Fully implantable hearing aid in the incudostapedial joint gap.

Fully implantable hearing aid in the incudostapedial joint gap.
Hear Res. 2016 Mar 31;
Authors: Koch M, Eßinger TM, Stoppe T, Lasurashvili N, Bornitz M, Zahnert T
Abstract
A fully implantable hearing aid is introduced which is a combined sensor-actuator-transducer designed for insertion into the incudostapedial joint gap (ISJ). The active elements each consist of a thin titanium membrane with an applied piezoelectric single crystal. The effectiveness of the operating principle is verified in a temporal bone study. We also take a closer look at the influence of an implantation-induced increase in middle ear stiffness on the transducer's output. An assembly of the transducer with 1 mm thickness is built and inserted into six temporal bones. At this thickness, the stiffness of the annular ligament is considerably increased, which leads to a loss in functional gain for the transducer. It is assumed that a thinner transducer would reduce this effect. In order to examine the performance for a prospective reduced pretension, we increased the gap size at the ISJ by 0.5 mm by removing the capitulum of the stapes in four temporal bones. The TM is stimulated with a broadband multisine sound signal in the audiological frequency range. The movement of the stapes footplate is measured with a laser Doppler vibrometer. The sensor signal is digitally processed and the amplified signal drives the actuator. The resulting feedback is minimized by an ac...

Source: Hearing Research - March 30, 2016 Category: Audiology Authors: Koch M, Eßinger TM, Stoppe T, Lasurashvili N, Bornitz M, Zahnert T Tags: Hear Res Source Type: research