Chronic Pain SyndromeFIBRO-NEPNCT06527183
Fibromyalgia and Small Fiber Neuropathy
An observational study of Chronic Pain Syndrome, run by Hospital Ambroise Paré Paris at 2 sites in France.
Trial summary
The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Chronic Pain Syndrome
- What is being tested?
- Skin punch biopsy to demonstrate small fiber neuropathy
- How many people
- 150 participants
- Where
- 2 sitesFrance
- Study dates
- 4 Jan 2022to May 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: Patients with fibromyalgia, other chronic pains (nociplastic or nociceptive) and healthy subjects
Who may be able to join
- patients over 18 years of age with no age limit -
- having given their signed consent to take part in the study
- affiliated to the French social security system
- able to be followed for the entire duration of the study
- reading and understanding French
- accepting the principle of the study and able to comply with its conditions
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- suffering from chronic pain for at least six months of at least moderate intensity (≥ 4/10)
- fibromyalgia detected by the FiRST questionnare and defined by the revised diagnostic criteria of the WHO or chronic nociceptive or nociplastic pain without associated fibromyalgia.
- chronic pain for at least 6 months of at least moderate intensity (≥ 4/10)
- untreated or with stable analgesic treatment for at least 2 weeks prior to inclusion- normal neurological examination at inclusion
Who cannot join
- litigation or compensation-seeking
- cancer for less than 2 years
- known cause of small-fiber neuropathy such as diabetes, systemic disease, hypothyroidism, alcohol, renal failure, genetic disease
- clinical or EMG neuropathy
- peripheral or central nervous system pathology with or without associated neuropathic pain
- uncontrolled chronic pathology such as : morbid obesity, sleep apnea, uncontrolled hypertension, etc. - psychosis, previous suicide attempt
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- drug or psychoactive substance abuse
- cognitive or psychological disorders incompatible with compliance with and/or understanding of the protocol
- participation in another biomedical research protocol.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
France2 sites, 2 recruiting
- Recruiting
Inserm U987
Boulogne-Billancourt, 92100
Nadine ATTAL, 0033149095931, nadine.attal@aphp.fr
Didier BOUHASSIRA
- Recruiting
Centre d'Evaluation et de Traitement de la douleur
Paris, 75014
Serge PERROT, 0033158414141, serge.perrot@aphp.fr
Anne-Priscille TROUVIN
About this study
Official title: Fibromyalgia and Small Fiber Neuropathy : Which Prevalence and Which Relationship With Pain ?
The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy. It will thus be possible to verify whether or not patients with small fiber neuropathy have a particular clinical profile in terms of pain, physical activity, comorbidities or pain impact.
Read the detailed description
Small fiber neuropathy has been observed in a large proportion of fibromyalgia patients. However, the pathophysiological role of these neurological abnormalities in determining the pain and other symptoms of fibromyalgia, and the specificity of these abnormalities, are not well understood.
The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy. It will thus be possible to verify whether or not patients with small fiber neuropathy have a particular clinical profile in terms of pain, physical activity, comorbidities or pain impact.
- Conditions
- Chronic Pain Syndrome
- Being tested
- Skin punch biopsy to demonstrate small fiber neuropathy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Skin punch biopsy to demonstrate small fiber neuropathyDiagnostic test
Also called Other diagnostic tests will include laser evoked potentiels, quantitative sensory testing, sudoscan, and confocal corneal microscopu
Skin punch biopsy to assess intrapidermal nerve fiber density
| Study group | Role | What they receive |
|---|---|---|
| Patients with fibromyalgia | Patients with fibromyalgia based on ACR criteria Receives: Diagnostic Test: Skin punch biopsy to demonstrate small fiber neuropathy | |
| Patients with other chronic pain (paired for the other groups) | Patients with chronic pain other than fibromyalgia and neuropathic pain, eg nociplastic pains or nociceptive pains Receives: Diagnostic Test: Skin punch biopsy to demonstrate small fiber neuropathy | |
| Paired healthy subjects | Healthy subjects paired for gender and age Receives: Diagnostic Test: Skin punch biopsy to demonstrate small fiber neuropathy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Prevalence of small fiber neuropathy or pathology as assessed with skin punch biopsy in patients with fibromyalgia as compared to patients with other chronic pains and healthy subjects
intraepidermal nerve fiber density
Measured: Baseline and at 6 months
Secondary outcomes (5)
Correlation between intraepidermal nerve fiber density and pain or other patient reported outcome measures (quality of life, distress, disability...)
Correlation statistics (Spearman Rho)
Measured: Baseline and at 6 months
Investigate the potential specificity of the results obtained by comparing them with pain patients without fibromyalgia or nerve damage (patients with any nociceptive or nociplastic pain without fibromyalgia) matched for age and gender
Direct group comparisons
Measured: Baseline and at 6 months
Monitor the evolution of abnormalities obtained over time (6 months) and correlate them with the evolution of pain and associated symptoms.
Comparison of intraepidermal nerve fiber density and other diagnostic measures between baseline and 6 months
Measured: 6 months
Determine the sensitivity and diagnostic value of corneal confocal microscopy and laser evoked potentials as compared with skin punch biopsy for exploring nociceptive fibers
Sensitivity and specificy of these tests compared to skin punch biopsy
Measured: Baseline and at 6 months
Determine the diagnostic value of the sudoscan and quantified sensory tests compared with other tests for exploring nociceptive fibers in these patients
Sensitivity and specificy of sudoscan and quantitative sensory testing compared to skin punch biopsy
Measured: Baseline and at 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Jul 2024
- Study start4 Jan 2022
- Primary completionDec 2025 (estimated)
- Study completionMay 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chronic Pain SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospital Ambroise Paré Paris
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Nadine ATTAL, Hospital Ambroise Paré Paris
- Investigators
- Nadine ATTAL, MD PhD, Principal investigator, APHP
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06527183
- Sponsor's protocol ID
- 2020-A03400-39
- Acronym
- FIBRO-NEP
- Status last verified
- Sep 2025
- First submitted
- 24 Jul 2024
- Last updated
- 10 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 10 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Fibromyalgia and Small Fiber Neuropathy : Which Prevalence and Which Relationship With Pain ?
- ClinicalTrials.gov ID
- NCT06527183
- Acronym / sponsor ID
- FIBRO-NEP / 2020-A03400-39
- Conditions
- Chronic Pain Syndrome
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 150 participants (estimated)
- Lead sponsor
- Hospital Ambroise Paré ParisUniversity, hospital or other
- Study start
- 4 Jan 2022 (actual)
- Primary completion
- Dec 2025 (estimated)
- Study completion
- May 2026 (estimated)
- First posted
- 30 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy. It will thus be possible to verify whether or not patients with small fiber neuropathy have a particular clinical profile in terms of pain, physical activity, comorbidities or pain impact.
Detailed description
Small fiber neuropathy has been observed in a large proportion of fibromyalgia patients. However, the pathophysiological role of these neurological abnormalities in determining the pain and other symptoms of fibromyalgia, and the specificity of these abnormalities, are not well understood.
The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy. It will thus be possible to verify whether or not patients with small fiber neuropathy have a particular clinical profile in terms of pain, physical activity, comorbidities or pain impact.
Study design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Patients with fibromyalgia | – | Diagnostic Test: Skin punch biopsy to demonstrate small fiber neuropathyPatients with fibromyalgia based on ACR criteria |
| Patients with other chronic pain (paired for the other groups) | – | Diagnostic Test: Skin punch biopsy to demonstrate small fiber neuropathyPatients with chronic pain other than fibromyalgia and neuropathic pain, eg nociplastic pains or nociceptive pains |
| Paired healthy subjects | – | Diagnostic Test: Skin punch biopsy to demonstrate small fiber neuropathyHealthy subjects paired for gender and age |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- Patients with fibromyalgia, other chronic pains (nociplastic or nociceptive) and healthy subjects
Key inclusion criteria (10 listed)
- patients over 18 years of age with no age limit -
- having given their signed consent to take part in the study
- affiliated to the French social security system
- able to be followed for the entire duration of the study
- reading and understanding French
Key exclusion criteria (9 listed)
- litigation or compensation-seeking
- cancer for less than 2 years
- known cause of small-fiber neuropathy such as diabetes, systemic disease, hypothyroidism, alcohol, renal failure, genetic disease
- clinical or EMG neuropathy
- peripheral or central nervous system pathology with or without associated neuropathic pain
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Skin punch biopsy to demonstrate small fiber neuropathyAlso: Other diagnostic tests will include laser evoked potentiels, quantitative sensory testing, sudoscan, and confocal corneal microscopuSkin punch biopsy to assess intrapidermal nerve fiber density | Diagnostic test | Paired healthy subjects, Patients with fibromyalgia, Patients with other chronic pain (paired for the other groups) |
Primary outcome
Prevalence of small fiber neuropathy or pathology as assessed with skin punch biopsy in patients with fibromyalgia as compared to patients with other chronic pains and healthy subjects
Time frame: Baseline and at 6 months
intraepidermal nerve fiber density
5 secondary outcomes
Correlation between intraepidermal nerve fiber density and pain or other patient reported outcome measures (quality of life, distress, disability...)
Time frame: Baseline and at 6 months
Investigate the potential specificity of the results obtained by comparing them with pain patients without fibromyalgia or nerve damage (patients with any nociceptive or nociplastic pain without fibromyalgia) matched for age and gender
Time frame: Baseline and at 6 months
Monitor the evolution of abnormalities obtained over time (6 months) and correlate them with the evolution of pain and associated symptoms.
Time frame: 6 months
Determine the sensitivity and diagnostic value of corneal confocal microscopy and laser evoked potentials as compared with skin punch biopsy for exploring nociceptive fibers
Time frame: Baseline and at 6 months
Determine the diagnostic value of the sudoscan and quantified sensory tests compared with other tests for exploring nociceptive fibers in these patients
Time frame: Baseline and at 6 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 10 Sep 2025.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Nadine ATTAL, MD PhD principal investigator
APHP
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Chronic Pain Syndrome, run by Hospital Ambroise Paré Paris at 2 sites in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 10 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Nadine ATTAL, MD PhD (0033149095931, nadine.attal@aphp.fr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Prevalence of small fiber neuropathy or pathology as assessed with skin punch biopsy in patients with fibromyalgia as compared to patients with other chronic pains and healthy subjects (time frame: Baseline and at 6 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Sep 2025.