Gender differences in pain: do emotions play a role?

Mind over chronic pain: A meta-analysis of cognitive restructuring in chronically ill adults

OBJECTIVE

This meta-analysis synthesizes research on the impact of cognitive restructuring on chronic pain intensity, aiming to integrate diverse methodologies and findings while evaluating potential moderators.

METHODS

Following PRISMA guidelines, we systematically searched multiple databases (PubMed, Web of Science, JSTOR, Sage, Social Science Research Network, PsycArticles, ScienceDirect, and Education Resources Information Center) until July 2023. Studies involving adults (≥18 years) diagnosed with chronic conditions who underwent cognitive restructuring to reduce chronic pain intensity, were included. Eligible studies compared this intervention with a control group. We excluded studies incorporating cognitive restructuring within broader interventions, lacking statistical data, or not written in English. Study quality was assessed using the Cochrane Risk of Bias tool (RoB 2).

RESULTS

After reviewing 18,312 studies, we selected 11 studies published between 1991 and 2022, involving 693 participants with chronic conditions. A significant large overall effect size was found (d = 0.94, 95% CI 0.48 to 1.40). Moderation analyses revealed significant differences based on sex and study quality, with effects less pronounced among females and more substantial in higher-quality studies.

CONCLUSION

Despite limitations such as statistical instability due to a small number of studies in certain moderator categories and methodological variability, this meta-analysis highlights the robust effects of cognitive restructuring on chronic pain intensity. The findings are valuable for guiding power calculations and future research expectations. Clinically, these results support the significant effect of cognitive restructuring in both individual and group settings, regardless of age, particularly when facilitated by teams that include psychologists.

Biobehavioral Predictors of Pain Intensity, Pain Interference, and Chronic Pain Episodes: A Prospective Cohort Study of African-American Adults

Racial disparities in pain experiences are well-established, with African-American (AA) adults reporting higher rates of daily pain, increased pain severity, and greater pain-related interference compared to non-Hispanic Whites. However, the biobehavioral factors that predict the transition to chronic pain among AA adults are not well understood. This prospective cohort study provided a unique opportunity to evaluate predictors of chronic pain onset among 130 AA adults (81 women), ages 18 to 44, who did not report chronic pain at their baseline assessment and subsequently completed follow-up assessments at 6- and 12-months. Outcome measures included pain intensity, pain-related interference, and chronic pain status. Comprehensive assessments of sociodemographic and biobehavioral factors were used to evaluate demographics, socioeconomic status, stress exposure, psychosocial factors, prolonged hypothalamic-pituitary-adrenal secretion, and quantitative sensory testing responses. At baseline, 30 adults (23.1%) reported a history of prior chronic pain. Over the 12-month follow-up period, 13 adults (10.0%) developed a new chronic pain episode, and 18 adults (13.8%) developed a recurrent chronic pain episode. Whereas socioeconomic status measures (ie, annual income, education) predicted changes in pain intensity over the follow-up period, quantitative sensory testing measures (ie, pain threshold, temporal summation of pain) predicted changes in pain interference. A history of chronic pain and higher depressive symptoms at baseline independently predicted the onset of a new chronic pain episode. The present findings highlight distinct subsets of biobehavioral factors that are differentially associated with trajectories of pain intensity, pain-related interference, and onset of chronic pain episodes in AA adults. PERSPECTIVE: This prospective study sought to advance understanding of biobehavioral factors that predicted pain outcomes over a 12-month follow-up period among AA adults without chronic pain at their initial assessment. Findings revealed distinct subsets of factors that were differentially associated with pain intensity, pain-related interference, and onset of chronic pain episodes.

The effect of emotion regulation on the emotional modulation of pain and nociceptive flexion reflex

ABSTRACT

Positive emotions inhibit pain, whereas negative emotions facilitate pain. Thus, many psychosocial interventions capitalize on this emotion-pain relationship to improve patients' abilities to regulate emotion (ie, reduce negative emotion, increase positive emotion), influence nociception, and manage pain. This study extended the existing literature to examine whether emotion regulation procedures could influence emotional modulation of the nociceptive flexion reflex (NFR), a marker of spinal nociception. To elicit emotion, 2 blocks of pleasant, neutral, and unpleasant pictures were presented. In block 1, participants were asked to passively view pictures during which painful electric stimulations were delivered to evoke pain and the NFR. Valence, arousal, corrugator electromyogram, and skin conductance response were used to measure emotional responses to pictures. To manipulate emotion regulation, participants were randomized to either suppress (downregulate) or enhance (upregulate) their emotion during block 2 (other procedures same as block 1). Instructions to suppress decreased subjective and physiological responding to emotional pictures, reduced emotional modulation of pain, and generally decreased NFR magnitude (regardless of picture content). Instructions to enhance emotion increased subjective responding to emotional pictures but did not alter physiological responding to pictures or emotional modulation of pain/NFR in predictable ways. Results imply that downregulation/suppression of negative emotions may work best to reduce pain facilitation. Furthermore, this study contributes to the existing literature that shows that pain and pain signaling is tightly coupled with emotional states and that emotion regulation can impact pain perception.

The relationship between gender, psychosocial factors, pain, health literacy and health-related quality of life in parents of Norwegian adolescents one year into the COVID-19 pandemic

BACKGROUND

Stress impacts healthy behaviours and may influence life and health-related quality of life (HRQOL). A stressful event occurred when the COVID-19 pandemic hit in March 2020. The present study aims to explore possible gender differences in stress, psychosocial factors (self-efficacy, self-esteem, loneliness), pain, HL, and HRQOL in parents of adolescents one year into the COVID-19 pandemic, and to explore possible associations between gender, demographic and psychosocial factors, pain, HL, and HRQOL.

METHODS

Parents of adolescents aged 16-17 took part in the study from January to February 2021, when the COVID-19 pandemic was ongoing. Data on socio-demographics, stress, self-efficacy, self-esteem, pain, HL, loneliness, and HRQOL were collected. HRQOL was assessed using RAND-36.

RESULTS

Among the 320 parents from the general population, the mean age was 47.6 (standard deviation (SD) = 4.6) years, 81% were mothers, 79% were married or cohabiting, 81% had a university degree, and the majority worked full time (78%) or part time (13%). The average pain score was low, 0.48 (95% CI [0.43-0.54]). However, 50% of the parents reported persistent pain and more mothers reported persistent pain compared to fathers (53% vs. 37%). The parents' mean (SD) score for RAND-36 was 52.1 (95% CI [51.2-53.0]) for the physical component summary (PCS) score and 51.0 (95% CI [50.0-52.1]) for the mental component summary (MCS) score. Mothers reported significantly lower scores for all the eight RAND-36 domains and the PCS and MCS scores. Adjusting for gender, age, living condition, education, pain, HL, self-efficacy and loneliness, we revealed no associations between stress and RAND-36-PCS. University education of four years or more was positively associated (B = 3.29, 95% CI: [0.78-5.80]) with RAND-36-PCS, while persistent pain was negatively associated (B = -7.13, CI: [-9.20- -5.06]). We identified a strong negative association between RAND-36-MCS and stress (B = -43.11, CI: [-48.83- -37.38]) and a positive association with older age (B = 0.21, CI: [ 0.04, 0.39)].

CONCLUSION

One year into the COVID-19 pandemic, we identified a strong negative association between stress and mental HRQOL, while pain was strongly negatively associated with physical HRQOL.

The effect of experimental emotion induction on experimental pain: a systematic review and meta-analysis

ABSTRACT

The idea that emotions can influence pain is generally recognized. However, a synthesis of the numerous individual experimental studies on this subject is lacking. The aim of the present systematic review and meta-analysis was to synthesize the existing evidence on the effect of experimental emotion induction on experimental pain in nonclinical adults. PsycInfo and PubMed were searched up until April 10, 2023, for studies assessing differences in self-reported pain between emotion induction groups and/or control groups or between conditions within group. Risk of bias was assessed for the individual studies. The literature search yielded 78 relevant records of 71 independent studies. When compared with control conditions, the pooled results revealed a statistically significant pain-attenuating effect of positive emotion induction (between-group: Hedges g = -0.48, 95% CI: -0.72; -0.25, K = 9; within-group: g = -0.24, 95% CI: -0.32; -0.15, K = 40), and a statistically significant pain-exacerbating effect of negative emotion induction in within-group analyses but not between-group analyses (between-group: g = -0.29, 95% CI: -0.66; 0.07, K = 10; within-group: g = 0.14, 95% CI: 0.06; 0.23, K = 39). Bayesian meta-analysis provided strong support for an effect of positive emotion induction but weak support for an effect of negative emotion induction. Taken together, the findings indicate a pain-attenuating effect of positive emotion induction, while the findings for negative emotion induction are less clear. The findings are discussed with reference to theoretical work emphasizing the role of motivational systems and distraction for pain. Limitations include considerable heterogeneity across studies limiting the generalizability of the findings.

Physical activity, sitting time, and thermal quantitative sensory testing responses in African Americans

Introduction

Prior research suggests that African Americans (AAs) have more frequent, intense, and debilitating pain and functional disability compared with non-Hispanic Whites (NHWs). Potential contributing factors to this disparity are physical activity and sedentary behavior, given that AAs are less physically active, and physical activity is associated with antinociception (whereas sedentary behavior is linked to pronociception). However, impact of these factors on pain processing has largely been unexplored in AAs, especially before chronic pain onset.

Objective

This study examined relationships between physical activity, sedentary behavior (sitting time), and laboratory measures of pain and pain modulation in adult AAs. These included heat pain threshold and tolerance, temporal summation of pain (TSP, a marker of central sensitization), and conditioned pain modulation (CPM, a marker of descending pain inhibition).

Methods

Multiple regressions were conducted to examine the effects of physical activity and sitting time on heat threshold and tolerance. Multilevel models were conducted to assess the relationship between physical activity, sitting time, and temporal summation of pain. Additional multilevel models were conducted to assess the relationship between physical activity, sitting time, and conditioned pain modulation.

Results

Higher level of physical activity, but not sitting time, was associated with reduced TSP slopes. Neither physical activity nor sitting time was associated with CPM slopes. No significant relationships between physical activity or sitting time and heat pain threshold or tolerance were detected.

Conclusions

These findings suggest that physical activity is associated with reduced TSP, an effect which may be driven by reduced spinal hyperexcitability in more active individuals. Thus, structural and individual interventions designed to increase physical activity in healthy, young AAs may be able to promote antinociceptive processes (ie, reduced TSP/reduced pain facilitation) potentially protective against chronic pain.

Electrophysiological correlates of semantic pain processing in the affective priming

Introduction

Pain plays a fundamental role in the well-being of the individual, and its semantic content may have specific properties compared to other negative domains (i.e., fear and anger) which allows the cognitive system to detect it with priority. Considering the influence of the affective context in which stimuli (targets) are evaluated, it is possible that their valence could be differentially processed if preceded by negative stimuli (primes) associated with pain than negative stimuli not associated with pain. Thus, the present study aims to investigate the electrophysiological correlates of the implicit processing of words with pain content by using an affective priming paradigm.

Methods

Event-related potentials (ERPs) were recorded while participants were presented with positive and negative word targets (not associated with pain) that were preceded by positive, negative (not associated with pain), and pain word primes. Participants were asked to judge the valence of the target word.

Results

Results showed faster reaction times (RTs) in congruent conditions, especially when the negative target was preceded by a pain prime rather than a positive one. ERPs analyses showed no effect of pain at an early-stage processing (N400), but a larger waveform when the pain prime preceded the positive prime on the LPP.

Discussion

These results reaffirm the importance that valence has in establishing the priority with which stimuli are encoded in the environment and highlight the role that pain has in the processing of stimuli, supporting the hypothesis according to which the valence and the semantics of a stimulus interact with each other generating a specific response for each type of emotion.

Gender differences in interactions and depressive symptoms among hospitalized older patients living with dementia

Alzheimer's disease or a related dementia (ADRD) disproportionately affects women with two-thirds of individuals with ADRD comprised of women. This study examined gender-related differences in the quality of staff-patient interactions and depressive symptoms among hospitalized older patients living with dementia. This secondary analysis utilized baseline data of 140 hospitalized older patients with dementia who participated in the final cohort of a randomized controlled trial (ClinicalTrials.gov identifier: NCT03046121) implementing Family centered Function-focused Care (Fam-FFC). On average, the participants (male = 46.1%, female = 52.9%) were 81.43 years old (SD = 8.29), had positive interactions with staff and lower depressive symptoms based on Quality of Interaction Schedule (QUIS) scores and Cornell Scale for Depression in Dementia (CSDD) scores, respectively. Although males had more positive interactions (male = 6.06, SD = 1.13; female = 5.59, SD = 1.51) and lesser depressive symptoms (male = 7.52, SD = 4.77; female = 8.03, SD = 6.25) than females, no statistically significant gender differences were observed in linear models with appropriate covariates or multivariant analysis of covariant (MANCOVA). However, the multigroup regression conducted to further probe marginally significant moderation effect of gender and pain on staff-patient interactions demonstrated that greater pain was significantly related to lower quality or less positive staff-patient interactions for females compared to males (χ2diff (1) = 4.84, p = .03). Continued evaluation of gender differences is warranted to inform care delivery and interventions to improve care for hospitalized older patients with dementia.

Do Men and Women Have a Different Association between Fear-Avoidance and Pain Intensity in Chronic Pain? An Experience Sampling Method Cohort-Study

Background: Fear-avoidance is one of the factors associated with chronic pain. However, it remains unclear whether the association between fear-avoidance and pain depends on sex. The present study aimed to investigate whether the association between fear-avoidance and pain intensity differed between men and women in chronic pain patients. Additionally, the potential confounding effect of affective experiences on the association between fear-avoidance and pain intensity was analyzed. Method: This cohort study included hospital referred chronic pain patients (n = 45). Short momentary assessment questions according to the experience sampling method (ESM) were used to repeatedly assess patients’ pain intensity, level of fear-avoidance and positive as well as negative affect during their daily life. Linear mixed-effects models were applied in the statistical analysis. Unadjusted and adjusted models were made, in which the latter corrected for statistically significant affective experiences and baseline variables, taking the Aikake Information Criterion into account to assess a better model of fit. Results: The results demonstrated an association between fear-avoidance and pain intensity that differed for men and women. In men (n = 13), no association between these variables was found (−0.04 (95% CI: −0.14, 0.06) with a p-value of 0.48), whereas in women (n = 32), an increase in fear-avoidance was associated with a (slight) increase in pain intensity (0.18 (95% CI 0.06, 0.30) with a p-value of 0.003). Affect did not confound the above-mentioned findings. Conclusion: Our data supports previous research highlighting the importance of sex differences in pain experience. These findings may be relevant for clinicians to consider more personalized (i.e., gender specific) pain management in chronic pain patients.

Effects of psychosocial stress and performance feedback on pain processing and its correlation with subjective and neuroendocrine parameters

OBJECTIVES

Previous research on stress-induced pain modulation suggests that moderate psychological stress usually leads to hyperalgesia while more severe threat results in hypoalgesia. However, existing studies often lack suitable control conditions imperative to identify mere stress effects. Similarly, research mainly focused on pure anticipation of a social threat, not taking into consideration actual experiences of social evaluation. Therefore, we set out to investigate actual social up- and downgrading combined with a standardized stress paradigm to evaluate short-term and prolonged changes in pain perception and their potential association with neuroendocrine and subjective stress parameters.

METHODS

We allocated 177 healthy women to four experimental conditions, either the standard version of the Trier Social Stress Test (TSST) followed by positive, negative or no performance feedback, or a well-matched but less demanding placebo version of the TSST. Stress responses were assessed with ratings, salivary alpha-amylase, and salivary cortisol. To capture putative effects of stress on pain, heat pain threshold, ratings of phasic heat pain stimuli, and conditioned pain modulation were measured.

RESULTS

Despite a largely successful stress induction, results do not support a reliable influence of experimentally induced social stress-with or without subsequent performance feedback-on pain in women. Further, we found no clear association of pain modulation and changes in neuroendocrine or subjective stress responses.

CONCLUSIONS

Our results contrast previous studies, which repeatedly demonstrated stress-induced hypo- or hyperalgesia. This might be due to methodological reasons as former research was often characterized by high heterogeneity regarding the applied stressors, low sample sizes, and lacking or inconclusive control conditions. Thus, our results raise the question whether pain modulation in women by experimental psychosocial stress might have been overestimated in the past. Future research is necessary, which should employ parametric stress induction methods including well-matched control tasks, taking into consideration the participants' gender/sex and the time course of the stress response relative to pain assessment. The study is registered as DRKS00026946 at 'Deutsches Register Klinischer Studien' (DRKS) and can be also found at the World Health Organization's search portal.

Does Gender Moderate the Relationship Between Chronic Pain and Substance Use Disorder? Insights From a National Canadian Population Survey

BACKGROUND

Though it has been shown that men have a higher lifetime prevalence of substance use disorder and a lower prevalence of chronic pain than women, there is little research to date focusing on gender differences in the relationship between chronic pain and substance use disorder. This study examined whether gender moderates the relationship of chronic pain and substance use disorder. We also sought to examine the gender differences in the associations between specific pain types-arthritis, migraine, and back pain, and substance use disorder.

METHODS

The data were drawn from the 2012 Canadian Community Health Survey-Mental Health (CCHS-MH 2012) with individuals aged 20 years and older living in the 10 Canadian provinces (N = 23,089). A two-level logistic mixed effects model was used to account for provincial differences.

RESULTS

Our findings indicated gender moderated the association between arthritis as well as migraine, and substance use disorder. However, no moderation effect of gender on the relationship between back pain and substance use disorder was found. Specifically, the strength of the association between arthritis and substance use disorder was stronger among men (OR_interaction = 0.62, 95% CI: 0.53 to 0.73), whereas the strength of the association between migraine and substance use disorder was stronger among women (OR_interaction = 1.45, 95% CI: 1.18 to 1.79). In addition, geographical location was found to explain a small proportion (2.3%-2.4%) of the overall variance in SUD.

CONCLUSIONS

The results suggest that gender moderated the relations between arthritis as well as migraine, and substance use disorder, respectively. Treatment programs for pain and substance misuse might benefit from an approach tailored to gender differences.

Racial and weight discrimination associations with pain intensity and pain interference in an ethnically diverse sample of adults with obesity: a baseline analysis of the clustered randomized-controlled clinical trial the goals for eating and moving (GEM) study

BACKGROUND

Everyday experiences with racial (RD) and weight discrimination (WD) are risk factors for chronic pain in ethnically diverse adults with obesity. However, the individual or combined effects of RD and WD on pain in adults with obesity is not well understood. There are gender differences and sexual dimorphisms in nociception and pain, but the effect of gender on relationships between RD, WD, and pain outcomes in ethnically diverse adults with obesity is unclear. Thus, the purposes of this study were to: 1) examine whether RD and WD are associated with pain intensity and interference, and 2) explore gender as a moderator of the associations between RD, WD, and pain.

METHODS

This is a baseline data analysis from a randomized, controlled clinical trial of a lifestyle weight-management intervention. Eligible participants were English or Spanish-speaking (ages 18-69 years) and had either a body mass index of ≥30 kg/m2 or ≥ 25 kg/m2 with weight-related comorbidity. RD and WD were measured using questions derived from the Experiences of Discrimination questionnaire (EOD). Pain interference and intensity were measured using the PROMIS 29 adult profile V2.1. Linear regression models were performed to determine the associations between WD, RD, gender, and pain outcomes.

RESULTS

Participants (n = 483) reported mild pain interference (T-score: 52.65 ± 10.29) and moderate pain intensity (4.23 ± 3.15). RD was more strongly associated with pain interference in women (b = .47, SE = .08, p < 001), compared to men (b = .14, SE = .07, p = .06). Also, there were no significant interaction effects between RD and gender on pain intensity, or between WD and gender on pain interference or pain intensity.

CONCLUSIONS

Pain is highly prevalent in adults with obesity, and is impacted by the frequencies of experiences with RD and WD. Further, discrimination against adults with obesity and chronic pain could exacerbate existing racial disparities in pain and weight management. Asking ethnically diverse adults with obesity about their pain and their experiences of RD and WD could help clinicians make culturally informed assessment and intervention decisions that address barriers to pain relief and weight loss.

TRIAL REGISTRATION

NCT03006328.

Interaction Between Sex and Cardiac Interoceptive Accuracy in Measures of Induced Pain

Pain perception is influenced by several factors, and among them, affect, sex, and perception of bodily signals are assumed to play a prominent role. The aim of the present study is to explore how sex, cardiac interoceptive accuracy, and the interaction of the latter two influence the perception of experimentally induced pain. We investigated a large sample of young adults (n = 159, 50.9% female, age: 23.45, SD = 3.767), assessing current positive and negative affective state with the Positive and Negative Affect Schedule (both involved as control variables), cardiac interoceptive accuracy with the mental heartbeat tracking task, and pain sensitivity with electrical stimulation on the back of the dominant hand, applying a repeated-measures staircase protocol. Males showed a significantly higher pain threshold and tolerance level than females, whereas cardiac interoceptive accuracy was not associated with pain sensitivity. The impact of sex × cardiac interoceptive accuracy interaction was significant for pain threshold only, while pain tolerance was predicted only by sex. According to these findings, the associations between pain sensitivity, cardiac IAc, and sex might be more complicated than it was supposed in previous studies. Interactions between factors impacting pain perception appear worthy of further investigation.

Reduced behavioral withdrawal responses during fear retrieval in adult mice and rats

Pain triggers emotional changes in humans and animals, including fear and anxiety. Conversely, fear and anxiety may enhance suffering of patients with pain. However, in animal models of acute pain, it has been reported that fear may inhibit pain by activating endogenous inhibitory systems. In this study, we wanted to examine if behavioral withdrawal responses may be affected during fear retrieval, a condition where fear-associated tone is applied. We found that thermal pain thresholds were significantly increased during fear retrieval. Our results indicate that animals are suffering fear like-events, while their behavioral responses are inhibited. These results indicate that it will be important to evaluate both emotional and behavioral withdrawal responses for future development of new pain medicine.

Assessing peripheral fibers, pain sensitivity, central sensitization, and descending inhibition in Native Americans: main findings from the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) have a higher prevalence of chronic pain than other U.S. racial/ethnic groups, but there have been few attempts to understand the mechanisms of this pain disparity. This study used a comprehensive battery of laboratory tasks to assess peripheral fiber function (cool/warm detection thresholds), pain sensitivity (eg, thresholds/tolerances), central sensitization (eg, temporal summation), and pain inhibition (conditioned pain modulation) in healthy, pain-free adults (N = 155 NAs, N = 150 non-Hispanic Whites [NHWs]). Multiple pain stimulus modalities were used (eg, cold, heat, pressure, ischemic, and electric), and subjective (eg, pain ratings and pain tolerance) and physiological (eg, nociceptive flexion reflex) outcomes were measured. There were no group differences on any measure, except that NAs had lower cold-pressor pain thresholds and tolerances, indicating greater pain sensitivity than NHWs. These findings suggest that there are no group differences between healthy NAs and NHWs on peripheral fiber function, central sensitization, or central pain inhibition, but NAs may have greater sensitivity to cold pain. Future studies are needed to examine potential within-group factors that might contribute to NA pain risk.

Pain-related anxiety promotes pronociceptive processes in Native Americans: bootstrapped mediation analyses from the Oklahoma Study of Native American Pain Risk

INTRODUCTION

Evidence suggests Native Americans (NAs) experience higher rates of chronic pain than the general US population, but the mechanisms contributing to this disparity are poorly understood. Recently, we conducted a study of healthy, pain-free NAs (n = 155), and non-Hispanic whites (NHWs, n = 150) to address this issue and found little evidence that NAs and NHWs differ in pain processing (assessed from multiple quantitative sensory tests). However, NAs reported higher levels of pain-related anxiety during many of the tasks.

OBJECTIVE

The current study is a secondary analysis of those data to examine whether pain-related anxiety could promote pronociceptive processes in NAs to put them at chronic pain risk.

METHODS

Bootstrapped indirect effect tests were conducted to examine whether pain-related anxiety mediated the relationships between race (NHW vs NA) and measures of pain tolerance (electric, heat, ischemia, and cold pressor), temporal summation of pain and the nociceptive flexion reflex (NFR), and conditioned pain modulation of pain/NFR.

RESULTS

Pain-related anxiety mediated the relationships between NA race and pain tolerance and conditioned pain modulation of NFR. Exploratory analyses failed to show that race moderated relationships between pain-related anxiety and pain outcomes.

CONCLUSION

These findings imply that pain-related anxiety is not a unique mechanism of pain risk for NAs, but that the greater tendency to experience pain-related anxiety by NAs impairs their ability to engage descending inhibition of spinal nociception and decreases their pain tolerance (more so than NHWs). Thus, pain-related anxiety may promote pronociceptive processes in NAs to place them at risk for future chronic pain.

Sensory, Affective, and Catastrophizing Reactions to Multiple Stimulus Modalities: Results from the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) have a higher prevalence of chronic pain than any other U.S. racial/ethnic group; however, little is known about the mechanisms for this pain disparity. This study used quantitative sensory testing to assess pain experience in healthy, pain-free adults (n = 137 NAs (87 female), n = 145 non-Hispanic whites (NHW; 68 female)) after painful electric, heat, cold, ischemic, and pressure stimuli. After each stimulus, ratings of pain intensity, sensory pain, affective pain, pain-related anxiety, and situation-specific pain catastrophizing were assessed. The results suggested that NAs reported greater sensory pain in response to suprathreshold electric and heat stimuli, greater pain-related anxiety to heat and ischemic stimuli, and more catastrophic thoughts in response to electric and heat stimuli. Sex differences were also noted; however, with the exception of catastrophic thoughts to cold, these finding were not moderated by race/ethnicity. Together, findings suggest NAs experience heightened sensory, anxiety, and catastrophizing reactions to painful stimuli. This could place NAs at risk for future chronic pain and could ultimately lead to a vicious cycle that maintains pain (eg, pain → anxiety/catastrophizing → pain). PERSPECTIVE: NAs experienced heightened sensory, anxiety, and catastrophizing reactions in response to multiple pain stimuli. Given the potential for anxiety and catastrophic thoughts to amplify pain, this characteristic may place them at risk for pain disorders and could lead to a vicious cycle that maintains pain.

Association between migrant worker experience, limitations on insurance coverage, and hospitalization for schizophrenia in Hunan Province, China

BACKGROUND

While transnational migration has been shown to be a risk factor for schizophrenia, studies have not examined whether massive internal rural-to-urban migration in China in recent years has increased the risk of hospitalization for schizophrenia, or schizophrenia symptom severity among migrants.

METHOD

In a sample of patients acutely hospitalized with schizophrenia in Changsha, Hunan Province, China (N=334), the proportion of past migrant workers among patients was compared to the proportion of past migrant workers in the general adult population of Hunan. Past migrants were also compared to non-migrants on age of onset, and on symptom severity using the Positive and Negative Syndrome Scale (PANSS). The risk ratio for being a migrant among those hospitalized for schizophrenia was stratified by age and gender subgroups. Multiple regression analysis was used to evaluate group differences in age of onset and symptoms.

RESULTS

Of 334 patients diagnosed with schizophrenia hospitalized for <180days, 150 (44.9%) were identified as having been migrant workers compared to 31.0% in the general adult population of Hunan for a risk ratio of 1.45, a risk that was higher for women (2.19) than for men (1.09). Migrant workers also had higher scores than others on total PANSS symptoms.

CONCLUSION

Migrant workers appear to be at greater risk of hospitalization for schizophrenia than other residents of Hunan and showed more severe psychopathology. These findings may reflect specific lack of health insurance coverage for workers migrating to non-native provinces in China, thereby delaying access to treatment.

The Increased Sex Differences in Susceptibility to Emotional Stimuli during Adolescence: An Event-Related Potential Study

The present study investigated how pubertal development and sex interact to influence humans’ emotion susceptibility during adolescence. Event-related potentials were recorded for highly emotional, mildly emotional and neutral stimuli in positive and negative blocks, when 73 adolescents (36 pre-/early pubertal students, 19 boys, 10–12 years old; 37 mid-/late pubertal students, 18 boys, 11–13 years old) performed an implicit emotion task. Behavioral analysis showed higher positive mood ratings for pre-/early compared to mid-/late pubertal subjects, irrespective of sex and block. ERP analysis demonstrated increasing Late Positive Potential (LPP) amplitudes from neutral, Mildly Positive (MP) to Highly Positive (HP) stimuli in pre-/early pubertal, but not in mid-/late pubertal adolescents. However, girls exhibited higher P3a amplitudes during mid-/late relative to pre-/early puberty for negative stimuli irrespective of intensity; while this puberty effect was absent in boys. In addition, girls compared to boys exhibited a more pronounced LPP enhancement effect for Highly Negative (HN) stimuli and a lower threshold of responding to negative stimuli in P3b amplitudes, regardless of puberty. These results suggest that, though there is a puberty-independent sensitivity to negative stimuli in girls relative to boys, puberty selectively intensifies girls’ attention bias for negative stimuli and reduces experiential sensitivity to positive stimuli in both sexes. The implication of these results for the sex-related psychopathology during adolescence were discussed.

Sex moderates the effects of positive and negative affect on clinical pain in patients with knee osteoarthritis

BACKGROUND AND AIMS

Sex differences in clinical pain severity and response to experimental pain are commonly reported, with women generally showing greater vulnerability. Affect, including state (a single rating) and stable (average daily ratings over two weeks) positive affect and negative affect has also been found to impact pain sensitivity and severity, and research suggests that affect may modulate pain differentially as a function of sex. The current study aimed to examine sex as a moderator of the relationships between affect and pain-related outcomes among participants with knee osteoarthritis (KOA).

METHODS

One hundred and seventy-nine participants (59 men) with KOA completed electronic diaries assessing clinical pain, positive affect, and negative affect. A subset of participants (n=120) underwent quantitative sensory testing, from which a single index of central sensitization to pain was derived. We used multiple regression models to test for the interactive effects of sex and affect (positive versus negative and stable versus state) on pain-related outcomes. We used mixed effects models to test for the moderating effects of sex on the relationships between state affect and pain over time.

RESULTS

Sex differences in affect and pain were identified, with men reporting significantly higher stable positive affect and lower central sensitization to pain indexed by quantitative sensory testing, as well as marginally lower KOA-specific clinical pain compared to women. Moreover, there was an interaction between stable positive affect and sex on KOA-specific clinical pain and average daily non-specific pain ratings. Post hoc analyses revealed that men showed trends towards an inverse relationship between stable positive affect and pain outcomes, while women showed no relationship between positive affect and pain. There was also a significant interaction between sex and stable negative affect and sex on KOA-specific pain such that men showed a significantly stronger positive relationship between stable negative affect and KOA-specific pain than women. Sex did not interact with state affect on pain outcomes.

CONCLUSIONS

Findings suggest that men may be particularly sensitive to the effects of stable positive affect and negative affect on clinical pain. Future work with larger samples is needed in order to identify potential mechanisms driving the sex-specific effects of affect on pain.

IMPLICATIONS

The current study provides novel data that suggesting that the association of positive affect, negative affect, and pain are different in men versus women with KOA. Further understanding of the difference in affective expression between men and women may lead to the development of novel therapeutic interventions and help to identify additional modifiable factors in the prevention and management of pain.

Validating the factor structure and testing measurement invariance of modified Short-Form McGill Pain Questionnaire (Ortho-SF-MPQ) for orthodontic pain assessment

OBJECTIVE

To validate the factor structure of recently modified Short-Form McGill Pain Questionnaire (Ortho-SF-MPQ) to assess orthodontic pain; and to test its Measurement Invariance (MI) across gender.

METHODS

180 orthodontic patients were enrolled in this study. 0.016 inch Super-elastic NiTi arch wire was used in 0.022″ × 0.028″ slot pre-adjusted edgewise appliance. After initial arch wire placement, pain was assessed at T1 (24 hours), T2 (day 3), and T3 (day 7) by using the Ortho-SF-MPQ which consists of seven sensory (pressure, sore, aching, tight, throbbing, pulling, miserable) and four affective (uncomfortable, strange, frustrating, annoying) descriptors. Confirmatory factor analysis (CFA) models were fitted for analysis. Multiple-groups CFA (MG-CFA) approach was used for MI testing.

RESULTS

Data from 172 patients (85 male, 87 female) with mean age 14.2 years (SD 1.4) was analysed. CFA model fit indices value at T1 (RMSEA 0.048; CFI 0.995; TLI 0.995), T2 (RMSEA 0.051; CFI 0.998; TLI 0.997), and T3 (RMSEA 0.040; CFI 0.998; TLI 0.998) confirmed the validity of two-factor structure of Ortho-SF-MPQ in assessing orthodontic pain. MG-CFA model based non-significant scaled chi-square difference test (Satorra-Bentler method) for weak invariance (T1: χ² = 6.566, df = 9, p = 0.682; T2: χ² = 14.637, df = 9, p = 0.101; T3 (χ² = 14.248, df = 9, p = 0.114) and strong invariance (T1: χ² = 25.874, df = 20, p = 0.170; T2: χ² = 25.052, df = 20, p = 0.199; T3: χ² = 18.889, df = 20, p = 0.529) confirmed MI across male and female groups.

CONCLUSION

Two-factor structure (sensory and affective) of Ortho-SF-MPQ is structurally valid and invariant to measure pain in male and female orthodontic patents after initial arch wire placement.

Hint1 gene deficiency enhances the supraspinal nociceptive sensitivity in mice

INTRODUCTION

Previous studies have indicated a possible role of histidine triad nucleotide-binding protein 1 (HINT1) on sustaining the regulatory crosstalk of N-methyl-D-aspartate acid glutamate receptors (NMDARs) and G-protein-coupled receptors (GPCRs) such as the μ-opioid receptor (MOR). Both receptors are present in the midbrain periaqueductal gray neurons, an area that plays a central role in the supraspinal antinociceptive process.

METHODS

In the present study, a battery of pain-related behavioral experiments was applied to Hint1 knockout, heterozygous and wild-type mice. Both the male and female mice were investigated to assess the differences between genders.

RESULTS

Hint1-/- mice presented significant shorter latency at 50°C in both male and female in hot plate test while no significant difference was found in tail filck test. In Von Frey hairs test Hint1-/- mice were more sensitive than Hint1+/+ mice, presenting a lower withdrawal threshold and enhanced relative frequency of paw withdrawal. The average flinches and licking time of Hint1-/- mice were more than that of Hint1+/+ mice in formalin test.

CONCLUSION

The absence of Hint1 gene-enhanced supraspinal nociceptive sensitivity in mice, including thermal, mechanical and inflammatory hyperalgesia. Meanwhile, there was no certain evidence indicating the haploinsufficiency and gender differences of Hint1 gene in pain-related behaviors.

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.

Pain-related and negative semantic priming enhances perceived pain intensity

BACKGROUND

Negative affective and pain-related cues, such as pictures or words, have been shown to act as primes and enhance the perceived intensity of subsequent painful events. For pain-related semantic primes, it remains unclear whether this effect depends on negative valence itself or, specifically, on the pain-relatedness of the words.

OBJECTIVES

To investigate the effect of pain-related, negative affective (pain-unrelated) and neutral semantic primes on the perception of subsequent noxious target stimuli.

METHODS

Pain ratings in response to noxious electrical stimulation of light and moderate intensity were examined in 39 healthy subjects after subjects were exposed to semantic primes of different meaning and valence (pain-related, negative, positive and neutral adjectives) presented with different interstimulus intervals (0 ms, 500 ms and 1500 ms).

RESULTS

Increased pain ratings of noxious stimuli were observed following pain-related and negative compared with neutral primes.

DISCUSSION

The results support the motivational priming theory for semantic stimuli, indicating that affectively negative semantic primes increase subjective pain intensity. However, a specific pain-related priming effect was not reliably demonstrated. Additionally, it is shown that experimental parameters (ie, stimulus intensity and interstimulus interval) modify the extent of negative and pain-related semantic priming.

CONCLUSIONS

Verbal priming plays a role for the perception of noxious stimuli in a time-dependent manner.

Nonpharmacologic approaches for pain management during labor compared with usual care: a meta-analysis

OBJECTIVES

To assess the effects of nonpharmacologic approaches to pain relief during labor, according to their endogenous mechanism of action, on obstetric interventions, maternal, and neonatal outcomes.

DATA SOURCE

Cochrane library, Medline, Embase, CINAHL and the MRCT databases were used to screen studies from January 1990 to December 2012.

STUDY SELECTION

According to Cochrane criteria, we selected randomized controlled trials that compared nonpharmacologic approaches for pain relief during labor to usual care, using intention-to-treat method.

RESULTS

Nonpharmacologic approaches, based on Gate Control (water immersion, massage, ambulation, positions) and Diffuse Noxious Inhibitory Control (acupressure, acupuncture, electrical stimulation, water injections), are associated with a reduction in epidural analgesia and a higher maternal satisfaction with childbirth. When compared with nonpharmacologic approaches based on Central Nervous System Control (education, attention deviation, support), usual care is associated with increased odds of epidural OR 1.13 (95% CI 1.05-1.23), cesarean delivery OR 1.60 (95% CI 1.18-2.18), instrumental delivery OR 1.21 (95% CI 1.03-1.44), use of oxytocin OR 1.20 (95% CI 1.01-1.43), labor duration (29.7 min, 95% CI 4.5-54.8), and a lesser satisfaction with childbirth. Tailored nonpharmacologic approaches, based on continuous support, were the most effective for reducing obstetric interventions.

CONCLUSION

Nonpharmacologic approaches to relieve pain during labor, when used as a part of hospital pain relief strategies, provide significant benefits to women and their infants without causing additional harm.

Emotional modulation of pain and spinal nociception in persons with major depressive disorder (MDD)

Major depressive disorder (MDD) is associated with risk for chronic pain, but the mechanisms contributing to the MDD and pain relationship are unclear. To examine whether disrupted emotional modulation of pain might contribute, this study assessed emotional processing and emotional modulation of pain in healthy controls and unmedicated persons with MDD (14 MDD, 14 controls). Emotionally charged pictures (erotica, neutral, mutilation) were presented in 4 blocks. Two blocks assessed physiological-emotional reactions (pleasure/arousal ratings, corrugator electromyography (EMG), startle modulation, skin conductance) in the absence of pain and 2 blocks assessed emotional modulation of pain and the nociceptive flexion reflex (NFR, a physiological measure of spinal nociception) evoked by suprathreshold electric stimulations. Results indicated pictures generally evoked the intended emotional responses; erotic pictures elicited pleasure, subjective arousal, and smaller startle magnitudes, whereas mutilation pictures elicited displeasure, corrugator EMG activation, and subjective/physiological arousal. However, emotional processing was partially disrupted in MDD, as evidenced by a blunted pleasure response to erotica and a failure to modulate startle according to a valence linear trend. Furthermore, emotional modulation of pain was observed in controls but not MDD, even though there were no group differences in NFR threshold or emotional modulation of NFR. Together, these results suggest supraspinal processes associated with emotion processing and emotional modulation of pain may be disrupted in MDD, but brain to spinal cord processes that modulate spinal nociception are intact. Thus, emotional modulation of pain deficits may be a phenotypic marker for future pain risk in MDD.

Orthodontic pain: an interaction between age and sex in early and middle adolescence

OBJECTIVE

To investigate the age and sex interaction effect on orthodontic pain in adolescence during the initial phase of fixed orthodontic treatment.

MATERIALS AND METHODS

Three hundred participants (mean age 13.85 ± 1.98 years; 152 female, 148 male) met all inclusion criteria and enrolled in the study designed as 2 × 2 factorial trial with two levels each for age (11-14 years; 14-17 years) and sex (male; female). A 0.16-inch superelastic NiTi wire was used in a 0.022-inch slot (Roth's prescription) preadjusted edgewise appliance for initial leveling and alignment of mandibular anterior dentition. The follow-up period was 7 days. Pain was assessed by using 100 mm visual analog scale for one baseline and nine follow-up repeated measurements at prespecified time points. Data were analyzed by using generalized linear mixed effect model analysis.

RESULTS

Three participants were lost to follow-up, and 17 participants were not considered for analysis due to incomplete or improperly completed questionnaire. Therefore, 280 participants (mean age 13.96 ± 2.01 years; 138 female, 142 male) were analyzed for results. Results showed that age and sex interaction had statistically significant effect on pain (F  =  3.56; P  =  .0151; df 3/218). In the 11-14 year age group, there was no significant difference for pain between male and female. In the 14-17 year age group, girls reported significantly greater pain compared to 14- to 17 year-old boys (t  =  2.76; P  =  .0209). Pain reported by 14- to 17-year-old girls was also significantly greater compared to 11- to 14-year-old boys (t  =  2.91; P  =  .0206).

CONCLUSIONS

Age and sex interaction has significant effect on orthodontic pain during adolescence, and 14- to 17-year-old girls experienced maximum pain.

Sex differences in brain response to anticipated and experienced visceral pain in healthy subjects

Women demonstrate higher pain sensitivity and prevalence of chronic visceral pain conditions such as functional gastrointestinal disorders than men. The role of sex differences in the brain processing of visceral pain is still unclear. In 16 male and 16 female healthy subjects we compared personality, anxiety levels, skin conductance response (SCR), and brain processing using functional MRI during anticipation and pain induced by esophageal distension at pain toleration level. There was no significant difference in personality scores, anxiety levels, SCR, and subjective ratings of pain between sexes. In group analysis, both men and women demonstrated a similar pattern of brain activation and deactivation during anticipation and pain consistent with previous reports. However, during anticipation women showed significantly greater activation in the cuneus, precuneus, and supplementary motor area (SMA) and stronger deactivation in the right amygdala and left parahippocampal gyrus, whereas men demonstrated greater activation in the cerebellum. During pain, women demonstrated greater activation in the midcingulate cortex, anterior insula, premotor cortex, and cerebellum and stronger deactivation in the caudate, whereas men showed increased activity in the SMA. The pattern of brain activity suggests that, during anticipation, women may demonstrate stronger limbic inhibition, which is considered to be a cognitive modulation strategy for impending painful stimulation. During pain, women significantly activate brain areas associated with the affective and motivation components of pain. These responses may underlie the sex differences that exist in pain conditions, whereby women may attribute more emotional importance to painful stimuli compared with men.

Morning types are less sensitive to pain than evening types all day long

BACKGROUND

Diurnal variations in pain have been observed in experimental protocols, post-surgery states and pathological conditions. Chronotype is considered to have the most profound effect on diurnal variations, and in addition, previous studies suggest that evening types may be more vulnerable to pain than morning types. This study aimed to examine whether or not morning and evening chronotypes differ in terms of their daily levels and diurnal fluctuations of pain sensitivity.

METHODS

A total of 16 morning-healthy and 15 evening-healthy men were selected using the Morningness-Eveningness Questionnaire and underwent nine measurements during 1 day (between 08:15 and 20:15 h), each consisting of five heat stimuli situated at the ventral side of the wrist.

RESULTS

A marked difference between chronotypes was found, with morning types showing less sensitivity to pain than evening types all day long [M = 50.1; standard error (SE) = 1 and M = 47.2; SE = 1, respectively; pain thresholds in centigrade]. Diurnal variations in pain were not statistically significant.

CONCLUSIONS

The results showed that chronotype could be an important factor determining sensitivity to pain, regardless of time of day.

Sex similarities and differences in pain-related periaqueductal gray connectivity

This study investigated sex similarities and differences in pain-related functional connectivity in 60 healthy subjects. We used functional magnetic resonance imaging and psychophysiological interaction analysis to investigate how exposure to low vs high experimental pain modulates the functional connectivity of the periaqueductal gray (PAG). We found no sex differences in pain thresholds, and in both men and women, the PAG was more functionally connected with the somatosensory cortex, the supplemental motor area, cerebellum, and thalamus during high pain, consistent with anatomic predictions. Twenty-six men displayed a pain-induced increase in PAG functional connectivity with the amygdala caudate and putamen that was not observed in women. In an extensive literature search, we found that female animals have been largely overlooked when the connections between the PAG and the amygdala have been described, and that women are systematically understudied with regard to endogenous pain inhibition. Our results emphasize the importance of including both male and female subjects when studying basic mechanisms of pain processing, and point toward a possible sex difference in endogenous pain inhibition.

Review of neuroimaging studies related to pain modulation

Background and purpose: A noxious stimulus does not necessarily cause pain. Nociceptive signals arising from a noxious stimulus are subject to modulation via endogenous inhibitory and facilitatory mechanisms as they travel from the periphery to the dorsal horn or brainstem and on to higher brain sites. Research on the neural structures underlying endogenous pain modulation has largely been restricted to animal research due to the invasiveness of such studies (e.g., spinal cord transection, brain lesioning, brain site stimulation). Neuroimaging techniques (e.g., magnetoencephalography (MEG), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI)) provide non-invasive means to study neural structures in humans. The aim is to provide a narrative review of neuroimaging studies related to human pain control mechanisms.

Methods: The approach taken is to summarise specific pain modulation mechanisms within the somatosensory (diffuse noxious inhibitory controls, acupuncture, movement), affective (depression, anxiety, catastrophizing, stress) and cognitive (anticipation/placebo, attention/distraction, hypnosis)domains with emphasis on the contribution of neuroimaging studies.

Results and conclusions: Findings from imaging studies are complex reflecting activation or deactivation in numerous brain areas. Despite this, neuroimaging techniques have clarified supraspinal sites involved in a number of pain control mechanisms. The periaqueductal grey (PAG) is one area that has consistently been shown to be activated across the majority of pain mechanisms. Activity in the rostral ventromedial medulla known to relay descending modulation from the PAG, has also been observed both during acupuncture analgesia and anxiety-induced hyperalgesia. Other brain areas that appear to be involved in a number of mechanisms are the anterior cingulate cortex, prefrontal cortex, orbitofrontal cortex and nucleus accumbens, but their exact role is less clear.

Implications: Neuroimaging studies have provided essential information about the pain modulatory pathways under normal conditions, but much is still to be determined. Understanding the mechanisms of pain control is important for understanding the mechanisms that contribute to failed pain control in chronic pain. Applying fMRI outside the brain, such as in the trigeminal nucleus caudalis of the spinotrigeminal pathway and in the dorsal horn of the spinal cord, and coupling brain activity with activity at these sites may help improve our understanding of the function of brain sites and shed light on functional connectivity in the pain pathway.

© 2011 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Modulation of nociceptive and acoustic startle responses to an unpredictable threat in men and women

The present study examined whether a moderately aversive abdominal threat would lead to greater enhancement in affect- and pain-related defensive responding as indexed by the acoustic startle reflex (ASR) and nociceptive flexion reflex (NFR) in women compared to men. We also predicted sex differences in threat-related autonomic arousal measured by skin conductance responses (SCRs) to acoustic startle and noxious sural nerve stimulation. Unpredictable threat was manipulated by alternating 30-second safe ("no abdominal stimulation will be given") and threat ("abdominal stimulation may occur at anytime") periods. The experiment consisted of 2 blocks, each containing 4 safe and 4 threat periods in which the ASR or NFR was randomly probed 9-21 seconds following period onset. Unpredictable abdominal threat potentiated both ASR and NFR responses compared to periods signaling safety. SCRs to acoustic startle probes and noxious sural nerve stimulation were also significantly elevated during the threat vs safe periods. No sex differences in ASR or startle-evoked SCRs emerged. However, nociceptive responding was moderated by sex; females showed significant increases in NFR magnitudes across both safe and threat periods compared to males. Females also showed greater threat-potentiated SCRs to sural nerve stimulation than males. Our findings indicate that both affect- and pain-related defense and arousal systems are strongly influenced by threat of an aversive, unpredictable event, a situation associated with anticipatory anxiety. Females, compared to males, showed greater nociceptive responding and pain modulation when exposed to an unpredictable threatening context, whereas affect-driven ASR responses showed no such sex differentiation.

The modulation of pain by attention and emotion: a dissociation of perceptual and spinal nociceptive processes

Emotions and attention have been shown to influence the perception of pain and several psychophysiological studies have suggested an implication of descending modulatory mechanisms to explain these effects. However, the specificity of the neurophysiological mechanisms underlying the emotional and attentional modulation of pain still remains unclear. In order to differentiate the supra-spinal and spinal mechanisms involved in emotional and attentional modulation of pain, we measured pain perception (self-ratings) and the RIII reflex in healthy volunteers during the presentation of pleasant, unpleasant and neutral pictures, as well as during a baseline condition with no visual distractor (Experiment 1). In a second experiment, we manipulated the emotional arousal induced by pleasant and unpleasant pictures in order to compare more directly the effects of distraction and arousal. Whereas emotional valence influenced pain and the amplitude of the RIII reflex in the same direction (negative > positive), distraction by neutral pictures reduced pain but increased the RIII reflex relative to baseline. Increased arousal further potentiated the effects of negative valence on both pain and the RIII reflex and the effects of positive emotions on pain, as previously reported. However, arousal did not potentiate the inhibitory effect of positive pictures on the RIII and seems insufficient to account for the effect of distraction on the RIII. Overall, these data provide further evidence that attention and emotion modulate pain through partially dissociable neurophysiological mechanisms.

Illness perceptions and mood states are associated with injury-related outcomes in athletes

BACKGROUND

Athletes have to cope adequately with the consequences of their injury in order to return into sports as soon as possible. Besides the physical characteristics of the injury, illness perceptions and emotional responses impact the behavioural responses to the injury.

PURPOSE

To apply Leventhal's Common Sense Model as a theoretical framework in the field of sports medicine, pertaining to injured athletes.

METHODS

In a sample of 95 injured athletes participating in different sports, sociodemographic, injury and sport-related characteristics, the Illness Perception Questionnaire-Revised-Sports (IPQ-R-S) and the Profile Of Mood States were assessed.

RESULTS

Injured athletes' most experienced symptoms were pain (82%) and loss of strength (50%), associated with a high controllability; they see their injury as not chronic, with minor consequences for daily life and minor emotional consequences. Athletes with an injury of longer duration have minor psychological attributions, 28% suffer from fatigue, which is strongly related to a negative mood state.

CONCLUSIONS

Illness perceptions and mood states are related to injury characteristics. Clinicians ought to incorporate patients' views about their injuries into their treatment in order to increase the concordance between patient's and clinician's perceptions, thereby increasing chances of a quick and uneventful recovery.

Differences in pain, psychological symptoms, and gender distribution among patients with left- vs right-sided chronic spinal pain

OBJECTIVE

To determine pain levels, function, and psychological symptoms in relation to predominant sidedness of pain (right or left) and gender in patients being treated for chronic spinal pain.

DESIGN

Prospective cohort study.

PATIENTS

Patients with chronic neck or low back pain undergoing a nerve block procedure in a specialty pain medicine clinic. INTERVENTIONS/OUTCOMES: Patients completed the Hospital Anxiety and Depression Scale and the Brief Pain Inventory just prior to the procedure. Pain history and demographic variables were collected from a chart review. Chi-square, Pearson correlations, and multivariate statistics were used to characterize the relationships between side of pain, gender, pain levels, pain interference, and psychological symptoms.

RESULTS

Among 519 subjects, men with left-sided pain (N = 98) were found to have significantly greater depression and anxiety symptoms and worse pain-related quality of life (P < 0.01), despite having similar pain levels as men with right-sided pain (N = 91) or women with left- or right-sided pain (N = 289). In men, psychological symptoms had a significantly greater correlation with pain levels than in women (P < 0.01).

CONCLUSION

In this sample, men with left-sided spinal pain report worse quality of life and more psychological symptoms than women. These data provide clinical evidence corroborating basic neuroscience findings indicating that the right cerebral hemisphere is preferentially involved in the processing of pain and negative affect. These data suggest that men appear more right hemisphere dominant in pain and affect processing. These findings have implications for multidisciplinary assessment and treatment planning in men.

Are there sex differences in affective modulation of spinal nociception and pain?

Sex differences in the processing and experience of emotion exist. The present study examined whether sex differences in emotion lead to sex differences in affective modulation of pain and spinal nociception (assessed by nociceptive flexion reflex, NFR). Participants were healthy men (n = 47) and women (n = 73). Prior to affective modulation testing, electrocutaneous pain sensitivity was assessed (NFR threshold, pain threshold, pain tolerance). Affective modulation of pain and NFR was then assessed by presenting pictures that vary in emotional valence and arousal (mutilation, attack, death, neutral, families, adventure, erotica) during which suprathreshold electrocutaneous stimulations were delivered. Subjective emotional reactions were assessed after every picture, and nociceptive reactions were assessed after every suprathreshold stimulus. Results indicated women had greater pain sensitivity and also responded more negatively to attack pictures and less positively to erotic pictures. But despite these differences, affective modulation of pain/NFR was not moderated by sex: erotic pictures inhibited pain/NFR and mutilation pictures enhanced pain/NFR. Together, this implies subjective emotional experience does not completely mediate picture-evoked modulation of pain/NFR, a supposition that was further supported by exploratory analyses that demonstrated picture-evoked modulation of pain/NFR was present even after controlling for intra- and inter-individual differences in emotional reactions to pictures. Implications and limitations of these findings are discussed.

PERSPECTIVE

Evidence suggests that women are more sensitive to experimental and clinical pain, but the mechanisms contributing to these sex differences are poorly understood. Affective processes are known to play a role in regulating pain signaling and pain experience; therefore, the present study examined whether sex differences in affective experience contribute to sex differences in pain. Results indicate that in healthy individuals affective processes may not contribute to sex differences in pain.