Research On Microscopic Dynamic Characteristics Of Cochlea By Round Window Stimulation

Deafness is one of the most common diseases in society,and it is necessary to use a hearing aid for hearing compensation according to the degree of hearing loss of the patient.Because the hearing aid has sound feedback,small output gain,and ear plugging and so on the insufficiency.In order to solve this problem,many domestic and foreign institutions have studied the middle ear implant(MEI)that mechanically stimulates the ear tissue to compensate for hearing loss.However,the MEI used in clinical is mainly designed to directly drive the middle ear ossicular chain,for some patients with ossicular chain breaks and congenital middle ear malformation,the traditional MEI is difficult to transmit sound energy to the inner ear effectively through the oval window.In order to solve the above problems,the round-window stimulating type MEI has become a research hotspot in recent years,it has the advantage of not being affected by the integrity of the auditory ossicular chain.However,the evaluation criterion of the round-window stimulating type MEI still uses the traditional MEI's evaluation criterion,such as the stapes displacement.Because round-window stimulating type MEI and the traditional MEI have opposite energy transmission paths in the cochlea,and the cochlea is asymmetrical relative to the basilar membrane,so when the same energy is input to the cochlea,there must be a deviation between the displacement of stapes caused by the round-window stimulating type MEI and the displacement of stapes during normal sound transmission.Therefore,there will be a deviation when the displacement of stapes is directly used as the evaluation criterion of round-window stimulating type MEI.Hearing is mainly caused by the change of membrane potential caused by shear movement of inner hair cells.In view of the above problems,this paper constructs a microcosmic dynamic model of the organ of corti of cochlea.Comparative analysis of dynamic characteristics of the stereocilia of the inner hair cells under the round-window stimulation and normal sound transmission.The stereocilia shear displacement of the inner hair cells is used as the evaluation criterion of the round-window stimulating type MEI,and the stapes displacement is corrected by this standard,so that the stapes displacement can accurately reflect the hearing compensation effect of the round-window stimulating type MEI.The details are as follows:First,a macroscopic model of the cochlea and the microscopic finite element model of the basal turn,middle turn and apical turn of the cochlea were established.The model calculation results are compared with relevant experimental data to verify the reliability of the model;Secondly,the cochlea basal turn,middle turn and apical turn fluid pressures calculated by the cochlea macroscopic model were applied to the corresponding cochlea microscopic finite element model.The round-window stimulating type MEI was analyzed by using the evaluation criterion of the basilar membrane displacement and the stereocilia shear displacement of the inner hair cells,and the deviation between two evaluation criterion is calculated.Finally,according to the macroscopic model of the cochlea,the deviation of the stapes displacement and the basilar membrane displacement as the evaluation criterion were obtained.The deviation between stapes displacement and the stereocilia shear displacement of inner hair cells as the round-window stimulating type MEI's evaluation criterion was calculated,and then the correction value of the stapes displacement as the round-window stimulating type MEI evaluation criterion was obtained.