Розвиток методів моделювання зовнішнього та середнього вуха людини

Abstract

In the world, almost 10% of people have a variety of hearing disorders. Nearly 500 million people live with deafness; more than 32 million of them are children. Therefore, the problem of studying the human hearing system to improve the theoretical and practical equipment of diagnosis for the further treatment of people with hearing impairments is extremely acute. This article is devoted to the analysis of experimentally obtained amplitude-frequency characteristics of the middle ear and to the development of theoretical foundations and the method of electromechanical analogies for the construction of middle ear frequency response. The main possible approaches for theoretical obtaining of the external and middle ear frequency response based on the results of the average frequency response of a healthy person are analyzed, namely: a mechanical model with concentrated parameters, a finite element method and an electromechanical analogy method. The first approach proposes a mechanical model in which each component of the system, namely: malleus, incus and stapes, ladder is described as an object having certain mechanical and physical characteristics. The simplest oscillatory system is the mass suspended on a spring. It is commonly believed that movement occurs in the absence of friction. This oscillatory system is a system with lumped parameters, however, this model is designed for objective diagnostic methods that involve the placement of an acoustic probe in the external auditory canal. A further development of mechanical analogies is the Finite Element Method (FEM). In this case, all the objects of the system are broken down into components in three-dimensional space, as a system with distributed parameters, each of which has strictly specified mechanical properties, its own way of connecting with the surrounding parts. Another approach is the method of electromechanical analogies, which is based on the similarity of equations describing oscillatory processes of mechanical and electrical nature. If the equations are similar, then their solutions are the same, so the solution of the mechanical problem can be replaced by the solution of similar electromechanical. By analogy to a mechanical system, the simplest electrical oscillating circuit is the connection of a coil and a capacitor. The oscillations in this circuit are the mutual conversion of the capacitor s electrical energy and the coil s magnetic energy. Electromechanical analogies were used to analyze the oscillations of the outer and middle ears. In this electrical quantities: voltage, capacitance, active resistance, inductance are mechanical: strength, flexibility, active mechanical resistance, mass. The equivalent circuit of the human middle ear was constructed and analyzed using the Simulink application package. The values of the resonant frequencies of the outer and middle ear (364, 748, 1430, 2390\xa0Hz) obtained in this model are in good agreement with the experimental results. As a result, an equivalent electrical circuit is proposed that takes into account both the outer ear and the middle ear, and allows you to reproduce more of the characteristic resonances of the frequency response of the average healthy person.