How a hearing aid restores quality of life

Bonebridge: More quality of life thanks to modern mechatronics

The Bonebridge is a state-of-the-art hearing implant that converts sound waves into electrical signals and transmits them wirelessly through the skin to an implant fixed in the temporal bone. There, the signals are transformed into mechanical vibrations that reach the cochlea via the skull bone – where they are perceived as sounds, just like in people with normal hearing.

The key advantage is that it can be implanted completely without penetrating the skin. This means: no externally visible device, unrestricted swimming and sporting activities – and a significantly reduced risk of infection. Skin irritation is also a thing of the past.

Thanks to its MRI compatibility, the system is suitable for magnetic fields of up to 1.5 Tesla.

People with malformations of the outer ear in particular benefit from this technology – not only due to the restoration of speech intelligibility, but also due to the minimally invasive procedure. The milling depth has been reduced from the original 9 millimetres to just 4.5 millimetres – a decisive advantage, especially for children.

In the ongoing collaboration between LCM and MED-EL as part of the COMET K2 Center for Symbiotic Mechatronics, the individual optimization tasks were combined for the first time and the system model environment, the LCM SyMSpace, was expanded for this purpose: The calculation of the transducer, the demodulator, the transmission characteristic of the transmitter coil – skin – receiver coil and the motion model of the magnetic and mechanical systems were linked together in a workflow and can be executed automatically. This means that the optimization can also be applied to the overall system and the actual target value, the hearing quality in the frequency range of the human hearing spectrum, can be optimized.

BIld Projket MED EL Hörgertät — New generation of implants (above), comparison of
drilling depth into the bone with old (left) and new (right) implant (photo credit: MED-EL)

Requirements

Complete implantability
No skin penetration
Maintenance-free
Magnetic resonance imaging must be possible
90% speech intelligibility (in previously almost deaf people)
Energy must be transferred inductively

Your benefit

Design and optimization of a highly efficient electromagnetic actuator under consideration of very complex boundary conditions
Optimization of the inductive transmission system and the demodulator circuit
Patented, MRI-compatible holding magnet system