Phenotypic Features of Central Sensitization

Redesigning the Care of Musculoskeletal Conditions With Lifestyle Medicine

Value-based health care has been accelerated by alternative payment models and has catalyzed the redesign of care delivery across the nation. Lifestyle medicine (LM) is one of the fastest growing medical specialties and has emerged as a high-value solution for root cause treatment of chronic disease. This review detailed a large integrated health care delivery system's value transformation efforts in the nonoperative treatment of musculoskeletal (MSK) conditions by placing patient-centric, team-based, lifestyle-focused care at the foundation. With an economic and treatment imperative to reimagine care, recognizing more intervention is not always better, a collaborative approach was designed, which placed functional improvement of the patient at the center. This article described the process of implementing LM into an MSK model of care. The change management process impacted clinical, operational, and benefit plan design to facilitate an integrated care model. A new understanding of patients' co-occurring physical impairments, medical comorbidities, and behavioral health needs was necessary for clinicians to make the shift from a pathoanatomic, transactional model of care to a biopsychosocial, longitudinal model of care. The authors explored the novel intersection of the implementation of a biopsychosocial model of care using LM principles to achieve greater value for the MSK patient population.

Early effect of onabotulinumtoxinA on EEG-based functional connectivity in patients with chronic migraine: A pilot study

OBJECTIVE

In this pilot prospective cohort study, we aimed to evaluate, using high-density electroencephalography (HD-EEG), the longitudinal changes in functional connectivity (FC) in patients with chronic migraine (CM) treated with onabotulinumtoxinA (OBTA).

BACKGROUND

OBTA is a treatment for CM. Several studies have shown the modulatory action of OBTA on the central nervous system; however, research on migraine is limited.

METHODS

This study was conducted at the Neurology Unit of "Policlinico Tor Vergata," Rome, Italy, and included 12 adult patients with CM treated with OBTA and 15 healthy controls (HC). Patients underwent clinical scales at enrollment (T0) and 3 months (T1) from the start of treatment. HD-EEG was recorded using a 64-channel system in patients with CM at T0 and T1. A source reconstruction method was used to identify brain activity. FC in δ-θ-α-β-low-γ bands was analyzed using the weighted phase-lag index. FC changes between HCs and CM at T0 and T1 were assessed using cross-validation methods to estimate the results' reliability.

RESULTS

Compared to HCs at T0, patients with CM showed hyperconnected networks in δ (p = 0.046, area under the receiver operating characteristic curve [AUC: 0.76-0.98], Cohen's κ [0.65-0.93]) and β (p = 0.031, AUC [0.68-0.95], Cohen's κ [0.51-0.84]), mainly involving orbitofrontal, occipital, temporal pole and orbitofrontal, superior temporal, occipital, cingulate areas, and hypoconnected networks in α band (p = 0.029, AUC [0.80-0.99], Cohen's κ [0.42-0.77]), predominantly involving cingulate, temporal pole, and precuneus. Patients with CM at T1, compared to T0, showed hypoconnected networks in δ band (p = 0.032, AUC [0.73-0.99], Cohen's κ [0.53-0.90]) and hyperconnected networks in α band (p = 0.048, AUC [0.58-0.93], Cohen's κ [0.37-0.78]), involving the sensorimotor, orbitofrontal, cingulate, and temporal cortex.

CONCLUSION

These preliminary results showed that patients with CM presented disrupted EEG-FC compared to controls restored by a single session of OBTA treatment, suggesting a primary central modulatory action of OBTA.

Nociplastic Pain and Pain-Motivated Drinking in Alcohol Use Disorder

Heavy chronic alcohol use may produce pain amplification through neurochemical and neuroplastic changes at multiple levels of the nervous system. Similar changes are thought to underlie nociplastic pain. The American College of Rheumatology Fibromyalgia Survey has been used as a surrogate for nociplastic pain, including among individuals with alcohol use disorder (AUD). However, studies linking nociplastic pain to pain-motivated drinking are lacking. The present study aimed to determine if nociplastic pain is associated with pain-motivated drinking in AUD. To achieve this aim, a new scale-the Pain-Motivated Drinking Scale (PMDS)-was developed to measure how often participants were motivated by pain to drink alcohol. Measurement properties of this new scale were determined, including its factor structure, internal consistency reliability, and construct validity. In this cross-sectional observational study, participants with AUD (n = 138) were consecutively recruited from the patient pool at an academic addiction treatment facility. Seventy-two percent (95, 72.0%) reported they drank alcohol "to get relief from physical pain" at least some of the time, and over forty-two percent (56, 42.4%) reported pain relief motivated their drinking at least half of the time. PMDS had a single-factor structure, strong internal consistency reliability, and construct validity. A multiple hierarchical linear regression was run to determine if nociplastic pain was associated with pain-motivated drinking. Nociplastic pain was associated with PMDS even after controlling for potential confounders and pain severity. These findings suggest nociplastic pain is uniquely associated with pain-motivated drinking in AUD. PERSPECTIVE: Nociplastic pain is independently associated with pain-motivated drinking in alcohol use disorder (AUD). The Pain-Motivated Drinking Scale (PMDS) is a new scale to measure how often people drink to cope with pain. PMDS has promising psychometric properties. Nociplastic pain may be uniquely associated with pain-motivated drinking in AUD.

Brain network hypersensitivity underlies pain crises in sickle cell disease

Sickle cell disease (SCD) is a genetic disorder causing painful and unpredictable Vaso-occlusive crises (VOCs) through blood vessel blockages. In this study, we propose explosive synchronization (ES) as a novel approach to comprehend the hypersensitivity and occurrence of VOCs in the SCD brain network. We hypothesized that the accumulated disruptions in the brain network induced by SCD might lead to strengthened ES and hypersensitivity. We explored ES's relationship with patient reported outcome measures (PROMs) as well as VOCs by analyzing EEG data from 25 SCD patients and 18 matched controls. SCD patients exhibited lower alpha frequency than controls. SCD patients showed correlation between frequency disassortativity (FDA), an ES condition, and three important PROMs. Furthermore, stronger FDA was observed in SCD patients with a higher frequency of VOCs and EEG recording near VOC. We also conducted computational modeling on SCD brain network to study FDA's role in network sensitivity. Our model demonstrated that a stronger FDA could be linked to increased sensitivity and frequency of VOCs. This study establishes connections between SCD pain and the universal network mechanism, ES, offering a strong theoretical foundation. This understanding will aid predicting VOCs and refining pain management for SCD patients.

Application of a Clinical Approach to Diagnosing Primary Pain: Prevalence and Correlates of Primary Back and Neck Pain in a Community Physiatry Clinic

Chronic back or neck pain (CBNP) can be primary (nociplastic or neuroplastic; without clear peripheral etiology) or secondary (to nociceptive or neuropathic causes). Expanding on available models of nociplastic pain, we developed a clinic-ready approach to diagnose primary/nociplastic pain: first, a standard physical exam and review of imaging to rule out secondary pain; and second, a detailed history of symptom presentation to rule in primary pain. We trained a physician who evaluated 222 patients (73.9% female, age M = 59.6) with CBNP; patients separately completed pain and psychosocial questionnaires. We estimated the prevalence of primary CBNP and explored biomedical, imaging, and psychological correlates of primary CBNP. Although almost all patients (97.7%) had at least 1 spinal anomaly on imaging, the diagnostic approach estimated that 88.3% of patients had primary pain, 5.0% had secondary pain, and 6.8% had mixed pain. Patients with primary pain were more likely than the other 2 groups of patients (combined as "non-primary pain") to report certain functional conditions, central sensitization, and features such as sensitivity to light touch, spreading pain, and pain worsening with stress; however, no difference was detected in depression, anxiety, and pain catastrophizing between those with primary and nonprimary pain. These findings are consistent with prior estimates that 85 to 90% of CBNP is "nonspecific." Further research is needed to validate and perhaps refine this diagnostic approach, which holds the potential for better outcomes if patients are offered treatments targeted to primary pain, such as pain neuroscience education and several emerging psychological therapies. PERSPECTIVE: We developed an approach to diagnose chronic primary pain, which was applied in a physiatry clinic to 222 patients with CBNP. Most patients (88.3%) had primary pain, despite almost universal anomalies on spinal imaging. This diagnostic approach can guide educational and psychological treatments tailored for primary pain.

Clinical features of chronic primary pain in individuals presenting painful temporomandibular disorder and comorbidities

BACKGROUND

The diagnosis of chronic primary pain (CPP), according to the recently released International Classification of Disease (ICD-11) criteria, refers to conditions with complex aetiologies. CPP is characterized by specific clinical features such as generalized sensory hypersensitivity and widespread pain, and is associated with functional disability and emotional distress.

OBJECTIVE

This study investigated clinical features of CPP in individuals with painful temporomandibular disorders (TMD) and comorbidities (fibromyalgia, migraine and/or tension-type headache).

METHODS

This cross-sectional study was conducted with a sample of 129 individuals. Painful TMD, fibromyalgia and primary headaches were evaluated based on well-established international criteria. Generalized sensory hypersensitivity was assessed using psychophysical tests. Symptoms of anxiety and depression were assessed by the Generalized Anxiety Disorder-7 and Patient Health Questionnaire-9. The Central Sensitization Inventory was applied to assess central sensitization-related symptoms and the Pittsburg Sleep Quality Index to evaluate the quality of sleep. The presence of widespread pain was assessed using a body map. The sample was stratified into three groups: control (n = 25), TMD-painful TMD only (n = 35) and TMD + Cm-painful TMD and comorbidities (n = 69). Statistical analysis was performed using one-way ANOVA, chi-squared test and ANCOVA, considering gender as a covariate (α = .05).

RESULTS

Compared to controls, individuals presenting painful TMD and comorbidities showed lower pressure pain thresholds in all evaluated areas (p ≤ .012) and a higher number of painful areas in the body (p = .001). They presented more symptoms of anxiety (p = .040) and depression (p = .018), and a higher score in the Central Sensitization Inventory (p ≤ .006) than the other groups.

CONCLUSION

Individuals with painful TMD and comorbidities presented more clinical features of CPP compared to those affected by TMD only.

Mediators of the association between childhood trauma and pain sensitivity in adulthood: a Multidisciplinary Approach to the Study of Chronic Pelvic Pain Research Network analysis

ABSTRACT

Urologic chronic pelvic pain syndrome (UCPPS) is a complex, debilitating condition in which patients often report nonpelvic pain in addition to localized pelvic pain. Understanding differential predictors of pelvic pain only vs widespread pain may provide novel pathways for intervention. This study leveraged baseline data from the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network's Symptom Pattern Study to investigate the impact of childhood sexual and nonsexual violent trauma on pelvic and nonpelvic pain sensitivity among adult patients with UCPPS, as well as potential mediators of this association. Study participants who met inclusion criteria for UCPPS completed questionnaires assessing childhood and recent trauma, affective distress, cognitive dysfunction, and generalized sensory sensitivity. Experimental pain sensitivity was also evaluated using standardized pressure pain applied to the pubic region and the arm. Bivariate analyses showed that childhood violent trauma was associated with more nonviolent childhood trauma, more recent trauma, poorer adult functioning, and greater pain sensitivity at the pubic region, but not pain sensitivity at the arm. Path analysis suggested that childhood violent trauma was indirectly associated with pain sensitivity at both sites and that this indirect association was primarily mediated by generalized sensory sensitivity. More experiences of recent trauma also contributed to these indirect effects. The findings suggest that, among participants with UCPPS, childhood violent trauma may be associated with heightened pain sensitivity to the extent that trauma history is associated with a subsequent increase in generalized sensory sensitivity.

Plasma proteomic profiles of pain subtypes in adolescents and young adults with endometriosis

STUDY QUESTION

What are the similarities and differences in the systemic proteomic profiles by endometriosis-associated pain subtypes among adolescents and young adults with endometriosis?

SUMMARY ANSWER

Endometriosis-associated pain subtypes exhibited distinct plasma proteomic profiles.

WHAT IS KNOWN ALREADY

Endometriosis patients, especially those diagnosed in adolescents and young adults, are often plagued by various pain symptoms. However, it is not clear what biological processes underlie this heterogeneity.

STUDY DESIGN, SIZE, DURATION

We conducted a cross-sectional analysis using data and plasma samples from 142 adolescent or young adult participants of the Women's Health Study: From Adolescence to Adulthood cohort with laparoscopically confirmed endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We measured 1305 plasma protein levels by SomaScan. We classified self-reported endometriosis-associated pain into subtypes of dysmenorrhea, acyclic pelvic pain, life impacting pelvic pain, bladder pain, bowel pain, and widespread pain phenotype. We used logistic regression to calculate the odds ratios and 95% confidence intervals for differentially expressed proteins, adjusting for age, BMI, fasting status, and hormone use at blood draw. Ingenuity Pathway Analysis identified enriched biological pathways.

MAIN RESULTS AND THE ROLE OF CHANCE

Our study population consisted mainly of adolescents and young adults (mean age at blood draw = 18 years), with nearly all (97%) scored as rASRM stage I/II at laparoscopic diagnosis of endometriosis, which is a common clinical presentation of endometriosis diagnosed at a younger age. Pain subtypes exhibited distinct plasma proteomic profiles. Multiple cell movement pathways were downregulated in cases with severe dysmenorrhea and life impacting pelvic pain compared to those without (P < 7.5×10-15). Endometriosis cases with acyclic pelvic pain had upregulation of immune cell adhesion pathways (P < 9.0×10-9), while those with bladder pain had upregulation of immune cell migration (P < 3.7×10-8) and those with bowel pain had downregulation (P < 6.5×10-7) of the immune cell migration pathways compared to those without. Having a wide-spread pain phenotype involved downregulation of multiple immune pathways (P < 8.0×10-10).

LIMITATIONS, REASONS FOR CAUTION

Our study was limited by the lack of an independent validation cohort. We were also only able to explore any presence of a pain subtype and could not evaluate multiple combinations by pain subtypes. Further mechanistic studies are warranted to elucidate the differences in pathophysiology by endometriosis-pain subtype.

WIDER IMPLICATIONS OF THE FINDINGS

The observed variation in plasma protein profiles by pain subtypes suggests different underlying molecular mechanisms, highlighting the need for potential consideration of pain subtypes for effectively treating endometriosis patients presenting with various pain symptoms.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Department of Defense W81XWH1910318 and the 2017 Boston Center for Endometriosis Trainee Award. Financial support for establishment of and data collection within the A2A cohort were provided by the J. Willard and Alice S. Marriott Foundation. N.S., A.F.V., S.A.M., and K.L.T. have received funding from the Marriott Family Foundation. C.B.S. is funded by an R35 MIRA Award from NIGMS (5R35GM142676). S.A.M. and K.L.T. are supported by NICHD R01HD094842. S.A.M. reports serving as an advisory board member for AbbVie and Roche, Field Chief Editor for Frontiers in Reproductive Health, personal fees from Abbott for roundtable participation; none of these are related to this study. Other authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Musculoskeletal Pain, a Possible Indicator of Central Sensitization, Is Positively Associated With Lower Urinary Tract Symptom Progression in Community-Dwelling Older Men

BACKGROUND

Musculoskeletal pain, a possible marker of central sensitization, is associated with higher prevalence of lower urinary tract symptoms (LUTS) among older men. We investigated whether musculoskeletal pain is associated with LUTS progression.

METHODS

Participants were 5 569 men age ≥65 years enrolled in the prospective, multicenter Osteoporotic Fractures in Men (MrOS) Study. Self-reported musculoskeletal pain within 12 months before baseline was categorized as any pain and multilocation pain. Pain interference within 4 weeks of baseline was assessed with the SF-12 questionnaire. LUTS were assessed repeatedly with the American Urological Association Symptom Index (AUA-SI). Men with severe LUTS at baseline were excluded. LUTS progression was defined as the first occurrence of a ≥4-point AUA-SI increase during a 2-year follow-up interval. Incidence rate ratios (IRR) and 95% confidence intervals (CI) were estimated using multivariable pooled logistic regression.

RESULTS

LUTS progression was 37% higher among men with any musculoskeletal pain compared with men without pain (IRR 1.37, 95% CI: 1.21, 1.54). Positive associations were also observed between LUTS progression and pain at 1 (IRR 1.31, 95% CI: 1.13, 1.48) and ≥2 locations (IRR 1.42, 95% CI: 1.24, 1.60). Compared with men without pain interference, men with quite a bit/extreme pain interference were most likely to experience LUTS progression (minimal interference IRR 1.15, 95% CI: 1.03, 1.26; moderate interference IRR 1.28, 95% CI: 1.11, 1.45; quite a bit/extreme interference IRR 1.47, 95% CI: 1.22, 1.71).

CONCLUSIONS

Among men initially without severe LUTS, musculoskeletal pain is associated with an increased risk of LUTS progression. Studies using validated measures of central sensitization and LUTS progression among men are warranted.

Do "central sensitization" questionnaires reflect measures of nociceptive sensitization or psychological constructs? A systematic review and meta-analyses

ABSTRACT

Central sensitization (CS) is defined as an increased nociceptive responsiveness due to sensitization of neurons in the central nervous system, usually the result of prolonged nociceptive input or a disease state associated with noxious inputs (eg, polyarthritis). The concept of CS has recently been adopted in clinical assessments of chronic pain, but its diagnosis in humans may now include a wide range of hypervigilant responses. The purpose of this review is to ascertain whether self-report questionnaires linked with CS are associated with enhanced nociceptive responses or whether they measure sensitivity in a broader sense (ie, emotional responses). According to our published, PROSPERO-registered review protocol (CRD42021208731), a predefined search of studies that involve the Central Sensitization Inventory (CSI) or Pain Sensitivity Questionnaire (PSQ), correlated with either nociceptive sensory tests or emotional hypervigilance was conducted on MEDLINE, PsycINFO, and Web of Science. Correlations between the CSI or PSQ with our primary outcomes were extracted and meta-analysed. A review of 66 studies totalling 13,284 participants found that the CSI (but not the PSQ) strongly correlated with psychological constructs: depression, anxiety, stress, pain catastrophising, sleep, and kinesiophobia. The CSI and PSQ showed weak or no correlations with experimental measures of nociceptive sensitivity: pain thresholds, temporal summation, or conditioned pain modulation. The PSQ did, however, correlate strongly with phasic heat and tonic cold pain tests. The studies reviewed did not provide sufficient evidence that self-report measures reflect a canonical understanding of CS. The CSI more closely reflects psychological hypervigilance than increased responsiveness of nociceptive neurons.

Targets and study design for symptom-focused trials aimed at patients with cirrhosis: An expert consensus

BACKGROUND

Symptom-focused trials are critically needed for patients with cirrhosis. However, this work would benefit from standard processes and validated measures.

METHODS

A writing group was formed among hepatologists, nurses, palliative care providers, pharmacists, and clinical trial experts focused on symptom management in patients with cirrhosis to define the key (1) components of trial design, (2) symptom targets, (3) measurement, and (4) outcomes for each target. From July 2022 to January 2023, panelists participated in an iterative process of developing and arriving at a consensus for each component. The goal was to provide consensus definitions that can be operationalized in future clinical trials, including for patients with cirrhosis.

RESULTS

The panel reached a consensus on key reporting features for clinical trials, along with considerations for study design. Nine key symptom targets (muscle cramps, pruritus, pain, fatigue, sexual dysfunction, sleep disorders, depression and anxiety, nausea/vomiting, and dyspnea/breathlessness) were identified. The panel selected instruments that can be considered for clinical trials based on psychometric validation and previous experience. The panel identified ongoing needs, including instrument validation, safety data, evidence about non-pharmacologic interventions, and comparative effectiveness studies.

CONCLUSION

This expert panel identified key design, reporting, and measurement elements to standardize processes and measures in future symptom-focused clinical trials in the context of cirrhosis.

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.

Chronic overlapping pain conditions and long-term opioid treatment

OBJECTIVES

One in 5 people in the United States lives with chronic pain. Many patients with chronic pain experience a subset of specific co-occurring pain conditions that may share a common pain mechanism and that have been designated as chronic overlapping pain conditions (COPCs). Little is known about chronic opioid prescribing patterns among patients with COPCs in primary care settings, especially among socioeconomically vulnerable patients. This study aims to evaluate opioid prescribing among patients with COPCs in US community health centers and to identify individual COPCs and their combinations that are associated with long-term opioid treatment (LOT).

STUDY DESIGN

Retrospective cohort study.

METHODS

We conducted analyses of more than 1 million patients 18 years and older based on electronic health record data from 449 US community health centers across 17 states between January 1, 2009, and December 31, 2018. Logistic regression models were used to assess the relationship between COPCs and LOT.

RESULTS

Individuals with COPCs were prescribed LOT 4 times more often than individuals without a COPC (16.9% vs 4.0%). The presence of chronic low back pain, migraine headache, fibromyalgia, or irritable bowel syndrome combined with any of the other COPCs increased the odds of LOT prescribing compared with the presence of a single COPC.

CONCLUSIONS

Although LOT prescribing has declined over time, it remains relatively high among patients with certain COPCs and for those with multiple COPCs. These study findings suggest target populations for future interventions to manage chronic pain among socioeconomically vulnerable patients.

High intensity training improves symptoms of central sensitization at six-month follow-up in persons with chronic nonspecific low back pain: Secondary analysis of a randomized controlled trial

BACKGROUND

High intensity training (HIT) improves disability and physical fitness in persons with chronic nonspecific low back pain (CNSLBP). However, it remains unclear if HIT affects pain processing and psychosocial factors.

OBJECTIVE

To evaluate 1) the effects of HIT on symptoms of central sensitization and perceived stress and 2) the relationship of symptoms of central sensitization and perceived stress with therapy success, at six-month follow-up, in persons with CNSLBP.

METHODS

This is a secondary analysis of a previously published randomized controlled trial. Persons with CNSLBP (n = 51, age=43.6y) completed the Central Sensitization Inventory (CSI) and Perceived Stress Scale (PSS) at baseline (PRE) and six months after 12-week of HIT consisting of concurrent exercise therapy (FU). Two groups were formed based on CSI scores (low-CSI/high-CSI). First, linear mixed models were fitted for each outcome, with time and groups as covariates. Multiple comparisons were executed to evaluate group (baseline), time (within-group), and interaction (between-group) effects. Second, correlation and regression analyses were performed to evaluate if baseline and changes in CSI/PSS scores were related to therapy success, operationalized as improvements on disability (Modified Oswestry Disability Index), and pain intensity (Numeric Pain Rating Scale).

RESULTS

Total sample analyses showed a decrease in both CSI and PSS. Within-group analyses showed a decrease of CSI only in the high-CSI group and a decrease of PSS only in the low-CSI group. Between-group analyses showed a pronounced decrease favouring high-CSI (mean difference: 7.9; 95%CI: 2.1, 12.7) and no differences in PSS (mean difference: 0.1; 95%CI: -3.0, 3.2). CSI, but not PSS, was weakly related to therapy success.

CONCLUSION

HIT improves symptoms of central sensitization in persons with CNSLBP. This effect is the largest in persons with clinically relevant baseline CSI scores. HIT also decreases perceived stress.

Multisensory sensitivity differentiates between multiple chronic pain conditions and pain-free individuals

ABSTRACT

Multisensory sensitivity (MSS) to nonpainful stimuli has been identified as a risk factor for the presence of coexisting chronic pain conditions. However, it remains unclear whether MSS can differentiate pain phenotypes involving different levels of central sensitivity. Both pain-free and those with chronic pain, particularly fibromyalgia (FM), migraine, or low back pain (LBP) were recruited, with pain comorbidities assessed. MSS was highest in FM, followed by migraine, then LBP, and lowest in pain-free individuals (adjusted between condition Cohen d = 0.32-1.2, P ≤ 0.0007). However, when secondly grouping patients by the total number of pain comorbidities reported, those with a single pain condition (but not FM) did not have significantly elevated MSS vs pain-free individuals (adj d= 0.17, P = 0.18). Elevated MSS scores produced increased odds of having 2 or more pain comorbidities; OR [95% CI] =2.0 [1.15, 3.42], without, and 5.6 [2.74, 11.28], with FM ( P ≤ 0.0001). Furthermore, those with low MSS levels were 55% to 87% less likely to have ≥ 2 pain comorbidities with or without FM (OR 0.45 [0.22, 0.88]-0.13 [0.05, 0.39]; P ≤ 0.0001). Our findings support that MSS can differentiate between pain phenotypes with different degrees of expected central mechanism involvement and also serve as a risk and resilience marker for total coexisting chronic pain conditions. This supports the use of MSS as a marker of heightened central nervous system processing and thus may serve as a clinically feasible assessment to better profile pain phenotypes with the goal of improving personalized treatment.

Toward a causal model of chronic back pain: Challenges and opportunities

Chronic low back pain (cLBP) afflicts 8. 2% of adults in the United States, and is the leading global cause of disability. Neuropsychiatric co-morbidities including anxiety, depression, and substance abuse- are common in cLBP patients. In particular, cLBP is a risk factor for opioid addiction, as more than 50% of opioid prescriptions in the United States are for cLBP. Misuse of these prescriptions is a common precursor to addiction. While associations between cLBP and neuropsychiatric disorders are well established, causal relationships for the most part are unknown. Developing effective treatments for cLBP, and associated co-morbidities, requires identifying and understanding causal relationships. Rigorous methods for causal inference, a process for quantifying causal effects from observational data, have been developed over the past 30 years. In this review we first discuss the conceptual model of cLBP that current treatments are based on, and how gaps in causal knowledge contribute to poor clinical outcomes. We then present cLBP as a "Big Data" problem and identify how advanced analytic techniques may close knowledge gaps and improve clinical outcomes. We will focus on causal discovery, which is a data-driven method that uses artificial intelligence (AI) and high dimensional datasets to identify causal structures, discussing both constraint-based (PC and Fast Causal Inference) and score-based (Fast Greedy Equivalent Search) algorithms.

Contemporary management of pain in cirrhosis: Toward precision therapy for pain

Chronic pain is highly prevalent in patients with cirrhosis and is associated with poor health-related quality of life and poor functional status. However, there is limited guidance on appropriate pain management in this population, and pharmacologic treatment can be harmful, leading to adverse outcomes, such as gastrointestinal bleeding, renal injury, falls, and hepatic encephalopathy. Chronic pain can be categorized mechanistically into three pain types: nociceptive, neuropathic, and nociplastic, each responsive to different therapies. By discussing the identification, etiology, and treatment of these three mechanistic pain descriptors with a focus on specific challenges in patients with cirrhosis, we provide a framework for better tailoring treatments, including nonpharmacologic therapies, to patients' needs.

Generalized sensory sensitivity is associated with comorbid pain symptoms: a replication study in women with dysmenorrhea

ABSTRACT

Dysmenorrhea is characterized by high rates of transition to chronic pain. In a previous study using structural equation modeling, we demonstrated that several symptom domains associated with the emerging concept of nociplastic pain can be described using 2 symptom groups: generalized sensory sensitivity (GSS; composed of widespread pain, interceptive sensitivity, and environmental sensitivity) and SPACE (composed of unrefreshing sleep, pain, affective disturbances, cognitive issues, and reduced energy). Here, we perform a secondary cross-sectional analysis examining the same symptoms groups in a cohort of patients with dysmenorrhea without a diagnosis of chronic pain. Our purpose is to determine if the same symptom patterns are apparent and if they are associated with the presence and severity of comorbid pain. Participants were 201 women with dysmenorrhea. We replicated the hypothesized 2-factor structure in this cohort (comparative fit index = 0.971 and root mean square error of approximation =0.055; 90% CI: 0.000-0.097). Generalized sensory sensitivity was associated with the severity of bladder, bowel, and overall pain in multivariable models including SPACE, patient age, and BMI (all β > 0.32, all P < 0.05). Sleep, pain, affective disturbances, cognitive issues, and reduced energy were associated with menstrual pain during nonsteroidal anti-inflammatory drug use, whereas GSS was associated with the same in the absence of nonsteroidal anti-inflammatory drug use (both P < 0.05). This 2-factor model of symptoms seems to be replicable and valid in a cohort of women at risk for developing chronic pain conditions. These symptom groups are promising potential markers of future pain chronification and may point to patients in need of earlier or more aggressive intervention.

Pain Widespreadedness, and Not Primary Pain Location, is Associated With Comorbid Symptoms in Children With Chronic Pain

OBJECTIVES

Pediatric chronic pain represents heterogeneous diagnoses; often, primary pain location informs research classifications and treatment. In contrast, recent research has highlighted the role of widespread pain and this perspective has been adopted in assessments in specialty pediatric pain clinics. The lack of direct comparison between these 2 methods of categorizing pediatric chronic pain may hinder the adoption of evidence-based practices across the spectrum of care. Therefore, this study aimed to compare whether primary pain location or pain widespreadedness is more informative for pain-related symptoms in pediatric chronic pain.

METHODS

Youth (n=223) between the ages of 8 to 23 years (M=15.93, SD=2.11, 83% female) completed surveys upon intake at the pediatric chronic pain clinic. Free-text entries of primary pain location were coded into categories: headache, abdominal pain, and musculoskeletal pain. Additional domains assessed included widespread pain, pain interference, kinesiophobia, catastrophizing, anxiety, depression, sleep, and fatigue.

RESULTS

Differences based on primary pain location only emerged for kinesiophobia, F(2150)=8.20, P<0.001, with the highest scores among those with musculoskeletal pain. In contrast, controlling for sex, age, and pain intensity, pain widespreadedness was associated with pain interference, pain catastrophizing, fatigue, anxiety, and depression (P<0.05).

DISCUSSION

Pain widespreadedness was more consistently associated with pain-related outcomes among pediatric chronic pain patients than primary pain location, and body maps may be useful in determining a nociplastic pain mechanism to inform treatment. Improved assessment of pediatric pain mechanisms may help advance more precise treatment delivery.

Bad company: Loneliness longitudinally predicts the symptom cluster of pain, fatigue, and depression in older adults

BACKGROUND

Pain, fatigue, and depression frequently co-occur as a symptom cluster. While commonly occurring in those with cancer and autoimmune disease, the cluster is also found in the absence of systemic illness or inflammation. Loneliness is a common psychosocial stressor associated with the cluster cross-sectionally. We investigated whether loneliness predicted the development of pain, fatigue, depression, and the symptom cluster over time.

METHODS

Data from the Health and Retirement Study were used. We included self-respondents ≥50 year-old who had at least two measurements of loneliness and the symptom cluster from 2006-2016 (n = 5974). Time-varying loneliness was used to predict pain, fatigue, depression, and the symptom cluster in the subsequent wave(s) using generalized estimating equations (GEE) and adjusting for sociodemographic covariates, living arrangement, and the presence of the symptom(s) at baseline.

RESULTS

Loneliness increased the odds of subsequently reporting pain (aOR 1.22, 95% CI 1.08, 1.37), fatigue (aOR 1.47, 95% CI 1.32, 1.65), depression (aOR 2.33, 95% CI 2.02, 2.68), as well as the symptom cluster (aOR 2.15, 95% CI 1.74, 2.67). The median time between the baseline and final follow-up measurement was 7.6 years (IQR 4.1, 8.2).

CONCLUSIONS

Loneliness strongly predicts the development of pain, fatigue, and depression as well as the cluster of all three symptoms several years later in a large, nonclinical sample of older American adults. Future studies should examine the multiple pathways through which loneliness may produce this cluster, as well as examine whether other psychosocial stressors also increase risk. It is possible that interventions which address loneliness in older adults may prevent or mitigate the cluster of pain, fatigue, and depression.

Clinical identification of the stimulus intensity to measure temporal summation of second pain

Temporal summation of second pain (TSSP) has been suggested as a psychophysical index for central sensitization, one of the critical mechanisms in the chronification of pain. However, there is no gold standard for protocols to measure TSSP. The purpose was to establish the stimulus intensity for measuring TSSP. Female patients with chronic myofascial temporomandibular disorders pain (n = 16) and healthy female volunteers with no pain (n = 15) participated. Pain thresholds (PT °C) were measured, and repetitive heat stimuli at three stimulus intensities (PT °C, PT + 1 °C, PT + 2 °C) were applied. TSSP parameters were quantified as TSSP magnitude (TSm) and TSSP frequency (TSf). In healthy female volunteers, pain ratings significantly decreased at PT °C (p < 0.050), besides TSm and TSf at PT + 2 °C were significantly higher than those at PT °C (p < 0.025). In chronic pain patients, pain ratings significantly increased at PT + 1 °C and PT + 2 °C (p < 0.050). At PT + 2 °C, TSm and TSf in chronic pain patients were significantly higher than those in healthy volunteers (p < 0.050). It could be helpful to measure TSSP with the stimulus intensity adjusted individually to the patient’s pain thresholds + 2 °C for assessing central sensitization.

Effect of vitamin B6 on pain, disease severity, and psychological profile of fibromyalgia patients; a randomized, double-blinded clinical trial

BACKGROUND

Given the role of vitamin B6 on pronociceptive/antinociceptive neurotransmitters balance, metabolic reactions, and inflammation, it is important to clarify the effect of vitamin B6 on pain and psychological disturbance in fibromyalgia (FM). This study aimed to evaluate whether an 80-mg daily dose of vitamin B6 improves pain, disease severity and psychological symptoms of FM compared to a placebo.

METHODS

This randomized, double-blinded, placebo-controlled trial was performed on the FM patients whose diagnosis was confirmed by a rheumatologist based on the 2016 American College of Rheumatology (ACR). 90 Patients were randomized to receive either vitamin B6 (80 mg daily) or placebo in a 1:1 ratio, with a permuted block size of 30 stratified by disease severity. Primary outcomes included the Revised Fibromyalgia Impact Questionnaire (FIQR), Hospital Anxiety and Depression Scale (HADS), 12-item short-form health survey (SF-12), and pain visual analog scale (pain-VAS)). The mean differences in outcomes (before and after treatment) were compared between the vitamin B6 and placebo groups using an independent T-test. An ANCOVA model adjusted for baseline outcome value was also provided to compare the outcomes between the two groups.

RESULTS

Of 90 eligible patients, 60 patients (31 patients in vitamin B6 and 29 in the placebo group) completed the trial. Overall, the FIQR, pain-VAS, and HADS-anxiety scores improved after treatment in both vitamin B6 and placebo groups; However, there was no statistically significant intergroup difference regarding primary outcomes. ANCOVA model also showed no difference in the treatment effects.

CONCLUSIONS

Our results showed no priority for vitamin B6 over placebo in FM patients. Considering the potential ameliorating role of vitamin B6 on pain and psychological symptoms, acknowledgment of vitamin B6 as a relatively safe adjuvant treatment needs larger future studies.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials: IRCT20200920048782N2 on 2021/10/04.

Central sensitization in opioid use disorder: a novel application of the American College of Rheumatology Fibromyalgia Survey Criteria

Central sensitization may be an underlying mechanism linking chronic pain and opioid use disorder associated with opioid use disorder onset, maintenance, escalation, treatment delay, and relapse.

Introduction:

Central sensitization (CS) involves dysfunctional central nervous system pain modulation resulting in heightened pain perception. Central sensitization is not commonly assessed among patients with opioid use disorder (OUD), despite the fact that pain has been implicated in the development, maintenance, and relapse of OUD and chronic opioid use may produce opioid-induced hyperalgesia. Central sensitization is a plausibly important mechanism underlying the complex relationship between OUD and chronic pain. However, this premise is largely untested.

Methods:

Participants with OUD (n = 141) were recruited from an academic addiction treatment center in Columbus, Ohio. An established surrogate measure of CS, the American College of Rheumatology 2011 Fibromyalgia Survey Criteria, was administered using electronic survey. Participants also responded to questions about pain interference (Brief Pain Inventory), quality of life (RAND-36), and items regarding pain beliefs and expectations of pain and addiction treatment. Descriptive analyses, Spearman rho correlations, and Mann–Whitney U tests were performed.

Results:

Hypothesized relationships were confirmed between degree of CS, pain interference, and health-related quality of life. Degree of CS was also positively correlated with greater endorsement of pain as a reason for the onset, maintenance, and escalation of OUD; treatment delay; and OUD relapse. Participants with the American College of Rheumatology 2011 Fibromyalgia Survey Criteria ≥13 had significantly greater endorsement of pain as a reason for delaying OUD treatment, continuing and increasing opioid use, and precipitating OUD relapse.

Conclusions:

This study provides early evidence CS may underlie previously observed connections between clinically salient features of chronic pain and OUD, potentially informing future mechanistic research and precision treatment.

Pain descriptors and determinants of pain sensitivity in knee osteoarthritis: a community-based cross-sectional study

Objectives

To explore pain characteristics in individuals with knee osteoarthritis (KOA), to compare pain sensitivity across individuals with KOA, chronic back pain (CBP) and pain-free individuals (NP), and to examine the relationship between clinical and pain characteristics with pain sensitivity in KOA.

Methods

Cross-sectional, community-based online survey. Two datasets were combined comprising Dutch individuals of ≥ 40 years of age, experiencing chronic knee pain (KOA, N = 445), chronic back pain (CBP, N = 504), or no pain (NP, N = 256). Demographic and clinical characteristics, global health, physical activity/exercise, and pain characteristics including intensity, spreading, duration, quality (SF-MPQ), and sensitivity (PSQ) were assessed. Differences between (sub)groups were examined using analyses of variance or Chi-square tests. Regression analyses were performed to examine determinants of pain sensitivity in the KOA group.

Results

Quality of pain was most commonly described as aching, tender, and tiring-exhausting. Overall, the KOA group had higher levels of pain sensitivity compared to NP group, but lower levels than the CBP group. Univariately, pain intensity, its variability and spreading, global health, exercise, and having comorbidities were weakly related to pain sensitivity (standardized betas: 0.12-0.27). Symptom duration was not related to pain sensitivity. Older age, higher levels of continuous pain, lower levels of global health, and exercise uniquely contributed, albeit modest, to pain sensitivity (P&lt;0.05).

Conclusion

Continuous pain such as aching and tenderness in combination with decreased physical activity may be indicative for a subgroup of individuals at risk for pain sensitivity and, ultimately, poor treatment outcomes.

Current Challenges in the Management of Chronic Pelvic Pain in Women: From Bench to Bedside

Chronic pelvic pain (CPP) affects a significant proportion of women worldwide And has a negative impact on several aspects of these women’s lives including mental health, work, relationships and sexual function, among others. This set of factors ultimately reflects negatively on quality Of life. The physiopathology of CPP is complex and remains to be fully clarified; however, recent advances have increased understanding of the mechanisms involved in chronic pain in general, and more specifically, CPP. Nonetheless, even when a detailed clinical history is obtained, meticulous physical examination is performed and imaging resources are appropriately used, the organic cause of the pain may still fail to be identified in a substantial number of women with CPP. Management of CPP may therefore be challenging. This narrative review was aimed at adding to the available literature on the subject, presenting and discussing the principal characteristics of CPP in women. The paper highlights gaps in the literature while providing the most up-to-date evidence associated with the physiopathology and classification of pain, its diagnosis and treatment. In addition, current challenges in the management of women with CPP are discussed.

Autism and chronic ill health: an observational study of symptoms and diagnoses of central sensitivity syndromes in autistic adults

BACKGROUND

Autistic adults, particularly women, are more likely to experience chronic ill health than the general population. Central sensitivity syndromes (CSS) are a group of related conditions that are thought to include an underlying sensitisation of the central nervous system; heightened sensory sensitivity is a common feature. Anecdotal evidence suggests autistic adults may be more prone to developing a CSS. This study aimed to investigate the occurrence of CSS diagnoses and symptoms in autistic adults, and to explore whether CSS symptoms were related to autistic traits, mental health, sensory sensitivity, or gender.

METHODS

The full sample of participants included 973 autistic adults (410 men, 563 women, mean age = 44.6) registered at the Netherlands Autism Register, who completed questionnaires assessing autistic traits, sensory sensitivity, CSS, physical and mental health symptoms. The reliability and validity of the Central Sensitization Inventory (CSI) in an autistic sample was established using exploratory and confirmatory factor analyses. Chi2 analyses, independent t-tests, hierarchical regression and path analysis were used to analyse relationships between CSS symptoms, autistic traits, measures of mental health and wellbeing, sensory sensitivity, age and gender.

RESULTS

21% of participants reported one or more CSS diagnosis, and 60% scored at or above the clinical cut-off for a CSS. Autistic women were more likely to report a CSS diagnosis and experienced more CSS symptoms than men. Sensory sensitivity, anxiety, age and gender were significant predictors of CSS symptoms, with sensory sensitivity and anxiety fully mediating the relationship between autistic traits and CSS symptoms.

LIMITATIONS

Although this study included a large sample of autistic adults, we did not have a control group or a CSS only group. We also could not include a non-binary group due to lack of statistical power.

CONCLUSIONS

CSS diagnoses and symptoms appear to be very common in the autistic population. Increased awareness of an association between autism and central sensitisation should inform clinicians and guide diagnostic practice, particularly for women where CSS are common and autism under recognised.

Assessing Multisensory Sensitivity Across Scales: Using the Resulting Core Factors to Create the Multisensory Amplification Scale

Multisensory sensitivity (MSS), observed in some chronic pain patients, may reflect a generalized central nervous system sensitivity. While several surveys measure aspects of MSS, there remains no gold standard. We explored the underlying constructs of 4 MSS-related surveys (80 items in total) using factor analyses using REDCap surveys (N = 614, 58.7% with pain). Four core- and 6 associated-MSS factors were identified from the items assessed. None of these surveys addressed all major sensory systems and most included additional related constructs. A revised version of the Somatosensory Amplification Scale was developed, encompassing 5 core MSS systems: vision, hearing, smell, tactile, and internal bodily sensations: the 12-item Multisensory Amplification Scale (MSAS). The MSAS demonstrated good internal consistency (alpha = 0.82), test-retest reliability (ICC3,1 = 0.90), and construct validity in the original and in a new, separate cohort (R = 0.54-0.79, P < .0001). Further, the odds of having pain were 2-3.5 times higher in the highest sex-specific MSAS quartile relative to the lowest MSAS quartile, after adjusting for age, sex, BMI, and pain schema (P < .03). The MSAS provides a psychometrically comprehensive, brief, and promising tool for measuring the core-dimensions of MSS. PERSPECTIVE: Multiple multisensory sensitivity (MSS) tools are used, but without exploration of their underlying domains. We found several measures lacking core MSS domains, thus we modified an existing scale to encompass 5 core MSS domains: light, smell, sound, tactile, and internal bodily sensations using only 12 items, with good psychometric properties.

Central sensitization inventory in endometriosis

ABSTRACT

A key clinical problem is identifying the patient with endometriosis whose pain is complicated by central nervous system sensitization, where conventional gynecologic treatment (eg, hormonal therapy or surgery) may not completely alleviate the pain. The Central Sensitization Inventory (CSI) is a questionnaire previously validated in the chronic pain population. The objective of this study was an exploratory proof-of-concept to identify a CSI cutoff in the endometriosis population to discriminate between individuals with significant central contributors (identified by central sensitivity syndromes [CSS]) to their pain compared to those without. We analyzed a prospective data registry at a tertiary referral center for endometriosis, and included subjects aged 18 to 50 years with endometriosis who were newly or re-referred to the center in 2018. The study sample consisted of 335 subjects with a mean age of 36.0 ± 7.0 years. An increasing number of CSS was significantly correlated with dysmenorrhea, deep dyspareunia, dyschezia, and chronic pelvic pain scores (P < 0.001), and with the CSI score (0-100) (r = 0.731, P < 0.001). Receiver operating characteristic analysis indicated that a CSI cutoff of 40 had a sensitivity of 78% (95% CI: 72.7%-84.6%) and a specificity of 80% (95% CI: 70.3%-84.5%) for identifying a patient with endometriosis with ≥3 CSS. In the group with CSI ≥ 40, 18% retrospectively self-reported pain nonresponsive to hormonal therapy and 40% self-reported daily pain, compared with 6% and 20% in the CSI < 40 group (P = 0.003 and 0.002, respectively). In conclusion, a CSI ≥ 40 may be a practical tool to help identify patients with endometriosis with pain contributors related to central nervous system sensitization.

Cannabidiol Product Dosing and Decision-Making in a National Survey of Individuals with Fibromyalgia

Many people with fibromyalgia use cannabidiol (CBD) products despite limited rigorous evidence of benefit. In the current study, we conducted a secondary analysis of a cross-sectional survey of N = 878 people with fibromyalgia to investigate naturalistic decision making around CBD product choices, use patterns, and dosing. We subgrouped participants based on use of high-THC cannabis (HTC) in the past year (yes/no) as previous studies have shown that HTC use influences CBD use patterns. The study population was largely female (93.6%), white (91.5%) and 55.5 years old on average. Participants typically purchased CBD products online or at dispensaries, with purchasing driven by personal research (63%) rather than endorsement from medical professionals (16%). Overall, tinctures and topicals were the most common administration routes endorsed. However, participants in the past-year HTC group used inhalation routes far more frequently than those who did not (39.8% vs 7.1%). Among participants using CBD tinctures or edibles, the average dose per session was 16 mg and 24 to 27 mg per day, although approximately one-third of participants did not know what dose of CBD they used. Participants using both inhalation and non-inhalation administration routes reported greater symptom relief than those using non-inhalation routes alone. However, there was no consistent relationship between CBD dose and reported effects, possibly due to expectancy effects around CBD products or interindividual variability. Our granular investigation reveals variability of CBD product dosing practices for fibromyalgia, and how past-year HTC use influences CBD product use. Future clinical trials should investigate the potential benefits of low-dose (<50mg) botanical CBD products. PERSPECTIVE: This article shows that past-year HTC use strongly influences how people with fibromyalgia choose and use CBD products. Participants typically used <50 mg/d of CBD, and there was no relationship between higher CBD dose and reported therapeutic benefit. Future clinical trials should investigate therapeutic benefits of low dose CBD.

The Organ of Vision and the Stomatognathic System-Review of Association Studies and Evidence-Based Discussion

The stomatognathic system is a functional complex of tissues and organs located within the oral and craniofacial cavities. The craniofacial anatomical factors and the biomechanics of the temporomandibular joints affect many systems throughout the body, including the organ of vision. However, few scientific reports have shown a relationship between the organ of vision and the stomatognathic system. The purpose of this review is to provide an overview of connections along neural, muscle-fascial, and biochemical pathways between the organ of vision and the stomatognathic system. Based on the literature presented in this review, the connections between the organ of vision and the stomatognathic system seem undeniable. Understanding the anatomical, physiological, and biochemical interrelationships may allow to explain the interactions between the mentioned systems. According to the current knowledge, it is not possible to indicate the main linking pathway; presumably, it may be a combination of several presented pathways. The awareness of this relationship among dentists, ophthalmologists, physiotherapists, and optometrists should increase for the better diagnosis and treatment of patients.

Are Reports of Pain, Disability, Quality of Life, Psychological Factors, and Central Sensitization Related to Outcomes of Quantitative Sensory Testing in Patients Suffering From Chronic Whiplash Associated Disorders?

BACKGROUND

Chronic whiplash associated disorders (CWAD) are characterized by long-lasting symptoms of neck pain occurring after an acceleration-deceleration injury. Central sensitization (CS) has been suggested as the possible underlying mechanism for these symptoms, and is characterized by changes in the central nervous system. Besides CS, psychological factors are believed to play an important role in the experience of (chronic) pain.

OBJECTIVE

Investigating the relationships between self-reported pain, disability, quality of life, psychological factors, and symptoms of CS; and electrical-based quantitative sensory testing (QST) outcomes in CWAD patients. Secondly, to investigate the differences in QST between CWAD patients and pain-free controls.

METHODS

Seventy-two individuals with CWAD and 55 pain-free controls underwent electrical stimuli-based QST. Detection and pain thresholds (EPT), temporal summation (TS), and conditioned pain modulation were examined. Spearman correlation and linear mixed models analyses were performed to assess, respectively, the hypothesized associations and group differences in QST.

RESULTS

The Pain Catastrophizing magnification subscale correlated with the left wrist EPT (r=-0.332; P=0.004), and the Pain Anxiety Symptom Scale-20 with the left wrist (r=-0.325; P=0.005) and ankle (r=-0.330; P=0.005) EPT. TS at the ankle correlated with the CS inventory (r=0.303; P=0.010), Short Form 36 pain subscale (r=-0.325; P=0.005), and Illness Perception Questionnaire revised consequences subscale (r=0.325; P=0.005). EPTs left (P=0.011) and right wrist (P=0.023) were lower in the CWAD group, but conditioned pain modulation and TS did not differ between groups.

CONCLUSION

QST outcomes relate to psychological constructs, rather than to self-reported pain intensity and distribution. Local hyperalgesia was found in individuals with CWAD, but no differences in endogenous pain facilitation nor inhibition.

Rhythmic Change of Cortical Hemodynamic Signals Associated with Ongoing Nociception in Awake and Anesthetized Individuals: An Exploratory Functional Near Infrared Spectroscopy Study

BACKGROUND

Patients undergoing surgical procedures are vulnerable to repetitive evoked or ongoing nociceptive barrage. Using functional near infrared spectroscopy, the authors aimed to evaluate the cortical hemodynamic signal power changes during ongoing nociception in healthy awake volunteers and in surgical patients under general anesthesia. The authors hypothesized that ongoing nociception to heat or surgical trauma would induce reductions in the power of cortical low-frequency hemodynamic oscillations in a similar manner as previously reported using functional magnetic resonance imaging for ongoing pain.

METHODS

Cortical hemodynamic signals during noxious stimuli from the fontopolar cortex were evaluated in two groups: group 1, a healthy/conscious group (n = 15, all males) where ongoing noxious and innocuous heat stimulus was induced by a contact thermode to the dorsum of left hand; and group 2, a patient/unconscious group (n = 13, 3 males) receiving general anesthesia undergoing knee surgery. The fractional power of low-frequency hemodynamic signals was compared across stimulation conditions in the healthy awake group, and between patients who received standard anesthesia and those who received standard anesthesia with additional regional nerve block.

RESULTS

A reduction of the total fractional power in both groups-specifically, a decrease in the slow-5 frequency band (0.01 to 0.027 Hz) of oxygenated hemoglobin concentration changes over the frontopolar cortex-was observed during ongoing noxious stimuli in the healthy awake group (paired t test, P = 0.017; effect size, 0.70), and during invasive procedures in the surgery group (paired t test, P = 0.003; effect size, 2.16). The reduction was partially reversed in patients who received a regional nerve block that likely diminished afferent nociceptive activity (two-sample t test, P = 0.002; effect size, 2.34).

CONCLUSIONS

These results suggest common power changes in slow-wave cortical hemodynamic oscillations during ongoing nociceptive processing in conscious and unconscious states. The observed signal may potentially promote future development of a surrogate signal to assess ongoing nociception under general anesthesia.

EDITOR’S PERSPECTIVE

The predictors for altered central pain modulation in individuals with nonspecific chronic low back pain: A systematic review

BACKGROUND

Research suggests that the prognosis of chronic nonspecific low back pain is poor when there is an alteration in the central pain processing pathway. This alteration creates a cascade of events, leading to poor outcomes. An overview of the predictors which increase this heightened pain perception is needed.

OBJECTIVES

To review the studies identifying predictors for altered central main modulation in individuals with nonspecific chronic low back pain.

DESIGN

This is a systematic review.

METHODS

PubMed, Cochrane Library, Science Direct, Scopus, Ovid, Embase, Web of Science, and CINAHL were searched from inception to 25th May 2021. Titles, abstracts, and full text were searched for eligible articles, which met the set criteria. Research articles that have employed outcome measure specific to altered central pain modulation and assessed at least one predictor were included.

RESULTS

Six studies (n = 1389) were included in this review. The following five groups of predictors were identified: (1) psychological, (2) psychosocial (education, employment status, pain catastrophizing, and kinesiophobia), (3) sensory profile, (4) gender, and (5) others (illness and cognitive factors). Positive evidence of association was found for psychological predisposition and psychosocial (pain catastrophizing and employment and education status), whereas no evidence of association was found for kinesiophobia and cognitive factors.

CONCLUSION

This review identified the predictors for altered central pain modulation in chronic nonspecific low back pain. This alteration could be responsible for the suspected poor outcomes even post treatment. Furthermore, the knowledge of predictors could potentially aid the therapist in planning a treatment regime when poor outcomes are suspected.

Yoga, cognitive-behavioural therapy versus education to improve quality of life and reduce healthcare costs in people with endometriosis: a randomised controlled trial

INTRODUCTION

Endometriosis is a debilitating chronic inflammatory condition highly burdensome to the healthcare system. The present trial will establish the efficacy of (1) yoga and (2) cognitive-behavioural therapy (CBT), above (3) education, on quality of life, biopsychosocial outcomes and cost-effectiveness.

METHODS AND ANALYSIS

This study is a parallel randomised controlled trial. Participants will be randomly allocated to yoga, CBT or education. Participants will be English-speaking adults, have a diagnosis of endometriosis by a qualified physician, with pain for at least 6 months, and access to internet. Participants will attend 8 weekly group CBT sessions of 120 min; or 8 weekly group yoga sessions of 60 min; or receive weekly educational handouts on endometriosis. The primary outcome measure is quality of life. The analysis will include mixed-effects analysis of variance and linear models, cost-utility analysis from a societal and health system perspective and qualitative thematic analysis.

ETHICS AND DISSEMINATION

Enrolment in the study is voluntary and participants can withdraw at any time. Participants will be given the option to discuss the study with their next of kin/treating physician. Findings will be disseminated via publications, conferences and briefs to professional organisations. The University's media team will also be used to further disseminate via lay person articles and media releases.

TRIAL REGISTRATION NUMBER

ACTRN12620000756921p; Pre-results.

Nociplastic pain: towards an understanding of prevalent pain conditions

Nociplastic pain is the semantic term suggested by the international community of pain researchers to describe a third category of pain that is mechanistically distinct from nociceptive pain, which is caused by ongoing inflammation and damage of tissues, and neuropathic pain, which is caused by nerve damage. The mechanisms that underlie this type of pain are not entirely understood, but it is thought that augmented CNS pain and sensory processing and altered pain modulation play prominent roles. The symptoms observed in nociplastic pain include multifocal pain that is more widespread or intense, or both, than would be expected given the amount of identifiable tissue or nerve damage, as well as other CNS-derived symptoms, such as fatigue, sleep, memory, and mood problems. This type of pain can occur in isolation, as often occurs in conditions such as fibromyalgia or tension-type headache, or as part of a mixed-pain state in combination with ongoing nociceptive or neuropathic pain, as might occur in chronic low back pain. It is important to recognise this type of pain, since it will respond to different therapies than nociceptive pain, with a decreased responsiveness to peripherally directed therapies such as anti-inflammatory drugs and opioids, surgery, or injections.

Substituting Cannabidiol for Opioids and Pain Medications Among Individuals With Fibromyalgia: A Large Online Survey

People report substituting cannabis for pain medications, but whether cannabidiol (CBD) is used similarly remains unknown. CBD products can be CBD alone (isolate), hemp extract (containing <0.3% Δ-9-tetrahydrocannabinol [THC], other cannabinoids, and terpenes), or CBD-cannabis (containing >0.3% THC). In a secondary analysis from a cross-sectional survey, we examined substitution patterns among n = 878 individuals with fibromyalgia who currently used CBD. We sub-grouped participants by most commonly used CBD product (CBD isolate, hemp, CBD-cannabis, no preference) and whether they substituted CBD for medications. We investigated rationale for substituting, substitution-driven medication changes, CBD use patterns, and changes in pain-related symptoms (eg, sleep, anxiety). The study population was 93.6% female and 91.5% Caucasian, with an average age of 55.5 years. The majority (n = 632, 72.0%) reported substituting CBD products for medications, most commonly NSAIDs (59.0%), opioids (53.3%), gabapentanoids (35.0%), and benzodiazepines (23.1%). Most substituting participants reported decreasing or stopping use of these pain medications. The most common reasons for substitution were fewer side effects and better symptom management. Age, hemp products, past-year use of marijuana, and higher somatic burden were all associated with substituting (P's ≤ .05). Those who substituted reported larger improvements in health and pain than those who did not. Participants using CBD-cannabis reported significantly more substitutions than any other group (P's ≤ .001) and larger improvements in health, pain, memory, and sleep than other subgroups. This widespread naturalistic substitution for pain medications suggests the need for more rigorous study designs to examine this effect. PERSPECTIVE: This article shows that people with fibromyalgia are deliberately substituting CBD products for conventional pain medications despite the dearth of evidence suggesting CBD products may be helpful for fibromyalgia. CBD's medication-sparing and therapeutic potential should be examined in more rigorous study designs.

Characterizing chronic pain phenotypes in multiple sclerosis: a nationwide survey study

ABSTRACT

Chronic pain is highly prevalent in multiple sclerosis (MS). Pain heterogeneity may contribute to poor treatment outcomes. The aim of this study was to characterize pain phenotypes distributions in persons with MS and compare pain phenotypes in terms of pain intensity, frequency of chronic overlapping pain conditions, and use and analgesic effects of different classes of pain medications. Data were collected through a national web-based survey with measures of neuropathic (painDETECT) and nociplastic pain (Fibromyalgia Survey Criteria), chronic overlapping pain conditions, and pain medication use and pain relief. In a sample of N = 842 adults with chronic pain and MS, the largest proportion (41%) showed evidence of nociceptive pain, 27% had mixed neuropathic/nociplastic pain, 23% had nociplastic pain, and 9% had neuropathic pain. Nociplastic pain was associated with significantly higher pain intensity and frequency of chronic overlapping pain conditions. Across all pain types, high frequency of pain medication use along with poor-modest pain relief was reported. Cannabis use for pain was more common, and pain relief ratings were higher among those with nociplastic pain, relative to nociceptive pain. Although NSAID use was highest among those with nociplastic pain (80%), pain relief ratings for NSAIDs were highest among those with nociceptive pain. These findings underscore the need for multidimensional assessment of pain in MS with greater emphasis on the identification of pain phenotype. An improved characterization of pain as a multifaceted condition in MS could inform therapeutic approaches.

Electronic Delivery of Pain Education for Chronic Overlapping Pain Conditions: A Prospective Cohort Study

OBJECTIVE

To examine the impact of educational materials for chronic overlapping pain conditions (COPCs), the feasibility of delivering materials online, and to explore its impact on self-reported self-management applications at 3-month follow-up.

DESIGN

Prospective cohort study.

SETTING

Online.

SUBJECTS

Individuals from a university-wide active research repository with ≥1 coded diagnostic COPC by ICD-9/10 in the medical record.

METHODS

We determined the number of COPCs per participant as indicated by diagnostic codes in the medical record. Consenting participants completed self-report questionnaires and read educational materials. We assessed content awareness and knowledge pre- and post-exposure to education. Comprehension was assessed via embedded questions in reading materials in real time. Participants then completed assessments regarding concept retention, self-management engagement, and pain-related symptoms at 3-months.

RESULTS

N = 216 individuals enrolled, with 181 (84%) completing both timepoints. Results indicated that participants understood materials. Knowledge and understanding of COPCs increased significantly after education and was retained at 3-months. Patient characteristics suggested the number of diagnosed COPCs was inversely related to age. Symptoms or self-management application did not change significantly over the 3-month period.

CONCLUSIONS

The educational materials facilitated teaching of key pain concepts in self-management programs, which translated easily into an electronic format. Education alone may not elicit self-management engagement or symptom reduction in this population; however, conclusions are limited by the study's uncontrolled design. Education is likely an important and meaningful first step in comprehensive COPC self-management.

Cannabidiol Use for Fibromyalgia: Prevalence of Use and Perceptions of Effectiveness in a Large Online Survey

Cannabidiol (CBD) is widely advertised as helpful for chronic pain management but research is limited. Using a cross-sectional, anonymous survey, we examined patterns of naturalistic CBD use among individuals with fibromyalgia (FM) and other chronic pain conditions. Our objective was to better understand rates of CBD use, reasons for use and discontinuation, communication with healthcare professionals about CBD, and perceptions of CBD effectiveness and safety among people with FM. After excluding incomplete surveys, our study population consisted of N = 2,701 participants with fibromyalgia, primarily in the United States. Overall, 38.1% reported never using CBD, 29.4% reported past CBD use, and 32.4% reported current CBD use. Past-year cannabis use was strongly associated with past or current CBD use. Those using CBD typically did so due to inadequate symptom relief, while those not using CBD typically cited safety concerns as their reason for not using CBD. Two-thirds of participants disclosed CBD use to their physician, although only 33% asked for physician advice on using CBD. Participants used CBD for numerous FM-related symptoms (most commonly pain), and generally reported slight to much improvement across symptom domains. Around half of participants reported side effects, which were typically minor. Our findings are limited by selection bias and our cross-sectional design, which prevents causal associations. In conclusion, CBD use is common among individuals with FM and many individuals using CBD report improvements across numerous FM-related symptoms. Our findings highlight the need for additional rigorous studies to better understand CBD's potential for FM management. PERSPECTIVE: This article indicates that CBD use is common among people with fibromyalgia, and the results suggest that many derive benefit from using CBD across multiple symptoms domains. Clinicians should discuss CBD use with fibromyalgia patients, and future studies are needed to rigorously assess CBD's therapeutic value for fibromyalgia symptoms.

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.

Phenotypes of Women with and Without Endometriosis and Relationship with Functional Pain Disability

Objective

Primary dysmenorrhea and secondary dysmenorrhea due to endometriosis share overlapping symptoms and likely demonstrate aspects of central sensitization. The present study aimed to identify distinct phenotypes of women who have dysmenorrhea with and without endometriosis to shed light on the unique mechanisms contributing to the pathogenesis of each condition.

Methods

An online survey was used to investigate the relationship between ratings of menstrual pain severity, menstrual symptoms (abdominal cramps, abdominal discomfort, low back pain, headache, body aches, bloating, nausea, diarrhea, increased bowel movements), widespread pain, and functional pain disability in a community sample of 1,354 women (aged 18–50) with menstrual pain in Australia.

Results

Compared with women without endometriosis, those with endometriosis had statistically significant higher menstrual pain severity (P&lt;0.01), symptom severity and fatigue (all symptoms P&lt;0.001, although only cramps and bloating were clinically significant), widespread pain sites (P&lt;0.001), and functional pain disability (P&lt;0.001, although this difference was not clinically significant). When examining symptoms by pain severity, women with severe menstrual pain were more likely to experience symptoms than women with less severe pain, regardless of the presence of endometriosis. Similar predictors of functional pain disability emerged for women with and without endometriosis, such as body aches, nausea, fatigue, and widespread pain, respectively, suggesting the presence of central sensitization in both groups. Logistic regression revealed that after accounting for menstrual pain severity (odds ratio [OR], 1.61) and duration (OR, 1.04), symptoms of bloating (OR, 1.12), nausea (OR, 1.07), and widespread pain sites (OR, 1.06) significantly predicted the presence of endometriosis.

Conclusions

The findings suggest that phenotypes specific to endometriosis can be identified.

Measures of central sensitization and their measurement properties in musculoskeletal trauma: A systematic review

BACKGROUND AND OBJECTIVE

Chronic pain following musculoskeletal trauma is common, which may partially be attributed to the early presence of central sensitization (CS). Multiple measures are suggested to assess clinical features of CS, yet no systematic review has evaluated the measurement properties of these measures in a musculoskeletal trauma population.

DATABASES AND DATA TREATMENT

This systematic review, which followed a published and PROSPERO registered protocol (CRD42018091531), aimed to establish the scope of CS measures used within a musculoskeletal trauma population and evaluate their measurement properties. Searches were conducted in two stages by two independent reviewers. The Consensus-based Standards for the selection of Health Measurement Instruments (COSMIN) checklist was used to evaluate risk of bias and overall quality was assessed using the modified Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

From 86 studies, 30 different CS outcome measures were identified. Nine studies evaluated measurement properties of nine outcome measures; eight evaluated reliability and one evaluated construct validity. Measures included seven quantitative sensory testing methods (pressure, cold and electrical pain thresholds; warm, cold and vibration detection thresholds; vibration perception thresholds), pain drawings and a pinwheel. Risk of bias was assessed as doubtful/inadequate for all but one study, overall quality of evidence was low/very low for all measures. Reliability of measures ranged from poor to excellent.

CONCLUSIONS

Many measures are used to evaluate CS but with limited established measurement properties in musculoskeletal trauma. High quality research to establish measurement properties of CS outcome measures is required.

Multisensory Sensitivity is Related to Deep-Tissue but Not Cutaneous Pain Sensitivity in Healthy Individuals

PURPOSE

Some individuals with chronic pain find daily life sensations (eg, noise, light, or touch) aversive. This amplification of multisensory sensations has been associated with centrally mediated plasticity; for example, greater multisensory sensitivity (MSS) occurs in patients with fibromyalgia than rheumatoid arthritis. However, whether MSS preferentially relates to pain measures which reflect central influences (eg, dynamic quantitative sensory testing (QST) or referred pain), or whether the MSS-pain relationship requires priming from chronic pain, is unknown. Thus, this cross-sectional study investigated the relationships between MSS assessed in a pain-free state and evoked pain sensitivity.

METHODS

Experimental intramuscular infusion pain and multiple static and dynamic QST were assessed in 465 healthy, pain-free adults: pain thresholds using pressure (PPTs) and heat (HPTs), temporal summation of pain (TSP) using pressure, heat or punctate stimuli, and conditioned pain modulation (CPM) using pressure or heat test stimuli. MSS was assessed using 7 items from Barsky's Somatosensory Amplification Scale. Differences in pain and QST between sex-specific MSS quartiles were assessed, adjusting for multiple comparisons. All participants completed at least one intramuscular infusion condition, but not all were asked to complete each QST (n=166-465).

RESULTS

Both static and dynamic QST differed between highest and lowest MSS quartiles using pressure stimuli: lower PPTs (adjusted-p<0.01); increased pressure TSP (adjusted-p=0.02); lower pressure CPM (adjusted-p=0.01). However, none of the heat or punctate QST measures (HPTs, TSP, or CPM) differed between MSS quartiles (adjusted-p>0.05). Odds of experiencing TSP or referred pain was not greater, whereas CPM was 8-fold less likely, in those with highest MSS.

CONCLUSION

Normal variation in non-noxious MSS is related to both static and dynamic pain sensitivity, without sensitization associated with chronic pain, but is dependent on the QST stimulus. Thus, common influences on MSS and pain sensitivity may involve central mechanisms but are likely more complex than previously recognized.

Psychological Therapy for Centralized Pain: An Integrative Assessment and Treatment Model

OBJECTIVE

Chronic pain is a significant health problem that is increasing in prevalence, and advances in treatment are needed.

METHODS

We briefly review the leading evidence-based psychological therapies for chronic pain-cognitive-behavioral and acceptance/mindfulness-based therapies-and examine several limitations and missing perspectives of these approaches. We review six lesser-known interventions that address these limitations, and we describe our integrative model for psychological assessment and treatment of centralized pain. We present a typical patient and describe how we apply this approach, along with challenges to its implementation and possible solutions to these challenges.

RESULTS

Greater pain treatment efficacy may be possible if clinicians: (a) distinguish patients with primarily centralized (i.e., somatoform or nociplastic) pain from those with primarily peripheral (nociceptive, inflammatory, or neuropathic) pain; (b) acknowledge the capacity of the brain not only to modulate pain but also generate as well as attenuate or eliminate centralized pain; (c) consider the powerful role that adverse life experiences and psychological conflicts play in centralized pain; and (d) integrate emotional processing and interpersonal changes into treatment. Our integrative treatment involves delivering a progression of interventions, as needed, to achieve pain reduction: tailored pain neuroscience education, cognitive and mindfulness skills to decrease the pain danger alarm mechanism, behavioral engagement in avoided painful and other feared activities, emotional awareness and expression to reverse emotional avoidance and overcome trauma or psychological conflict, and adaptive communication to decrease interpersonal stress.

CONCLUSIONS

This integrative assessment and treatment model has the potential to substantially reduce and sometimes eliminate centralized pain by changing the cognitive, behavioral, emotional, and interpersonal processes that trigger and maintain centralized pain.

Examining the Adjustment Patterns of Adults With Multiple Chronic Pain Conditions and Multiple Pain Sites: More Pain, No Gain

The present study examined how multiple chronic pain conditions and pain sites are associated with sociodemographics, chronic pain adjustment profiles, and emotional distress. A total of 2,407 individuals who reported at least 6 months of having consistent pain severity, pain interference, and/or emotional burden due to pain were recruited through random digit dialing across the United States. Participants' chronic pain adjustment profiles (ie, pain intensity, pain interference, emotional burden, pain catastrophizing, pain coping, pain attitudes, and social resources) were assessed. Anxiety and depressive symptoms were also measured using a subsample of 181 participants who provided 3-month follow-up data. More than 60% of individuals with chronic pain reported having multiple pain conditions. Middle-aged single women with fibromyalgia, disability and of low socioeconomic status reported a greater number of pain conditions and pain sites. Structural equation modeling revealed that a higher number of pain conditions and sites were associated with more dysfunctional chronic pain adjustment profiles. The subsample analyses showed that reporting a greater number of pain conditions predicted a higher level of depression and anxiety 3 months later, controlling for pain-related anxiety and depressive symptoms, pain severity and interference at baseline. Having multiple pain conditions and sites may represent a psychosocial barrier to successful adjustment to chronic pain. PERSPECTIVE: This article argues for the importance of assessing the number of co-occurring chronic pain conditions and bodily areas that are affected by pain in both pain research and clinical settings. Measuring and incorporating such information could potentially enhance our nascent understanding of the adjustment processes of chronic pain.

Emotional Awareness and Expression Therapy for Chronic Pain: Rationale, Principles and Techniques, Evidence, and Critical Review

PURPOSE OF REVIEW

Patients with chronic pain, especially primary or centralized pain, have elevated rates of psychosocial trauma and intrapersonal or intrapsychic conflict. To address these risk factors and potentially reduce pain, the authors developed emotional awareness and expression therapy (EAET). This article presents the rationale for EAET, describes its principles and techniques, reviews its development and early testing as well as recent clinical trials, and critically analyzes the evidence base.

RECENT FINDINGS

Four initial trials (between 2006 and 2011) demonstrated the efficacy of earlier versions of EAET. Four recent randomized, controlled trials of different EAET durations (1 to 8 sessions) and formats (individual or group) in patients with fibromyalgia, irritable bowel syndrome, pelvic pain, or medically unexplained symptoms support the earlier findings. EAET reliably reduces pain and interference, although improvements in anxiety and depression are less reliably achieved and may be delayed. The largest and best conducted trial found superiority of EAET over cognitive-behavioral therapy for fibromyalgia. Patient retention in EAET is high, and adverse events are rare. EAET merits inclusion as a treatment option for primary pain conditions, and it may be the preferred treatment for some patients. Research is needed on EAET with other pain conditions and samples, using better controls and comparison conditions, and on additional ways to motivate and help patients engage in successful emotional processing.

Chronic pain syndromes: overlapping phenotypes with common mechanisms

The common chronic pain syndromes of fibromyalgia, regional pain syndrome, and complex regional pain syndrome have been made to appear separate because they have been historically described by different groups and with different criteria, but they are really phenotypically accented expressions of the same processes triggered by emotional distress and filtered or modified by genetics, psychology, and local physical factors.