Testing sudomotor function can be a fast and accurate method for detecting early stages of neuropathies. Sweat gland nerve fibers are thin and long and are susceptible to damage at a very early stage of disease, such as diabetes.
SUDOSCAN is a medical device that has been cleared by the FDA as a galvanic skin response (GSR) test and sudomotor function test. In GSR, changes in the voltage measured from the surface of the skin are recorded. These voltage changes are thought to arise from activation of sweat glands (sudomotor function).
You will be asked to take your shoes and socks off; then you will stand on the sensor plates for the feet and place your hands on the hand sensor plates. If you are unable to stand still for 3 minutes on the plates, your physician will ask you to sit for the test.
SUDOSCAN evaluates sudomotor function on the palm of the hands and soles of the feet. It uses a very low DC voltage ≤ 4 volts to activate the sweat glands and measures the current of chloride ions that flow out of the sweat glands in response to the electric impulse.
The test runs for 2 to 3 minutes. You may feel slight tingling in your hands and/or feet, or you may feel nothing at all.
SUDOSCAN test results are provided as hands and feet conductances measured in microSiemens (μS). In studies, high conductances have been found to correlate with normal sweat function and healthy innervation (small C-fibers). Low conductances were associated with peripheral or autonomic neuropathy.
Physicians get simple and immediate information on small autonomic fiber status and can use it to:
– Confirm whether your symptoms may be due to a neuropathy
– Assess a change in your medical status
– Evaluate why your treatment may or may not be working.
Anyone can get tested on SUDOSCAN to assess their sudomotor function unless they have a specific contra-indication.
Abnormal sweating (also known as sudomotor dysfunction) is recognized by the American Academy of Neurology (AAN), American Diabetic Association (ADA), and American Academy of Clinical Endocrinologists (AACE) as a symptom of autonomic neuropathy, a common complication of diabetes, Parkinson Disease, and amyloidosis for example. Sudomotor tests such as SUDOSCAN are used in the evaluation of autonomic and small fiber neuropathies.
A large study performed on healthy individuals showed no significant differences in hand or feet ESC between men and women.
Sweat gland function can vary by ethnicity and produce minor differences in hands and feet ESC among African Americans, Asians, and Caucasians. Your doctor will interpret your SUDOSCAN results based on available research data.
A large database of healthy individuals demonstrated that SUDOSCAN conductances do not change significantly with age in adults.
Clinical tests demonstrated that temperature does not impact test results. However, it is recommended not to perform a SUDOSCAN test if the electrodes are too cold or on a patient immediately after coming in from an extremely cold environment.
Measurements were performed before and after high impact exercise on more than 100 subjects. Tests showed a non-significant variation between these two measurements.
There is no safety concern for testing children on SUDOSCAN, and preliminary data obtained from clinical studies in pediatric age ranges are encouraging. However, outside of research trials, SUDOSCAN use remains restricted to the adult population until FDA clearance is obtained for pediatric age groups.
Yes. SUDOSCAN can be used to measure peripheral sudomotor function, which can be impaired in various disease states, such as type 1 diabetes.
HbA1C is used to monitor blood glucose levels over the preceding 3-month period, whereas SUDOSCAN measures sweat gland function. Therefore, there is no strict correlation between HbA1c and SUDOSCAN results, but they can each provide very important and different information about your medical condition.
Nerve conduction studies (NCS, also known as EMG) measure the function of large, myelinated nerves, and SUDOSCAN measures the function of small sweat gland nerve fibers. The two tests are therefore not likely to correlate since they measure 2 different types of nerves.
Palms and soles must be free of dirt, ointments, or lotions prior to testing. Washing with soap and water is always the best option. Make sure that your hands and feet are DRY before placing them on the electrodes.
Most medications should not influence the results of your test. Your doctor will review the drugs you take and determine their interactions prior to testing
Safety tests have concluded that SUDOSCAN meets the electrical standards for active implantable medical devices. Patients with pacemakers may perform a SUDOSCAN test with a medical doctor present.
Retesting with SUDOSCAN can safely be done any time. Your physician can decide with you if another test is necessary based on changes in your treatment or your condition.