Design of an implantable seismic sensor placed on the ossicular chain

Sachse, M.; Hortschitz, Wilfried; Stifter, Matthias; Steiner, Harald; Sauter, Thilo

doi:10.1016/j.medengphy.2013.03.012

Cited by 11 publications

(22 citation statements)

References 13 publications

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“…Most current hearing devices use microphones that are sensitive to sound pressure levels ranging from around 30 to 140 dB SPL [ 35 ], which matches this dynamic range. Considering that the sensitivity of human hearing is a function of frequency, the input range has also been defined from 30 to 100 phon [ 23 ], what equals 30 and 100 dB SPL at 1 kHz respectively. In general, the lower limit of the sensor’s dynamic range is defined by the sensor’s internal noise, while the superior limit marks the beginning of significant distortions/non-linearities of the sensor.…”

Section: Hearing Devices General Sensor Requirements and Sensor Perfomentioning

confidence: 99%

“…For example, sensitivity of common electret condenser microphones (ECM), with a 2.5 mm diameter membrane, used in conventional hearing aids, varies from 20 to 30 dB ref 1 mV/Pa [ 6 , 35 , 38 ]. Whereas the sensitivity of a piezoresistive MEMS accelerometer has been reported as mere 6 dB [ 16 , 39 ], and for capacitive sensors varied from − 9 to 30 dB [ 20 , 23 , 40 ]. Similarly, ECM’s EIN may be as low as 20 dB SPL at 1 kHz [ 7 ], whereas a capacitive accelerometer implanted in the middle ear may detect only SPL above 35 dB at the same frequency [ 21 ], and yet a piezoresistive accelerometer’s EIN may be 60 dB SPL at 1 kHz [ 16 ].…”

Section: Hearing Devices General Sensor Requirements and Sensor Perfomentioning

confidence: 99%

“…In the case of a sensor coupled to the ME, its size must allow for its handling and implantation in the limited space of the ME cavity. Sachse et al [ 23 ] suggests a maximum dimension of 2 mm for middle ear sensors with a single point of attachment as in the accelerometer configuration. In the case of sensors which also considers a fixation point to ME cavity walls, such as the Esteem device [ 15 ], the limitations to the sensor size are less restrictive and are likely based on the available space within the ME cavity.…”

Section: Hearing Devices General Sensor Requirements and Sensor Perfomentioning

confidence: 99%

“…A more recent work on a capacitive MEMS accelerometer (F2) was published by Sachse et al in 2013 [ 23 ]. A lumped parameter model of the sensor was developed in order to consider mechanical and electrical noise, and to calculate the resonance frequency.…”

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.…”

Section: Introductionmentioning

confidence: 99%

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A technical review and evaluation of implantable sensors for hearing devices

et al. 2018

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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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Section: Hearing Devices General Sensor Requirements and Sensor Perfomentioning

confidence: 99%

Section: Hearing Devices General Sensor Requirements and Sensor Perfomentioning

confidence: 99%

Section: Hearing Devices General Sensor Requirements and Sensor Perfomentioning

confidence: 99%

Section: Description Of Implantable Sensorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A technical review and evaluation of implantable sensors for hearing devices

et al. 2018

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Creation of an incus recess for a middle-ear microphone using a drill or laser ablation: a comparison of equivalent noise level and middle ear transfer function

Morse

Mitchell‐Innes

Prokopiou

et al. 2022

Eur Arch Otorhinolaryngol

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Purpose Studies have assessed the trauma and change in hearing function from the use of otological drills on the ossicular chain, but not the effects of partial laser ablation of the incus. A study of the effectiveness of a novel middle-ear microphone for a cochlear implant, which required an incus recess for the microphone balltip, provided an opportunity to compare methods and inform a feasibility study of the microphone with patients. Methods We used laser Doppler vibrometry with an insert earphone and probe microphone in 23 ears from 14 fresh-frozen cadavers to measure the equivalent noise level at the tympanic membrane that would have led to the same stapes velocity as the creation of the incus recess. Results Drilling on the incus with a diamond burr created peak noise levels equivalent to 125.1–155.0 dB SPL at the tympanic membrane, whilst using the laser generated equivalent noise levels barely above the baseline level. The change in middle ear transfer function following drilling showed greater variability at high frequencies, but the change was not statistically significant in the three frequency bands tested. Conclusions Whilst drilling resulted in substantially higher equivalent noise, we considered that the recess created by laser ablation was more likely to lead to movement of the microphone balltip, and therefore decrease performance or result in malfunction over time. For patients with greatly reduced residual hearing, the greater consistency from drilling the incus recess may outweigh the potential benefits of hearing preservation with laser ablation.

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On the design of a MEMS piezoelectric accelerometer coupled to the middle ear as an implantable sensor for hearing devices

Gesing

Alves

Paul

et al. 2018

Sci Rep

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The presence of external elements is a major limitation of current hearing aids and cochlear implants, as they lead to discomfort and inconvenience. Totally implantable hearing devices have been proposed as a solution to mitigate these constraints, which has led to challenges in designing implantable sensors. This work presents a feasibility analysis of a MEMS piezoelectric accelerometer coupled to the ossicular chain as an alternative sensor. The main requirements of the sensor include small size, low internal noise, low power consumption, and large bandwidth. Different designs of MEMS piezoelectric accelerometers were modeled using Finite Element (FE) method, as well as optimized for high net charge sensitivity. The best design, a 2 × 2 mm2 annular configuration with a 500 nm thick Aluminum Nitride (AlN) layer was selected for fabrication. The prototype was characterized, and its charge sensitivity and spectral acceleration noise were found to be with good agreement to the FE model predictions. Weak coupling between a middle ear FE model and the prototype was considered, resulting in equivalent input noise (EIN) lower than 60 dB sound pressure level between 600 Hz and 10 kHz. These results are an encouraging proof of concept for the development of MEMS piezoelectric accelerometers as implantable sensors for hearing devices.

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Design of an implantable seismic sensor placed on the ossicular chain

Cited by 11 publications

References 13 publications

A technical review and evaluation of implantable sensors for hearing devices

A technical review and evaluation of implantable sensors for hearing devices

Creation of an incus recess for a middle-ear microphone using a drill or laser ablation: a comparison of equivalent noise level and middle ear transfer function

On the design of a MEMS piezoelectric accelerometer coupled to the middle ear as an implantable sensor for hearing devices

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