A Piezoelectric Bellows Round-Window Driver (PBRD) for Middle-Ear Implants

Abstract

We describe a new implantable hearing-aid output device, a piezoelectric bellows roundwindow driver (PBRD), which is expected to be unaffected by external magnetic fields. The core elements of the PBRD are a piezoelectric element and a gold-coated copper bellows of low stiffness that transmits piezoelectric displacements, without significant attenuation, to the round window (RW). We analyzed structural and mechanical vibrations when confirming bellows transmission efficiency using a finite element model simulation. The PBRD was bench-tested under no-load conditions to determine its frequency response characteristics. We compared the outputs of the PBRD and a commercial floating-mass transducer in situ in human cadaveric temporal bones with responses measured using a laser Doppler vibrometer. PBRD outputs were excellent at both low (0.1-0.7 kHz) and high (2-16 kHz) frequencies; thus, the PBRD has the potential to compensate for conductive and/or sensorineural hearing loss. The frequency-response performance of the PBRD is better than that of conventional RW drivers (actuators or transducers). INDEX TERMS Piezoelectric bellows round-window driver (PBRD), Middle-ear implants, Finite element analysis, Human temporal bone, Conductive or sensorineural hearing loss

Effect of Driver Mass Loading on Bone Conduction Transfer in an Implantable Bone Conduction Transducer

“…The number of people with noise-induced hearing loss is increasing [3]. Hearing devices employ various sound transmission mechanisms [4], [5], [6], [7], [8], [9], [10], [11], [12]; the most popular hearing devices are air conduction hearing aids (ACHAs), middle ear implants (MEIs), and cochlear implants (CIs) [13], [14], [15]. The indications for ACHAs and CIs are mild-to-moderate and profound loss or deafness, respectively [16], [17].…”

Design Study of a Round Window Piezoelectric Transducer for Active Middle Ear Implants

“…Various types of middle-ear implant transducers [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ] that stimulate round window (RW) have been developed [ 11 , 12 , 13 , 14 , 15 ]. However, there is no highly stable and practical RW transducer for middle-ear implants except for the floating mass transducer (FMT) developed by MED-EL Inc. (Innsbruck, Austria) [ 16 , 17 ].…”