Electrochemical impedance spectroscopy for characterizing neural electrodes

Electrochemical impedance spectroscopy (EIS) has been extensively employed in the field of neural stimulation over the past 25 years. This review summarizes the early applications, major contributions, rudimentary use, and recent advances of EIS in neural applications. EIS is widely used in both research and clinical neurostimulation to monitor changes in electrode impedance due to foreign body response and glial encapsulation. The key parameters for in vitro and in vivo measurements are discussed along with the guidelines for data interpretation.