Electrophysical Properties and Determination of the Impedance of Vestibular Labyrinth Tissues

A detailed electric model of current transmission through vestibular labyrinth tissues is suggested based on the anatomic structure of the labyrinth taking into account electrophysical properties of hair and basilar cells of neuroepithelium. Formulas for the impedance of the vestibular organ are derived and phase shifts of the stimulating current are calculated based on experimental data on the electrophysical and anatomic characteristics of vestibular labyrinth tissues of a guinea pig. The dispersion of the impedance is investigated for the frequencies in the range 101–5·104 Hz. It is shown that the phase shift of the current relative to the voltage applied between the electrode and the vestibular nerve is nonmonotonic in character and depends on the frequency. A minimum negative phase shift of the current is observed at f = 200 Hz. Taking into account of the cellular structures of the hair and basilar cells in the electric circuit shows that in the examined frequency range they bring significant contribution to the total impedance. The suggested electric model and the results of calculations can provide the basis for diagnostics of vestibular labyrinth diseases and design of vestibular implants of a new type.