TY - JOUR
T1 - Fitting the determined impedance in the guinea pig inner ear to Randles circuit using square error minimization in the range of 100 Hz to 50 kHz
AU - Pleshkov, M.O.
AU - D'Alessandro, S.
AU - Svetlik, M.V.
AU - Starkov, D.N.
AU - Zaitsev, V.A.
AU - Handler, M.
AU - Baumgarten, D.
AU - Saba, R.
AU - van de Berg, R.
AU - Demkin, V.P.
AU - Kingma, H.
N1 - Publisher Copyright:
© 2022 The Author(s). Published by IOP Publishing Ltd.
PY - 2022/3/1
Y1 - 2022/3/1
N2 - Objective. Several lumped and distributed parameter models of the inner ear have been proposed to improve vestibular implant stimulation. The models should account for all significant physical phenomena that influence the current propagation, such as the electrical double layer (EDL) and medium polarization. The electrical properties of the medium are reflected in the electrical impedance; therefore, the study aimed to measure the impedance in the guinea pig inner ear and construct its equivalent circuit. Approach. The electrical impedance was measured from 100 Hz to 50 kHz between a pair of platinum electrodes immersed in 0.9% NaCl saline solution using sinusoidal voltage signals. The Randles circuit was fitted to the measured impedance in the saline solution in order to estimate the EDL parameters (C, W, and R-ct) of the electrode interface in saline. Then, the electrical impedance was measured between all combinations of the electrodes located in the semicircular canal ampullae and the vestibular nerve in the guinea pig in vitro. The extended Randles circuit considering the medium polarization (R-i, R-e, C-m) together with EDL parameters (C, R-ct) obtained from the saline solution was fitted to the measured impedance of the guinea pig inner ear. The Warburg element was assumed negligible and was not considered in the guinea pig model. Main results. For the set-up used, the obtained EDL parameters were: C=27.09*10(-8) F,R-ct=18.75k Omega.The average values of intra-, extracellular resistances, and membrane capacitance were R-i=4.74 k Omega, Re=45.05k Omega, Cm=9.69*10(-8)F, Significance. The obtained values of the model parameters can serve as a good estimation of the EDL for modelling work. The EDL, together with medium polarization, plays a significant role in the electrical impedance of the guinea pig inner ear, therefore, they should be considered in electrical conductivity models to increase the credibility of the simulations.
AB - Objective. Several lumped and distributed parameter models of the inner ear have been proposed to improve vestibular implant stimulation. The models should account for all significant physical phenomena that influence the current propagation, such as the electrical double layer (EDL) and medium polarization. The electrical properties of the medium are reflected in the electrical impedance; therefore, the study aimed to measure the impedance in the guinea pig inner ear and construct its equivalent circuit. Approach. The electrical impedance was measured from 100 Hz to 50 kHz between a pair of platinum electrodes immersed in 0.9% NaCl saline solution using sinusoidal voltage signals. The Randles circuit was fitted to the measured impedance in the saline solution in order to estimate the EDL parameters (C, W, and R-ct) of the electrode interface in saline. Then, the electrical impedance was measured between all combinations of the electrodes located in the semicircular canal ampullae and the vestibular nerve in the guinea pig in vitro. The extended Randles circuit considering the medium polarization (R-i, R-e, C-m) together with EDL parameters (C, R-ct) obtained from the saline solution was fitted to the measured impedance of the guinea pig inner ear. The Warburg element was assumed negligible and was not considered in the guinea pig model. Main results. For the set-up used, the obtained EDL parameters were: C=27.09*10(-8) F,R-ct=18.75k Omega.The average values of intra-, extracellular resistances, and membrane capacitance were R-i=4.74 k Omega, Re=45.05k Omega, Cm=9.69*10(-8)F, Significance. The obtained values of the model parameters can serve as a good estimation of the EDL for modelling work. The EDL, together with medium polarization, plays a significant role in the electrical impedance of the guinea pig inner ear, therefore, they should be considered in electrical conductivity models to increase the credibility of the simulations.
KW - electrical impedance
KW - inner ear
KW - guinea pig
KW - equivalent circuit
KW - electrical double layer
KW - polarization
KW - ELECTRICAL-STIMULATION
KW - DIELECTRIC-PROPERTIES
KW - TISSUES
KW - ANATOMY
U2 - 10.1088/2057-1976/ac4c4a
DO - 10.1088/2057-1976/ac4c4a
M3 - Article
C2 - 35042198
SN - 2057-1976
VL - 8
JO - Biomedical Physics & Engineering Express
JF - Biomedical Physics & Engineering Express
IS - 2
M1 - 025005
ER -