A Pilot Study of Small Fiber Neuropathy Prevalence in Fibromyalgia Patients Compared to Healthy Subjects Using Sudoscan®

Study Overview
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Brief Summary
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Fibromyalgia (FM) is characterized by chronic diffuse pain and affects 0.5 to 5% of the population, with a higher prevalence in women1. This condition is characterized by joint and muscle pain, also associated with fatigue, migraine, sleeps disorders, depression and irritable bowel syndrome2. The presentation of these various symptoms varies greatly from one patient to another, with great heterogeneity in clinical, physical, social, psychological and therapeutic responses. . A recent parliamentary inquiry report called for recognition of the disease and recommended to build a unified care path for patients; a collective expertise is led by INSERM to help in patient care. Faced with the heterogeneity of FM, several international studies have attempted to identify subgroups of patients based essentially on clinical symptoms of the disease3-8, including a recent Korean study of 313 patients9, which suggested four groups, but with methodological limitations, not taking into account the new criteria10 for evaluating FM. Recent studies have also shown that there is a peripheral neuropathic component in the mechanisms of this pathology, demonstrated by a decrease in the density of the epidermal nerve fibers11-12, called small fiber neuropathy (SFN) neuropathy. It is an attack of small sensory and sympathetic nerve fibers, causing pain, paresthesia as well as disturbances of the autonomous system. Other studies also suggested that a significant proportion of patients diagnosed with fibromyalgia had SFN, demonstrated by cutaneous biopsy13-14 or confocal microscopy of the cornea15. A new device, the Sudoscan®, makes it possible to detect a SFN much simpler, faster and less invasive than the technique of ophthalmology or biopsy. Although this Sudoscan® test has been used extensively in conditions such as diabetes16-19, no study has been used to assess the presence of SFN in FM. The aim of this pilot study is to identify the prevalence of SFN in FM patients, using this new non-invasive device, in order to have a better defined representation of the prevalence of small-fiber neuropathy in an FM population compared to a group of healthy volunteer matched in age, sex, BMI and by menopausal status for women.

Detailed Description
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Only one visit (2 to 3h) : Inclusion of the patient Clinical examination ; evaluation of pain for FM patients Measurement of the electrochemical conductance of the hands and feet using Sudoscan® Evaluation of quality of life, anxiety, depression, sleep quality, fatigue, catastrophizing and social precarity End of study

Official Title
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A Pilot Study of Small Fiber Neuropathy Prevalence in Fibromyalgia Patients Compared to Healthy Subjects Using Sudoscan®

Conditions
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Fibromyalgia

Intervention / Treatment
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* Device: Sudoscan®


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Patient over 18 years of age and under 65 years of age, Male or female patient, Patient with fibromyalgia (according to the ACR criteria of 2016), Cooperation and understanding sufficient to comply with the requirements of the study, Acceptance of written consent, Affiliation to the French Social Security system. Inclusion criteria healthy subjects: Subject of more than 18 years, Woman or man, Healthy voluntary non-painful subjects matched by age (+/- 5 years), by sex, by BMI (+/- 10%) and by menopausal status for women, Cooperation and understanding sufficient to comply with the requirements of the study, Acceptance of written consent, Affiliation to the French Social Security system, Registration or acceptance of registration in the National Register of Volunteers participating in research. Exclusion Criteria: Exclusion criteria patients: Patient with a physical inability to place the palms of the hands or the soles of the feet on the electrodes of Sudoscan®, Patient with a medical and / or surgical history judged by the investigator or his representative to be incompatible with the test (in particular a disease known to give neuropathies of small fibers: diabetes, Gougerot-Sjögren's disease, vasculitis, sarcoidosis, chronic ethylism ...), Pregnant or nursing woman Patient participating in another clinical trial, or in a period of exclusion, or having received a total amount of compensation in excess of EUR 4500 over the 12 months preceding the start of the trial, Patient benefiting from a measure of legal protection (curatorship, guardianship, safeguard of justice ...), Patient not affiliated to the French Social Security system. Exclusion criteria healthy subjects : Physical inability to place the palms of the hands or the soles of the feet on the electrodes of Sudoscan®. Medical and / or surgical history judged by the investigator or his representative to be incompatible with the test, Pregnant or nursing woman Participating in another clinical trial, or within the exclusion period, or having received a total amount of compensation in excess of EUR 4500 over the 12 months preceding the start of the trial, Cooperation and an understanding that does not permit strict compliance with the conditions laid down in the Protocol, Benefiting from a measure of legal protection (curatorship, guardianship, safeguard of justice ...), Not affiliated to the French Social Security system.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: FM patients<br>50 fibromyalgia patients/50 healthy subjects | Device: Sudoscan®<br>* Sudoscan® is a new device that provides rapid, non-invasive and reproducible quantitative assessment of sweat function. It makes it possible to measure the ability of the sweat glands to release chloride ions in response to electrochemical activation and thus to detect the presence of a neuropathy with small fibers. This new device therefore makes it possible to detect an SFN in a much simpler and faster way than the technique of ophthalmology, or biopsy. Sudoscan® has been tested to assess the neuropathies of small nerve fibers in several diseases, in particular diabetes, chemotherapy-induced polyneuropathy, familial amyloid polyneuropathy or Fabry disease. The interest of Sudoscan® lies in the fact that this device is non-invasive and rapid. Its diagnostic value has been compared with other neurophysiological tests.<br>|
| Active Comparator: Healthy subjects<br>50 fibromyalgia patients/50 healthy subjects | Device: Sudoscan®<br>* Sudoscan® is a new device that provides rapid, non-invasive and reproducible quantitative assessment of sweat function. It makes it possible to measure the ability of the sweat glands to release chloride ions in response to electrochemical activation and thus to detect the presence of a neuropathy with small fibers. This new device therefore makes it possible to detect an SFN in a much simpler and faster way than the technique of ophthalmology, or biopsy. Sudoscan® has been tested to assess the neuropathies of small nerve fibers in several diseases, in particular diabetes, chemotherapy-induced polyneuropathy, familial amyloid polyneuropathy or Fabry disease. The interest of Sudoscan® lies in the fact that this device is non-invasive and rapid. Its diagnostic value has been compared with other neurophysiological tests.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measure of the electrochemical conductance (µS) using Sudoscan® | Evaluation of the prevalence of fibromyalgia patients with small fibro neuropathy in comparison with healthy volunteers by measuring the electrochemical conductance of the palms of the hands (middle right and left hands) and feet (middle right and left) in μS using Sudoscan®. | at day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Biometric criteria | Collection of the age in years | at day 1 | 
| Biometric criteria | Collection of sex, (male or female) | at day 1 | 
| Biometric criteria | Collection weight in kilograms, height in meters, weight and eight will be combined to report BMI in kg/m², | at day 1 | 
| Biometric criteria | phototype Fitzpatrick classification | at day 1 | 
| Numerical scale | This scale allows the patient to note pain on a graduation with a minimum score of 0 and a maximum score of 10. Higher value represent worse outcome. | at day 1 | 
| Brief Pain Inventory | The BPI gives two main scores: a pain severity score and a pain interference score | at day 1 | 
| Fibromyalgia Impact Questionnaire | The revised FIQ questionnaire is a 10-item self-questionnaire that assesses the impact of fibromyalgia. The first item is subdivided into 10 questions that assess the impact of the disease in everyday life | at day 1 | 
| Quality of life (SF-12) | 12 questions and an index is determined for both physical and mental health (0-100). Higher scores indicate greater physical and mental health | at day 1 | 
| Anxiety and Depression (HAD) | The HAD scale is a 14-item self-administered questionnaire completed by the patient. These items are divided into two subscales: 7 items to assess depression and 7 items to assess anxiety. Higher value represent worse outcome. | at day 1 | 
| Depression (Beck Depression Inventory) | Each item consists of 4 sentences corresponding to 4 degrees of increasing intensity of a symptom: from 0 to 3. In the counting, it is necessary to take into account the highest rating chosen for the same series. The overall score is obtained by adding the scores of the 13 items. The range of the scale is from 0 to 39. The higher the score, the more the subject is depressed. | at day 1 | 
| Pittsburgh Sleep Quality Index | 19-item self-administered questionnaire used to assess the quality of sleep. Higher value represent worse quality of sleep. | at day 1 | 
| Chronic fatigue Severity Scale | 9-item self-questionnaire to assess the patient's fatigue intensity. The patient is asked to circle a number from 1 to 7 for each question, a low value representing a low intensity. Higher value represents worse fatigue. | at day 1 | 
| Pain Catastrophizing Scale | This questionnaire consists of 13 items. The patient will have to indicate how much he has thoughts or emotions when he feels pain by giving a score between 0 and 4, 0: not at all, 4: all the time. The final score is the sum of the scores for each question. Higher value represent worse outcome. | at day 1 | 
| Assessment of socio-professional category, precariousness and health inequalities (Score EPICES). | The EPICES questionnaire consists of 11 binary questions (yes / no) to calculate an individual score indicating the precariousness and inequalities of health ranging from 0 to 100. Higher value represent worse outcome. | at day 1 | 
| Measure of the electrochemical conductance (µS) using Sudoscan® | Assess the reproducibility (2 passes) of Sudoscan® in each participant: measurement of the electrochemical conductance of the palms of the hands (middle right and left hands) and feet (middle right and left) in μS using the Sudoscan®, 30 minutes after the first measurement. | at day 1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fibromyalgia, Small fiber neuropathy, Sudoscan®