In vivo experiments in the cat with an implantable piezoelectric hearing aid transducer

Plinkert, P. K.; Baumann, J. W.; Lenarz, Thomas; Keiner, S.; Leysieffer, H.; Zenner, H. P.

doi:10.1007/s004059900209

Cited by 7 publications

(3 citation statements)

References 20 publications

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“…Secondly, the coupling way of gluing the FPM onto the handle of malleus didn't ensure a firm junction between the FPM and the ossicles. This partly constricts the vibrating sensitivity of FPM [18,37]. Thirdly, there might be a damping effect of the long interconnecting wires between the microphone and the power supply, the ground line, the output line, These connections could add measurably to the system, dampen the malleus response, increase stiffness and severely curtail the low frequency response.…”

Section: Discussionmentioning

confidence: 99%

Feasible pickup from intact ossicular chain with floating piezoelectric microphone

Kang

Gao

Chi³

et al. 2012

BioMedical Engineering OnLine

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ObjectivesMany microphones have been developed to meet with the implantable requirement of totally implantable cochlear implant (TICI). However, a biocompatible one without destroying the intactness of the ossicular chain still remains under investigation. Such an implantable floating piezoelectric microphone (FPM) has been manufactured and shows an efficient electroacoustic performance in vitro test at our lab. We examined whether it pick up sensitively from the intact ossicular chain and postulated whether it be an optimal implantable one.MethodsAnimal controlled experiment: five adult cats (eight ears) were sacrificed as the model to test the electroacoustic performance of the FPM. Three groups were studied: (1) the experiment group (on malleus): the FPM glued onto the handle of the malleus of the intact ossicular chains; (2) negative control group (in vivo): the FPM only hung into the tympanic cavity; (3) positive control group (Hy-M30): a HiFi commercial microphone placed close to the site of the experiment ear. The testing speaker played pure tones orderly ranged from 0.25 to 8.0 kHz. The FPM inside the ear and the HiFi microphone simultaneously picked up acoustic vibration which recorded as .wav files to analyze.ResultsThe FPM transformed acoustic vibration sensitively and flatly as did the in vitro test across the frequencies above 2.0 kHz, whereas inefficiently below 1.0 kHz for its overloading mass. Although the HiFi microphone presented more efficiently than the FPM did, there was no significant difference at 3.0 kHz and 8.0 kHz.ConclusionsIt is feasible to develop such an implantable FPM for future TICIs and TIHAs system on condition that the improvement of Micro Electromechanical System and piezoelectric ceramic material technology would be applied to reduce its weight and minimize its size.

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Section: Discussionmentioning

confidence: 99%

Feasible pickup from intact ossicular chain with floating piezoelectric microphone

Kang

Gao

Chi³

et al. 2012

BioMedical Engineering OnLine

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“…Advantages of CAI are: [15,22]. The microphone was implanted underneath the skin of the outer ear canal and connected via cable to the main unit located in a bony implant cavity behind the ear and housing the control unit as well as the power supply.…”

Section: Cochlear Amplifier Implantsmentioning

confidence: 99%

Restoring Hearing with Active Hearing Implants / Wiederherstellung des Gehörs mit aktiven Hörimplantaten

Federspil

Plinkert²

2004

Biomedizinische Technik/Biomedical Engineering

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Due to shortcomings of conventional hearing aid technology, such as unsatisfactory sound quality due to limited frequency range and undesired distortion, occlusion of the outer ear canal, and acoustic feedback with high amplification, but also psychological aspects of stigmatization, a significant of patients in need of hearing aids are actually not wearing them. Active hearing implants can be distinguished in: (1) impedance transformation implants (ITI), (2) cochlear amplifier implants (CAI), (3) cochlear implants (CI), and (4) brain stem implants (BSI). Whereas ITI are designed for patients with middle ear hearing loss, CAI are intended to restore hearing in patients with inner ear hearing loss. Advantages of CAI may be: (1) improved sound fidelity, (2) no occlusion of the outer ear canal, (3) no feedback, and (4) invisibility. However, not all features are true for every device. CI replace inner ear function in deaf or almost deaf patients. This article gives an overview on the range of active hearing implants to restore hearing and outlines the future use of computer and robot aided surgery.

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“…Such excitation forces are typically measured in only one dimension using load cells, though there have also been efforts to measure them in two dimensions using atomic force microscopy techniques [1]. Piezoelectric micro-actuators represent another technique for exciting biological structures with calculated or calibrated forces [2]-[4], but for such actuators the 3-D force and moment components are nearly impossible to measure. As the dimensions of a given biological structure of interest become smaller, the measurement of excitation forces becomes increasingly difficult, and even estimations of the forces can suffer from relatively large errors due to inaccuracies in determining the dimensions and positions of the actuator and structures under study.…”

Section: Introductionmentioning

confidence: 99%

A 3-D Force and Moment Motor for Small-Scale Biomechanics Experiments

Sim

Puria

2009

IEEE Sensors J.

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The inability to identify 3-D force and moment components for actuators and sensors is a major limiting factor in the study of 3-D force interactions with small-scale biological structures. While recent advances have been made in the measurement of stimulating forces using load cells and atomic-force microscopy in experimental preparations of biological structures such as mammalian temporal bones, these techniques have mostly been limited to one or two dimensions. In this paper, a method is described for stimulating biological structures using a small magnet (2 mg Sm2Co17 ) and a nearby currentconducting coil (46 gauge, 50 turns), that allows the 3-D Lorentz forces and moments acting on the magnet to be calculated. To make these calculations possible, the dimensions and placements of the magnet and coil are accurately determined (within 10 mum for in vitro preparations) using high-resolution micro-CT imaging. This noncontact force motor method has been used to study the mechanics of the malleus-incus complex in the mammalian middle ear in addition to basilar membrane mechanics and fluid flow inside the cochlea, and it can also be applied to the study of other biomechanical structures. Abstract-The inability to identify 3-D force and moment components for actuators and sensors is a major limiting factor in the study of 3-D force interactions with small-scale biological structures. While recent advances have been made in the measurement of stimulating forces using load cells and atomic-force microscopy in experimental preparations of biological structures such as mammalian temporal bones, these techniques have mostly been limited to one or two dimensions. In this paper, a method is described for stimulating biological structures using a small magnet (2 mg 2 17 ) and a nearby current-conducting coil (46 gauge, 50 turns), that allows the 3-D Lorentz forces and moments acting on the magnet to be calculated. To make these calculations possible, the dimensions and placements of the magnet and coil are accurately determined (within 10 m for in vitro preparations) using high-resolution micro-CT imaging. This noncontact force motor method has been used to study the mechanics of the malleus-incus complex in the mammalian middle ear in addition to basilar membrane mechanics and fluid flow inside the cochlea, and it can also be applied to the study of other biomechanical structures.

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In vivo experiments in the cat with an implantable piezoelectric hearing aid transducer

Cited by 7 publications

References 20 publications

Feasible pickup from intact ossicular chain with floating piezoelectric microphone

Feasible pickup from intact ossicular chain with floating piezoelectric microphone

Restoring Hearing with Active Hearing Implants / Wiederherstellung des Gehörs mit aktiven Hörimplantaten

A 3-D Force and Moment Motor for Small-Scale Biomechanics Experiments

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