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Fully Implantable Hearing Aids

Fully Implantable Hearing Aids

Active middle ear implants (AMEI) offer rehabilitation for a large group of hearing impaired patients, including some that cannot, for one reason or another, be treated with externally worn hearing aids. The demand for fully implantable solution that completely eliminates the need for external components is therefore high. One major challenge is the development of the active electroacoustic transducer components, e.g. implantable microphone and receiver. The current state of the art is the Carina Implant(Cochlear Ldt., Australia), which uses a subcutaneous microphone and an electrodynamic driver.

In collaboration with MED-EL Medical Electronics GmbH, Austria, the researchers at ERCD are developing a novel system that comprises two piezoelectric membrane transducers in a single titanium housing. Its location of operation, inside the incudostapedial joint (ISJ), requires a high degree of miniaturization for all components involved: The whole device is only about 2.5x4x0.6mm (W/L/H). Using active compensation based on adaptive filtering for feedback control, the device has been shown to provide more than 30 dB functional gain above 1500 Hz. This makes it eligible as an amplifier for mid- to high frequencies, a possible medical indication: Moderate to severe high frequency hearing loss, such as a typical presbyacusis. Further research includes a fully implantable AMEI based on the Vibrant Soundbridge (MED-EL, Austria) and the ERCD implantable piezoelectric microphone.


  • Eßinger, T.M., Koch, M., Bornitz, M., Lasurashvili, N., Neudert, M., Zahnert, T., 2019. Sensor-actuator component for a Floating Mass Transducer-based fully implantable hearing aid. Hear. Res.
  • Essinger, T.M., Koch, M., Bornitz, M., Zahnert, T., 2016. Adaptive Mechanical Stabilization of a Free-Floating Fully Implantable Hearing Aid. Otol Neurotol 37, e377–e383.

  • Essinger, T.M., Hoffmann, R., 2015. Feedback suppression in a mechanically coupled, short signal path sensor-actuator system for use as a hearing implant, in: 2015 38th International Conference on Telecommunications and Signal Processing (TSP). pp. 1–4.
  • Koch, M., Essinger, T.M., Bornitz, M., Stoppe, T., Zahnert, T., 2015. Simulation of the working range of an implantable hearing aid transducer by use of different piezoelectric materials, in: IMAPS/ACerS 11th International CICMT Conference and Exhibition. pp. 144–148.
  • Koch, M., Eßinger, T.M., Bornitz, M., Zahnert, T., 2014. Examination of a mechanical amplifier in the incudostapedial joint gap: FEM simulation and physical model. Sens. Basel 14, 14356–14374.
  • Koch, M., Essinger, T.M., Stoppe, T., Lasurashvili, N., Bornitz, M., Zahnert, T., 2016. Fully implantable hearing aid in the incudostapedial joint gap. Hear Res 340, 169–178.,