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Note: In the US, the ESC score is only available via prescription (Rx).


 

What is Electrochemical Skin Conductance?

Electrochemical skin conductance is a non-invasive measurement of the sudomotor function [1]. It measures the sweat gland function in the soles of your feet. In other words, it measures sweat gland innervation and assesses disorders of the autonomic nervous system, which is a component of the peripheral nervous system [2][3].

 

What is the autonomic nervous system ?

The autonomic nervous system is a component of the peripheral nervous system that regulates involuntary physiologic processes including heart rate, blood pressure, respiration, digestion, and sexual arousal. It contains three anatomically distinct divisions: sympathetic, parasympathetic, and enteric [3]. Sweating is under the control of the sympathetic nervous system, which orchestrates the body's reaction to stressful situations and emergencies. 

 

What is the sudomotor function and how can it be impaired?

Sweat glands produce water to regulate body temperature and evacuate small molecules. Specific eccrine sweat glands without hair are located on hands and feet and are innervated by thin, unmyelinated sympathetic C nerve fibers. In patients with diabetes, studies have shown a reduction in those small nerves leading to sudomotor dysfunction [4] [5]. This type of peripheral autonomic neuropathy (PAN) is one of the earliest detectable abnormalities in small fiber neuropathies affecting sudomotor function. Consequently during the last two decades, assessing sudomotor function became furthermore important in the early detection of  peripheral autonomic neuropathy in diabetes [6] but also other diseases [7].

 

What is peripheral autonomic neuropathy?

Peripheral autonomic neuropathy refers to the damage to the nerves of  the peripheral nervous system (nerves located outside the brain and the spinal cord). The prevalence of peripheral neuropathy is estimated at 1% of the adult population and over 10% of the population over 55 years old [8]. Peripheral neuropathy often causes weakness, numbness, loss of sensation or pain, usually in the hands and feet, and is independently associated with increased mortality.

 

What is the technology behind Electrochemical Skin Conductance?

 

 

Your scale measures the sweat glands activity on the feet, an area with one of the highest sweat gland densities, by applying a low voltage on the soles of the feet via the glass plate and its ITO conductive electrodes. The device records the conductance related to the quantity of chloride ions attracted from the sweat glands and detected by the electrodes. The level of conductance depends on the number of chloride ions that react with the electrodes. Your device measures the current for several voltage steps and deduces a conductance that corresponds to your Electrochemical Skin Conductance.

 

 

When nerves have a high amount of innervation, this direct current extracts a considerable amount of chloride ions from the sweat ducts to the surface of your skin. Therefore, if the density of nerves around the sweat glands is high, the sweat gland activity measured by your device will be high.

In the presence of normal sweat function, the Electrochemical Skin Conductance score is high.

When the density of the small nerves around the sweat glands is reduced, the sweat gland stimulation decreases due to reduced innervation, thus fewer chloride ions are drawn to the electrodes.

In the presence of low sweat function, the Electrochemical Skin Conductance score is low, which may be a sign of peripheral autonomic neuropathy.

 

What are the different results I can get?

Electrochemical Skin Conductance (ESC) score is available as a number between 0 and 100 and a qualitative indication “Normal” or “Low” depending on whether the score is above or below 50.

 

Normal

Your ESC score is within the normal range, indicating normal nerve activity. You can help maintain the health of your nerves by taking care of your overall health. This includes staying hydrated, eating healthy, getting regular physical activity and restful sleep, and working with your doctor to manage any health issues that you may have.

Low

Your ESC score is lower than average, indicating possible signs of neuropathy. You can help keep your nerves healthy by taking care of your overall health. This includes healthy eating, getting regular physical activity, and working with your doctor to manage any health issues that you may have. To better understand if you are at risk for peripheral neuropathy, talk with a healthcare professional and always consult with your doctor before making any medical decisions.

Pending

 

The reading might be pending if we are not able to accurately assess your score. We might invite you to take a Guided Scan measurement using specific conditions in order to get a result. To get the most accurate measurements always take the ESC score measurements in the conditions described in the Guided Scan. 

 

 

How do I perform an ESC measurement? 

  1. Step on the scale barefoot. 
  2. Make sure your feet are well centered on the scale as pictured:

  1. Remain completely still and do not talk during the ESC measurement. 

Note: that you might not get a score at every weigh-in (a pending status might be shown on the scale and in the app). 

 

The ESC algorithm will perform routine checks in order to give you a final reading at the end of the month. During the month, depending on the confidence level of the algorithm, a predictive score may be shown.To ensure the most accurate results, we might ask you to perform your next measurement under specific conditions. By doing so, a final/confirmed score will be shown at the end of the month.

 

 


References

1. Porubcin, M. G. & Novak, P. Diagnostic Accuracy of Electrochemical Skin Conductance in the Detection of Sudomotor Fiber Loss. Front. Neurol. 11, (2020).

2. Vinik, A. I., Nevoret, M.-L. & Casellini, C. The New Age of Sudomotor Function Testing: A Sensitive and Specific Biomarker for Diagnosis, Estimation of Severity, Monitoring Progression, and Regression in Response to Intervention. Front. Endocrinol. 6, 94 (2015).

3. Waxenbaum, J. A., Reddy, V. & Varacallo, M. Anatomy, Autonomic Nervous System. in StatPearls (StatPearls Publishing, 2023).

4. Casellini, C. M., Parson, H. K., Richardson, M. S., Nevoret, M. L. & Vinik, A. I. Sudoscan, a noninvasive tool for detecting diabetic small fiber neuropathy and autonomic dysfunction. Diabetes Technol. Ther. 15, 948–953 (2013).

5. Gandhi, P. G. & Gundu, H. R. Detection of neuropathy using a sudomotor test in type 2 diabetes. Degener. Neurol. Neuromuscul. Dis. 5, 1–7 (2015).

6. Carbajal-Ramírez, A., Hernández-Domínguez, J. A., Molina-Ayala, M. A., Rojas-Uribe, M. M. & Chávez-Negrete, A. Early identification of peripheral neuropathy based on sudomotor dysfunction in Mexican patients with type 2 diabetes. BMC Neurol. 19, 109 (2019).

7. Raasing, L. R. M., Vogels, O. J. M., Veltkamp, M., van Swol, C. F. P. & Grutters, J. C. Current View of Diagnosing Small Fiber Neuropathy. J. Neuromuscul. Dis. 8, 185–207.

8. Hughes, R. A. Epidemiology of peripheral neuropathy. Curr. Opin. Neurol. 8, 335–338 (1995).

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