A computer model of the ear may help to improve cochlear implants

Pavel Jungwirth, a member of the Learned Society, and his colleagues from the Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences and from the cochlear implant company MED-EL, based in Austria, have developed a complete computer model of the ear. It can be used to simulate hearing of mammals, including humans, from the outer ear all the way to the auditory nerve. The results of their research have been published in the journal Hearing Research recently. This model will not only facilitate the further research of the human ear but may also help to improve and better adjust compensation devices for people with hearing impairment including cochlear implants.

The detailed design of the model based on up-to-date experimental data allows for the investigation of partial hearing mechanisms and their defects, including genetic, molecular, and microscopic factors. It will also allow experts to learn more about the detailed mechanisms of various forms of hearing impairment and may open ways to improve hearing aids and cochlear implants. This is also because the present computer model makes it possible to obtain data that are difficult to acquire experimentally. Performing invasive measurements on the human ear is hardly feasible, the only alternative being animal models. In addition, computer modelling makes it possible to understand the system as a whole.

Pavel Jungwirth's research was motivated, among other things, by the hearing difficulties of one of his sons.
Photo IOCB CAS

The new computer model of the peripheral auditory system maps in detail how sound is being converted into mechanical vibrations in the middle and inner ear. It then simulates how these vibrations trigger electrical signals in outer and inner hair cells in the cochlea and how these signals get transformed through the action of neurotransmitters into electrical impulses in the cochlear nerve. These signals then get transferred to the central nervous system.

Why did physical chemist Pavel Jungwirth start research that, at first glance, did not thematically fit into the scientific scope of his research group at the IOCB? ‘It's a mixture of craziness and personal reasons,’ he says and explains: ‘My younger son Matěj has a severe hearing impairment, and I wanted to understand better principles of hearing. Besides, I realized that the transmission of information in the ear is mediated by fluxes of calcium and potassium ions, which is exactly what my research group works on.’

Pavel Jungwirth admits that in 2011, when he embarked on the project, he, perhaps naively, believed that it was a job for at most two or three years. It all began when he started to cooperate with Pavel Mistrík from the company MED-EL, which uses computer models in the development of cochlear implants. In the end, the research was brought to a successful completion only after twelve years, thanks to the key contribution of Jungwirth’s talented and hard-working student, Ondřej Ticháček.

The freshly published computer model of the ear, implemented in the programming language and numerical computing environment MATLAB, is now available to the broad scientific community. This means that it can be used by anyone interested in modelling different types of hearing disorders or searching for ways to better compensate them with hearing aids or cochlear implants.

With the use of the press release of the IOCB CAS

Original article: Tichacek, O.; Mistrík, P.; Jungwirth, P. From the outer ear to the nerve: A complete computer model of the peripheral auditory system. Hear. Res. 2023, 440, 108900.
https://doi.org/10.1016/j.heares.2023.108900

Prof. Pavel Jungwirth, Distinguished Chair and leader of the Molecular Modeling research group at IOCB Prague
Photo Tomáš Belloň, IOCB Prague