AUTHOR=Vittrant Benjamin , Ayoub Hanna , Brunswick Philippe 

TITLE=From Sudoscan to bedside: theory, modalities, and application of electrochemical skin conductance in medical diagnostics

JOURNAL=Frontiers in Neuroanatomy

VOLUME=Volume 18 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/neuroanatomy/articles/10.3389/fnana.2024.1454095

DOI=10.3389/fnana.2024.1454095

ISSN=1662-5129

ABSTRACT=The human body possesses two main types of sweat glands, apocrine and eccrine, with eccrine glands distributed widely across the skin, including hair-covered areas. While eccrine glands on palms and soles enhance grip, those on the rest of the body primarily contribute to thermoregulation. The sudomotor function, regulated by the sympathetic division of the Autonomic Nervous System, controls sweating through cholinergic and adrenergic pathways. Eccrine glands' activation involves intricate processes, including neurotransmitter binding, ion channel modulation, and voltage generation. The Sudoscan technology utilizes electrochemical skin conductance (ESC) to non-invasively measure sudomotor function. This method, standardized for accuracy, has established normative benchmarks, demonstrating reliability across diverse populations. Sudoscan's diagnostic efficacy is comparable to invasive methods like intraepidermal nerve fiber density testing, making it a valuable tool for diagnosing small fiber neuropathy. Moreover, it exhibits correlations with corneal nerve fiber length, offering insights into various neuropathic conditions. In comparison with traditional sudomotor function tests, Sudoscan proves superior in terms of accessibility, simplicity, and reliability, with a potential to replace or complement existing diagnostic measures. However, the Electrochemical Skin Conductance (ESC) measured by Sudoscan should be distinguished from other skin conductance measures, such as Galvanic Skin response (GSR)/Electro-Dermal activity (EDA). Despite being based on a shared physiological principle, ESC serves a specific diagnostic purpose in evaluating sudomotor function, distinguishing it from continuous monitoring tools like GSR/EDA. The technology's success has led to its integration into consumer health devices (BodyScan from Withings), showcasing its versatility beyond clinical settings. Future research endeavors may explore ESC applications in diverse medical fields and leverage real-world data obtained through integrated consumer devices. The collaborative efforts of researchers and engineers promise to unveil new insights into sudomotor function and its implications for broader health monitoring.This work provides a comprehensive overview of the Electrochemical Skin Conductance (ESC), covering topics such as eccrine gland physiology, sudomotor function, Sudoscan technology, normative benchmarks, diagnostic comparisons, and future applications.