-square, independent samples t-test, and repeated measure analysis of variance test were used.

MAIN OUTCOME MEASURES

The mean scores of the STAI TX-1 were used to analyze the results.

RESULTS

The mean STAI TX-1 scores were measured before reflexology, in the latent and active phases of labor and early in postpartum period (four times in total). The mean STAI TX-1 scores were higher in the experimental group than in the control group (p < 0.001). The mean STAI TX-1 scores postreflexology application (when cervical dilation was 3-4 cm) and during the active phase of the labor (when cervical dilation was 6-8 cm) of the pregnant women in the experimental group were lower than those of the control group (respectively p = 0.010, p < 0.001). In the experimental group, there was no statistically significant difference between the mean STAI TX-1 scores pre- and postreflexology (p = 0.820). The mean STAI TX-1 scores in the early postpartum period were similar in the experimental and control groups (p = 0.080).

CONCLUSION

Foot reflexology was found to have a positive effect in lowering the total anxiety scores of the pregnant women. Reflexology is a noninvasive and economical method, which may be used by health professionals to reduce problems during labor. A decrease in anxiety experienced at birth improves women's positive birth experiences, promotes a secure mother-infant attachment, and protects postpartum mental health.

Dexamethasone-suppressed Salivary Cortisol and Pain Sensitivity in Female Twins

OBJECTIVES

Hypothalamic-pituitary-adrenal (HPA) axis dysregulation is associated with chronic pain. Studying pain sensitivity and the HPA axis could elucidate the role of stress in chronic pain development, which might be influenced by familial factors, including genes.

METHODS

Associations between pain sensitivity and salivary cortisol and familial confounding in these associations were examined in 88 female, community-based twin pairs (75% monozygotic, mean age 29 y). Cortisol was assessed after 0.25 mg dexamethasone (DEX), recovery from 0.25 mg DEX, and after 0.5 mg DEX. Cold pressor task (CPT) pain ratings were obtained at threshold and at tolerance. Conditioned pain modulation (CPM) was examined using thermal heat as the testing stimulus and hot water as the conditioning stimulus. Generalized estimating equation models were used and adjusted for baseline pain rating, age, and other relevant covariates.

RESULTS

After controlling for baseline cortisol, greater cortisol suppression following DEX administration and lower recovery cortisol levels were associated with higher pain ratings at tolerance during the CPT (Bs=-2.42 to -17.82; Ps=0.031 to<0.001) as well as with reduced CPM (Bs=-0.92 to -1.68; Ps=0.003 to 0.046). Interestingly, familial confounding was evident in the CPT and CPM during recovery from DEX administration, but not immediately following DEX administration.

DISCUSSION

These findings contribute to understanding possible mechanisms underlying chronic pain by demonstrating that HPA axis response to negative feedback is related to pain sensitivity.

Understanding Monitoring Technologies for Adults With Pain: Systematic Literature Review

BACKGROUND

Monitoring of patients may decrease treatment costs and improve quality of care. Pain is the most common health problem that people seek help for in hospitals. Therefore, monitoring patients with pain may have significant impact in improving treatment. Several studies have studied factors affecting pain; however, no previous study has reviewed the contextual information that a monitoring system may capture to characterize a patient's situation.

OBJECTIVE

The objective of this study was to conduct a systematic review to (1) determine what types of technologies have been used to monitor adults with pain, and (2) construct a model of the context information that may be used to implement apps and devices aimed at monitoring adults with pain.

METHODS

A literature search (2005-2015) was conducted in electronic databases pertaining to medical and computer science literature (PubMed, Science Direct, ACM Digital Library, and IEEE Xplore) using a defined search string. Article selection was done through a process of removing duplicates, analyzing title and abstract, and then reviewing the full text of the article.

RESULTS

In the final analysis, 87 articles were included and 53 of them (61%) used technologies to collect contextual information. A total of 49 types of context information were found and a five-dimension (activity, identity, wellness, environment, physiological) model of context information to monitor adults with pain was proposed, expanding on a previous model. Most technological interfaces for pain monitoring were wearable, possibly because they can be used in more realistic contexts. Few studies focused on older adults, creating a relevant avenue of research on how to create devices for users that may have impaired cognitive skills or low digital literacy.

CONCLUSIONS

The design of monitoring devices and interfaces for adults with pain must deal with the challenge of selecting relevant contextual information to understand the user's situation, and not overburdening or inconveniencing users with information requests. A model of contextual information may be used by researchers to choose possible contextual information that may be monitored during studies on adults with pain.

Psychobiological response to pain in female adolescents with nonsuicidal self-injury

BACKGROUND

Nonsuicidal self-injury (NSSI) is associated with reduced pain sensitivity and alterations in top-down processing of nociceptive information. The experience of acute pain is characterized by reactivity of the autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal (HPA) axis, which to our knowledge has not been systematically investigated in the context of NSSI.

METHODS

Adolescents fulfilling DSM-5 diagnostic criteria for NSSI and matched healthy controls received cold pain stimulation. We obtained self-reports on psychological distress and measured blood pressure, heart rate variability (HRV) and saliva cortisol. Regression analyses were used to investigate group differences on observed difference scores, adjusting for confounding variables.

RESULTS

We included 30 adolescents engaging in NSSI and 30 controls in our study. Adolescents in the NSSI group showed a greater pain threshold. Groups significantly differed in their psychological response to pain. In patients with NSSI, mood and body awareness increased after painful stimulation; in controls it decreased. Tension increased in controls only. The HPA axis response to painful stimulation was increased in the NSSI compared with the control group. Analysis of ultra-short-term recordings of HRV revealed significant group differences during the anticipation of pain and recovery.

LIMITATIONS

Future studies should incorporate multiple measures of saliva cortisol and replicate the present findings in a naturalistic setting.

CONCLUSION

Compared with controls, individuals engaging in NSSI show psychological benefits in response to pain. Biological findings highlight decreased physiologic arousal before and prolonged arousal (ANS and HPA axis response) after painful stimulation in adolescents engaging in NSSI. Greater pain-inflicted autonomic arousal and cortisol secretion may counteract dissociative states, reduce negative affect and increase body awareness in adolescents engaging in NSSI, lending support for a neurobiological pathomechanism underlying the intraindividual and antisuicide functions of NSSI.

Posttraumatic stress disorder and somatic complaints: Contrasting Vietnam and OIF/OEF Veterans' experiences

OBJECTIVE

To replicate and expand upon the relationship of somatic symptoms and posttraumatic stress disorder (PTSD) by comparing symptoms among service eras in US Veterans.

METHOD

Data were collected from 226 Vietnam and 132 Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF) Veterans who were referred to a Veterans Affairs (VA) hospital PTSD outpatient clinic between 2005 and 2013. Veterans were administered self-report inventories and a clinical interview to measure somatic symptoms and PTSD severity. A subset of Veterans (n=185) screening positive for PTSD were administered the Clinician Administered PTSD Scale (CAPS) to measure PTSD severity. Multiple moderated linear regressions were used to examine the influence of service era on the relationship between somatic and PTSD symptoms.

RESULTS

There were no significant differences between service eras in pain severity, pain interference, and total somatic symptoms reported. Vietnam Veterans were more likely to report limb/join pain (p<.05), fainting (p<.01), and shortness of breath (p<.001), whereas OIF/OEF Veterans were more likely to complain of headaches (p<.001). A significant interaction effect occurred between service era and dizziness (p<.05) and chest pain (p<.01), with OIF/OEF Veterans reporting higher levels of these symptoms significantly more likely than Vietnam Veterans to also experience more severe PTSD.

CONCLUSION

Findings are consistent with previous research demonstrating the relationship of somatic symptoms and PTSD across service eras but provide additional data concerning similarities and differences of somatic symptoms between eras. Potential explanations for observed service era differences in somatic symptoms are discussed.

Sex Differences in Arm Muscle Fatigability With Cognitive Demand in Older Adults

BACKGROUND

Muscle fatigability can increase when a stressful, cognitively demanding task is imposed during a low-force fatiguing contraction with the arm muscles, especially in women. Whether this occurs among older adults (>60 years) is currently unknown.

QUESTIONS/PURPOSES

We aimed to determine if higher cognitive demands, stratified by sex, increased fatigability in older adults (>60 years). Secondarily, we assessed if varying cognitive demand resulted in decreased steadiness and was explained by anxiety or cortisol levels.

METHODS

Seventeen older women (70±6 years) and 13 older men (71±5 years) performed a sustained, isometric, fatiguing contraction at 20% of maximal voluntary contraction until task failure during three sessions: high cognitive demand (high CD=mental subtraction by 13); low cognitive demand (low CD=mental subtraction by 1); and control (no subtraction).

RESULTS

Fatigability was greater when high and low CD were performed during the fatiguing contraction for the women but not for the men. In women, time to failure with high CD was 16±8 minutes and with low CD was 17±4 minutes, both of which were shorter than time to failure in control contractions (21±7 minutes; high CD mean difference: 5 minutes [95% confidence interval {CI}, 0.78-9.89], p=0.02; low CD mean difference: 4 minutes [95% CI, 0.57-7.31], p=0.03). However, in men, no differences were detected in time to failure with cognitive demand (control: 13±5 minutes; high CD mean difference: -0.09 minutes [95% CI, -2.8 to 2.7], p=1.00; low CD mean difference: 0.75 minutes [95% CI, -1.1 to 2.6], p=0.85). Steadiness decreased (force fluctuations increased) more during high CD than control. Elevated anxiety, mean arterial pressure, and salivary cortisol levels in both men and women did not explain the greater fatigability during high CD.

CONCLUSIONS

Older women but not men showed marked increases in fatigability when low or high CD was imposed during sustained static contractions with the elbow flexor muscles and contrasts with previous findings for the lower limb. Steadiness decreased in both sexes when high CD was imposed.

CLINICAL RELEVANCE

Older women are susceptible to greater fatigability of the upper limb with heightened mental activity during sustained postural contractions, which are the foundation of many work-related tasks.

Measuring mechanical pain: the refinement and standardization of pressure pain threshold measurements

Pain thresholds are widely used in behavioral research, but unlike other pain modalities, a standardized assessment of pressure pain remains a challenge. In this research, we describe the application of an automatic pressure algometer with a linear increase in force. Ergonomically designed fixation devices were developed to increase the accuracy and to shorten the time of each measurement. Ten healthy volunteers were included in a pilot study to test the algometry method. Pressure pain thresholds (PPTs) were investigated over 2 experimental days in three nonconsecutive runs at 29 measurement sites. During the experiment, subjects reported their subjective sleepiness, level of state-anxiety, psychological status and the perceived pain intensity of each measurement. Pain intensity ratings indicate that instructions were followed. State-anxiety and subjective sleepiness levels were low throughout the experiment. The method has proven to be suitable for standardized PPT measurements across the body in an ergonomic, safe, and user-friendly fashion.

Impact of physical activity on pain perception in an animal model of endometriosis

BACKGROUND

Symptoms of endometriosis, such as pain and infertility, are considered significant sources of stress. In many chronic conditions, exercise can act as a stress buffer and influence pain perception. We tested the impact of swimming exercise on pain perception and pain receptors in an animal model of endometriosis.

METHODS

Endometriosis (Endo) was induced in female rats by suturing uterine horn tissue next to the intestinal mesentery. Sham rats received sutures only. Rats were exposed to swimming exercise for 7 consecutive days, while no-exercise rats were left in the home cage. Fecal pellets were counted after swimming as an index of anxiety, and serum corticosterone levels measured. Pain perception was assessed using the hot plate test for hyperalgesia and Von Frey test for allodynia. Mu-opioid receptor (MOR) and neurokinin-1 receptor expression in the spinal cord was measured by immunofluorescence.

RESULTS

Fecal pellet counts were higher in those animals that swam (p<0.05), but no significant difference in corticosterone was found. Although Endo-exercise rats had higher colonic damage (p<0.05) with more cellular infiltration, the lesions were smaller than in Endo-no exercise rats (p<0.05). Exercise did not ameliorate the hyperalgesia, whereas it improved allodynia in both groups. MOR expression was significantly higher in Endo-exercise vs. Endo-no exercise rats (p<0.01), similar to Sham-no exercise levels.

CONCLUSIONS

Our results point toward beneficial effects of swimming exercise during endometriosis progression. Physical interventions might be investigated further for their ability to reduce perceived stress and improve outcomes in endometriosis.

Muscle fatigability and control of force in men with posttraumatic stress disorder

INTRODUCTION

Acute stress can increase fatigability and decrease steadiness of sustained low-force contractions that are required for functional tasks in upper limb muscles. Whether motor performance is more impaired in people with a chronic stress disorder is not known.

PURPOSE

This study compared the fatigability and steadiness (force fluctuations) of handgrip muscles in veterans with posttraumatic stress disorder (PTSD) and civilian controls in the presence and absence of varying levels of cognitive demand.

METHODS

Eighteen veterans with PTSD and 21 healthy controls (33 ± 9 yr) attended three randomized experimental sessions to perform an isometric fatiguing contraction (20% of maximal strength) with the handgrip muscles. Two sessions involved performing a cognitive task during the fatiguing contraction: 1) difficult mental math task (stressor) and 2) a simple mental math task (mental attentiveness). A third session involved a fatiguing contraction with no mental task (control).

RESULTS

Stress elevated heart rate, blood pressure, and levels of anxiety in veterans with PTSD (P < 0.05) but blunted cortisol levels (P < 0.05). Time to failure was briefer (7.2 ± 2.5 vs 9.3 ± 5.2 min, P = 0.03), and force fluctuations increased at a greater rate for veterans with PTSD than for controls (P < 0.05). Cognitive stress did not influence time to failure or force fluctuations for either group (P > 0.05).

CONCLUSIONS

Veterans with PTSD demonstrated greater fatigability and loss of steadiness (greater force fluctuations) of the handgrip muscles compared with healthy controls.

SIGNIFICANCE

Male veterans with PTSD demonstrated altered neuromuscular function of arm muscles that potentially affects functional tasks during daily, ergonomic, and military activities.

No effects of hydrocortisone and dexamethasone on pain sensitivity in healthy individuals

BACKGROUND

There is some evidence that stress-induced cortisol increase leads to a decrease in pain, while lowering cortisol levels enhances pain sensitivity, but no study has yet investigated both pharmacological enhancement and reduction of cortisol levels in the same individuals.

METHODS

Firstly, we tested in 16 healthy individuals whether the treatment with hydrocortisone and dexamethasone, respectively, results in altered pain thresholds. Secondly, we aimed to test whether hormone effects are different across the pain range by using ratings for pain stimuli with varying intensity; and thirdly, we tested whether cortisol levels influence the discrimination ability for painful stimuli.

RESULTS

Despite substantial effects of dexamethasone and hydrocortisone administration on cortisol levels, no effect of these drugs was seen in terms of pain sensitivity (pain threshold, pain rating, pain discrimination ability), although comprehensively examined. However, in the placebo condition, a significant negative correlation between cortisol and pain thresholds was seen. Similarly, there were also strong negative associations between cortisol levels in the placebo condition and pain thresholds after drug treatment (especially after hydrocortisone).

CONCLUSION

These findings suggest that short-term variations of cortisol do not influence pain sensitivity whereas, in general, high levels of cortisol are associated with increased pain sensitivity, at least for weak to moderate stimuli.

Effectiveness of jyoti meditation for patients with chronic neck pain and psychological distress--a randomized controlled clinical trial

Chronic neck pain is a common medical complaint partly mediated by psychosocial distress and having a high socioeconomic impact. There is preliminary evidence that stress reduction by meditation might be beneficial in chronic pain syndromes. We aimed to evaluate the effectiveness of an 8-week meditation program (jyoti meditation) in patients with chronic neck pain by means of a randomized clinical trial. Eighty-nine patients (aged 49.7 ± 10.5 years, 73 female) with chronic neck pain who scored >40 mm on a 100-mm visual analog scale and had concomitant increased perceived stress were randomized to an 8-week meditation program (jyoti meditation) with weekly 90-minute classes (n = 45) or to a home-based exercise program (n = 44) with a wait list offer for meditation. Both groups were instructed to practice at home. Outcomes were assessed at baseline and after 8 weeks. Primary outcome measure was change of mean pain at rest (visual analog scale score) from baseline to week 8. Secondary outcomes included pain at motion, functional disability, pain-related bothersomeness, perceived stress, quality of life, and psychological outcomes. Patients had neck pain for a mean of 11 years. Eighteen patients in the meditation group and 16 patients in the exercise group were lost to follow-up. Meditation training significantly reduced pain when compared to the exercise group after 8 weeks (reduction of 45.5 ± 23.3 mm to 21.6 ± 17.2 mm in the meditation group, and 43.8 ± 22.0 mm to 37.7 ± 21.5 mm in the exercise group; mean difference: 13.2 mm [95% confidence interval: 2.1, 24.4; P = .02]). Pain-related bothersomeness decreased more in the meditation group (group difference 11.0 mm [95% confidence interval: 1.0, 21.0; P = .03]). No significant treatment effects were found for pain at motion, psychological scores, and quality of life, although the meditation group showed nonsignificant greater improvements compared to the exercise group. In conclusion, meditation may support chronic pain patients in pain reduction and pain coping. Further well-designed studies including more active control comparisons and longer-term follow-up are warranted.

PERSPECTIVE

This article presents the results of a randomized controlled trial on the clinical effects of an 8-week meditation program or self-care exercise in patients with chronic neck pain. Meditation reduced pain at rest but not disability and might be a useful treatment option for pain management of chronic neck pain.

Acute psychosocial stress reduces pain modulation capabilities in healthy men

Anecdotes on the ability of individuals to continue to function under stressful conditions despite injuries causing excruciating pain suggest that acute stress may induce analgesia. However, studies exploring the effect of acute experimental stress on pain perception show inconsistent results, possibly due to methodological differences. Our aim was to systematically study the effect of acute stress on pain perception using static and dynamic, state-of-the-art pain measurements. Participants were 29 healthy men who underwent the measurement of heat-pain threshold, heat-pain intolerance, temporal summation of pain, and conditioned pain modulation (CPM). Testing was conducted before and during exposure to the Montreal Imaging Stress Task (MIST), inducing acute psychosocial stress. Stress levels were evaluated using perceived ratings of stress and anxiety, autonomic variables, and salivary cortisol. The MIST induced a significant stress reaction. Although pain threshold and pain intolerance were unaffected by stress, an increase in temporal summation of pain and a decrease in CPM were observed. These changes were significantly more robust among individuals with stronger reaction to stress ("high responders"), with a significant correlation between the perception of stress and the performance in the pain measurements. We conclude that acute psychosocial stress seems not to affect the sensitivity to pain, however, it significantly reduces the ability to modulate pain in a dose-response manner. Considering the diverse effects of stress in this and other studies, it appears that the type of stress and the magnitude of its appraisal determine its interactions with the pain system.

Functional brain imaging in gastroenterology: to new beginnings

With more than 100 studies published over the past two decades, functional brain imaging research in gastroenterology has become an established field; one that has enabled improved insight into the supraspinal responses evoked by gastrointestinal stimulation both in health and disease. However, there remains considerable inter-study variation in the published results, largely owing to methodological differences in stimulation and recording techniques, heterogeneous patient selection, lack of control for psychological factors and so on. These issues with reproducibility, although not unique to studies of the gastrointestinal tract, can lead to unjustified inferences. To obtain consistent and more clinically relevant results, there is a need to optimize and standardize brain imaging studies across different centres. In addition, the use of complementary and more novel brain imaging modalities and analyses, which are now being used in other fields of research, might help unravel the factors at play in functional gastrointestinal disorders. This Review highlights the areas in which functional brain imaging has been useful and what it has revealed, the areas that are in need of improvement, and finally suggestions for future directions.

Modulation of intracortical inhibition in response to acute psychosocial stress is impaired among individuals with chronic neck pain

OBJECTIVE

Psychosocial stress has been associated with a variety of chronic pain disorders although the mechanisms responsible for this relationship are unknown. The purpose of this study was to compare the excitability of intracortical and corticospinal pathways to the trapezius muscle in individuals with and without chronic neck pain during exposure to low and high levels of psychosocial stress.

METHODS

Single and paired-pulse transcranial magnetic stimulation was used to assess motor evoked potentials (MEPs) and short-interval intracortical inhibition (SICI) during mental math performed in the presence and absence of social evaluative threat.

RESULTS

All participants demonstrated higher amplitude MEPs in the high stress compared to the low stress condition (p < 0.01). Participants with chronic neck pain had significantly greater SICI than healthy participants in the low stress condition (p = 0.03). During exposure to the stressor, healthy participants showed an increase in SICI, whereas participants with neck pain showed no change (group difference for change in SICI, p < 0.01).

CONCLUSIONS

These findings suggest that individuals with chronic neck pain inhibit motor output to the trapezius in the presence of minor stressors, and are unable to compensate for additional stress-evoked increases in corticospinal excitability through further modulation of SICI. This observation has potential implications for the management of patients who have difficulty relaxing painful muscles during times of stress.

Palmar skin conductance variability and the relation to stimulation, pain and the motor activity assessment scale in intensive care unit patients

Introduction

Many intensive care unit (ICU) patients describe pain and other adverse feelings that may impact long-term psychological morbidity. Sympathetically mediated palmar skin conductance variability is related to emotionally induced perspiration and correlates with pain levels in the perioperative setting but has not been studied in ICU patients.

Methods

Twenty non-intubated and 20 intubated general ICU patients were included in this observational study. Patients were monitored with the MED-STORM Pain Monitoring System^®. The number of skin conductance fluctuations per second (NSCF) was measured in parallel with bedside observation during one hour of intensive care, including rest, procedures and patient-staff interactions. Arousal-agitation level was monitored with the motor activity assessment scale (MAAS). Pain was monitored with the numeric rating scale (0 to 10) in patients able to communicate or by observation in patients unable to communicate.

Results

In non-intubated patients, NSCF increased with increasing stimulation/pain but also with higher MAAS (P = 0.002). An interaction effect was found, with increased NSCF response to stimulation/pain with increasing MAAS (P < 0.001).

In intubated patients, NSCF increased significantly with increasing stimulation/pain (P < 0.001). In contrast to non-intubated patients, no difference in NSCF between MAAS levels was found for any given degree of stimulation in intubated patients.

Conclusions

In critically ill patients, NSCF may be more useful evaluating emotional distress rather than pain alone. It needs to be assessed whether NSCF monitoring is clinically useful and whether controlling emotional distress with the aid of such monitoring may impact on patient care and outcomes.

Clinical stress assessment using a visual analogue scale

BACKGROUND

Clinicians increasingly require short, efficient methods for assessing distress, both in applied research and clinical settings. Most of the available questionnaires are unsuitable for busy clinical settings. The visual analogue scale (VAS) is widely but empirically used to assess perceived stress.

AIMS

To provide evidence on two of the psychometric properties of the VAS: its discriminative sensitivity (capacity to highlight a difference between groups) and its interconcept validity (the relationship between VAS stress assessment and the assessment of different, but similar concepts).

METHODS

Employees attending occupational health centres were randomly selected and completed the VAS and also either the Perceived Stress Scale (PSS) or the Hospital Anxiety and Depression Scale (HADS). Analyses of variance were performed to study group effects (age, sex, marital status, parental status, occupational status) on stress scores (PSS and VAS).

RESULTS

In total, 763 employees participated of whom 501 completed the PSS and 262 the HADS. P-values obtained for the effects of sex, age and occupational status were lower with the VAS than with the PSS. Correlations between the VAS and the anxiety subscale, depression subscale and total score of the HADS were 0.66, 0.45 and 0.65, respectively. Other tools used to assess aspects of psychological distress are known to have similar correlations.

CONCLUSIONS

Our findings provide evidence that the VAS is at least as discriminating as a questionnaire when it comes to highlighting differences in stress levels between two groups, and the observed correlations with related constructs support its construct validity.

Acute psychosocial stress: does the emotional stress response correspond with physiological responses?

Most stress experiences are accompanied by physiological and psychological responses. Laboratory stressors such as the Trier Social Stress Test (TSST) induce reliable stress responses, which are mainly assessed for biological parameters such as cortisol. The associations between physiological and psychological responses to the TSST have been rarely investigated and are addressed in this review. Up to August 2011, 358 studies were published in PubMed examining the impact of the TSST (71%) or variations of the protocol. A total of 49 studies were considered based on the following three inclusion criteria: (1) exposure to the standard TSST or slightly modified TSST versions, (2) at least one assessment of subjective emotional stress experience before, during or after the TSST, (3) reported associations between acute physiological and emotional stress measures. Significant correlations between cortisol responses and perceived emotional stress variables were found in approximately 25% of the studies. Our descriptive analysis revealed various essential elements that potentially contribute to this apparent dissociation, reaching from differing assessment approaches and methodological features of the stress protocols to possible mediating factors and interindividual differences in the degree of psychophysiological correspondence.

Skill execution and sleep deprivation: effects of acute caffeine or creatine supplementation - a randomized placebo-controlled trial

BACKGROUND

We investigated the effects of sleep deprivation with or without acute supplementation of caffeine or creatine on the execution of a repeated rugby passing skill.

METHOD

Ten elite rugby players completed 10 trials on a simple rugby passing skill test (20 repeats per trial), following a period of familiarisation. The players had between 7-9 h sleep on 5 of these trials and between 3-5 h sleep (deprivation) on the other 5. At a time of 1.5 h before each trial, they undertook administration of either: placebo tablets, 50 or 100 mg/kg creatine, 1 or 5 mg/kg caffeine. Saliva was collected before each trial and assayed for salivary free cortisol and testosterone.

RESULTS

Sleep deprivation with placebo application resulted in a significant fall in skill performance accuracy on both the dominant and non-dominant passing sides (p < 0.001). No fall in skill performance was seen with caffeine doses of 1 or 5 mg/kg, and the two doses were not significantly different in effect. Similarly, no deficit was seen with creatine administration at 50 or 100 mg/kg and the performance effects were not significantly different. Salivary testosterone was not affected by sleep deprivation, but trended higher with the 100 mg/kg creatine dose, compared to the placebo treatment (p = 0.067). Salivary cortisol was elevated (p = 0.001) with the 5 mg/kg dose of caffeine (vs. placebo).

CONCLUSION

Acute sleep deprivation affects performance of a simple repeat skill in elite athletes and this was ameliorated by a single dose of either caffeine or creatine. Acute creatine use may help to alleviate decrements in skill performance in situations of sleep deprivation, such as transmeridian travel, and caffeine at low doses appears as efficacious as higher doses, at alleviating sleep deprivation deficits in athletes with a history of low caffeine use. Both options are without the side effects of higher dose caffeine use.

Anxiety disorders in headache patients in a specialised clinic: prevalence and symptoms in comparison to patients in a general neurological clinic

Data from several studies indicate an association of headache with anxiety disorders. In this study, we assessed and differentiated anxiety disorders in 100 headache patients by using the PSWQ (Penn State Worry Questionnaire) screening tool for generalised anxiety disorder (GAD) and the ACQ (Agoraphobic Cognitions Questionnaire) and BSQ (Body Sensation Questionnaire) for panic disorder (PD). Control groups were constructed: (1) on the basis of epidemiological studies on PD and GAD in the general population and (2) by including neurological patients. 37.0% of headache patients had a GAD. 27% of headache patients met the score for PD in the BSQ, 4.0% in the ACQ. Significant results were obtained in comparison to the general population (p < 0.001) and with regard to GAD in comparison with a sample of neurological patients (p < 0.005). The BSQ significantly correlated with the number of medication days (p < 0.005). The results confirm the increased prevalence of GAD in headache patients. PD seems to increase the risk of medication overuse.

Pain perception after isometric exercise in women with fibromyalgia

OBJECTIVE

The purpose of this study was to identify exercise protocols incorporating isometric contractions that provide pain relief in women with fibromyalgia.

DESIGN

A before-after trial.

SETTING

A physical therapy department in an academic setting.

PARTICIPANTS

Fifteen women (mean ± SD, 52±11y) with fibromyalgia.

INTERVENTIONS

Subjects completed 4 sessions: 1 familiarization and 3 experimental. The following randomized experimental sessions involved the performance of isometric contractions with the elbow flexor muscles that varied in intensity and duration: (1) 3 maximal voluntary contractions (MVCs), (2) 25% MVC held to task failure, and (3) 25% MVC held for 2 minutes.

MAIN OUTCOME MEASURES

Experimental pain (pain threshold and pain rating), Fibromyalgia Impact Questionnaire, and fibromyalgia pain intensity (visual analog scale).

RESULTS

After all 3 isometric contractions, there was considerable variability between subjects in the pain response. Based on the changes in experimental pain, subjects were divided into 3 groups (increase, decrease, no change in pain). Multiple regression analysis revealed that age, baseline experimental pain, and change in fibromyalgia pain intensity were significant predictors of the experimental pain response after the isometric contractions.

CONCLUSIONS

We identified subgroups of women with fibromyalgia based on how they perceived pain after isometric contractions. The greatest pain relief for women with fibromyalgia occurred at a younger age and in women with the greatest experimental pain before exercise. Additionally, we established a link between experimental and clinical pain relief after the performance of isometric contractions.