Fibromyalgia as a chronic primary pain syndrome: issues to discuss

Variability of Reaction Time as a Marker of Executive Function Impairments in Fibromyalgia

In addition to chronic widespread pain and depression and anxiety symptoms, patients with fibromyalgia frequently experience cognitive problems. This study investigated executive functions in fibromyalgia via a Go/No-Go task. To obtain comprehensive information about performance, traditional and ex-Gaussian parameters of reaction time (RT) variability were used, in addition to speed and accuracy indices. Ex-Gaussian parameters show an excellent fit to empirical RT distributions. Fifty-two female fibromyalgia patients and twenty-eight healthy controls participated. The task included 60 visual stimuli, which participants had to respond to (Go stimuli) or withhold the response to (No-Go stimuli). After 30 trials, the task rule changed, such that previous No-Go stimuli had to be responded to. Performance was indexed by the hit rate, false alarm rate, and mean (M) and intraindividual standard deviation (SD) of RT and the ex-Gaussian parameters mu, sigma, and tau. Mu and sigma indicate the M and SD of the Gaussian distribution; tau reflects the M and SD of the exponential function. Patients exhibited a lower hit rate, higher M RT, and higher tau than controls. Moreover, patients showed greater decrease of the hit rate after the change of task rule. In the entire sample, SD, sigma, and tau were inversely associated with the hit rate and positively associated with the false alarm rate. While the greater decline in hit rate after the change in task rule indicates deficient cognitive flexibility, the lack of any difference in false alarm rate suggests intact response inhibition. Higher M RT reflects reduced cognitive or motor speed. Increased tau in fibromyalgia indicates greater fluctuations in executive control and more frequent temporary lapses of attention. For the first time, this study demonstrated that indices of RT variability, in particular those derived from the ex-Gaussian function, may complement speed and accuracy parameters in the assessment of executive function impairments in fibromyalgia. Optimized assessment may facilitate the personalization of therapies aimed at improving the cognitive function of those with the disorder.

Fibromyalgia: Recognition and Management in the Primary Care Office

Fibromyalgia is a chronic pain condition manifested by chronic generalized pain, fatigue, disordered sleep, and cognitive difficulties, persistent for at least 3 months. Other common complaints/conditions include symptoms of irritable bowel syndrome, headaches, intermittent paresthesias, and various mood disorders. Women are more commonly affected than men. The treatment approach should be individualized and focused on associated mood disorders, sleep, exercise, correction of maladaptive responses to pain, and coping with stress.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Chronic pain in the 11th revision of the International Classification of Diseases: users' questions answered

ABSTRACT

The upcoming 11th revision of the International Classification of Diseases (ICD-11) will include a comprehensive classification of chronic pain for the first time, which is based on the biopsychosocial definition of chronic pain. This presents a great opportunity for pain research and clinical practice. The new classification consists of seven main diagnostic categories of chronic pain, which are further divided into increasingly specific levels of diagnoses. Each diagnosis is characterized by clearly defined operationalized criteria. Future users will need to familiarize themselves with the new system and its application. The aim of the present publication is to provide users of the ICD-11 chronic pain classification with answers to frequently asked questions regarding the ICD-11 as a whole, the ICD-11 chronic pain classification, and its application to common pain syndromes. The questions compiled here reached the International Association for the Study of Pain Task Force via different routes (e.g., at conferences, by letter, or during field testing). Furthermore, the authors collected questions posted to the ICD-11 browser and contacted early users of the classification to enquire about their most frequent difficulties when applying the new diagnoses. The authors of the present publication prepared answers to these frequently asked questions. This publication intends to act as a guide for the future users of the new ICD-11 chronic pain classification, hence facilitating its implementation.

Differences and similarities among questionnaires to assess pain status in chronic widespread pain population: a quantitative analysis

Objective

In clinical practice, multiple questionnaires are often used as part of the diagnosis of chronic widespread pain. Body Surface Area (BSA), Visual Analogue Scale (VAS), Fibromyalgia Diagnostic Criteria (FDC) and Central Sensitization Inventory (CSI) have all been used as screening tools to assess pain status in individuals with widespread pain. However, substantial overlap can be observed among these commonly employed questionnaires. This study aimed to quantitatively determine the most independent and dependent clinical characteristics obtained through these questionnaires and to examine potential redundancies.

Methods

Seventy-nine participants with widespread pain, 61 females and 18 males, from a chronic pain outpatient clinic were recruited. The FDC, BSA, VAS and the CSI were measured for all participants. A principal component analysis (PCA) using a varimax rotation was used to determine which clinical measures represented separate constructs of widespread pain. This was followed by a regression analysis to assess redundancy between the constructs and related pain characteristics.

Results

The identified three-component PCA solution was characterized by (1) the FDC and CSI score, (2) the VAS score and (3) the BSA score. This indicates that the BSA and the VAS scores capture independent patient information. From the regression analysis, the FDC and CSI scores shared approximately 80% of the variance, indicative of substantial overlap between scores.

Conclusion

Our findings demonstrated that BSA and VAS scores were independent clinical measures of widespread chronic pain, while the FDC and CSI scores were not independent, were highly correlated and provided redundant information. Clinicians should continue using both the BSA and VAS; however, either only FDC or CSI will be beneficial during clinical assessment of widespread chronic pain.

Fibromyalgia: Recognition and Management in the Primary Care Office

Fibromyalgia is a chronic pain condition manifested by chronic generalized pain, fatigue, disordered sleep, and cognitive difficulties, persistent for at least 3 months. Other common complaints/conditions include symptoms of irritable bowel syndrome, headaches, intermittent paresthesias, and various mood disorders. Women are more commonly affected than men. The treatment approach should be individualized and focused on associated mood disorders, sleep, exercise, correction of maladaptive responses to pain, and coping with stress.

Chronic generalized pain disrupts whole brain functional connectivity in mice

Fibromyalgia (FM) is a generalized chronic pain condition whose pathophysiology is poorly understood, and both basic and translational research are needed to advance the field. Here we used the Sluka model to test whether FM-like pain in mice would produce detectable brain modifications using resting-state (rs) functional Magnetic Resonance Imaging (fMRI). Mice received intramuscular acid saline treatment, images were acquired at 7 T 5 days post-treatment, and pain thresholds tested 3 weeks post-scanning. Data-driven Independent Component Analysis revealed significant reduction of functional connectivity (FC) across several component pairs, with major changes for the Retrosplenial cortex (RSP) central to the default mode network, and to a lesser extent the Periaqueductal gray (PAG), a key pain processing area. Seed-to-seed analysis focused on 14 pain-related areas showed strongest FC reduction for RSP with several cortical areas (somatosensory, prefrontal and insular), and for PAG with both cortical (somatosensory) and subcortical (habenula, thalamus, parabrachial nucleus) areas. RSP-PAG FC was also reduced, and this decreased FC tended to be positively correlated with pain levels at individual subject level. Finally, seed-voxelwise analysis focused on PAG confirmed seed-to-seed findings and, also detected reduced PAG FC with the anterior cingulate cortex, increasingly studied in aversive pain effects. In conclusion, FM-like pain triggers FC alterations in the mouse, which are detected by rs-fMRI and are reminiscent of some human findings. The study reveals the causal fingerprint of FM-like pain in rodents, and indicates that both RSP and PAG connectional patterns could be suitable biomarkers, with mechanistic and translational value, for further investigations.

Update Fibromyalgiesyndrom

In der neuen Klassifikation der Krankheiten (ICD-11) der Weltgesundheitsorganisation wurde das FMS – ohne Absprache mit rheumatologischen Fachgesellschaften – aus dem Kapitel „Erkrankungen des muskuloskelettalen System und des Bindegewebes“ entfernt und in ein neu geschaffenes Kapitel „Chronischer Schmerz“ aufgenommen. Pathologische Befunde an den kleinen Nervenfasern bei einer Untergruppe von Patienten belegen nicht, dass das FMS eine Neuropathie der kleinen Nervenfasern ist. Die Überprüfung der sogenannten Tender Points zur Diagnose des FMS ist nicht mehr erforderlich. Es wurden mehrere neue diagnostische Kriterien entwickelt, welche zur symptombasierten Diagnose neben chronischen Schmerzen in mehreren Körperregionen nicht-erholsamen Schlaf und Müdigkeit (körperlich und / oder geistig) erfordern. Die nach klinischen Kriterien durchführbare Schweregradeinteilung (leicht, mittel, schwer) des FMS ist wichtig für eine abgestufte Versorgung. In Abhängigkeit von psychologischen Befunden stehen verschiedene evidenzbasierte psychotherapeutische Verfahren zur Verfügung, welche bei schweren Formen des FMS eingesetzt werden sollen. Ein komorbides (sekundäres) FMS ist bei entzündlich-rheumatischen Erkrankungen häufig und führen zu falsch hohen Aktvitätsscores. Cannabisbasierte Arzneimittel sind eine Therapieoption für eine Untergruppe von FMS-Patienten.

Sensor Technologies to Manage the Physiological Traits of Chronic Pain: A Review

Non-oncologic chronic pain is a common high-morbidity impairment worldwide and acknowledged as a condition with significant incidence on quality of life. Pain intensity is largely perceived as a subjective experience, what makes challenging its objective measurement. However, the physiological traces of pain make possible its correlation with vital signs, such as heart rate variability, skin conductance, electromyogram, etc., or health performance metrics derived from daily activity monitoring or facial expressions, which can be acquired with diverse sensor technologies and multisensory approaches. As the assessment and management of pain are essential issues for a wide range of clinical disorders and treatments, this paper reviews different sensor-based approaches applied to the objective evaluation of non-oncological chronic pain. The space of available technologies and resources aimed at pain assessment represent a diversified set of alternatives that can be exploited to address the multidimensional nature of pain.