ABSTRACT
Impedance spectroscopy methods have been widely used for noninvasive illness monitoring. Although commercialized solutions for enzyme-based treatments exist, they are intrusive, uncomfortable for patients to use, and cannot be sustained. Also, there are numerous obstacles to be overcome before spectroscopy-based noninvasive illness diagnosis is widely used in clinical settings. Electrical impedance techniques for spectroscopy offer the benefits of being inexpensive and simple to utilize. With a focus on the gadgets that may be included in wearable platforms, this chapter briefly discusses the current developments in noninvasive continuous monitoring based on skin impedance measurement via electrical impedance spectroscopy (EIS) and bio-impedance spectroscopy (BIS). Further, the principle of noninvasive sensors, the effect of skin structure, the role of electrode material, the application of EIS and BIS, and their future expectations are also discussed.
