Abstract:Implantable assembly components that are biocompatible and highly miniaturized are an important objective for hearing aid development. We introduce a mechanical transducer, which could be suitable as part of a prospective fully-implantable hearing aid. The transducer comprises a sensor and an actuator unit in one housing, located in the joint gap between the middle ear ossicles, the incus and stapes. The setup offers the advantage of a minimally invasive and reversible surgical solution. However, feedback betw… Show more
“…To solve these problems, many institutions began to investigate the implantable middle ear hearing devices (IMEHDs). Different from conventional hearing aids, which operate by overdriving the eardrum with their loudspeaker’s acoustic energy, IMEHDs compensate hearing loss by their implanted transducers’ mechanical stimulation to the ossicles (i.e., malleus, incus, stapes) [ 6 , 7 , 8 ], eardrum [ 9 , 10 , 11 ], or round window [ 12 , 13 , 14 , 15 ]. This IMEHDs’ mechanical simulation eliminates the acoustic feedback problem of hearing aids and increases the sound’s fidelity [ 16 ].…”
Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate less high-frequency output. To address this problem, we proposed and designed a new piezoelectric transducer based on a piezoelectric stack for the IMEHD. This new transducer, attached to the incus body with a coupling rod, stimulates the ossicular chain in response to the expansion-and-contraction of its piezoelectric stack. To test its feasibility for hearing loss compensation, a bench testing of the transducer prototype and a temporal bone experiment were conducted, respectively. Bench testing results showed that the new transducer did have a broad frequency bandwidth. Besides, the transducer was found to have a low total harmonic distortion (<0.75%) in all frequencies, and small release time (1 ms). The temporal bone experiment further proved that the transducer has the capability to produce sufficient vibrations to compensate for severe sensorineural hearing loss, especially at high frequencies. This property benefits the treatment of the most common sloping high-frequency sensorineural hearing loss. To produce a 100 dB SPL equivalent sound pressure at 1 kHz, its power consumption is 0.49 mW, which is low enough for the transducer to be utilized in the IMEHD.
“…To solve these problems, many institutions began to investigate the implantable middle ear hearing devices (IMEHDs). Different from conventional hearing aids, which operate by overdriving the eardrum with their loudspeaker’s acoustic energy, IMEHDs compensate hearing loss by their implanted transducers’ mechanical stimulation to the ossicles (i.e., malleus, incus, stapes) [ 6 , 7 , 8 ], eardrum [ 9 , 10 , 11 ], or round window [ 12 , 13 , 14 , 15 ]. This IMEHDs’ mechanical simulation eliminates the acoustic feedback problem of hearing aids and increases the sound’s fidelity [ 16 ].…”
Implantable middle ear hearing devices (IMEHDs) have been developed as a new technology to overcome the limitations of conventional hearing aids. The piezoelectric cantilever transducers currently used in the IMEHDs have the advantages of low power consumption and ease of fabrication, but generate less high-frequency output. To address this problem, we proposed and designed a new piezoelectric transducer based on a piezoelectric stack for the IMEHD. This new transducer, attached to the incus body with a coupling rod, stimulates the ossicular chain in response to the expansion-and-contraction of its piezoelectric stack. To test its feasibility for hearing loss compensation, a bench testing of the transducer prototype and a temporal bone experiment were conducted, respectively. Bench testing results showed that the new transducer did have a broad frequency bandwidth. Besides, the transducer was found to have a low total harmonic distortion (<0.75%) in all frequencies, and small release time (1 ms). The temporal bone experiment further proved that the transducer has the capability to produce sufficient vibrations to compensate for severe sensorineural hearing loss, especially at high frequencies. This property benefits the treatment of the most common sloping high-frequency sensorineural hearing loss. To produce a 100 dB SPL equivalent sound pressure at 1 kHz, its power consumption is 0.49 mW, which is low enough for the transducer to be utilized in the IMEHD.
“…Various different ways of maximising microphone performance for piezoelectric devices have been trialled. By placing a piezoelectric sheet in the gap between a disarticulated incudostapedial joint on a temporal bone model a sensitivity of about -60 dB re 1 V / Pa for sound between 20-120 dB SPL was achieved (Koch, Esinger, Bornitz, & Zahnert, 2014). In a previous temporal bone model, however, it was difficult to avoid the sheet touching the middle ear which led to significantly reduced sensitivity.…”
Totally implantable cochlear implants may be able to address many of the problems cochlear implant users have around cosmetic appearances, discomfort, and restriction of activities. The major technological challenges that need to be solved to develop a totally implantable device relate to implanted microphone performance. Previous attempts at implanting microphones for cochlear implants have not performed as well as conventional cochlear implant microphones, and in addition have struggled with extraneous body or surface contact noise. Microphones can be implanted under the skin or act as sensors in the middle ear; however, evidence from middle ear implants suggest body and contact noise can be overcome by converting ossicular chain movements into digital signals. This article reviews implantable microphone systems and discusses the technology behind them.
“…The total size of the oval-shaped transducer is , and its total mass is . A FE model of the device was developed, and a prototype was tested in TBs, having its response measured with a low-noise preamplifier (SR560), and in a set-up simulating the human ME with synthetic materials [ 24 ]. Fig.…”
Section: Description Of Implantable Sensorsmentioning
confidence: 99%
“…The performance of most of the implantable sensors has been analyzed by means of different techniques, including lumped parameter models [ 23 ], finite element (FE) models [ 19 ], or experimentally through tests with prototypes in laboratory set-ups [ 24 ] or directly in animal or human temporal bones (TBs) [ 16 , 20 ]. Nevertheless, for the sensor designs that can be found in TIHAs currently commercialized ( Carina and Esteem ) technical information is quite scarce, and the literature related to these commercial devices [ 25 , 26 ] have focused mainly on patient satisfaction and clinical evaluation.…”
Most commercially available cochlear implants and hearing aids use microphones as sensors for capturing the external sound field. These microphones are in general located in an external element, which is also responsible for processing the sound signal. However, the presence of the external element is the cause of several problems such as discomfort, impossibility of being used during physical activities and sleeping, and social stigma. These limitations have driven studies with the goal of developing totally implantable hearing devices, and the design of an implantable sensor has been one of the main challenges to be overcome. Different designs of implantable sensors can be found in the literature and in some commercial implantable hearing aids, including different transduction mechanisms (capacitive, piezoelectric, electromagnetic, etc), configurations microphones, accelerometers, force sensor, etc) and locations (subcutaneous or middle ear). In this work, a detailed technical review of such designs is presented and a general classification is proposed. The technical characteristics of each sensors are presented and discussed in view of the main requirements for an implantable sensor for hearing devices, including sensitivity, internal noise, frequency bandwidth and energy consumption. The feasibility of implantation of each sensor is also evaluated and compared.
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