A MEMS Condenser Microphone-Based Intracochlear Acoustic Receiver.

GOAL

Intracochlear sound pressure (ICSP) measurements are limited by the small dimensions of the human inner ear and the requirements imposed by the liquid medium. A robust intracochlear acoustic receiver (ICAR) for repeated use with a simple data acquisition system that provides the required high sensitivity and small dimensions does not yet exist. The work described in this report aims to fill this gap and presents a new microelectromechanical systems (MEMS) condenser microphone (CMIC)-based ICAR concept suitable for ICSP measurements in human temporal bones.

METHODS

The ICAR head consisted of a passive protective diaphragm (PD) sealing the MEMS CMIC against the liquid medium, enabling insertion into the inner ear. The components of the MEMS CMIC-based ICAR were expressed by a lumped element model (LEM) and compared to the performance of successfully fabricated ICARs.

RESULTS

Good agreement was achieved between the LEM and the measurements with different sizes of the PD. The ICSP measurements in a human cadaver temporal bone yielded data in agreement with the literature.

CONCLUSION

Our results confirm that the presented MEMS CMIC-based ICAR is a promising technology for measuring ICSP in human temporal bones in the audible frequency range.

SIGNIFICANCE

A sensor for evaluation of the biomechanical hearing process by quantification of ICSP is presented. The concept has potential as an acoustic receiver in totally implantable cochlear implants.