Development of a passive implant with external selective stimulation of the middle ear for the therapy of sensorineural hearing loss

• Applicant: Professor Dr. Sebastian Schraven
• Subject Area: Otolaryngology, Phoniatrics and Audiology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 533952089

The increasing prevalence of sensorineural hearing loss is a public challenge for the compensation of this handicap in the society. Up to one third of patients fitted with conventional hearing aids do not benefit sufficiently from hearing rehabilitation. In addition, anatomical conditions and chronic inflammation of the outer ear make conventional hearing aids difficult to fit and result in insufficient sound amplification. The spectrum of implantable, active hearing systems (bone conduction hearing aids, active middle ear implants (AMEI) and cochlear implants) expands the possibilities of care, but there is potential for optimization in some details. In the indication area of implantable hearing aids, it is mainly the effective sound transmission into the cochlea. In addition, the reduction of the complexity of active components is desired in order to make future technological progress available for already fitted patients without reimplantation. Preliminary work showed that the ossicular chain can be stimulated safely and efficiently via the short incus process bypassing the outer ear after antrotomy. The goal of the proposed project is to develop a passive middle ear implant with external selective stimulation by vibration. After antrotomy, a standardized coupling at the short incus process is to be connected to an osteosynthesis plate that reconstructs the resulting bony defect. After an appropriate healing period, the passive implant, which does not involve the implantation of any electronics, can be externally stimulated by vibration to excite the cochlea bypassing the outer ear. The project involves a translational approach: The work objectives are (1) implant development and (2) functional measurements of the implant as well as (3) simulation of implant loading are experimental and will be performed on human temporal bones by laser Doppler vibrometric (LDV) measurements. Translational aspects are (4) the development of an objective coupling assessment by impedance measurements on the external bone conduction transducer and (5) the analysis of defect reconstruction after antrotomy by an osteosynthesis plate when an AMEI is implanted to avoid retroauricular skin retraction. Finally, (6) the possibility of additional bone conduction transfer is investigated in 14 patients treated with an AMEI. Clinical analyses include subjective and objective audiometry procedures, cross-sectional imaging and questionnaires. Given the symptoms limiting social and professional life and the large number of affected patients with sensorineural hearing loss, new findings in this field are of great clinical and socioeconomic interest.

• DFG Programme: Research Grants
• Co-Investigators: Professor Dr. Robert Mlynski; Dr. Florian Schmidt