Evaluation of Electrode-modiolus Distance and Cochlear Fibrosis Using Depth Sounding and Spectroscopy Tools

TIM measurements are based on cochlear implant back-telemetry function. Each electrode contact is stimulated in monopolar mode. Transimpedance is represented by the ratio between the voltage measured at each recording electrode and the current injected at the stimulation contact. The result of the measurements is a matrix of 21x21 transimpedances. Stimulation current cannot be perceived by a patient thus making TIM measurements a non-invasive and painless procedure. The test duration is only 2-3 minutes

Depth sounding and spectroscopy are based on the matrixes obtained after TIM imaging. Deep sounding measures the capacitances throughout the electrode array whereas spectroscopy determines the phase of every transimpedance value. These tests take 10 to 15 minutes together. The stimulation intensity used by depth sounding technique can be perceived by a patient. If it is considered as unpleasant, the test will be stopped.

CBCT is a routine postoperative assessment after CI, non-invasive and painless for patients.