Slowly Repeated Evoked Pain as a Marker of Central Sensitization in Fibromyalgia: Diagnostic Accuracy and Reliability in Comparison With Temporal Summation of Pain

Quantitative Sensory Testing in Fibromyalgia Syndrome: A Scoping Review

Background/Objectives: Quantitative sensory testing (QST) is one of the most reliable methods for assessing Fibromyalgia Syndrome (FMS). Despite its importance, there are still controversies regarding the correct interpretation of evoked responses, as they may vary depending on the protocol, individual characteristics, disease severity, and other factors. This study aims to examine how QST has been applied as an outcome measure in FMS. Methods: We considered three databases (Medline, Embase, and Web of Science) until June 2024. From a total of 2512 studies, 126 (39 RCTs and 87 non-RCTs) were selected for full reading after assessment for risk of bias and eligibility criteria. These criteria included at least one type of QST and a clear diagnosis of fibromyalgia (FMS). Results: The results highlighted a lack of standardization in QST, as no reported protocols were followed and there was no specific number of tender points tested for FMS. Additionally, there was inconsistency in the selection of sites and types of tests conducted. Conclusions: This heterogeneity in methodology may affect the comparability and interpretation of results, underscoring the urgent need for standardized guidelines for conducting QST in fibromyalgia studies. A clear understanding of how QST has been measured could prompt a reevaluation of current approaches to FMS assessment, leading to more accurate interpretations and, ultimately, improved management of this complex condition.

Pain sensitisation in patients with sickle cell disease: A preliminary study

BACKGROUND

Responses to experimental pain have suggested central and peripheral sensitisation in adult patients with sickle cell disease (SCD). Recent studies have proposed an algometry-derived dynamic measure of pain sensitisation, slowly repeated evoked pain (SREP), which is useful in the discrimination of painful conditions related to central sensitisation. Pain and fatigue are two symptoms that affect the general functioning of patients with SCD most significantly, however, research about experimental dynamic pain measures and their relation to the main symptoms of SCD (pain and fatigue) is still scarce.

OBJECTIVE

This preliminary study aimed to test the utility of the SREP protocol for detecting pain sensitisation in patients with SCD, and to evaluate the associations of pain sensitisation, pain threshold, and pain tolerance with the main clinical symptoms of SCD, pain and fatigue.

METHODS

Twenty-two female outpatients with SCD and 20 healthy women participated. Pain threshold, pain tolerance, and pain sensitisation were assessed by algometry in the fingernail. Clinical pain, fatigue, anxiety, depression and pain catastrophizing were evaluated.

RESULTS

No group differences were found in pain threshold and tolerance. However, using the SREP protocol, pain sensitisation was greater in patients than in healthy participants, even after controlling for psychological variables and body mass index. Pain threshold and tolerance were inversely associated with fatigue levels in the SCD group, with pain tolerance being the main predictor.

CONCLUSIONS

Pain threshold and tolerance did not discriminate between patients and healthy individuals, but were useful for predicting fatigue severity in SCD. The SREP protocol provides a useful dynamic measure of pain for the discrimination and detection of enhanced pain sensitisation in patients with SCD, which could contribute to more personalised pain evaluations and treatment for these patients.

Explaining persistent physical symptoms to patients in general practice: can tests to measure central sensitisation add value? A mixed-methods study

INTRODUCTION

General practitioners (GPs) often face challenges in explaining to patients with persistent physical symptoms (PPS) why their symptoms persist. Providing an explanation of the central sensitisation (CS) mechanism to patients could be helpful, yet GPs do not routinely test for signs of CS in these patients. The aim of this study was to explore the value of applying a test to assess CS in enhancing explanations provided to patients.

METHODS

In this prospective study, 25 GPs applied three tests, selected through a Delphi study, to assess CS-related symptoms: (1) the Central Sensitisation Inventory (CSI); (2) an algometer for measuring pressure pain thresholds (PPT); and (3) a monofilament for assessing temporal summation. Following the tests, both the GP and the patient completed a short questionnaire. Subsequently, GPs shared their experiences in focus groups and interviews, while a sample of patients was interviewed individually. The questionnaires were analysed quantitatively, and the focus groups and interviews were analysed qualitatively.

RESULTS

GPs reported that all tests were feasible to perform during consultations; testing took less than 5 min in 25% of cases and between 5 and 10 min in 60% of cases. In approximately 50% of cases, an additional consultation was required to perform the test. The results of the CSI confirmed CS-related symptoms more frequently (74%) than the algometer (46%) and the monofilament (43%). Consequently, many GPs preferred the CSI. Patients did not show a preference for any specific test; two-third found the tests valuable and approximately 50% reported that the explanation of CS was clearer when a test was used.

CONCLUSIONS

Testing during the consultation was feasible, although an additional consultation was required in 50% of the cases. GPs preferred the CSI because its results confirmed CS-related symptoms more frequently than those from the algometer and monofilament.

The problem of residual pain in the assessment of rheumatoid arthritis activity

Residual pain is a major unmet medical need observed in patients suffering from rheumatoid arthritis (RA), which decreases their quality of life, even after achieving remission or low disease activity. The article has two aims: 1) to present mechanisms involved in the pathophysiology of residual pain, both inflammatory and non-inflammatory, i.e. neuropathic and nociplastic pain, as well as secondary pain syndromes, i.e. osteoarthritis and fibromyalgia, which can contribute to residual pain; 2) to show the limitations of current disease activity measures recommended by European Alliance of Associations for Rheumatology (EULAR) and American College of Rheumatology (ACR), which raise the need for a separate assessment of pain, and examples of methods that could be used by medical professionals to assess the pain and make a differential diagnosis. In conclusion, establishing a valid method to assess pain is essential to identify the pathomechanism of residual pain and to create treatments tailored specifically to individual RA patients.

Effects of Nature-Based Multisensory Stimulation on Pain Mechanisms in Women with Fibromyalgia Syndrome: A Randomized Double-Blind Placebo-Controlled Trial

BACKGROUND

The term "nature-based sensory stimuli" refers to the sensory information produced by biotic and abiotic agents from natural environments. The literature has reported the beneficial effects of these agents on various pain dimensions in non-clinical populations.

AIMS

To evaluate the potential analgesic effects of nature-based multisensory stimulation in women with fibromyalgia syndrome.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group trial with a 1:1 allocation ratio was conducted. Forty-two women with fibromyalgia syndrome interacted with either different plant species with flowers, stones, and soil organic matter or their synthetic imitations for 30 minutes. Outcome measurements were performed before and after the intervention, including clinical pain intensity using the Numeric Rating Scale, cold pain thresholds using the Cold Pressor Test, mechanical hyperalgesia and wind-up using a monofilament, and pressure pain thresholds using a pressure algometer.

RESULTS

Analyses revealed group × time interactions for clinical pain intensity (F = 7.915, p = .008), cold-water immersion time (F = 7.271, p = .010), mechanical hyperalgesia (F = 4.701, p = .036), and pressure pain threshold (p ≤ .017). Between-group differences were found in clinical pain intensity (p = .012), cold pain thresholds (p = .002), and pressure pain thresholds (p < .05). The experimental group exhibited reduced clinical pain intensity (p = .001) and increased pressure pain thresholds (p ≤ .034).

CONCLUSIONS

Women with fibromyalgia syndrome may benefit from multisensory stimulation using biotic and abiotic agents from natural environments for 30 minutes. Interacting with flowering plants and soil components appears to induce analgesic effects.

Preference for Hedonic Goals in Fibromyalgia; Is It Always an Avoidance Mechanism? Looking the Relationship with Pain Acceptance from a Positive Psychology Perspective

The aim of this study was to analyze the effect of openness to experience on pain acceptance through positive affect (PA) considering the moderating role of preference for mood management goals in women with fibromyalgia (FM). A cross-sectional study (n = 231) was carried out. A simple mediation model and a moderate mediation model were conducted by SPSS macro-PROCESS. Results showed that PA mediated positively the effect of openness to experience on acceptance (B = 0.46, SE = 0.80, t = 5,59; 95% CI = [0.3016, 0.6298], p < .001) and that the contribution of openness to experience to PA varied at different values of mood management goals (medium: - .04; ß = .40, p < .001; high: .95; ß = .61, p<.001). Findings may serve as a foundation for tailored interventions to promote activity through acceptance focusing on PA and mood management goals among women with medium to high level of hedonic goals.

Impact of homeostatic body hydration status, evaluated by hemodynamic measures, on different pain sensitization paths to a chronic pain syndrome

Contrasting findings on the mechanisms of chronic pain and hypertension development render the current conventional evidence of a negative relationship between blood pressure (BP) and pain severity insufficient for developing personalized treatments. In this interdisciplinary study, patients with fibromyalgia (FM) exhibiting clinically normal or elevated BP, alongside healthy participants were assessed. Different pain sensitization responses were evaluated using a dynamic 'slowly repeated evoked pain' (SREP) measure, as well as static pain pressure threshold and tolerance measures. Cardiovascular responses to clino-orthostatic (lying-standing) challenges were also examined as acute re- and de-hydration events, challenging cardiovascular and cerebrovascular homeostasis. These challenges involve compensating effects from various cardiac preload or afterload mechanisms associated with different homeostatic body hydration statuses. Additionally, hair cortisol concentration was considered as a factor with an impact on chronic hydration statuses. Pain windup (SREP) and lower pain threshold in FM patients were found to be related to BP rise during clinostatic (lying) rehydration or orthostatic (standing) dehydration events, respectively. These events were determined by acute systemic vasoconstriction (i.e., cardiac afterload response) overcompensating for clinostatic or orthostatic cardiac preload under-responses (low cardiac output or stroke volume). Lower pain tolerance was associated with tonic blood pressure reduction, determined by permanent hypovolemia (low stroke volume) decompensated by permanent systemic vasodilation. In conclusion, the body hydration status profiles assessed by (re)activity of systemic vascular resistance and effective blood volume-related measures can help predict the risk and intensity of different pain sensitization components in chronic pain syndrome, facilitating a more personalized management approach.

Psychoeducation for Fibromyalgia Syndrome: A Systematic Review of Emotional, Clinical and Functional Related-Outcomes

Fibromyalgia Syndrome (FMS) is a chronic condition of widespread pain accompanied by several symptoms such as stiffness, fatigue, sleep problems, depression, anxiety, and cognitive deficits. To date, there is no specific treatment for FMS. The European League Against Rheumatism, and the majority of the international recommendations for managing FMS, has claimed psychoeducational intervention as the first step in FMS treatment for adequate symptoms management. However, scientific studies in this regard are scarce, diverse, and with contradictory findings. Results integration from analogous studies could provide a clear presentation of the real clinical value of psychoeducation in FMS. Therefore, the current systematic review aims at exploring the effect of psychoeducation on emotional, clinical, and functional symptoms of FMS patients and encourages researchers towards psychoeducation's procedure optimization and systematization. The systematic review was conducted according to the guidelines of the Cochrane Collaboration and PRISMA statements. The selected articles were evaluated using the Cochrane risk of bias (ROB) assessment tool. The selected articles were extracted from PubMed, Scopus, and Web of Science databases. The literature search identified 11 studies eligible for the systematic review. The ROB evaluation revealed that 2 of the 11 studies showed a low quality, the other 2 had a moderate quality, and the remaining 7 studies exhibited a high quality. Results showed that psychoeducation is generally included as an important first therapeutic step in multicomponent treatments for FMS. Moreover, psychoeducation generally seems to be quite beneficial in reducing emotional (i.e., number of days feeling emotionally well, general anxiety, depression levels, etc.) and clinical symptoms (levels of fatigue, morning stiffness, pain intensity, etc.), as well as increasing functional status (i.e., general physical function, morning fatigue, stiffness, etc.). Despite that psychoeducation´s clinical benefits are highlighted, there is scarce amount of research on psychoeducation beyond its usefulness as part of multicomponent treatments.

Algometry for the assessment of central sensitisation to pain in fibromyalgia patients: a systematic review

INTRODUCTION

The pathophysiology of fibromyalgia (FM) is related to central sensitisation (CS) to pain. Algometry allows assessing CS based on dynamic evoked pain. However, current algometrýs protocols require optimising, unifying and updating.

OBJECTIVES

1) identify the dynamic pain measures used most frequently to effectively assess CS processes in FM, and 2) consider the future of the algometry assessing CS in these patients.

METHODS

Cochrane Collaboration guidelines and PRISMA statements were followed. The protocol was registered in PROSPERO database (ID: CRD42021270135). The selected articles were evaluated using the Cochrane risk of bias (ROB) assessment tool. The PubMed, Scopus, and Web of Science databases were searched.

RESULTS

Thirty-four studies were selected, including measures such as temporal summation of pain (TSP), aftersensations (AS), spatial summation of pain (SSP), the noxious flexion reflex (NFR) threshold, conditioned pain modulation (CPM), cutaneous silent period (CuSP), and slowly repeated evoked pain (SREP); and evoked pain combined with neuroimaging. Each measure offered various advantages and limitations. According to ROB, 28 studies were of low quality, 3 of moderate quality, and 3 of high quality.

CONCLUSIONS

Several pain indicators have been demonstrated to successfully examine CS involvement in FM in the last years. Algometry, especially when it involves diverse body sites and tissues, might provide further insight into (1) the evaluation of psychological factors known to influence pain experience, (2) new dynamic pain indicators, and (3) the simultaneous use of certain neuroimaging techniques. Further research clarifying the mechanisms underlying some of these measures, and homogenisation and optimisation of the algometrýs protocols, are needed. KEY MESSAGESAlgometry allows for assessing Central Sensitisation by applying dynamic evoked pain.The future of algometry could relapse in its combination with neuroimaging.Recently-emerged pain indicators should be considered for algometrýs new protocols.

When It Hurts, a Positive Attitude May Help. The Moderating Effect of Positive Affect on the Relationship Between Walking, Depression, and Symptoms in Women with Fibromyalgia

BACKGROUND

Increased exercise is a marker of health in fibromyalgia (FM). However, patients frequently avoid physical activity as a way of minimizing the pain they feel. This deprives them of opportunities to obtain positive reinforcement, increasing functional impact.

AIMS

This study examines the mediating role of depressive symptoms between walking (as physical exercise), functional impact, and pain, at different levels of positive affect (PA) among women with fibromyalgia.

DESIGN

Cross-sectional correlational study.

SETTINGS

Mutual aid associations for fibromyalgia in Spain.

PARTICIPANTS

231 women diagnosed with FM.

METHODS

Moderate mediation analyses were conducted using PROCESS.

RESULTS

First, a simple mediation model showed that depression mediated the effect of walking on functional impact, but not on pain. Additionally, the moderated mediated model showed that this effect was significant at medium and high levels of PA, but not when levels of PA were low.

CONCLUSIONS

Provision of resources focused on positive affect seem to increase the positive effects of walking on functional impact through the reduction of depressive symptoms. Nurses can improve adherence of patients with FM to walking behavior through increasing positive affect.

Is reduced health-related quality of life a primary manifestation of fibromyalgia? A comparative study with Rheumatoid arthritis

BACKGROUND

Fibromyalgia syndrome (FMS) is a chronic pain condition associated with a significant reduction in health-related quality of life (HRQoL). This study compared the different components of HRQoL between FMS and rheumatoid arthritis (RA) patients, and evaluated the relationships between HRQoL and clinical and emotional factors in FMS and RA patients.

METHOD

Women with FMS (n = 80), RA (n = 43) and healthy women (n = 67) participated in the study. HRQoL was assessed by the SF-36 survey. Associations between HRQoL and symptom severity were assessed by correlation and multiple linear regression analyses.

RESULTS

FMS patients displayed lower values for all SF-36 variables than RA patients and healthy participants, while RA patients showed lower values for all SF-36 variables than healthy participants. These group differences persisted after statistically controlling for demographic, clinical and emotional variables. Clinical and emotional factors were inversely associated with SF-36 scores in the overall FMS + RA sample. Depression and fatigue were the strongest negative predictors. However, after the statistical control of the effect of diagnosis (FMS vs. RA) in the regression analysis, most of the associations disappear.

CONCLUSIONS

The fact that group differences in HRQoL remained highly significant after statistically controlling of group differences in clinical symptom severity, and that associations between clinical symptoms and HRQoL disappear when the type of diagnosis was considered in the regression analysis, suggest that impairment of HRQoL could be considered a primary feature of FMS.

Whole-Body Cryostimulation in Fibromyalgia: A Scoping Review

Currently, all available therapies for the control and management of fibromyalgia (FM) are mostly focused on relieving patients’ symptoms and improving their quality of life. The purpose of this review is to provide an up-to-date overview of the evidence supporting the beneficial effects of whole-body cryostimulation (WBC) in patients with FM and evidence-based guidance on the possible adjuvant use of WBC in the treatment of FM. We searched the most recent literature by retrieving 10 eligible studies, 4 of which were abstracts only, from a total of 263 records. Thermal stress caused by cryostimulation induces an analgesic effect, improving pain, redox balance, and inflammatory symptoms in an exercise-mimicking fashion. In addition, it reduces the feeling of fatigue, improves mood, and reduces mental health deterioration with positive consequences on depressive states and improved sleep quality. Although the studies included in this review are not of sufficient quality and quantity to draw definitive conclusions about the effectiveness of WBC in FM, initial evidence indicates WBC as a promising add-on option in the multidisciplinary treatment of FM, due to its rapid action and high patients’ compliance. The application of WBC protocols has the potential to expand therapeutic options for the treatment of FM and related disorders; however, larger, high-quality primary studies are still needed.

Assessing Walking Programs in Fibromyalgia: A Concordance Study between Measures

This study analyzes the degree of agreement between three self-report measures (Walking Behavior, WALK questionnaire and logbooks) assessing adherence to walking programs through reporting their components (minutes, rests, times a week, consecutive weeks) and their concordance with a standard self-report of physical activity (IPAQ-S questionnaire) and an objective, namely number of steps (pedometer), in 275 women with fibromyalgia. Regularized partial correlation networks were selected as the analytic framework. Three network models based on two different times of assessment, namely T1 and T2, including 6 weeks between both, were used. WALK and the logbook were connected with Walking Behavior and also with the IPAQ-S. The logbook was associated with the pedometers (Z-score > 1 in absolute value). When the behavior was assessed specifically and in a detailed manner, participants’ results for the different self-report measures were in agreement. Specific self-report methods provide detailed information that is consistent with validated self-report measures (IPAQ-S) and objective measures (pedometers). The self-report measures that assess the behavioral components of physical activity are useful when studying the implementation of walking as physical exercise.

Tests for central sensitization in general practice: a Delphi study

INTRODUCTION

Central sensitization (CS) may explain the persistence of symptoms in patients with chronic pain and persistent physical symptoms (PPS). There is a need for assessing CS in the consultation room. In a recently published systematic review, we made an inventory of tests for CS. In this study we aimed to assess which tests might have added value, might be feasible and thus be suitable for use in general practice.

METHODS

We conducted a Delphi study consisting of two e-mail rounds to reach consensus among experts in chronic pain and PPS. We invited 40 national and international experts on chronic pain and PPS, 27 agreed to participate. We selected 12 tests from our systematic review and additional searches; panellists added three more tests in the first round. We asked the panellists, both clinicians and researchers, to rate these 15 tests on technical feasibility for use in general practice, added value and to provide an overall judgement for suitability in general practice.

RESULTS

In two rounds the panellists reached consensus on 14 of the 15 tests: three were included, eleven excluded. Included were the Central Sensitization Inventory (CSI), pressure pain thresholds (PPTs) and monofilaments. No consensus was reached on the Sensory Hypersensitivity Scale.

CONCLUSION

In a Delphi study among an international panel of experts, three tests for measuring CS were considered to be suitable for use in general practice: the Central Sensitization Inventory (CSI), pressure pain thresholds (PPTs) and monofilaments.

Pain neuroscience education combined with usual treatment for fibromyalgia syndrome: A randomized controlled trial

AIM

The aim of this study was to investigate the effectiveness of pain neuroscience education (PNE) in addition to usual treatment in patients with fibromyalgia syndrome.

METHODS

Forty patients were randomized into 2 groups. The experimental group underwent PNE sessions over 6 weeks in addition to pharmacological treatment, and the control group was given only pharmacological treatment. The primary outcome measure was functional status and the secondary outcome measures were widespread pain pressure threshold and kinesiophobia level. All assessments were conducted before the intervention and at the end of the 6th and 12th weeks by the same blinded researcher.

RESULTS

The intervention group had significantly greater improvement than the control group in terms of the mean total scores in the Fibromyalgia Impact Questionnaire (P = .001) and the Tampa Scale of Kinesiophobia (P = .001) with large effect sizes. The intervention group also had significantly greater improvement in the pain pressure threshold values of the cervical (P = .040), thoracic (P = .001), lumbar (P < .001), elbow (P = .005) and calf (P = .006) regions with moderate-to-large effect sizes.

CONCLUSION

This study showed that the addition of 6-week PNE sessions to pharmacological treatment was successful in improving functional status, widespread pain pressure threshold, and level of kinesiophobia in patients with fibromyalgia syndrome during a 12-week follow-up period.

Spa Therapy for the Treatment of Fibromyalgia: An Open, Randomized Multicenter Trial

Fibromyalgia is a common chronic pain pathology with an incidence of 4.3 per 1,000 person-years. An open, randomized clinical trial of patients with fibromyalgia comparing an immediate vs. delayed 18-day spa therapy in five spa therapy care facilities in France enrolled 220 patients. Randomization was in blocks of four, stratified by center, severity of fibromyalgia and previous spa therapy. Patients continued usual treatment. The main endpoint was the number of patients achieving minimal clinically important difference at 6 months, defined as 14% change in their baseline fibromyalgia impact questionnaire score. The intention-to-treat analysis included 100 and 106 patients in the intervention and control groups, respectively. At 6 months, 45/100 (45.0%) and 30/106 (28.3%) patients in the intervention and control groups, respectively, achieved a minimal clinically important difference (P= .013). There was also a significant improvement in pain, fatigue, and symptom severity (secondary outcomes) in the intervention group but not for generic quality of life (QOL), sleep or physical activity. None of the 33 serious adverse events reported by 25 patients were related to the spa therapy. Our results demonstrate the benefit of spa treatment in patients with fibromyalgia. PERSPECTIVE: A 12-month, open, randomized clinical trial of 220 patients with fibromyalgia compared an immediate versus delayed (ie, after 6 months) 18-day spa therapy. The results showed a clinically significant improvement at 6 months for those who received immediate therapy which was maintained up to 12 months. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT02265029.

Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

ABSTRACT

Mechanism-based classification of pain has been advocated widely to aid tailoring of interventions for individuals experiencing persistent musculoskeletal pain. Three pain mechanism categories (PMCs) are defined by the International Association for the Study of Pain: nociceptive, neuropathic, and nociplastic pain. Discrimination between them remains challenging. This study aimed to build on a framework developed to converge the diverse literature of PMCs to systematically review methods purported to discriminate between them; synthesise and thematically analyse these methods to identify the convergence and divergence of opinion; and report validation, psychometric properties, and strengths/weaknesses of these methods. The search strategy identified articles discussing methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system. Studies that assessed the validity of methods to discriminate between categories were assessed for quality. Extraction and thematic analysis were undertaken on 184 articles. Data synthesis identified 200 methods in 5 themes: clinical examination, quantitative sensory testing, imaging, diagnostic and laboratory testing, and pain-type questionnaires. Few methods have been validated for discrimination between PMCs. There was general convergence but some disagreement regarding findings that discriminate between PMCs. A combination of features and methods, rather than a single method, was generally recommended to discriminate between PMCs. Two major limitations were identified: an overlap of findings of methods between categories due to mixed presentations and many methods considered discrimination between 2 PMCs but not others. The results of this review provide a foundation to refine methods to differentiate mechanisms for musculoskeletal pain.

Slowly repeated evoked pain (SREP) as a central sensitization marker in episodic migraine patients

Migraine headache is a pain condition characterized by severe and recurrent unilateral head pain. Among other mechanisms, central pain sensitization processes seem to be involved in the disorder. An experimental protocol based on slowly repeated evoked pain (SREP) has been shown to indicate pain sensitization in fibromyalgia patients and differentiate these patients from healthy individuals and rheumatoid arthritis patients. This study examined SREP sensitization in migraine patients and explored its potential usefulness as a central sensitization marker. The SREP protocol was administered to 40 episodic migraine (EM) patients not currently experiencing a headache and 40 healthy controls. SREP consisted of a series of 9 suprathreshold painful pressure stimuli of 5 s duration and a 30 s interstimulus interval. SREP sensitization was indexed by the increase in pain ratings across the stimuli. Pain threshold, pain tolerance and temporal summation of pain were also assessed. SREP sensitization was observed in EM, but not in healthy individuals (p < .001). SREP differentiated between EM and healthy individuals with up to 75% diagnostic accuracy. Pain threshold, pain tolerance and temporal summation of pain did not show significant discriminative ability. An SREP index value of 0.5 was the most sensitive cut-off for detecting central pain sensitization when prioritizing diagnostic sensitivity (0.88). Results provide evidence for SREP as a possible central sensitization marker with potential clinical utility in migraine patients. Inclusion of SREP in Quantitative Sensory Testing protocols may enhance the assessment of altered pain modulation in different pain conditions.

Attentional function in fibromyalgia and rheumatoid arthritis

Concentration difficulties, forgetfulness and mental slowness are common in fibromyalgia syndrome (FMS); initial findings suggest that rheumatoid arthritis (RA) may also be accompanied by cognitive impairments. This study aimed to compare attentional performance between patients with FMS and RA. Attention was quantified in the domains of alerting, orienting and executive control using the Attentional Network Test-Interaction (ANT-I) in 56 women with FMS, 41 women with RA and 50 healthy women. Pain severity was statistically controlled in the group comparison. While FMS patients exhibited longer reaction times and made more errors on the ANT-I than RA patients and healthy women, performance did not differ between RA patients and healthy women. The magnitude of group differences did not vary by the experimental conditions of the ANT-I, suggesting a general attentional deficit in FMS rather than specific impairments in the domains of alerting, orienting and executive control. Differences between patient groups may relate to the different pathogenetic mechanisms involved in the disorders, i.e. inflammatory processes in RA and central nervous sensitization in FMS. In FMS, heightened activity in the pain neuromatrix may interfere with attention, because it requires enhanced neural resources in brain areas that are involved in both pain and attentional processing.

Addition of Slowly Repeated Evoked Pain Responses to Clinical Symptoms Enhances Fibromyalgia Diagnostic Accuracy

OBJECTIVE

Fibromyalgia is a chronic pain syndrome characterized by central sensitization. A novel protocol based on slowly repeated evoked pain (SREP) appears to be a useful marker of pain sensitization in fibromyalgia patients. Whether SREP enhances diagnostic accuracy beyond key clinical symptoms that characterize fibromyalgia has not been examined.

METHODS

Fifty fibromyalgia patients, 30 rheumatoid arthritis patients, and 50 healthy individuals were evaluated to assess clinical pain, as well as fatigue, insomnia, pain catastrophizing, and negative mood. The SREP protocol consisted of a series of nine low-intensity painful pressure stimuli of five seconds' duration with 30-second interstimulus intervals. SREP sensitization was indexed by increases in pain intensity ratings across stimuli.

RESULTS

SREP sensitization was observed in fibromyalgia but not in rheumatoid arthritis or healthy individuals. As expected, fibromyalgia patients exhibited a more negative psychosocial profile than did rheumatoid arthritis patients and healthy individuals. SREP was positively associated with clinical pain, fatigue, insomnia, and catastrophizing, but not with negative mood. SREP discriminated fibromyalgia cases from rheumatoid arthritis and healthy individuals even when current clinical pain was included in the analysis. Combining fatigue, insomnia, and SREP led to near perfect diagnostic accuracy (99%) in differentiating fibromyalgia from healthy individuals and 86.3% accuracy in discriminating fibromyalgia from rheumatoid arthritis.

CONCLUSIONS

These results provide further evidence of SREP as a marker of pain sensitization in fibromyalgia and suggest that it captures aspects of fibromyalgia not fully captured by clinical features. Combining SREP with assessment of clinical features could potentially improve fibromyalgia diagnosis.

Reduced activity, reactivity and functionality of the sympathetic nervous system in fibromyalgia: An electrodermal study

Alterations in autonomic activity are well established in fibromyalgia syndrome (FMS). Previous studies found reduced parasympathetic activity and sympathetic reactivity to physical and stress manipulations. However, sympathetic activity at rest has not been well studied in FMS. Sweating is exclusively controlled by sympathetic mechanisms. In this study, skin conductance (SC), as an indirect measure of sweating, was analyzed in 45 women with FMS and 38 healthy women. Tonic SC levels were recorded during a 4-minute rest period, and a breathing maneuver consisting of deep breathing with posterior breath holding was used to evoke SC responses. Associations of tonic SC with state anxiety and body temperature, measured in the hand, were explored to determine sweat functionality. The results showed reduced tonic SC levels, with a less marked decrease in SC during the recording period, and blunted SC reactivity to the breathing manipulation in FMS patients relative to healthy participants. Positive associations of SC with state anxiety and body temperature were observed in healthy participants, but these associations were absent in FMS patients. These results indicate alterations of sweating in FMS, suggesting reduced tonic and reactivity sympathetic influences. Furthermore, the absence of associations between SC levels and state anxiety and body temperature in the patient sample suggested a loss of functionality of the autonomic nervous system in FMS. Diminished autonomic regulation in FMS would reduce the ability to cope with environmental demands, thus favoring increases in stress and pain levels. Finally, the observed reduction in sweating is in accordance with evidence of small nerve fiber neuropathy in FMS.

Reliability, Factor Structure and Predictive Validity of the Widespread Pain Index and Symptom Severity Scales of the 2010 American College of Rheumatology Criteria of Fibromyalgia

Fibromyalgia syndrome (FMS) is a chronic condition of widespread pain. In 2010, the American College of Rheumatology (ACR) proposed new diagnostic criteria for FMS based on two scales: the Widespread Pain Index (WPI) and Symptoms Severity (SS) scale. This study evaluated the reliability, factor structure and predictive validity of WPI and SS. In total, 102 women with FMS and 68 women with rheumatoid arthritis (RA) completed the WPI, SS, McGill Pain Questionnaire, Trait Anxiety Inventory, Fatigue Severity Scale, Oviedo Quality of Sleep Questionnaire, and Beck Depression Inventory. Pain threshold and tolerance and a measure of central sensitization to pain were obtained by pressure algometry. Values on WPI and SS showed negative-skewed frequency distributions in FMS patients, with most of the observations concentrated at the upper end of the scale. Factor analysis did not reveal single-factor models for either scale; instead, the WPI was composed of nine pain-localization factors and the SS of four factors. The Cronbach’s α (i.e., Internal consistency) was 0.34 for the WPI,0.83 for the SS and 0.82 for the combination of WPI and SS. Scores on both scales correlated positively with measures of clinical pain, fatigue, insomnia, depression, and anxiety but were unrelated to pain threshold and tolerance or central pain sensitization. The 2010 ACR criteria showed 100% sensitivity and 81% specificity in the discrimination between FMS and RA patients, where discrimination was better for WPI than SS. In conclusion, despite their limited reliability, both scales allow for highly accurate identification and differentiation of FMS patients. The inclusion of more painful areas in the WPI and of additional symptoms in the SS may reduce ceiling effects and improve the discrimination between patients differing in disease severity. In addition, the use of higher cut-off values on both scales may increase the diagnostic specificity in Spanish samples.

Diagnostic Criteria for Fibromyalgia: Critical Review and Future Perspectives

Fibromyalgia syndrome (FMS) is a chronic illness characterized by widespread pain and other clinical and emotional symptoms. The lack of objective markers of the illness has been a persistent problem in FMS research, clinical management, and social recognition of the disease. A critical historical revision of diagnostic criteria for FMS, especially those formulated by the American College of Rheumatology (ACR), was performed. This narrative review has been structured as follows: Introduction; historical background of FMS, including studies proposing and revising the diagnostic criteria; the process of development of the ACR FMS diagnostic criteria (1990 and 2010 versions); revisions of the 2010 ACR FMS diagnostic criteria; the development of scales based on the 2010 and 2011 criteria, which could help with diagnosis and evaluation of the clinical severity of the disease, such as the Polysymptomatic Distress Scale and the FMS Survey Questionnaire; relationships of prevalence and sex ratio with the different diagnostic criteria; validity and diagnostic accuracy of the ACR FMS criteria; the issues of differential diagnosis and comorbidity; the strength and main limitations of the ACR FMS criteria; new perspectives regarding FMS diagnosis; and the impact of the novel findings in the diagnosis of FMS. It is concluded that despite the official 2010 FMS diagnostic criteria and the diagnostic proposal of 2011 and 2016, complaints from health professionals and patients continue.

Emotional intelligence impairments in women with fibromyalgia: Associations with widespread pain

This study aimed at testing the differences in emotional intelligence ability between women with fibromyalgia (cases) and their age-matched counterparts not with fibromyalgia from the general population (controls) and analysing the association between emotional intelligence ability and widespread pain in women with fibromyalgia. A total of 133 cases and 77 controls participated in this cross-sectional study. Controls performed better than cases on emotion understanding. Higher emotion perception and management were significantly associated with lower widespread pain. Therefore, women with fibromyalgia may experience difficulties in understanding emotional information. In fibromyalgia, higher emotion perception and management abilities are independently related to lower widespread pain.

Juvenile Fibromyalgia and Headache Comorbidity in Children and Adolescents: A Literature Review

Juvenile fibromyalgia (JFM) is a chronic pain syndrome with onset in developmental age, characterized by widespread musculoskeletal pain associated with other neurological or nonneurological symptoms. Headache is one of the most frequent comorbid conditions with JFM, but this association is still poorly studied in the juvenile population. The literature review was conducted searching through PubMed, Scopus, and Web of Science with a combination of the following free-text terms: "fibromyalgia," "juvenile fibromyalgia," "headache," "primary headache," "migraine," "children," "adolescents," and "comorbidity." The research resulted only in two specific studies regarding comorbidity JFM + Juvenile Headache (JH). From each study, we extracted data about sample features, clinical characteristics of both JFM and PH, and assessment tools. The clinical approach to JFM and JH should include a complete examination of the main causes of comorbid diseases, thus improving the therapeutic approach to the patient in developmental age.

Psychological impact of fibromyalgia: current perspectives

Fibromyalgia syndrome (FMS) is a chronic disorder characterized by widespread and persistent musculoskeletal pain and other frequent symptoms such as fatigue, insomnia, morning stiffness, cognitive impairment, depression, and anxiety. FMS is also accompanied by different comorbidities like irritable bowel syndrome and chronic fatigue syndrome. Although some factors like negative events, stressful environments, or physical/emotional traumas may act as predisposing conditions, the etiology of FMS remains unknown. There is evidence of a high prevalence of psychiatric comorbidities in FMS (especially depression, anxiety, borderline personality, obsessive-compulsive personality, and post-traumatic stress disorder), which are associated with a worse clinical profile. There is also evidence of high levels of negative affect, neuroticism, perfectionism, stress, anger, and alexithymia in FMS patients. High harm avoidance together with high self-transcendence, low cooperativeness, and low self-directedness have been reported as temperament and character features in FMS patients, respectively. Additionally, FMS patients tend to have a negative self-image and body image perception, as well as low self-esteem and perceived self-efficacy. FMS reduces functioning in physical, psychological, and social spheres, and also has a negative impact on cognitive performance, personal relationships (including sexuality and parenting), work, and activities of daily life. In some cases, FMS patients show suicidal ideation, suicide attempts, and consummated suicide. FMS patients perceive the illness as a stigmatized and invisible disorder, and this negative perception hinders their ability to adapt to the disease. Psychological interventions may constitute a beneficial complement to pharmacological treatments in order to improve clinical symptoms and reduce the impact of FMS on health-related quality of life.

Blood pressure-related pain modulation in fibromyalgia: Differentiating between static versus dynamic pain indicators

INTRODUCTION

Resting blood pressure (BP) has been found to be inversely associated with evoked pain responsiveness in healthy populations. However, some reports suggest that BP-related pain modulation may be dysfunctional in chronic pain patients. This study examined whether BP-related pain modulation, indexed by both static and dynamic evoked pain responses, is altered in fibromyalgia (FM) patients compared to pain-free individuals.

METHOD

Pain threshold and tolerance as static evoked pain measures and slowly repeated evoked pain (SREP) as a dynamic evoked pain index were measured in 30 FM patients and 27 healthy controls. BP was continuously recorded throughout a 5 minute pre-pain rest period.

RESULTS

SREP sensitization was observed only in the FM group. Higher BP predicted elevated pain threshold and tolerance in healthy individuals, but not in FM. Conversely, BP was inversely associated with SREP sensitization in FM whereas no association was found in healthy controls.

CONCLUSIONS

Static evoked pain measures suggested BP-related pain inhibitory dysfunction in FM. In contrast, for pain sensitization as indexed by SREP, FM displayed the expected BP-related inhibitory effects. BP-related pain modulation is manifested in FM differentially for static versus dynamic pain indicators. Use of both types of evoked pain measures may be valuable in the study of mechanisms underlying altered pain modulatory systems in FM.

Cognitive deficits in fibromyalgia syndrome are associated with pain responses to low intensity pressure stimulation

Background

Fibromyalgia syndrome (FMS) is a chronic disorder characterized by widespread musculoskeletal pain and diffuse tenderness, accompanied by complaints including morning stiffness, fatigue, insomnia and affective symptoms. In addition, affected patients frequently experience cognitive impairments such as concentration difficulties, forgetfulness or problems in planning and decision-making. These deficits are commonly ascribed to interference between nociceptive and cognitive processing.

Method

The present study investigated the association of cognitive performance with (a) pain responses to low intensity pressure stimulation (0.45–2.25 kg/cm²), (b) responses to stronger (above-threshold) stimulation (2.70 kg/cm²), and (c) pain threshold and tolerance in 42 women with FMS. Tests of attention, memory, processing speed, and executive functions were applied.

Results

While no significant correlations were seen for pain threshold and pain tolerance, inverse associations arose between pain intensity ratings during pressure stimulation and performance in all evaluated cognitive domains. The magnitude of the correlations increased with decreasing stimulus intensity.

Conclusions

It may be concluded that pain experience during somatosensory stimulation of low intensity is more closely related to attention, memory and executive functions in FMS than the traditional measures of pain threshold and pain tolerance. Considering that pain responses to low intensity stimulation reflect the hyperalgesia and allodynia phenomena characterizing FMS, it may be hypothesized that central nervous pain sensitization is involved in cognitive impairments in the disorder.