Introduction: Cochlear neuromodulators play a significant role in restoring auditory perception for individuals with hearing impairments. A key factor in their effectiveness is the precise placement of the electrodes within the cochlea, as incorrect insertion can result in additional tissue damage. One method for assisting accurate electrode positioning involves measuring impedance, which can serve as a useful indicator during insertion.

Methods: Advanced bio-computational techniques offer a viable way to explore how the dielectric properties of different cochlear tissue layers influence impedance measurements—something that is difficult or impractical to study directly in cochlear implant (CI) patients. Although earlier modeling studies have often dismissed the capacitive characteristics of these tissues using the quasi-static (QS) approximation, it is well understood that biological tissues exhibit frequency-dependent filtering effects. As a result, the QS approximation may not always be sufficient, particularly when short-duration electrical pulses are involved. This study focused on examining how frequency-dependent dielectric properties of the cochlear tissues affect impedance measurements during electrode insertion. A volume conductor model representing the layered structure of the cochlea was developed, and the dielectric properties of each layer were obtained.

Results: Using cochlear neuromodulator parameters, simulations were carried out employing both the QS and transient solution (TS) methods. The outcomes from each method were compared to assess how the dielectric properties influenced the impedance results.

Conclusions: The findings suggest that above a certain frequency threshold, the capacitive effects of the cochlear tissues become significant and should be taken into account for accurate modeling.