The technical aspect of Sudomotor testing indicates measurement of BEC, or bio-electrochemical sweat skin conductance. This test tells us how capable a person’s sweat glands are of transferring chloride ions resulting from direct stimulation. This information then helps us quantify the innervation, or presence and integrity of nerves, that control sweat glands. Because these peripheral nerves are small and involve both the sympathetic and parasympathetic nervous systems, there is the potential for immediate and accurate diagnosis of neuropathic conditions.
Sudomotor scans work on the basis of reverse iontophoresis. Once we place small electrodes in various positions on the body, often the hands and the feet, we are able to draw out the ions we need to observe. The electrodes that are placed on the skin emit low-frequency voltage, which incites an electrochemical reaction with the ions being extracted from sweat glands.
It is this reaction that then provides us with the bio-electrochemical sweat skin conductance’s measurement necessary to identify early signs of neuropathy. In some cases, the test involves placing hands and feet on small metal plates that then deliver small bursts of voltage to the palms and soles. The voltage is so low that patients do not feel it.
The Sudomotor Scan is a painless, 3-minute test that we perform in our comfortable facility.
Testing sudomotor function can be a fast and accurate method for detecting early stages of distal small fiber neuropathy. Eccrine glands that are responsible for sweat response receive a rich supply of small blood vessels and are innervated by sympathetic C nerve fibers of the autonomic nervous system. These fibers are thin and long and so can be impaired at the very early stage of different metabolic diseases. “Sweat response may be the most sensitive test in detecting distal small fiber neuropathy” (Low PA and Gibbons CH publications).
Physicians AT Atlantic Endocrinology & Diabetes Center get simple and immediate information on small autonomic fiber status and use it in various medical settings:
• Proactive monitoring: Medicine is trending towards prevention and early detection of disease and complications. The long, thin, and unmyelinated, sympathetic sweat gland nerves degenerate slowly yet have the potential to quickly regenerate with changes in a patient’s environment. Therefore, physicians can use SUDOSCAN results to obtain an objective evaluation of sudomotor function in a patient with signs or symptoms suggestive of developing disease.
• Assessing the level of intensive glycemic control for diabetics: It is important to determine whether or not a patient has autonomic neuropathy before prescribing intensive forms of glycemic treatment. Autonomic dysfunction detected with SUDOSCAN may alert a physician to refer a patient for further autonomic function testing.
• patient drug or lifestyle compliance: SUDOSCAN allows a physician to quickly determine sudomotor functioning as a biomarker for peripheral nerve integrity. Worsening sudomotor function may signal poor patient response to treatment or lack of compliance and initiate a discussion between physician and patient on a change in therapy. This information is complementary to traditional blood tests, but is extremely fast and offers immediate results. No subjectivity is introduced via patient verbal responses and quantitative results allow a precise follow-up.
We may recommend Sudomotor Scans for a number of reasons. Ultimately, this diagnostic scan:
• Provides important data related to the peripheral autonomic nervous system and the potential for painful neuropathy.
• Facilitates the most accurate diagnosis of diabetic neuropathy compared to standardized testing.
• Provides valuable information related to the cause of peripheral neuropathy.
• Reaches high rates of sensitivity and specificity, related to the accuracy of test results.
• Evaluates autonomic and somatic nerve function (shown to be one of the best estimates of cardiovascular risk).
• Early intervention can greatly decrease the potential for severe and permanent nerve damage, which results in painful neuropathy.
• Supports fast adjustments to therapeutic care since it provides data related to the physical response of a treatment protocol.