Assessment of Small Fiber Neuropathy in Rare Diseases Using Sudoscan

Study Purpose

Sudoscan™ (Impeto Medical, Paris France) uses electrochemical skin conductance as a novel noninvasive method to detect sudomotor dysfunction. Several small studies have recently shown that Sudoscan use in the assessment of small fiber polyneuropathy (in diabetes mellitus) can be performed non-invasively, quickly and effectively. The investigators aim to study the use of Sudoscan in rare disease condition associated with small fiber polyneuropathy.

Recruitment Criteria

Accepts Healthy Volunteers

Healthy volunteers are participants who do not have a disease or condition, or related conditions or symptoms

Study Type

An interventional clinical study is where participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.

An observational clinical study is where participants identified as belonging to study groups are assessed for biomedical or health outcomes.

Searching Both is inclusive of interventional and observational studies.

Eligible Ages 8 Years - 70 Years
Gender All
More Inclusion & Exclusion Criteria

Inclusion Criteria:

  • - Males and females with confirmed disease: Fabry (by GLA enzymes and/or DNA testing) naïve and on ERT, Mitochondrial diseases (electron transport chain and/or DNA testing) or connective tissue diseases (clinical criteria and/or DNA testing when available) - Consenting adults (18 years and older) who agrees and consents to skin biopsy and QSART procedure

    Exclusion Criteria:

    - Subjects with cognitive, psychiatric, or other problems that preclude informed consent.
  • - Patients with history of glucose intolerance or diabetes.
- Patient on chemotherapy - People with any open or bleeding wounds at any sensor plate contact surface location - People with any type of implantable device - People with missing hand(s) and/or leg(s) - Pregnant women or women who are uncertain about a possible pregnancy - Patients sensitive to chemicals used to induce sweating - Patients with heat intolerance - Patients with bleeding disorders - Patients on current anticoagulant therapy - Patients with keloids on the intended biopsy site - People with hypersensitivity to local amide-type anesthetics

Trial Details

Trial ID:

This trial id was obtained from, a service of the U.S. National Institutes of Health, providing information on publicly and privately supported clinical studies of human participants with locations in all 50 States and in 196 countries.


Phase 1: Studies that emphasize safety and how the drug is metabolized and excreted in humans.

Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition) and additional safety data.

Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Phase 4: Studies occurring after FDA has approved a drug for marketing, efficacy, or optimal use.

Lead Sponsor

The sponsor is the organization or person who oversees the clinical study and is responsible for analyzing the study data.

Massachusetts General Hospital
Principal Investigator

The person who is responsible for the scientific and technical direction of the entire clinical study.

Amel Karaa, MD
Principal Investigator Affiliation Massachusetts General Hospital
Agency Class

Category of organization(s) involved as sponsor (and collaborator) supporting the trial.

Overall Status Recruiting
Countries United States

The disease, disorder, syndrome, illness, or injury that is being studied.

Small Fiber Neuropathy, Fabry Disease, Ehlers Danlos Syndrome, Mitochondrial Disease
Additional Details

Small fiber polyneuropathy (SFPN) is diagnosed through a combination of symptoms, signs and confirmatory diagnostic testing. Nerve conduction studies are not sensitive enough in most of the cases leaving the ankle skin biopsy with measurement of intraepidermal nerve fiber density (IENFD) as the main diagnostic tool. Despite its utility and reproducibility, skin biopsy is invasive, expensive and requires a central laboratory for processing and interpretation. Quantitative sudomotor axon reflex testing (QSART) is also routinely used for evaluation of small fiber neuropathy as sudomotor axons can also be involved. This test however remains technically challenging and requires testing conditions in specialized labs that are not always suitable for all patients' population. By comparing findings on skin biopsy and/or QSRT, accepted gold standard for diagnosing SFPN, the investigators seek to find faster, less-invasive ways to diagnose and monitor small-fiber polyneuropathy in rare diseases using Sudoscan measurement.

Arms & Interventions


Other: Sudoscan only

Patients in this arm will only undergoing testing with Sudoscan.

Other: Sudoscan Plus

Patients in this arm will get Sudoscan testing as well as a skin biopsy and QSART testing.


Device: - Sudoscan

The Sudoscan is a non invasive procedure and similar to standing on a scale to be weighed. Sudoscan measurements are made in compliance with the manufacturer's recommended procedures. The measurement is rapid and non-invasive, and requires no advance preparation.

Procedure: - Skin biopsy

For subjects that give additional consent, skin biopsy will be done in standard fashion under sterile conditions. Assessment of nerve fiber density typically involves a 3-mm punch biopsy of skin from the leg (10 cm above the external malleolus).

Procedure: - QSART

QSRT (quantitative sudomotor axon reflex test) testing involves having a technician wipe the subject's arms and leg with alcohol, then tissue to wipe it dry. Electrodes filled with acetylcholine are put on three areas of the leg and one on the wrist, stimulators are turned on and sweat responses are measured.

Contact a Trial Team

If you are interested in learning more about this trial, find the trial site nearest to your location and contact the site coordinator via email or phone. We also strongly recommend that you consult with your healthcare provider about the trials that may interest you and refer to our terms of service below.

Massachusetts General Hospital, Boston, Massachusetts




Massachusetts General Hospital

Boston, Massachusetts, 02114

Site Contact

Erica L Kelly

[email protected]