Bionic Ear
Perm Polytechnic University scientists are involved in the development of a bionic human ear prosthesis
Approximately four out of ten thousand children are born with microtia – an underdeveloped or completely absent auricle, which is often accompanied by partial or complete hearing impairment. One of the ways to restore the patient's ability to hear are devices that provide bone conduction of sound. Scientists of Perm Polytechnic University together with colleagues from PGMA and MGMSU have developed a bionic ear implant, now the project is at the stage of preclinical testing. The research was carried out with the financial support of the Perm Krai Government as part of the scientific project "Development of a bionic ear prosthesis based on intelligent and medical 3D technologies".
Articles on the progress of the study were published in the Perm Medical Journal (No. 3, 2022) and the Bulletin of the PSTU. Series: Radio engineering and Infocommunication systems" (No. 1(53), 2022).
— In the complex rehabilitation of patients with microtia, in addition to restoring hearing function, an aesthetic component is also important – the replacement of the defect of the outer ear by means of epitheses made of silicone material. However, it is worth noting that today the restoration of function and aesthetics are developing separately from each other. We are developing the design of a bionic ear prosthesis that allows us to restore both the bone conduction of sound and the aesthetics of the lost organ. To do this, it is necessary to bring the ear prosthesis, the fixing system, the microphone, the sound processing unit based on a specialized digital signal processor with built-in analog—to-digital and digital-to-analog converters, the Bluetooth radio channel module for wireless control and reception of external audio signals and the sound vibration emitter into a single structure," says associate professor of the Department of Automation and Telemechanics, a researcher at the laboratory methods of creation and design of systems "material-technology-construction", Candidate of Technical Sciences Igor Bezukladnikov.
Scientists have already developed a prototype of the prosthesis and have now moved on to the preclinical testing stage to assess its functional effectiveness. To do this, a test stand was assembled, in which a cubic polymer tank obtained using plastic 3D printing was used as a human head simulator. Sound transmission in such a design is quite close in characteristics to human bone tissue.
General view and cross section of the first test bench
However, the results made the developers doubt the optimality of the test bench. The correct cubic shape of the tank and the reflection of the signal from the polymer walls of the container filled with ballistic gel could lead to distortion of the data on the effectiveness of the prosthesis. Therefore, a new test bench was constructed, where the native pig's head was taken as a basis. This choice is due to the similarity of the hearing systems of pigs and humans.
Thanks to tests at the new stand, scientists were able to identify the shortcomings of the current design of the bionic ear, the main of which is the insufficient rigidity of the attachment of the ear emitter to the bone tissues of the head, due to which the sound becomes too high. Also, the use of an improved stand made it possible to determine the resonant characteristics of the "bionic ear – inner ear" system, which are subject to further compensation by software or hardware. In the future, this will allow you to debug the system to provide stereo sound both for patients with two prostheses and for those who have preserved hearing in one ear.
As part of further work on the project, it is planned to vary the attachment points of the prosthesis to improve the resonance characteristics.
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