The common link between functional somatic syndromes may be central sensitisation

A systematic review of quantitative EEG findings in Fibromyalgia, Chronic Fatigue Syndrome and Long COVID

Fibromyalgia Syndrome (FMS), Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Long COVID (LC) are similar multisymptom clinical syndromes but with difference in dominant symptoms in each individual. There is existing and emerging literature on possible functional alterations of the central nervous system in these conditions. This review aims to synthesise and appraise the literature on resting-state quantitative EEG (qEEG) in FMS, ME/CFS and LC, drawing on previous research on FMS and ME/CFS to help understand neuropathophysiology of the new condition LC. A systematic search of MEDLINE, Embase, CINHAL, PsycINFO and Web of Science databases for articles published between December 1994 and September 2023 was performed. Out of the initial 2510 studies identified, 17 articles were retrieved that met all the predetermined selection criteria, particularly of assessing qEEG changes in one of the three conditions compared to healthy controls. All studies scored moderate to high quality on the Newcastle-Ottawa scale. There was a general trend for decreased low-frequency EEG band activity (delta, theta, and alpha) and increased high-frequency EEG beta activity in FMS, differing to that found in ME/CFS. The limited LC studies included in this review focused mainly on cognitive impairments and showed mixed findings not consistent with patterns observed in FMS and ME/CFS. Our findings suggest different patterns of qEEG brainwave activity in FMS and ME/CFS. Further research is required to explore whether there are phenotypes within LC that have EEG signatures similar to FMS or ME/CFS. This could inform identification of reliable diagnostic markers and possible targets for neuromodulation therapies tailored to each clinical syndrome.

Functional Somatic Syndromes Are Associated With Varied Postoperative Outcomes and Increased Opioid Use After Spine Surgery: A Systematic Review

STUDY DESIGN

Systematic Review.

OBJECTIVE

To perform a systematic review assessing the relationship between functional somatic syndromes (FSSs) and clinical outcomes after spine surgery.

METHODS

A systematic review of online databases (PubMed and Web of Science) through December 2021 was conducted via PRISMA guidelines to identify all studies investigating the impact of at least one FSS (fibromyalgia, irritable bowel syndrome (IBS), chronic headaches/migraines, interstitial cystitis, chronic fatigue syndrome, multiple chemical sensitivity) on outcomes after spine surgery. Outcomes of interest included patient reported outcome measures (PROMs), postoperative opioid use, cost of care, complications, and readmission rates.

RESULTS

A total of 207 records were identified. Seven studies (n = 40,011 patients) met inclusion criteria with a mean MINORS score of 16.6 out of 24. Four studies (n = 21,086) reported postoperative opioid use; fibromyalgia was a strong risk factor for long-term opioid use after surgery whereas the association with chronic migraines remains unclear. Two studies (n = 233) reported postoperative patient reported outcome measures (PROMs) with mixed results suggesting a possible association between fibromyalgia and less favorable PROMs. One study (n = 18,692) reported higher postoperative complications in patients with fibromyalgia.

CONCLUSION

Patients with fibromyalgia and possibly migraines are at higher risk for prolonged postoperative opioid use and less favorable PROMs after spine surgery. There is limited research on the relationship between other Functional somatic syndromes (FSSs) and outcomes following spine surgery. Growing evidence suggests the variation in outcomes after spine procedures may be attributed to non-identifiable organic patient factors such as FSSs.

Sphincterotomy for Biliary Sphincter of Oddi Disorder and idiopathic Acute Recurrent Pancreatitis: THE RESPOND LONGITUDINAL COHORT

Objective

Sphincter of Oddi Disorders (SOD) are contentious conditions in patients whose abdominal pain, idiopathic acute pancreatitis (iAP) might arise from pressurization at the sphincter of Oddi. The present study aimed to measure the benefit of sphincterotomy for suspected SOD.

Design

Prospective cohort conducted at 14 U.S. centers with 12 months follow-up. Patients undergoing first-time ERCP with sphincterotomy for suspected SOD were eligible: pancreatobiliary-type pain with or without iAP. The primary outcome was defined as the composite of improvement by Patient Global Impression of Change (PGIC), no new or increased opioids, and no repeat intervention. Missing data were addressed by hierarchal, multiple imputation scheme.

Results

Of 316 screened, 213 were enrolled with 190 (89.2%) of these having a dilated bile duct, abnormal labs, iAP, or some combination. By imputation, an average of 122/213 (57.4% [95%CI 50.4-64.4]) improved; response rate was similar for those with complete follow-up (99/161, 61.5%, [54.0-69.0]); of these, 118 (73.3%) improved by PGIC alone. Duct size, elevated labs, and patient characteristics were not associated with response. AP occurred in 37/213 (17.4%) at a median of 6 months post-ERCP and was more likely in those with a history of AP (30.9 vs. 2.9%, p<0.0001).

Conclusion

Nearly 60% of patients undergoing ERCP for suspected SOD improve, although the contribution of a placebo response is unknown. Contrary to prevailing belief, duct size and labs are poor response predictors. AP recurrence was common and like observations from prior non-intervention cohorts, suggesting no benefit of sphincterotomy in mitigating future AP episodes.Key Messages: WHAT IS ALREADY KNOWN ON THIS TOPIC: It is not clear if the sphincter of Oddi can cause abdominal pain (Functional Biliary Sphincter of Oddi Disorder) and idiopathic acute pancreatitis (Functional Pancreatic Sphincter of Oddi Disorder), and whether ERCP with sphincterotomy can ameliorate abdominal pain or pancreatitis.WHAT THIS STUDY ADDS: Using multiple patient-reported outcome measures, most patients with suspected sphincter of Oddi disorder improve after ERCP with sphincterotomy.Duct size, elevated pancreatobiliary labs, and baseline patient characteristics are not independently associated with response.There is a high rate of recurrent acute pancreatitis within 12 months of sphincterotomy in those with a history of idiopathic acute pancreatitis.HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE, OR POLICY: Since a discrete population with a high (> 80-90%) response rate to sphincterotomy for suspected pancreatobiliary pain could not be identified, there is a need for additional observational and interventional studies that include phenotyping of patients using novel imaging or biochemical biomarkers.There remains a pressing need for quantitative nociceptive biomarkers to distinguish pancreatobiliary pain from other causes of abdominal pain or central sensitization.Discovery of blood-, bile-, or imaging-based biomarkers for occult microlithiasis and pancreatitis may be helpful in predicting who is likely to benefit from sphincterotomy.

Influence of central aspects of pain on self-management in people with chronic low back pain

OBJECTIVE

This observational study investigated whether central aspects of pain are associated with self-management domains in individuals with chronic low back pain (CLBP) undertaking a pain management program.

METHODS

Individuals with CLBP provided pain sensitivity and self-management data at baseline (n = 97) and 3-months (n = 87). Pressure pain detection threshold (PPT) at the forearm, temporal summation (TS) and conditioned pain modulation (CPM), Widespread Pain Index (WPI), and a Central Aspects of Pain factor (CAPf) were considered as central aspects of pain. Self-management was measured using the 8 domains of the Health Education Impact Questionnaire, as well as Pain Self Efficacy and Health Care Utilisation questionnaires.

RESULTS

PPT, CPM, WPI and CAPf predicted worse performance in several self-management domains at 3-months (r = 0.21 to 0.54, p < 0.05 overall). In multivariable regression models (adjusted for baseline scores of self-management, depression, catastrophization, pain and fatigue) low PPT, high TS, and high CAPf at baseline predicted poorer self-management at 3 months (R2 =0.14 to 0.52, β = -0.37 to 0.35, p < 0.05).

CONCLUSIONS

Central aspects of pain are associated with impaired self-management, over and above effects of pain intensity, fatigue, depression and catastrophizing.

PRACTICE IMPLICATIONS

Treatments that target central aspects of pain might help improve self-management in people with CLBP.

Chronic nonspecific multiple-sites pain [CNMSP] of unknown etiology: Biopsychosocial method of evaluation for the primary care level

Background

Understanding and dealing with chronic nonspecific pain (CNP) is the important entity at primary care hospital. Chronic nonspecific multiple-site pain [CNMSP] of unknown etiology creates diagnostic and therapeutic challenges for primary care physicians due to lack of guidance regarding evaluation and treatment.

Aims and Objectives

To classify and formulate the evaluation, treatment strategies, and prediction of prognosis of patients with CNMSP of unknown etiology.

Methods

Patients present with CNMSP of more than 3-month duration without any obvious medical cause. The biopsychosocial [BPS] model with 3P model was applied to see the biological, psychological, and social factors behind persistence. Finally, patients were classified into four groups for evaluation response to treatment and relapse rates in 12-month follow-up.

Results

Of the total 243 patients of CNMSP, 243 [96.3%] were females. Sixty [24.7%] patients had short duration, and 183 [75.3%] had long duration. Headache was in 115 [47%], low back pain ± leg pain in 96 [39.4%], cervical pain ± shoulder/arm pain in 83 [34.1%], and diffuse body pain in 50 [20.5%] in various combinations. A total of 155 [63.8%] patients had high somatization-sensitization index (SSI), and 144 [59.3%] had low ferritin level. Group 1 [high SSI and low ferritin] had 37.9% of patients, group 2 [high SSI and normal ferritin] had 25.9% of patients, group 3 [low to medium SSI with low ferritin] had 21.4% of patients, and group 4 [low to medium SSI with normal ferritin] had 14.8% of patients. Response to pain symptoms was better in group 1, and relapse rate was higher in group 2.

Conclusion

CNMSP of unknown etiology itself is a heterogeneous entity, and assessment based on the BPS model can be very useful to understand the treatment plan and outcome of these patients.

Practical multidisciplinary framework for the assessment and management of patients with unexplained chronic aerodigestive symptoms

OBJECTIVE

Patients experiencing unexplained chronic throat symptoms (UCTS) are frequently referred to gastroenterology and otolaryngology outpatient departments for investigation. Often despite extensive investigations, an identifiable structural abnormality to account for the symptoms is not found. The objective of this article is to provide a concise appraisal of the evidence-base for current approaches to the assessment and management of UCTS, their clinical outcomes, and related healthcare utilisation.

DESIGN

This multidisciplinary review critically examines the current understanding of aetiological theories and pathophysiological drivers in UCTS and summarises the evidence base underpinning various diagnostic and management approaches.

RESULTS

The evidence gathered from the review suggests that single-specialty approaches to UCTS inadequately capture the substantial heterogeneity and pervasive overlaps among clinical features and biopsychosocial factors and suggests a more unified approach is needed.

CONCLUSION

Drawing on contemporary insights from the gastrointestinal literature for disorders of gut-brain interaction, this article proposes a refreshed interdisciplinary approach characterised by a positive diagnosis framework and patient-centred therapeutic model. The overarching aim of this approach is to improve patient outcomes and foster collaborative research efforts.

Emotional Awareness and Expression Interview: Examining Interview Content and Patient Experiences in Two Medical Samples

A single session of Emotional Awareness and Expression Therapy (EAET)-the EAET Interview-was previously shown to lead to clinical benefits for patients with centralized somatic conditions in primary care (Ziadni et al. in Health Psychol 37(3):282-290, 2018) and tertiary care (Carty et al. in Pain Med 20(7):1321-1329, 2019) settings. There has yet to be an examination of patients' experiences of and reactions to the EAET Interview, which is crucial in evaluating possible clinical implementation of the interview. We conducted secondary analyses on 88 patients (M age = 41.32, 90.9% women) from the two prior trials (primary care N = 51; tertiary care N = 37). Analyses examined interview processes (stress disclosure themes, working alliance, and emotional processing) and patients' reactions to the interview (interview credibility and perceived value of the interview), comparing the two samples and examining correlations among these variables. All patients disclosed at least one stressful life experience, commonly interpersonal problems (89.2%) and childhood adversity (51.5%). Patients had moderately high levels of working alliance and emotional processing during the interview and reported high interview credibility and perceived value of the interview. More extensive emotional processing of stressors was associated with more positive patient reactions to the interview, including higher interview credibility (r = .23) and perceived value (r = .32). We conclude that the single-session EAET Interview was valued by most patients, and patients' emotional processing is particularly beneficial. Addressing the trauma and emotional conflicts of patients with centralized somatic conditions is both feasible and valuable in front-line medical settings.

Physical symptoms and brain morphology: a population neuroimaging study in 12,286 pre-adolescents

Physical symptoms, also known as somatic symptoms, are those for which medical examinations do not reveal a sufficient underlying root cause (e.g., pain and fatigue). The extant literature of the neurobiological underpinnings of physical symptoms is largely inconsistent and primarily comprises of (clinical) case-control studies with small sample sizes. In this cross-sectional study, we studied the association between dimensionally measured physical symptoms and brain morphology in pre-adolescents from two population-based cohorts; the Generation R Study (n = 2649, 10.1 ± 0.6 years old) and ABCD Study (n = 9637, 9.9 ± 0.6 years old). Physical symptoms were evaluated using continuous scores from the somatic complaints syndrome scale from the parent-reported Child Behavior Checklist (CBCL). High-resolution structural magnetic resonance imaging (MRI) was collected using 3-Tesla MRI systems. Linear regression models were fitted for global brain metrics (cortical and subcortical grey matter and total white matter volume) and surface-based vertex-wise measures (surface area and cortical thickness). Results were meta-analysed. Symptoms of anxiety/depression were studied as a contrasting comorbidity. In the meta-analyses across cohorts, we found negative associations between physical symptoms and surface area in the (i) left hemisphere; in the lateral orbitofrontal cortex and pars triangularis and (ii) right hemisphere; in the pars triangularis, the pars orbitalis, insula, middle temporal gyrus and caudal anterior cingulate cortex. However, only a subset of regions (left lateral orbitofrontal cortex and right pars triangularis) were specifically associated with physical symptoms, while others were also related to symptoms of anxiety/depression. No significant associations were observed for cortical thickness. This study in preadolescents, the most representative and well-powered to date, showed that more physical symptoms are modestly related to less surface area of the prefrontal cortex mostly. While these effects are subtle, future prospective research is warranted to understand the longitudinal relationship of physical symptoms and brain changes over time. Particularly, to elucidate whether physical symptoms are a potential cause or consequence of distinct neurodevelopmental trajectories.

Kappa opioid receptor agonists produce sexually dimorphic and prolactin-dependent hyperalgesic priming

ABSTRACT

Repeated stress produces hyperalgesic priming in preclinical models, but underlying mechanisms remain uncertain. As stress engages kappa opioid receptors (KORs), we hypothesized that repeated administration of KOR agonists might mimic, in part, stress-induced hyperalgesic priming. The potential contribution of circulating prolactin (PRL) and dysregulation of the expression of PRL receptor (PRLR) isoforms in sensory neurons after KOR agonist administration was also investigated. Mice received 3 daily doses of U-69593 or nalfurafine as a "first-hit" stimulus followed by assessment of periorbital tactile allodynia. Sixteen days after the first KOR agonist administration, animals received a subthreshold dose of inhalational umbellulone, a TRPA1 agonist, as the second-hit stimulus and periorbital allodynia was assessed. Cabergoline, a dopamine D2 receptor agonist, was used to inhibit circulating PRL in additional cohorts. Prolactin receptor isoforms were quantified in the V1 region of the trigeminal ganglion after repeated doses of U-69593. In both sexes, KOR agonists increased circulating PRL and produced allodynia that resolved within 14 days. Hyperalgesic priming, revealed by umbellulone-induced allodynia in animals previously treated with the KOR agonists, also occurred in both sexes. However, repeated U-69593 downregulated the PRLR long isoform in trigeminal neurons only in female mice. Umbellulone-induced allodynia was prevented by cabergoline co-treatment during priming with KOR agonists in female, but not male, mice. Hyperalgesic priming therefore occurs in both sexes after either biased or nonbiased KOR agonists. However, a PRL/PRLR-dependence is observed only in female nociceptors possibly contributing to pain in stress-related pain disorders in females.

Multiple Chemical Sensitivity: It's time to catch up to the science

Multiple chemical sensitivity (MCS) is a complex medical condition associated with low dose chemical exposures. MCS is characterized by diverse features and common comorbidities, including fibromyalgia, cough hypersensitivity, asthma, and migraine, and stress/anxiety, with which the syndrome shares numerous neurobiological processes and altered functioning within diverse brain regions. Predictive factors linked to MCS comprise genetic influences, gene-environment interactions, oxidative stress, systemic inflammation, cell dysfunction, and psychosocial influences. The development of MCS may be attributed to the sensitization of transient receptor potential (TRP) receptors, notably TRPV1 and TRPA1. Capsaicin inhalation challenge studies demonstrated that TRPV1 sensitization is manifested in MCS, and functional brain imaging studies revealed that TRPV1 and TRPA1 agonists promote brain-region specific neuronal variations. Unfortunately, MCS has often been inappropriately viewed as stemming exclusively from psychological disturbances, which has fostered patients being stigmatized and ostracized, and often being denied accommodation for their disability. Evidence-based education is essential to provide appropriate support and advocacy. Greater recognition of receptor-mediated biological mechanisms should be incorporated in laws, and regulation of environmental exposures.

Social cognition in chronic migraine with medication overuse: a cross-sectional study on different aspects of mentalization and social relationships

BACKGROUND

Social cognition refers to all mental operations to decipher information needed in social interactions. Here we aimed to outline the socio-cognitive profile of Chronic Migraine with Medication Overuse (CM + MO), given they are recognized to be at risk of socio-cognitive difficulties. Given the multidimensionality of this construct, we considered: (1) socio-cognitive abilities, (2) socio-cognitive beliefs, (3) alexithymia and autism traits, and (4) social relationships.

METHODS

Seventy-one patients suffering from CM + MO, 61 from episodic migraine (EM), and 80 healthy controls (HC) were assessed with a comprehensive battery: (1) the Faux Pas test (FP), the Strange Stories task (SS), the Reading Mind in the Eyes test (RMET), (2) the Tromsø Social Intelligence Scale, (3) the Toronto Alexithymia Scale, the Autism Spectrum Quotient, (4) the Lubben Social Network Scale, the Friendship Scale.

RESULTS

CM + MO: (1) performed similar to EM but worse than HC in the FP and SS, while they were worse than EM and HC in the RMET; (2) were similar to EM and HC in social intelligence; (3) had more alexithymic/autistic traits than EM and HC; (4) reported higher levels of contact with their family members but felt little support from the people around them than HC.

CONCLUSIONS

CM + MO results characterized by a profile of compromised socio-cognitive abilities that affects different dimensions. These findings may have a relevant role in multiple fields related to chronic headache: from the assessment to the management.

What psychological interventions are effective for the management of persistent physical symptoms (PPS)? A systematic review and meta-analysis

OBJECTIVES

Presentation of persistent physical symptoms is associated with increased health care utilization, yet clinical outcomes often remain suboptimal. This systematic review aimed to determine whether psychological interventions are effective for the management of PPS and if so, what are the features of the interventions and at what level of care are they delivered. The review also set out to establish which symptoms in those diagnosed with PPS can be effectively managed with psychological intervention.

METHODS

Studies were included if they clearly reported a psychological intervention, specified the study sample as adults with a diagnosis of persistent physical symptoms, included a comparator and as a minimum an outcome measure of somatic symptoms. Risk of bias was assessed using the EPHPP. Meta-analysis was conducted to estimate the overall effect of interventions on somatic symptoms (the primary outcome), anxiety and depression (secondary outcomes).

RESULTS

Seventeen papers of varying quality indicated that psychological interventions can be effective for the management of somatic symptoms reported by individuals with PPS within a primary care setting. Psychological interventions were also found to be effective at reducing depression symptoms in individuals with PPS in twelve of the included studies. However, the meta-analysis results suggest that the psychological interventions utilized within eleven of the included studies did not significantly impact anxiety symptoms.

CONCLUSIONS

Psychological interventions have some success in managing somatic symptoms in PPS patients within primary care settings although their effects on other psychological symptoms is more mixed. The review highlights the importance of establishing a clearer diagnostic classification to inform treatment trajectories and the need for appropriate training and support within a multi-disciplinary team to enable the provision of such therapies.

Patients With Functional Somatic Syndromes-Fibromyalgia, Irritable Bowel Syndrome, Chronic Headaches, and Chronic Low Back Pain-Have Lower Outcomes and Higher Opioid Usage and Cost After Shoulder and Elbow Surgery

PURPOSE

To perform a systematic review assessing the relationship between functional somatic syndromes (FSSs) and patient-reported outcome measures (PROMs), postoperative opioid consumption, and hospitalization costs after shoulder and elbow surgery.

METHODS

A systematic review of the PubMed and Web of Science databases was conducted according to Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines to identify all studies evaluating the effect of having at least 1 FSS (fibromyalgia, irritable bowel syndrome, chronic headaches, chronic low back pain) on outcomes after shoulder and elbow surgeries. Outcomes of interest included postoperative analgesic use, PROMs, and hospitalization costs.

RESULTS

The review identified a total of 320 studies, of which 8 studies met the inclusion criteria. The total number of participants in our 8 included studies was 57,389. Three studies (n = 620) reported PROMs. These studies demonstrated that the presence of at least 1 FSS is predictive of significantly greater pain scores and lower quality of recovery, Disability Arm Shoulder and Hand, American Shoulder and Elbow Surgeons Shoulder Score, and Single Assessment Numeric Evaluation scores postoperatively. Although scores were inferior in among patients with FSS, 2 of the 3 studies showed improvement in PROMs in this group of patients. Seven studies (n = 56,909) reported postoperative opioid use. Of these, 5 reported that a diagnosis of at least 1 FSS was a strong risk factor for long-term opioid use after surgery. One study (n = 480) found that time-driven activity-based costs were significantly greater in patients with FSSs.

CONCLUSIONS

Patients with functional somatic syndromes have less-favorable PROMs postoperatively, consume more opioids postoperatively, and have greater health care costs after elective shoulder and elbow procedures. Although PROMs among patients with FSSs are inferior compared with those without FSSs, PROMs still improved compared with baseline.

LEVEL OF EVIDENCE

Level III, systematic review of Level II-III studies.

Neurological susceptibility to environmental exposures: pathophysiological mechanisms in neurodegeneration and multiple chemical sensitivity

The World Health Organization lists air pollution as one of the top five risks for developing chronic non-communicable disease, joining tobacco use, harmful use of alcohol, unhealthy diets and physical inactivity. This review focuses on how host defense mechanisms against adverse airborne exposures relate to the probable interacting and overlapping pathophysiological features of neurodegeneration and multiple chemical sensitivity. Significant long-term airborne exposures can contribute to oxidative stress, systemic inflammation, transient receptor subfamily vanilloid 1 (TRPV1) and subfamily ankyrin 1 (TRPA1) upregulation and sensitization, with impacts on olfactory and trigeminal nerve function, and eventual loss of brain mass. The potential for neurologic dysfunction, including decreased cognition, chronic pain and central sensitization related to airborne contaminants, can be magnified by genetic polymorphisms that result in less effective detoxification. Onset of neurodegenerative disorders is subtle, with early loss of brain mass and loss of sense of smell. Onset of MCS may be gradual following long-term low dose airborne exposures, or acute following a recognizable exposure. Upregulation of chemosensitive TRPV1 and TRPA1 polymodal receptors has been observed in patients with neurodegeneration, and chemically sensitive individuals with asthma, migraine and MCS. In people with chemical sensitivity, these receptors are also sensitized, which is defined as a reduction in the threshold and an increase in the magnitude of a response to noxious stimulation. There is likely damage to the olfactory system in neurodegeneration and trigeminal nerve hypersensitivity in MCS, with different effects on olfactory processing. The associations of low vitamin D levels and protein kinase activity seen in neurodegeneration have not been studied in MCS. Table 2 presents a summary of neurodegeneration and MCS, comparing 16 distinctive genetic, pathophysiological and clinical features associated with air pollution exposures. There is significant overlap, suggesting potential comorbidity. Canadian Health Measures Survey data indicates an overlap between neurodegeneration and MCS (p < 0.05) that suggests comorbidity, but the extent of increased susceptibility to the other condition is not established. Nevertheless, the pathways to the development of these conditions likely involve TRPV1 and TRPA1 receptors, and so it is hypothesized that manifestation of neurodegeneration and/or MCS and possibly why there is divergence may be influenced by polymorphisms of these receptors, among other factors.

Prevalence and Characterization of Psychological Trauma in Patients with Fibromyalgia: A Cross-Sectional Study

Background

Preliminary evidence suggests that psychological trauma, especially childhood trauma, is a risk factor for the onset of fibromyalgia (FM).

Objective

The main objective of this study consisted of evaluating the prevalence and detailed characteristics of psychological trauma in a sample of patients with FM, the chronology of trauma across the lifespan, and its clinical symptoms. We also calculated whether childhood trauma could predict the relationship with different clinical variables.

Method

Eighty-eight females underwent an interview to assess sociodemographic data, psychiatric comorbidities, level of pain, FM impact, clinical symptoms of anxiety, depression, insomnia, quality of life, and psychological trauma.

Results

The majority of participants (71.5%) met the diagnostic criteria for current post-traumatic stress disorder (PTSD). Participants reported having suffered traumatic events throughout their lifespan, especially in childhood and early adolescence, in the form of emotional abuse, emotional neglect, sexual abuse, and physical abuse. Traumatic events predict both poor quality of life and a level of pain in adulthood. All patients showed clinically relevant levels of anxiety, depression, insomnia, suicidal thoughts, and pain, as well as somatic comorbidities and poor quality of life. Pain levels predicted anxiety, depression, dissociation, and insomnia symptoms. 84% of the sample suffered one or more traumatic events prior to the onset of pain.

Conclusions

Our data highlight the clinical complexity of patients with FM and the role of childhood trauma in the onset and maintenance of FM, as well as the high comorbidity between anxiety, depression, somatic symptoms, and FM. Our data also supports FM patients experiencing further retraumatization as they age, with an extremely high prevalence of current PTSD in our sample. These findings underscore the need for multidisciplinary programs for FM patients to address their physical pain and their psychiatric and somatic conditions, pay special attention to the assessment of psychological trauma, and provide trauma-focused interventions. Trial registration: ClinicalTrials.gov NCT04476316. Registered on July 20th, 2020.

Fluoxetine reverses hyperactivity of anterior cingulate cortex and attenuates chronic stress-induced hyperalgesia

Somatic symptom disorder (SSD), which occurs in about 5-7 percent of the adult population, involves heightened physical and emotional sensitivity to pain. However, its neural mechanism remains elusive and thus hinders effective clinical intervention. In this study, we employed chronic restraint stress (CRS)-induced hyperalgesia as a mouse model to investigate the neural mechanism underlying SSD and its pharmacological treatment. We found that CRS induced hyperactivity of anterior cingulate cortex (ACC), whereas chemogenetic inhibition of such hyperactivity could prevent CRS-induced hyperalgesia. Systematic application and ACC local infusion of fluoxetine alleviated CRS-induced hyperalgesia. Moreover, we found that fluoxetine exerted its anti-hyperalgesic effects through inhibiting the hyperactivity of ACC and upregulating 5-HT1A receptors. Our study thus uncovers the functional role of 5-HT signaling in modulating pain sensation and provides a neural basis for developing precise clinical intervention for SSD.

An observational study of centrally facilitated pain in individuals with chronic low back pain

Introduction

Central pain facilitation can hinder recovery in people with chronic low back pain (CLBP).

Objectives

The objective of this observational study was to investigate whether indices of centrally facilitated pain are associated with pain outcomes in a hospital-based cohort of individuals with CLBP undertaking a pain management programme.

Methods

Participants provided self-report and pain sensitivity data at baseline (n = 97) and again 3 months (n = 87) after a cognitive behavioural therapy-based group intervention including physiotherapy. Indices of centrally facilitated pain were pressure pain detection threshold, temporal summation and conditioned pain modulation at the forearm, Widespread Pain Index (WPI) classified using a body manikin, and a Central Mechanisms Trait (CMT) factor derived from 8 self-reported characteristics of anxiety, depression, neuropathic pain, fatigue, cognitive dysfunction, pain distribution, catastrophizing, and sleep. Pain severity was a composite factor derived from Numerical Rating Scales. Cross-sectional and longitudinal regression models were adjusted for age and sex.

Results

Baseline CMT and WPI each was associated with higher pain severity (CMT: r = 0.50, P < 0.001; WPI: r = 0.21, P = 0.04) at baseline and at 3 months (CMT: r = 0.38, P < 0.001; WPI: r = 0.24, P = 0.02). High baseline CMT remained significantly associated with pain at 3 months after additional adjustment for baseline pain (β = 2.45, P = 0.04, R 2 = 0.25, P < 0.0001). Quantitative sensory testing indices of pain hypersensitivity were not significantly associated with pain outcomes at baseline or at 3 months.

Conclusion

Central mechanisms beyond those captured by quantitative sensory testing are associated with poor CLBP outcome and might be targets for improved therapy.

The risk factors for self-reported fibromyalgia with and without multiple somatic symptoms: The Lifelines cohort study

OBJECTIVE

The numerous risk factors for fibromyalgia reflect its heterogeneous nature. This study assessed whether the predictors of fibromyalgia onset vary according to number of prior somatic symptoms.

METHODS

The prospective, population-based Lifelines cohort study included 138,617 adults without fibromyalgia or marked muscle pain. At baseline socio-demographic status, physical and psychiatric disorders, psycho-social and behavioural variables were assessed as potential predictors. At follow-up (mean 2.4 years later) new onsets of fibromyalgia were recorded by self-report. The predictors of new onsets of self-reported fibromyalgia were assessed using logistic regression with interaction terms between key variables and number of somatic symptoms.

RESULTS

At follow-up 679 (0.5%) participants reported new onset fibromyalgia. The strongest predictors were: female sex, rheumatoid and osteo-arthritis, IBS, impaired sleep, migraine, few years of education and impairment by bodily pain. Interaction terms with somatic symptoms were significant for years of education, low income, rheumatoid arthritis and no. of analgesics; these were predictors only for fibromyalgia with few somatic symptoms. Participants with multiple somatic symptoms had a higher number of predictors than those with few somatic symptoms.

CONCLUSION

This study suggests that people developing self-reported fibromyalgia with multiple pre-existing somatic symptoms have a high risk factor load reflecting risk factors for both fibromyalgia and multiple somatic symptoms. Self-reported fibromyalgia with few somatic symptoms has fewer predictors which may be specific to fibromyalgia. Future research could usefully study whether different pathophysiological mechanisms occur when fibromyalgia is preceded by high or low number of somatic symptoms.

Dysregulation of serum prolactin links the hypothalamus with female nociceptors to promote migraine

Migraine headache results from activation of meningeal nociceptors, however, the hypothalamus is activated many hours before the emergence of pain. How hypothalamic neural mechanisms may influence trigeminal nociceptor function remains unknown. Stress is a common migraine trigger that engages hypothalamic dynorphin/kappa opioid receptor (KOR) signalling and increases circulating prolactin. Prolactin acts at both long and short prolactin receptor isoforms that are expressed in trigeminal afferents. Following downregulation of the prolactin receptor long isoform, prolactin signalling at the prolactin receptor short isoform sensitizes nociceptors selectively in females. We hypothesized that stress may activate the kappa opioid receptor on tuberoinfundibular dopaminergic neurons to increase circulating prolactin leading to female-selective sensitization of trigeminal nociceptors through dysregulation of prolactin receptor isoforms. A mouse two-hit hyperalgesic priming model of migraine was used. Repeated restraint stress promoted vulnerability (i.e. first-hit priming) to a subsequent subthreshold (i.e. second-hit) stimulus from inhalational umbellulone, a TRPA1 agonist. Periorbital cutaneous allodynia served as a surrogate of migraine-like pain. Female and male KORCre; R26lsl-Sun1-GFP mice showed a high percentage of KORCre labelled neurons co-localized in tyrosine hydroxylase-positive cells in the hypothalamic arcuate nucleus. Restraint stress increased circulating prolactin to a greater degree in females. Stress-primed, but not control, mice of both sexes developed periorbital allodynia following inhalational umbellulone. Gi-DREADD activation (i.e. inhibition through Gi-coupled signalling) in KORCre neurons in the arcuate nucleus also increased circulating prolactin and repeated chemogenetic manipulation of these neurons primed mice of both sexes to umbellulone. Clustered regularly interspaced short palindromic repeats-Cas9 deletion of the arcuate nucleus KOR prevented restraint stress-induced prolactin release in female mice and priming from repeated stress episodes in both sexes. Inhibition of circulating prolactin occurred with systemic cabergoline, a dopamine D2 receptor agonist, blocked priming selectively in females. Repeated restraint stress downregulated the prolactin receptor long isoform in the trigeminal ganglia of female mice. Deletion of prolactin receptor in trigeminal ganglia by nasal clustered regularly interspaced short palindromic repeats-Cas9 targeting both prolactin receptor isoforms prevented stress-induced priming in female mice. Stress-induced activation of hypothalamic KOR increases circulating prolactin resulting in trigeminal downregulation of prolactin receptor long and pain responses to a normally innocuous TRPA1 stimulus. These are the first data that provide a mechanistic link between stress-induced hypothalamic activation and the trigeminal nociceptor effectors that produce trigeminal sensitization and migraine-like pain. This sexually dimorphic mechanism may help to explain female prevalence of migraine. KOR antagonists, currently in phase II clinical trials, may be useful as migraine preventives in both sexes, while dopamine agonists and prolactin/ prolactin receptor antibodies may improve therapy for migraine, and other stress-related neurological disorders, in females.

Review article: Physical and psychological comorbidities associated with irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders encountered by physicians in primary and secondary care. Patients with IBS commonly present with various extraintestinal complaints, which account for a substantial clinical and economic burden. The common extraintestinal comorbidities associated with IBS include anxiety, depression, somatisation, fibromyalgia, chronic fatigue syndrome, chronic pelvic pain, interstitial cystitis, sexual dysfunction and sleep disturbance. The presence of comorbidity in IBS poses a diagnostic and therapeutic challenge with patients frequently undergoing unnecessary investigations and interventions, including surgery. This review discusses the different physical and psychological comorbidities associated with IBS, the shared pathophysiological mechanisms and potential management strategies.

Longitudinal qEEG changes correlate with clinical outcomes in patients with somatic symptom disorder

OBJECTIVE

The quantitative electroencephalography (qEEG) of patients with somatic symptom disorder (SSD) was not yet thoroughly studied. This study aimed to investigate qEEG of SSD patients compared with those of normal controls (NCs), and changes therein after treatment.

METHODS

SSD patients currently without treatment and age- and sex-matched NCs were recruited. Spectral analysis of 64-channel EEG recording was performed and somatization, anxiety, and depression were evaluated via self-rating scales at baseline. After six months of treatment as usual, SSD patients were longitudinally followed up for assessments.

RESULTS

At baseline, the SSD group (n = 44) had higher alpha (p = 0.047) and lower beta 2 (p = 0.027) and gamma power (p = 0.001) compared with NCs (n = 29). After 6-month treatment, SSD patients showed improvement in symptoms, as well as increased beta 1 (p = 0.032), beta 2 (p = 0.012), and gamma power (p = 0.009) compared with baseline. A significant correlation was observed between the change in somatization score and temporal gamma power (r = -0.424, p = 0.031), and between the change in anxiety score and beta 2 power in the frontal (r = -0.420, p = 0.033) and central (r = -0.484, p = 0.012) regions.

CONCLUSIONS

EEG findings in this study may provide neurophysiological features of SSD. The alpha enhancement and reduced fast wave activity may reflect attentional dysfunction in patients with SSD. Decreased fast wave activity is reversible and may serve as a state marker of SSD.

Biomarkers in Interstitial Cystitis/Bladder Pain Syndrome with and without Hunner Lesion: A Review and Future Perspectives

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a debilitating urinary bladder condition that presents with a wide variety of clinical phenotypes. It is commonly characterized by persistent pelvic pain and lower urinary tract symptoms, such as urinary frequency and urgency. Current clinicopathological and genomic evidence has indicated that IC/BPS with Hunner lesions is a clinically relevant distinct subtype with proven bladder pathology of subepithelial chronic inflammatory changes that are characterized by enhanced local immune responses and epithelial denudation. However, other forms of IC/BPS lacking Hunner lesions are a symptom syndrome complex of non-inflammatory conditions with little evidence of bladder etiology, characterized by aberrant neural activity in neurotransmission systems which leads to central nervous sensitization with potential involvement of urothelial malfunction, or clinical presentation of somatic and/or psychological symptoms beyond the bladder. Given such distinct potential pathophysiology between IC/BPS subtypes, disease biomarkers of IC/BPS should be provided separately for subtypes with and without Hunner lesions. Tailored approaches that target characteristic immunological inflammatory processes and epithelial denudation for IC/BPS with Hunner lesions, or the sensitized/altered nervous system, urothelial malfunction, association with other functional somatic syndromes, and psychosocial problems for IC/BPS without Hunner lesions, are essential to identify optimal and reliable disease-specific IC/BPS biomarkers.

Central sensitisation in chronic fatigue syndrome and fibromyalgia; a case control study

INTRODUCTION

Chronic fatigue syndrome (CFS) and fibromyalgia (FM) are both complex conditions that are challenging to treat. This may be related to an incomplete understanding of their pathophysiology, itself obfuscated by their heterogeneity. The symptomatic overlap between them and their common comorbidity suggests a shared vulnerability, which might be explained by central sensitisation.

METHODS

19 CFS cases, 19 FM cases and 20 age and sex matched healthy controls (HC) were recruited primarily from secondary care clinics in London. Those with other pain disorders, psychiatric diagnoses and those taking centrally acting or opiate medications were excluded. Participants were asked to abstain from alcohol and over the counter analgaesia 48 h prior to assessment by static and dynamic quantitative sensory tests, including measures of temporal summation (TS) and conditioned pain modulation (CPM).

RESULTS

CS, as defined by the presence of both enhanced TS and inefficient CPM, was present in 16 (84%) CFS cases, 18 (95%) FM cases, and none of the HC (p < 0.001). Pressure pain thresholds were lower in CFS (Median222kPaIQR 146-311; p = 0.04) and FM cases (Median 189 kPa; IQR 129-272; p = 0.003) compared to HC (Median 311 kPa; IQR 245-377). FM cases differed from HC in cold-induced (FM = 22.6 °C (15.3-27.7) vs HC = 14.2 °C (9.0-20.5); p = 0.01) and heat-induced (FM = 38.0 °C (35.2-44.0) vs HC = 45.3 °C (40.1-46.8); p = 0.03) pain thresholds, where CFS cases did not.

CONCLUSION

Central sensitisation may be a common endophenotype in chronic fatigue syndrome and fibromyalgia. Further research should address whether central sensitisation is a cause or effect of these disorders.

Conditioned pain modulation and pain sensitivity in functional somatic disorders: The DanFunD study

Background

Disrupted pain regulation has been proposed as a component in functional somatic disorders (FSD). The objective of this study was to examine a general population sample, encompassing three delimitations of FSD while assessing pain sensitivity and conditioning pain modulation (CPM).

Methods

Pressure pain thresholds (PPTs) at the tibialis and trapezius muscles were recorded at baseline. During cold pressor stimulation of the hand, the tibialis PPTs were re‐assessed and the difference from baseline measures defined the CPM effect. Participants (n = 2,198, 53% females) were randomly selected from the adult Danish population. FSD was established by self‐reported symptom questionnaires.

Results

With a few exceptions, only weak associations were seen between PPTs and CPM in cases with FSD (p > .1). A high PPT was associated with lower odds of having multi‐organ bodily distress syndrome (OR^{PPT trapezius}: 0.66, 95% CI: 0.49–0.88, p = .005), with the symptom profile characterized by all symptoms (OR^{PPT trapezius}: 0.72, 95% CI: 0.58–0.90, p = .003 and OR^{PPT tibialis}: 0.75, 95% CI: 0.62–0.91, p = .004), and with multiple chemical sensitivity (OR^{PPT trapezius}: 0.81, 95% CI: 0.67–0.97, p = .022). High CPM was associated with high odds of having irritable bowel (OR^{CPM relative}: 1.22, 95% CI: 1.04–1.43, p = .013 and OR^{CPM absolute} = 2.66, 95% CI: 1.07–6.45, p = .033).

Conclusion

However, only PPT measured over the trapezius muscle were still significant after correction for multiple testing for the symptom profile characterized by all symptoms. Findings from this study do not support altered pain regulation in questionnaire‐based FSD which is in contrast with the existing presumption. Further epidemiological studies in this field are needed.

Significance

Disrupted pain regulation as measured by abnormal pain thresholds has been hypothesized as a central mechanism in Functional Somatic Disorders (FSD). The hypothesis has been raised in clinical setting where patients presented subjective and objective features of hypersensitivity. The present population‐based study does not support this notion. This points to the importance of further studies into the underlying pathophysiology mechanisms of FSD.

Central Sensitivity and Fibromyalgia

Fibromyalgia presents with symptoms of widespread pain, fatigue, sleeping and cognitive disturbances as well as other somatic symptoms. It often overlaps with other conditions termed 'central sensitivity syndromes' such as irritable bowel syndrome, chronic fatigue syndrome and temporomandibular disorder. Central sensitisation, mediated by amplified processing in the central nervous system, has been identified as the key pathogenic mechanism in these disorders. The term 'central sensitivity' can be used to collectively describe the clinical presentation of these disorders. Fibromyalgia is highly prevalent in most rheumatic diseases as well as non-rheumatic chronic diseases and if unrecognised results in high morbidity. It is diagnosed clinically after excluding important differential diagnoses. Diagnostic criteria have been developed as tools to help identify and diagnose fibromyalgia. Such tools can fulfill an important need when managing patients with rheumatic disease and other chronic diseases as a way to identify fibromyalgia and improve patient outcomes. Treatment involves an integrated approach including education, exercise, stress reduction and pharmacological therapies targeting the central nervous system. This approach is suitable for all presentations of central sensitivity and some central sensitivity syndromes have additional treatment options specific to the clinical presentation. This article is protected by copyright. All rights reserved.

Medically unexplained symptoms: assessment and management

Medically unexplained symptoms or persistent physical symptoms are common, real and are associated with significant distress, loss of functioning and high healthcare costs. History, examination and appropriate investigations are essential to make a diagnosis. Once the diagnosis has been made, exploring the impact of the symptoms helps us to tailor our advice to patients. This paper sets out a practical approach to taking a history, assessment and stepwise management principles.

Electroencephalography During Nociceptive Stimulation in Chronic Pain Patients: A Systematic Review

BACKGROUND

With its high temporal resolution, electroencephalography (EEG), a technique that records electrical activity of cortical neuronal cells, is a potentially suitable technique to investigate human somatosensory processing. By using EEG, the processing of (nociceptive) stimuli can be investigated, along with the functionality of the nociceptive pathway. Therefore, it can be applied in chronic pain patients to objectify whether changes have occurred in nociceptive processing. Typically, so-called event-related potential (ERP) recordings are used, where EEG signals are recorded in response to specific stimuli and characterized by latency and amplitude.

OBJECTIVE

To summarize whether differences in somatosensory processing occur between chronic pain patients and healthy controls, measured with ERPs, and determine whether this response is related to the subjective pain intensity.

DESIGN

Systematic review.

SETTING AND METHODS

PubMed, Web of Science, and Embase were consulted, and 18 case-control studies were finally included.

SUBJECTS

The chronic pain patients suffered from tension-type headache, back pain, migraine, fibromyalgia, carpal tunnel syndrome, prostatitis, or complex regional pain syndrome.

RESULTS

Chronic neuropathic pain patients showed increased latencies of the N2 and P2 components, along with a decreased amplitude of the N2-P2 complex, which was also obtained in FM patients with small fiber dysfunction. The latter also showed a decreased amplitude of the N2-P3 and N1-P1 complex. For the other chronic pain patients, the latencies and the amplitudes of the ERP components did not seem to differ from healthy controls. One paper indicated that the N2-P3 peak-to-peak amplitude correlates with the subjective experience of the stimulus.

CONCLUSIONS

Differences in ERPs with healthy controls can mostly be found in chronic pain populations that suffer from neuropathic pain or where fiber dysfunction is present. In chronic pain populations with other etiological mechanisms, limited differences were found or agreed upon across studies.

"My private theory is that it's all in the head": Understandings of chronic widespread pain among social workers from municipality job centers in Denmark

People with chronic widespread pain (CWP) are often unfit for work, and consequently they are dependent on the municipality job center to receive social support and sickness benefits. The job center's case management is based on a social worker's assessment of the citizen's health condition. This qualitative study investigates social workers' understandings of CWP. Interviews were carried out with 12 social workers. The results showed that the participants predominantly experienced the citizens' illnesses as psychosocially mediated-referring to trauma, or a lack of meaning in the citizens' lives. Only a few participants mentioned possibilities for somatic explanations of CWP.

The relationship of cortical activity induced by pain stimulation with clinical and cognitive features of somatic symptom disorder: A controlled functional near infrared spectroscopy study

OBJECTIVE

The neurobiological correlates of Somatic Symptom Disorder (SSD) introduced in the DSM-5 has been the focus of a limited investigation. We aimed to examine the cortical response to painful stimuli and its relationship to symptom severity as well as cognitive and psychological characteristics in proposed models of somatoform disorders.

METHODS

We measured hemodynamic responses by 52-channel functional near-infrared spectroscopy. We compared the cortical response to painful stimuli in index patients with SSD (N = 21) versus age, and gender matched healthy control subjects (N = 21). We used brush stimulation as the control condition. We analyzed the relationship of cortical activity with SSD symptom severity as well as somatosensory amplification (SSA), alexithymia, dysfunctional illness behaviour, worry, and neuroticism.

RESULTS

Patients with SSD had higher somatic symptom severity, SSA, alexithymia, neuroticism, illness-related worry, and behaviour. Somatic symptom severity was predicted by a model including SSA and subjective feeling of pain in the index patients. Activity in the left-angular and right-middle temporal gyri was higher in the SSD subjects than the controls during pain stimulation. Positive correlations were detected between mean pain threshold levels and left middle occipital gyrus activity, as well as between SSA-scores and right-angular gyrus activity during pain condition in the index patients with SSD.

CONCLUSION

We present the first evidence that representation of pain in terms of cortical activity is different in subjects with SSD than healthy controls. SSA has functional neuroanatomic correlates and predicts symptom severity in SSD and therefore is involved as a valid intermediate phenotype in SSD pathophysiology.

Internet-Administered Emotional Awareness and Expression Therapy for Somatic Symptom Disorder With Centralized Symptoms: A Preliminary Efficacy Trial

Background: There is growing evidence that trauma, psychosocial conflict, and difficulties with emotional processing contribute to centralized somatic symptoms. Emotional Awareness and Expression Therapy (EAET) was developed to address these factors and reduce symptoms, and EAET has shown efficacy in face-to-face formats. No trial of an internet-delivered EAET (I-EAET) exists, however, so we developed such an intervention and conducted an uncontrolled feasibility and potential efficacy trial of I-EAET for patients with Somatic Symptom Disorder (SSD) with centralized symptoms (SSD-CS). Method: After screening potential participants, a sample of 52 patients (50 women, two men; age M = 49.6, SD = 11.9) diagnosed with SSD-CS initiated treatment. I-EAET consisted of nine weekly modules focused on psychoeducation, emotional awareness and exposure, and anxiety regulation with self-compassion. Therapists communicated with each patient by email for about 20 min per week during treatment, answering questions and giving feedback on homework assignments. Patients completed measures of somatic symptoms, depression, anxiety, trauma-related symptoms, and functional disability before treatment and again at post-treatment and 4-month follow-up. Results: A large reduction in somatic symptoms (PHQ-15) occurred pre-to post-treatment (d = 1.13; 95% CI: 0.84-1.47) which was fully maintained at 4-month follow-up (d = 1.19; 95% CI: 0.88-1.56). Twenty-three percent of the patients at post-treatment and 27% at follow-up achieved a 50% or greater reduction in somatic symptoms, and about 70% achieved a minimally important clinical difference. In addition, at post-treatment, there were small to medium reductions (d's from 0.33 to 0.72) in anxiety (GAD-7), depression (PHQ-9), trauma-related symptoms (PCL-5), and functional disability (Sheehan Disability Scale). For all of these secondary outcomes, improvements were slightly to substantially larger at follow-up than at post-treatment (d's from 0.46 to 0.80). Conclusion: I-EAET appears to be a feasible treatment for adults with SSD and centralized symptoms, resulting in substantial and durable improvement not only in somatic symptoms but in other psychiatric symptoms and functioning. Controlled trials are needed determine the effects of I-EAET specifically and how this approach compares to face-to-face EAET and to other internet-delivered treatments, such as cognitive-behavioral interventions. Research should also identify treatment responders and mechanisms of change in EAET. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT04122846.

The Effects of Complete Decongestive Therapy or Intermittent Pneumatic Compression Therapy or Exercise Only in the Treatment of Severe Lipedema: A Randomized Controlled Trial

Background: Lack of diagnostic awareness of lipedema and frequent confusion with obesity or lymphedema may be an obstacle for treatment. The clinical effects of conservative treatment methods are not clearly known. This study investigated the effects of exercise-based rehabilitation combined with complete decongestive therapy (CDT) or intermittent pneumatic compression therapy (IPCT) or alone in patients with severe lipedema. Methods: Thirty-three women with severe (type 3, stage III or IV) lipedema diagnosed according to the revised-Wold criteria were randomized into three groups: Group 1 (CDT plus exercises), Group 2 (IPCT plus exercises), and Group 3 (control-exercises alone). All groups received 30 sessions of combined (aerobic, strengthening, and stretching) exercise program. In addition, there were CDT in Group 1 and IPCT in Group 2 five times a week for 6 weeks. The primary outcome measure was the limb volume measurements. The secondary outcome measures were anthropometric measurements (body weight, body mass index, waist-to-height ratio, waist-to-hip ratio), 6-minute walk test, visual analog scale for pain, fatigue severity scale, Beck Depression Inventory, and Short Form Health Survey-36 (SF-36). Results: Thirty-one participants completed the interventions. Limb volumes (p = 0.017, ηp² = 0.562 for right; p < 0.001, ηp² = 0.775 for left), pain (p = 0.045, ηp² = 0.199), and physical functioning subscore of SF-36 (p = 0.040, ηp² = 0.465) differed significantly between treatments originating from Group 1. Conclusions: All programs improved outcome measurements after the intervention. However, when the difference between treatments was investigated, CDT administered in addition to the exercises has been shown to provide significant improvements in reducing limb volumes, pain, and physical function. Clinical trial registration number: The study was registered at the US National Institutes of Health (ClinicalTrials.gov) (NCT03924999) and available at https://clinicaltrials.gov/ct2/show/NCT03924999?term=lipedema&draw=2&rank=6.

Characterization and preclinical evaluation of a protease activated receptor 2 (PAR2) monoclonal antibody as a preventive therapy for migraine

AIM

Migraine pain is thought to result from activation of meningeal nociceptors that might involve dural mast cell degranulation and release of proteases and pronociceptive mediators. Tryptase, the most abundant dural mast cell protease, has been demonstrated to stimulate dural mast cells, as well as trigeminal nociceptors by activating the protease activated receptor 2. Mast cell or neuronal protease activated receptors 2 may therefore represent a novel target for migraine treatment. In this study, we characterized and evaluated a novel protease activated receptor 2 monoclonal antibody as a preventive anti-migraine pain therapy in preclinical models.

METHODS

Flow cytometry, immunocytochemistry, calcium imaging, Homogeneous Time Resolved Technology (HTRF) epitope competition assay and serum pharmacokinetic (PK) assay in rats were performed to confirm the activity, specificity and in vivo stability of PAR650097, a novel anti- protease activated receptor 2 monoclonal antibody. In vivo assessment was performed in female C57BL/6J mice by evaluation of PAR650097 in preventing cutaneous allodynia elicited by (a) supradural injection of the protease activated receptor 2 agonist, Ser-Leu-Ile-Gly-Arg-Leu-amide trifluoroacetate (SLIGRL), or calcitonin gene-related (CGRP) peptide, and (b) induction of latent sensitization by priming with three daily episodes of restraint stress followed by challenge with a subthreshold inhalational exposure to umbellulone (UMB), a transient receptor potential ankyrin 1 (TRPA1) agonist. PAR650097 was administered as a pretreatment prior to the first restraint stress, umbellulone exposure, SLIGRL or calcitonin gene-related peptide injection. Additionally, fremanezumab, a calcitonin gene-related peptide antibody was administered as pre-treatment prior to supradural administration of calcitonin gene-related peptide or SLIGRL.

RESULTS

In vitro, PAR650097 demonstrated rapid interaction with protease activated receptor 2, enabling it to fully inhibit protease-induced protease activated receptor 2 activation, in human and mouse cells, with high potency. Furthermore, PAR650097 was highly selective for protease activated receptor 2, demonstrating no affinity for protease activated receptor 1 protein and no functional effect on the activation of cellular protease activated receptor 1 with thrombin. In addition, PAR650097 had an acceptable PK profile, compatible with testing the effects of selective protease activated receptor 2 inhibition in vivo. In vivo, PAR650097 blocked cutaneous allodynia induced by either supradural SLIGRL or calcitonin gene-related peptide. Fremanezumab abolished cutaneous allodynia induced by supradural CGRP, and partially attenuated cutaneous allodynia induced by SLIGRL. Administration of PAR650097, before the first restraint stress episode, did not prevent the acute stress-induced cutaneous allodynia or restraint stress priming revealed by cutaneous allodynia induced by inhalational umbellulone. In contrast, PAR650097 prevented expression of cutaneous allodynia when given before the umbellulone challenge in restraint stress-primed animals.

CONCLUSION

PAR650097 specifically inhibits endogenously expressed protease activated receptor 2 in human and mouse cells with high potency. This antibody has an acceptable PK profile in rodents and effectively blocked SLIGR-induced cutaneous allodynia. PAR650097 additionally prevented cutaneous allodynia induced by supradural calcitonin gene-related peptide, indicating that the protease activated receptor 2 receptor is a downstream consequence of calcitonin gene-related peptide actions. Fremanezumab effectively blocked calcitonin gene-related peptide-induced cutaneous allodynia and only partially reduced cutaneous allodynia induced by a protease activated receptor 2 activator, suggesting both calcitonin gene-related peptide-dependent and -independent mechanisms in promoting migraine pain. While PAR650097 did not prevent stress-induced cutaneous allodynia or priming, it effectively prevented cutaneous allodynia induced by a TRPA1 agonist in animals with latent sensitization. Activation of protease activated receptor 2, therefore, contributes to both calcitonin gene-related peptide-dependent and -independent mechanisms in promoting migraine-like pain. Therapeutic targeting of protease activated receptor 2 receptors may represent an anti-migraine pain strategy with a potentially broad efficacy profile.

Alexithymia and Somatization in Chronic Pain Patients: A Sequential Mediation Model

OBJECTIVE

To investigate whether chronic pain (CP) patients with somatization reported higher alexithymic traits than those without somatization and to study the different relationships between psychological characteristics, pain, health-related quality of life (HRQL), and somatization.

METHOD

A consecutive sample of 134 CP treatment-seeking outpatients were evaluated for alexithymia (TAS-20), somatization (PHQ-15), distress (HADS), HRQL (SF-12), and pain (BPI).

RESULTS

Patients with somatization (37.04%) reported significantly higher TAS-20 total scores (p < 0.001) and difficulty in identifying feelings (DIF) (p < 0.001) than those without somatization. The somatizer group had also a significantly higher disease duration, severity and interference of pain, distress, and lower HRQL than the non-somatizer group. Hierarchical regression analysis showed that although distress, pain interference and the mental HRQL component are closely related to somatization (R 2 = 0.55), DIF was the strongest predictor of severity of somatization (β = 0.31). A sequential indirect effect from DIF to somatization via distress symptoms and pain interference turned out to be significant [95% CI (0.01, 0.09)]. Support was also found for sequential mediation paths from DIF to somatization via distress and mental HRQL [95% CI (0.01, 0.11)].

CONCLUSIONS

Our results pointed-out that alexithymia, particularly DIF, may be major factor for somatization risk in CP patients. Longitudinal observations are needed for evaluating the role of alexithymia in clinical outcomes.

Pain in adolescent chronic fatigue following Epstein-Barr virus infection

Objectives Acute Epstein-Barr virus (EBV) infection is a trigger of Chronic Fatigue (CF) and Chronic Fatigue Syndrome (CFS). The aim of this cross-sectional study was to investigate pain symptoms and pressure pain thresholds in fatigued and non-fatigued adolescents six months after acute EBV-infection, and in healthy controls. This study is part of the CEBA-project (CF following acute EBV infection in adolescents). Methods A total of 195 adolescents (12-20 years old) that had undergone an acute EBV infection six months prior to assessment were divided into fatigued (EBV CF+) and non-fatigued (EBV CF-) cases based on questionnaire score. The EBV CF+ cases were further sub-divided according to case definitions of CFS. In addition, a group of seventy healthy controls was included. Symptoms were mapped with questionnaires. Pressure pain thresholds were measured through pressure algometry. One way ANOVA were used for between-group analyses. Linear regression analyses were used to explore associations between Pediatric Quality of Life (dependent variable), pain symptoms and other variables within the EBV (CF+) group. Results The EBV CF+ group had significantly higher scores for pain symptoms as compared with the EBV CF- group and healthy controls, but pressure pain threshold did not differ significantly. The number of pain symptoms as well as pain severity were strongly and independently associated with quality of life. Conclusions CF and CFS following acute EBV-infection in adolescents is characterized by high pain symptom burden, which in turn is associated with a decline in quality of life. Pain in CF and CFS is of considerable clinical importance, and should be a focal point for further investigation and intervention in these patient groups.

Changes in brain glucose metabolism and connectivity in somatoform disorders: an 18F-FDG PET study

Somatoform disorders (SFD) are defined as a syndrome characterized by somatic symptoms which cannot be explained by organic reasons. Chronic or recurrent forms of somatization lead to heavy emotional and financial burden to the patients and their families. However, the underlying etiology of SFD is largely unknown. The purpose of this study is to investigate the changed brain glucose metabolic pattern in SFD. In this study, 18 SFD patients and 21 matched healthy controls were enrolled and underwent an ¹⁸F-FDG PET scan. First, we explored the altered brain glucose metabolism in SFD. Then, we calculated the mean ¹⁸F-FDG uptake values for 90 AAL regions, and detected the changed brain metabolic connectivity between the most significantly changed regions and all other regions. In addition, the Pearson coefficients between the neuropsychological scores and regional brain ¹⁸F-FDG uptake values were computed for SFD patients. We found that SFD patients showed extensive hypometabolism in bilateral superolateral prefrontal cortex, insula, and regions in bilateral temporal gyrus, right angular gyrus, left gyrus rectus, right fusiform gyrus, right rolandic operculum and bilateral occipital gyrus. The metabolic connectivity between right insula and prefrontal areas, as well as within prefrontal areas was enhanced in SFD. And several brain regions were associated with the somatic symptoms, including insula, putamen, middle temporal gyrus, superior parietal gyrus and orbital part of inferior frontal gyrus. Our study revealed widespread alterations of the brain glucose metabolic pattern in SFD patients. Those findings might elucidate the neuronal mechanisms with glucose metabolism and shed light on the pathology of SFD.

A novel, injury-free rodent model of vulnerability for assessment of acute and preventive therapies reveals temporal contributions of CGRP-receptor activation in migraine-like pain

AIM

Development and characterization of a novel injury-free preclinical model of migraine-like pain allowing mechanistic assessment of both acute and preventive treatments.

METHODS

A "two-hit" hyperalgesic priming strategy was used to induce vulnerability to a normally subthreshold challenge with umbellulone, a transient receptor potential ankyrin 1 (TRPA1) activator, in uninjured female and male C57BL/6 mice. Priming (i.e. the first hit) was induced by three consecutive daily episodes of restraint stress; repeated umbellulone was also evaluated for potential priming effects. Sixteen days after the first restraint stress, mice received inhalational umbellulone (i.e. the second hit) to elicit migraine-like pain. Medications currently used for acute or preventive migraine therapy including propranolol (a beta blocker) and sumatriptan (5HT1_B/D agonist), as well as olcegepant, an experimental calcitonin gene related peptide (CGRP) receptor antagonist and nor-Binaltorphimine (nor-BNI), an experimental long-acting kappa opioid receptor (KOR) antagonist, were investigated for their efficacy to block priming and prevent or reverse umbellulone-induced allodynia in primed animals. To assess migraine-like pain, cutaneous allodynia was determined by responses to periorbital or hindpaw probing with von Frey filaments.

RESULTS

Repeated restraint stress, but not umbellulone exposure, produced transient cutaneous allodynia that resolved within 16 d. Restraint stress produced long-lasting priming that persisted beyond 16 d, as demonstrated by reinstatement of cutaneous allodynia following inhalational umbellulone challenge. Pretreatment with propranolol or nor-BNI prior to restraint stress prevented both transient cutaneous allodynia and priming, demonstrated by a lack of umbellulone-induced cutaneous allodynia. Following establishment of restraint stress priming, olcegepant, but not propranolol or nor-BNI, prevented umbellulone-induced cutaneous allodynia. When administered 1 h after umbellulone, sumatriptan, but not olcegepant, reversed umbellulone-induced cutaneous allodynia in restraint stress-primed rats.

CONCLUSION

We have developed a novel injury-free model with translational relevance that can be used to study mechanisms relevant to migraine-like pain and to evaluate novel acute or preventive treatments. Restraint stress priming induced a state of vulnerability to a subthreshold stimulus that has been referred to as "latent sensitization". The development of latent sensitization could be prevented by blockade of stress pathways with propranolol or with a kappa opioid receptor antagonist. Following establishment of latent sensitization, subthreshold stimulation with umbellulone reinstated cutaneous allodynia, likely from activation of meningeal TRPA1-expressing nociceptors. Accordingly, in restraint stress-primed animals, sumatriptan reversed umbellulone-induced cutaneous allodynia, supporting peripheral sites of action, while propranolol and nor-BNI were not effective. Surprisingly, olcegepant was effective in mice with latent sensitization when given prior to, but not after, umbellulone challenge, suggesting time-dependent contributions of calcitonin gene-related peptide receptor signaling in promoting migraine-like pain in this model. Activation of the calcitonin gene-related peptide receptor participates in initiating, but has a more limited role in maintaining, pain responses, supporting the efficacy of small molecule calcitonin gene-related peptide antagonists as preventive medications. Additionally, the effectiveness of sumatriptan in reversal of established pain thus suggests modulation of additional, non-calcitonin gene-related peptide receptor-mediated nociceptive mechanisms. Kappa opioid receptor antagonists may represent a novel preventive therapy for stress-related migraine.

Association between dysmenorrhea and chronic pain: a systematic review and meta-analysis of population-based studies

OBJECTIVE

The objective of the study was to synthesize the epidemiological findings for the associations between dysmenorrhea, including primary dysmenorrhea and endometriosis-associated dysmenorrhea and any chronic pain conditions, including chronic pelvic pain, and chronic nonpelvic pain.

DATA SOURCES

The data sources included PubMed, Embase, and CINAHL from inception to December 2019.

STUDY ELIGIBILITY CRITERIA

The study criteria included observational population-based studies in which the relationship between dysmenorrhea and the presence or severity of chronic pain was examined.

STUDY APPRAISAL AND SYNTHESIS METHODS

Each study was double coded and evaluated for bias based on the modified Newcastle and Ottawa Scale. Random-effect meta-analyses were conducted to quantify the associations between dysmenorrhea and the presence of chronic pelvic and nonpelvic pain.

RESULTS

Out of 9452 records, 32 studies were included, with 14 reporting associations between dysmenorrhea and chronic pelvic pain, and 20 for dysmenorrhea and chronic nonpelvic pain. Primary dysmenorrhea and endometriosis-associated dysmenorrhea were examined in 7 studies, respectively. More than 30% of the studies were categorized as poor quality, 56% as moderate, and 12.5% as high. Dysmenorrhea was positively associated with both the presence and severity of chronic pelvic and nonpelvic pain conditions. Based on 6689 women from 8 studies, those with chronic pelvic pain had 2.43 (95% confidence interval, 1.98-2.99, I², 42%) times the odds of having dysmenorrhea compared with those without. Based on 3750 women from 11 studies, those with chronic nonpelvic pain had 2.62 (95% confidence interval, 1.84-3.72, I², 72%) times the odds of having dysmenorrhea compared with those without. Overall, dysmenorrhea was associated with 2.50 (95% confidence interval, 2.02-3.10) times the odds of chronic pain, which did not differ by chronic pelvic vs chronic nonpelvic pain, community vs clinical populations, or different geographical regions.

CONCLUSIONS

Dysmenorrhea may be a general risk factor for chronic pain, although whether primary dysmenorrhea increases the risk for chronic pain is unclear. Given that adolescence is a sensitive period for neurodevelopment, elucidating the role of primary dysmenorrhea in pain chronicity in future longitudinal studies is important for preventing both chronic pelvic and nonpelvic pain.

Evolution of bodily distress disorders

PURPOSE OF REVIEW

The nomenclature and classification of somatoform disorders have undergone revisions in the fifth edition of the Diagnostic and Statistical Manual (DSM 5) and the upcoming eleventh edition of the International Classification of Diseases (ICD-11). The present review describes the changes that have evolved and highlight the possible challenges.

RECENT FINDINGS

Bodily distress disorders replace the term somatoform disorders. The emphasis on the symptoms to be medically unexplained has been removed. The need to have a certain number of symptoms associated with different organ systems has made way to the presence of one or more distressing bodily symptoms. The focus on psychological aspects like excessive attention, thoughts, and behaviors associated with bodily symptoms have been added to make it a more diagnosis of inclusion rather than exclusion. An additional qualifier of severity has been added, which highlights the importance of impairment associated with these symptoms.

SUMMARY

The diagnostic criteria for bodily distress disorders is a step towards making the diagnostic criteria clinically useful and appears to be applicable across the healthcare settings. However, the ability to discern this diagnosis with the newly revised classification of chronic pain and the possibility of over psychologizing the medical disorders need to be researched.

Anxiety-related factors associated with symptom severity in irritable bowel syndrome

BACKGROUND

Gastrointestinal symptom-specific anxiety and somatization have both been associated with higher symptom severity in patients with irritable bowel syndrome (IBS); however, this relationship has not been explored fully. Moreover, the performance of the visceral sensitivity index (VSI) for measuring gastrointestinal symptom-specific anxiety has not been examined in a UK population. We conducted a cross-sectional survey to examine these issues.

METHODS

Gastrointestinal symptom-specific anxiety was measured using the VSI, and somatization was measured via the patient health questionnaire-12 (PHQ-12) in adults from the UK community with Rome IV-defined IBS. Exploratory factor analysis was performed on the VSI, prior to subsequent analyses, to establish its factor structure. Multiple regression analysis was used to determine the relationship between demographic features, different factors of the VSI, somatization, and IBS symptom severity.

KEY RESULTS

A total of 811 individuals with IBS provided complete data. Factor analysis of the VSI revealed a three-factor structure, accounting for 47% of the variance. The first of these VSI factors and the PHQ-12 were both strongly and independently associated with IBS symptom severity, for the group as a whole and for all four IBS subtypes. Most VSI items concerned with overt gastrointestinal symptom-specific anxiety loaded onto the other two VSI factors that were not associated with symptom severity.

CONCLUSIONS AND INFERENCES

The factor structure of the VSI requires further investigation. Our findings cast doubt on the central role of gastrointestinal symptom-specific anxiety as a driver for symptom severity in IBS. Awareness of both gastrointestinal and extra-intestinal symptoms, however, is strongly associated with symptom severity.

Is oral dysaesthesia a somatic symptom disorder?

Oral dysaesthesia is a condition characterised by persistent alteration to oral sensation, perceived by the patient to be abnormal and unpleasant, in the absence of mucosal pathology. Its aetiology remains uncertain. The condition was attributed as a psychosomatic disease for much of the 20th century, but with newer technologies, recent literature has mostly focused on a possible peripheral or central neuropathic aetiology to oral dysaesthesia. Despite this, psychotropic medications and psychological treatments remain forefront in the armamentarium for the management of oral dysaesthesia. This article aims to review the literature surrounding the pathogenesis of oral dysaesthesia and explore whether oral dysaesthesia is a somatic symptom disorder.

Interstitial cystitis/bladder pain syndrome: The evolving landscape, animal models and future perspectives

Interstitial cystitis/bladder pain syndrome is a debilitating condition of unknown etiology characterized by persistent pelvic pain with lower urinary tract symptoms and comprises a wide variety of potentially clinically useful phenotypes with different possible etiologies. Current clinicopathological and genomic evidence suggests that interstitial cystitis/bladder pain syndrome should be categorized by the presence or absence of Hunner lesions, rather than by clinical phenotyping based on symptomatology. The Hunner lesion subtype is a distinct inflammatory disease with proven bladder etiology characterized by epithelial denudation and enhanced immune responses frequently accompanied by clonal expansion of infiltrating B cells, with potential engagement of infection. Meanwhile, the non-Hunner lesion subtype is a non-inflammatory disorder with little evidence of bladder etiology. It is potentially associated with urothelial malfunction and neurophysiological dysfunction, and frequently presents with somatic and/or psychological symptoms, that commonly result in central nervous sensitization. Animal models of autoimmune cystitis and neurogenic sensitization might serve as disease models for the Hunner lesion and non-Hunner lesion subtypes, respectively. Here, we revisit the taxonomy of interstitial cystitis/bladder pain syndrome according to current research, and discuss its potential pathophysiology and representative animal models. Categorization of interstitial cystitis/bladder pain syndrome based on cystoscopy is mandatory to design optimized treatment and research strategies for each subtype. A tailored approach that specifically targets the characteristic inflammation and epithelial denudation for the Hunner lesion subtype, or the urothelial malfunction, sensitized/altered nervous system and psychosocial problems for the non-Hunner lesion subtype, is essential for better clinical management and research progress in this complex condition.

Persistence of chronic cough in a community-based population

Chronic cough causes significant impairment in the quality of life and is often immune to treatment. Previous studies about its persistence have focused on patients managed in special cough clinics. Little is known about the persistence of chronic cough in unselected populations. In this prospective follow-up study, we investigated factors that predict the persistence of cough at 12-month follow-up in a community-based study of subjects with chronic cough. The first e-mail survey in 2017 included a questionnaire about current cough and its risk factors. The 264 subjects who reported chronic cough were sent a follow-up questionnaire 12 months later. The response rate was 77.7% (205 subjects), of whom 165 subjects (80.5%) still had cough in 2018. In multivariate analysis, the following baseline factors predicted the persistence of cough at 12 months; gastro-oesophageal reflux disease (adjusted OR (aOR) 5.02 (95% CI 1.10-22.83)), presence of a chemical trigger (aOR 2.88 (95% CI (1.20-7.00)), duration of cough more than 1 year (aOR 2.80 (95% CI 1.27-6.22)), frequent somatic symptoms (aOR 1.31 (95% CI 1.07-1.59)), and low number of family members (aOR 0.71 (95% CI 0.52-0.98)). In conclusion, most patients with chronic cough still suffer from cough 1 year later. The presence of gastro-oesophageal reflux disease is the main predictor for the persistence of cough.

Functional somatic disorders: discussion paper for a new common classification for research and clinical use

BACKGROUND

Functional somatic symptoms and disorders are common and complex phenomena involving both bodily and brain processes. They pose major challenges across medical specialties. These disorders are common and have significant impacts on patients' quality of life and healthcare costs.

MAIN BODY

We outline five problems pointing to the need for a new classification: (1) developments in understanding aetiological mechanisms; (2) the current division of disorders according to the treating specialist; (3) failure of current classifications to cover the variety of disorders and their severity (for example, patients with symptoms from multiple organs systems); (4) the need to find acceptable categories and labels for patients that promote therapeutic partnership; and (5) the need to develop clinical services and research for people with severe disorders. We propose 'functional somatic disorders' (FSD) as an umbrella term for various conditions characterised by persistent and troublesome physical symptoms. FSDs are diagnosed clinically, on the basis of characteristic symptom patterns. As with all diagnoses, a diagnosis of FSD should be made after considering other possible somatic and mental differential diagnoses. We propose that FSD should occupy a neutral space within disease classifications, favouring neither somatic disease aetiology, nor mental disorder. FSD should be subclassified as (a) multisystem, (b) single system, or (c) single symptom. While additional specifiers may be added to take account of psychological features or co-occurring diseases, neither of these is sufficient or necessary to make the diagnosis. We recommend that FSD criteria are written so as to harmonise with existing syndrome diagnoses. Where currently defined syndromes fall within the FSD spectrum - and also within organ system-specific chapters of a classification - they should be afforded dual parentage (for example, irritable bowel syndrome can belong to both gastrointestinal disorders and FSD).

CONCLUSION

We propose a new classification, 'functional somatic disorder', which is neither purely somatic nor purely mental, but occupies a neutral space between these two historical poles. This classification reflects both emerging aetiological evidence of the complex interactions between brain and body and the need to resolve the historical split between somatic and mental disorders.

Making Sense of "Somatization": A Systematic Review of its Relationship to Pediatric Pain

OBJECTIVES

Pain and other physical symptoms commonly co-occur in childhood. There is debate about the relevance of somatization in understanding pain. The present review critically appraised and synthesized the extant literature on the relationship between pediatric pain and somatization.

METHODS

A systematic review (PROSPERO registration #95956) was conducted in Medline, PsycINFO, EMBASE, and CINAHL using search terms related to pain and somatization in children and adolescents. A total of 156 articles were eligible for inclusion in the review. For studies that measured somatization using a symptom questionnaire, descriptions of "somatization" were extracted. Data regarding the relationship between pain and somatization were extracted for studies measuring somatization using a diagnostic category (e.g., Somatic Symptom and Related Disorders [SSRDs]).

RESULTS

While many studies using somatic symptom questionnaires described somatization as having a psychological component, this was not always captured in measurement tools. Pain was reported as a common symptom in patients with an SSRD diagnosis, though rates varied depending on the specific diagnosis and pain location. Rates of SSRD diagnoses among pain patients were less frequent than rates of pain amongst SSRD patients.

CONCLUSIONS

SSRDs and pain commonly co-occur, though rates differ depending on diagnosis and pain location. Understanding the relationship between pain and somatization is complicated by the discrepancy between how somatization is defined and measured in questionnaire studies. A comprehensive and measurable definition of somatization is needed so researchers can better identify the shared and unique contributions of pain and somatization in pediatric populations.

Persistent dentoalveolar pain disorder: A putative intraoral chronic overlapping pain condition

Chronic overlapping pain conditions (COPCs) are conditions that share several clinical characteristics and symptomatology, are usually considered idiopathic in nature, and are frequently comorbid. Currently, there are no established inclusion criteria to determine which conditions should be included under this umbrella term despite different systems proposed. Persistent dentoalveolar pain disorder (PDAP), also referred to as atypical odontalgia and thought to be a component of persistent idiopathic facial pain, is a chronic pain condition that manifests as a persistent tooth pain or pain over a dentoalveolar site formerly occupied by a tooth in the absence of detectable pathology during clinical or radiological examination. PDAP is considered idiopathic in nature, and its pathophysiological mechanisms are not fully understood. Our objective was to investigate whether PDAP fits the conceptual paradigm of COPC given its characteristics and commonalities with other COPC, based on published literature identified through a scoping review. We found that PDAP fits 16 out of 18 common characteristics among COPCs, and based on this finding, we discuss the implications of PDAP being considered a COPC.

Multisensory mechanisms of body perception in somatoform disorders

OBJECTIVE

According to one of the hypotheses, somatoform disorders (SD) are related to disturbed perception of bodily signals. We suspect that the disturbances and abnormalities of multisensory integration dynamics may be an additional SD mechanism. The objective of the research was to investigate multisensory bodily illusion dynamics in SD patients.

METHODS

A clinical group of SD patients (n = 16) and a control group (n = 17) participated in experiments aimed at eliciting a visual-tactile rubber hand illusion (RHI) and a visual-kinesthetic virtual hand illusion (VHI).

RESULTS

For both illusions studied, the illusion dynamics in SD patients differed from those of healthy subjects. The visual-tactile illusion on the subjective level appeared to be less strong in SD patients, and no proprioceptive drift (PD) was detected. The subjective dynamics of the visual-kinesthetic illusion in patients were similar to those of the control group, but the PD dynamics were different: after the termination of stimuli from the artificial limb, the proprioceptive system did not return to its initial state; on the contrary, PD continued to increase.

CONCLUSION

In comparison with the norm, patients with somatoform disorders display differences in multisensory mechanisms underlying the development of body perception. The results suggest that the disturbance of visual-tactile integration of the stimuli represents one of the mechanisms of body perception distortion in somatoform disorders. It may be assumed that one of the reasons for persistent symptom perception in SD patients is the rigidity of multisensory stimuli perception, at least in the visual-motor domain.