Naida M. Broadband electroacoustic systems for screening and restoring human hearing

The following new scientific results were obtained in the dissertation: 1. For the first time, the reflection coefficient of a sound pulse from the oscillatory sys-tem: eardrum-ossicles was proposed as a criterion for assessing the acoustic state of the middle ear. 2. For the first time, the problem of obtaining acoustic characteristics of the middle ear by the method of partial regions in relation to the ear model in the form of an acoustic horn was posed and solved. 3. A new model of an implant for restoring human hearing was proposed in the form of an acoustic line of communication between the external (external and middle ear) part of the ear and the oval window of the inner ear, with subsequent transmission of the sound signal to the cochlea. 4. For the first time, a theoretical study of the influence of cochlear implant parameters on the frequency properties and sensitivity of the proposed ultrasonic line of transmis-sion of acoustic information through the implant was conducted. The dissertation is devoted to modeling the human middle ear and artificial substitutes for its elements - ossicular implants (ossicular implants), experimental verification of the developed models using original measuring instruments, development of a broad-band echoscope to determine the normal state of the human middle ear, which uses the obtained parameters of the models, and development of new means of restoring hear-ing after differential diagnostics, such as a device for determining the acoustic parame-ters of ossicular implants of the human middle ear, and a cochlear implant with an in-novative acoustic line of communication between the external and internal parts. The content of the dissertation research is set out in 4 sections, which present the re-sults of the research and the justification of the main results of the work. The introduction substantiates the relevance of the dissertation work, formulates the goal and lists the tasks of the research, describes the applied research methods, and lists the tasks set for the research. In addition, information was provided on the relevance, scientific novelty and practical significance of the results obtained. The first section provides an analytical review of the literature. The structure of the human auditory system is presented with an indication of its parameters. Modern ob-jective methods of human hearing diagnostics used for express diagnostics are consid-ered, namely, acoustic impedancemetry and registration of evoked otoacoustic emis-sion. A new method of express hearing diagnostics - ear echoscopy - is considered in detail. In the second section, modeling of the human external and middle ear was carried out, taking into account damage. The main problem in objective hearing diagnostics is the large intersubject difference in data, the deviation of which from some average value in the norm can overlap the deviation from the norm. To solve it, a model of the human middle ear was developed using the finite element method, taking into account the ex-ternal auditory canal and ossicular implants. Based on the developed middle ear mod-els, clear individual quantitative parameters of the normal state of the human middle ear have been determined, which allow for express diagnostics in automatic mode. In the third section, a method for monitoring the state of the human middle ear has been de-veloped, and a broadband electroacoustic ear echoscope for its implementation, which is intended for screening monitoring of the normal state of the human middle ear. The developed method is based on measuring the reflection coefficient of an acoustic short pulse from the oscillatory system of the middle ear as a function of frequency. The use of short acoustic pulses allows, by changing their frequency and follow-up time, to ob-tain a change in the normal parameter and resonant frequency in real time. In the fourth section, a cochlear implant with an innovative acoustic communication line is developed, which consists of three main parts: a microphone; a sound pro-cessing device; and a row of electrodes. The practical significance of the results obtained in the dissertation work is that the following have been developed: - a broadband ear echoscope for: express diagnostics of the human middle ear; - an electroacoustic measuring device for individual selection of ossicular implants during surgical treatment of auditory system injuries; - a cochlear implant with an acoustic communication line for restoring human hearing in case of inner ear injuries; - in the training of specialists at the Department of Acoustic and Multimedia Electronic Systems in the specialty G5 Electronics, Electronic Communications, Instrumentation and Radio Engineering (171 Electronics). The work was carried out at the Department of Acoustic and Multimedia Electronic Systems of the National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”.