Noninvasive Galvanic Skin Sensor for Early Diagnosis of Sudomotor Dysfunction: Application to Diabetes

Sudomotor dysfunction is a major clinical manifestation of diabetic autonomic neuropathy and is an early sign of prediabetes. SUDOSCAN T, a noninvasive and quick method was developed to assess sudomotor function based on measurement of the electrical current response of the skin when different rectangular pulses of low voltage amplitudes are applied on nickel electrodes. Electrochemical skin conductance is then calculated from the resulting voltage and the generated current. This leads to an accurate noninvasive way to predict dysglycemia, including type II diabetes, without fasting requirement due to the sensitivity of Ni electrodes to human eccrine glands sweat. In this paper, the device principle is presented and its efficiency in early diagnosis of sudomotor dysfunction is demonstrated through large clinical results. The electrodes behavior and the electrochemical skin model are studied, through in vitro experiments and theoretical approach. The electrochemical reactions and the influence of several factors, including properties of ion channels of the sweat duct are analyzed.