scholarly journals Numerical Study and Optimization of a Novel Piezoelectric Transducer for a Round-Window Stimulating Type Middle-Ear Implant

Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 40 ◽  
Author(s):  
Houguang Liu ◽  
Hehe Wang ◽  
Zhushi Rao ◽  
Jianhua Yang ◽  
Shanguo Yang
Keyword(s):  
Middle Ear ◽  
Piezoelectric Transducer ◽  
Numerical Study ◽  
Round Window ◽  
Low Frequency ◽  
Element Model ◽  
Design Parameters ◽  
Middle Ear Implant ◽  
Middle Ear Implants ◽  
Human Ear

Round window (RW) stimulation is a new application of middle ear implants for treating hearing loss, especially for those with middle ear disease. However, most reports on it are based on the use of the floating mass transducer (FMT), which was not originally designed for round window stimulation. The mismatch of the FMT’s diameter and the round window membrane’s diameter and the uncontrollable preload of the transducer, leads to a high variability in its clinical outcomes. Accordingly, a new piezoelectric transducer for the round-window-stimulating-type middle ear implant is proposed in this paper. The transducer consists of a piezoelectric stack, a flextensional amplifier, a coupling rod, a salver, a plate, a titanium housing and a supporting spring. Based on a constructed coupling finite element model of the human ear and the transducer, the influences of the transducer design parameters on its performance were analyzed. The optimal structure of the supporting spring, which determines the transducer’s resonance frequency, was ascertained. The results demonstrate that our designed transducer generates better output than the FMT, especially at low frequency. Besides this, the power consumption of the transducer was significantly decreased compared with a recently reported RW-stimulating piezoelectric transducer.

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

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 946
Author(s):  
Dong Ho Shin
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Middle Ear ◽  
Piezoelectric Transducer ◽  
Round Window ◽  
Piezoelectric Element ◽  
Sensorineural Hearing ◽  
Flat Band ◽  
Middle Ear Implants ◽  
Output Characteristics

This report describes the design of a new piezoelectric transducer for round window (RW)-driven middle ear implants. The transducer consists of a piezoelectric element, gold-coated copper bellows, silicone elastomer (polydimethylsiloxane, PDMS), metal cylinder (tungsten), and titanium housing. The piezoelectric element is fixed to the titanium housing and mechanical resonance is generated by the interaction of the bellows, PDMS, and tungsten cylinder. The dimensions of PDMS and the tungsten cylinder with output characteristics suitable for compensation of sensorineural hearing loss were derived by mechanical vibrational analysis (equivalent mechanical model and finite element analysis (FEA)). Based on the results of FEA, the RW piezoelectric transducer was implemented, and bench tests were performed under no-load conditions to confirm the output characteristics. The transducer generates an average displacement of 219.6 nm in the flat band (0.1–1 kHz); the resonance frequency is 2.3 kHz. To evaluate the output characteristics, the response was compared to that of an earlier transducer. When driven by the same voltage (6 Vp), the flat band displacement averaged 30 nm larger than that of the other transducer, and no anti-resonance was noted. Therefore, we expect that the new transducer can serve as an output device for hearing aids, and that it will improve speech recognition and treat high-frequency sensorineural hearing loss more effectively.

Influence of ossicular chain malformation on the performance of round-window stimulation: A finite element approach

2019 ◽  
Vol 233 (5) ◽  
pp. 584-594 ◽  
Author(s):  
Houguang Liu ◽  
Hu Zhang ◽  
Jianhua Yang ◽  
Xinsheng Huang ◽  
Wen Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Basilar Membrane ◽  
Round Window ◽  
Low Frequency ◽  
Element Model ◽  
Ossicular Chain ◽  
Asymmetric Structure ◽  
Low Frequencies ◽  
Stapes Fixation

As a novel application of implantable middle ear hearing device, round-window stimulation is widely used to treat hearing loss with middle ear disease, such as ossicular chain malformation. To evaluate the influence of ossicular chain malformations on the efficiency of the round-window stimulation, a human ear finite element model, which incorporates cochlear asymmetric structure, was constructed. Five groups of comparison with experimental data confirmed the model’s validity. Based on this model, we investigated the influence of three categories of ossicular chain malformations, that is, incudostapedial disconnection, incus and malleus fixation, and fixation of the stapes. These malformations’ effects were evaluated by comparing the equivalent sound pressures derived from the basilar membrane displacement. Results show that the studied ossicular chain malformations mainly affected the round-window simulation’s performance at low frequencies. In contrast to the fixation of the ossicles, which mainly deteriorates round-window simulation’s low-frequency performance, incudostapedial disconnection increases this performance, especially in the absence of incus process and stapes superstructure. Among the studied ossicular chain malformations, the stapes fixation has a much more severe impact on the round-window stimulation’s efficiency. Thus, the influence of the patients’ ossicular chain malformations should be considered in the design of the round-window stimulation’s actuator. The low-frequency output of the round-window simulation’s actuator should be enhanced, especially for treating the patients with stapes fixation.

scholarly journals Evaluation of Round Window Stimulation Performance in Otosclerosis Using Finite Element Modeling

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Shanguo Yang ◽  
Dan Xu ◽  
Xiaole Liu
Keyword(s):  
Finite Element ◽  
Middle Ear ◽  
Bone Growth ◽  
Round Window ◽  
Element Model ◽  
Annular Ligament ◽  
Fe Model ◽  
Sound Stimulation ◽  
Partial Fixation ◽  
Human Ear

Round window (RW) stimulation is a new type of middle ear implant’s application for treating patients with middle ear disease, such as otosclerosis. However, clinical outcomes show a substantial degree of variability. One source of variability is the variation in the material properties of the ear components caused by the disease. To investigate the influence of the otosclerosis on the performance of the RW stimulation, a human ear finite element model including middle ear and cochlea was established based on a set of microcomputerized tomography section images of a human temporal bone. Three characteristic changes of the otosclerosis in the auditory system were simulated in the FE model: stapedial annular ligament stiffness enlargement, stapedial abnormal bone growth, and partial fixation of the malleus. The FE model was verified by comparing the model-predicted results with published experimental measurements. The equivalent sound pressure (ESP) of RW stimulation was calculated via comparing the differential intracochlear pressure produced by the RW stimulation and the normal eardrum sound stimulation. The results show that the increase of stapedial annular ligament and partial fixation of the malleus decreases RW stimulation’s ESP prominently at lower frequencies. In contrast, the stapedial abnormal bone growth deteriorates RW stimulation’s ESP severely at higher frequencies.

scholarly journals The Influence of Piezoelectric Transducer Stimulating Sites on the Performance of Implantable Middle Ear Hearing Devices: A Numerical Analysis

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 782 ◽  
Author(s):  
Liu ◽  
Zhao ◽  
Yang ◽  
Rao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Middle Ear ◽  
Hearing Aids ◽  
Piezoelectric Transducer ◽  
Basilar Membrane ◽  
Round Window ◽  
Element Model ◽  
Round Window Membrane ◽  
Hearing Devices

To overcome the inherent deficiencies of hearing aids, implantable middle ear hearing devices (IMEHDs) have emerged as a new treatment for hearing loss. However, clinical results show that the IMEHD performance varies with its transducer’s stimulating site. To numerically analyze the influence of the piezoelectric transducer’s stimulating sites on its hearing compensation performance, we constructed a human ear finite element model and confirmed its validity. Based on this finite element model, the displacement stimulation, which simulates the piezoelectric transducer’s stimulation, was applied to the umbo, the incus long process, the incus body, the stapes, and the round window membrane, respectively. Then, the stimulating site’s effect of the piezoelectric transducer was analyzed by comparing the corresponding displacements of the basilar membrane. Besides, the stimulating site’s sensitivity to the direction of excitation was also studied. The result of the finite element analysis shows that stimulating the incus body is least efficient for the piezoelectric transducer. Meanwhile, stimulating the round window membrane or the stapes generates a higher basilar membrane displacement than stimulating the eardrum or the incus long process. However, the performance of these two ideal sites’ stimulation is sensitive to the changes in the excitation’s direction. Thus, the round window membrane and the stapes is the ideal stimulating sites for the piezoelectric transducer regarding the driving efficiency. The direction of the excitation should be guaranteed for these ideal sites.

Research on coupling effects of actuator and round window membrane on reverse stimulation of human cochlea

2021 ◽  
pp. 095441192098796
Author(s):  
Lin Xue ◽  
Houguang Liu ◽  
Jianhua Yang ◽  
Songyong Liu ◽  
Yu Zhao ◽  
...  
Keyword(s):  
Middle Ear ◽  
Coupling Effect ◽  
Round Window ◽  
Ossicular Chain ◽  
Round Window Membrane ◽  
Coupling Impedance ◽  
Coupling Condition ◽  
Impedance Model ◽  
Middle Ear Implant ◽  
Human Ear

An active actuator of a middle-ear implant coupled to the round window membrane (RWM), which transmits vibration to the cochlea, has been used to compensate for hearing loss in patients. However, various factors affect the coupling condition between the actuator and the RWM, resulting in coupling leakage. In this study, a coupling impedance model of the human ear and the actuator was used to investigate the effect of inefficient coupling during reverse stimulation. First, the three-port circuit network model of the actuator was coupled with the acoustic impedance model of human ear reverse sound transmission. Meanwhile, the inefficient coupling impedance was estimated. Then, the effect of the actuator’s coupling on reverse stimulation was studied by comparing the reverse pressure transfer function. Furthermore, the inefficient coupling’s influence in the ear with middle-ear disorder was also investigated by simulating two typical forms of middle-ear disorder: otosclerosis and ossicular chain disarticulation. The results show that the change of the inefficient coupling impedance plays a significant role during reverse stimulation. Inefficient coupling of the actuator and the RWM deteriorates the cochlear response of reverse stimulation over the entire frequency range. Additionally, the coupling effect of the actuator does not change the influence tendency of middle-ear disorder on reverse stimulation’s performance, but changes the response amplitude of the reverse stimulation.

The effect of actuator and its coupling conditions on eardrum-stimulated middle ear implants: A numerical analysis

2016 ◽  
Vol 230 (12) ◽  
pp. 1074-1085 ◽  
Author(s):  
Dan Xu ◽  
Houguang Liu ◽  
Lei Zhou ◽  
Gang Cheng ◽  
Jianhua Yang ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Middle Ear ◽  
Element Model ◽  
Design Parameters ◽  
Optimal Position ◽  
Coupling Conditions ◽  
Middle Ear Implants ◽  
Human Middle Ear ◽  
Hearing Compensation

Consisting of the actuator and coupling layer, a finite element model of the human middle ear was used to analyze the effect of the actuator and its coupling conditions on the performance of the eardrum-stimulated middle ear implants. This model which was based on the right ear of a healthy adult was built via microcomputed tomography imaging and the technique of reverse engineering. Based on this finite element model, the linear viscoelasticity of the human middle ear soft tissues and three-layer structure of the eardrum pars tensa which was orthotropic were considered. The validity of the model was verified by comparing the model calculated results with experimental data. After that, the influence of the three main design parameters of the actuator and two aspects of the coupling layer were investigated by the finite element model. The results show that (1) the manubrium tip is the optimal position for the actuator to stimulate; (2) the increased cross-section of the actuator would worsen its hearing compensation performance, especially in the low frequencies; (3) both the patients’ residual hearing and the actuator’s hearing compensation performance at high frequencies will be deteriorated with the increase in the actuator’s mass; and (4) a coupling layer with a small Young’s modulus and an area approximating 80% of the eardrum would reduce the stress of the eardrum effectively.

scholarly journals Comparative study of efficiency and characteristics of FMT and DRT installed in human cadavers for round-window stimulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dong Ho Shin ◽  
Jong Hoon Kim ◽  
Peter Gottlieb ◽  
Yona Vaisbuch ◽  
Sunil Puria ◽  
...  
Keyword(s):  
Middle Ear ◽  
Hearing Aids ◽  
Round Window ◽  
Standard Of Care ◽  
Acoustic Hearing ◽  
Middle Ear Implants ◽  
Human Cadavers ◽  
Limited Frequency ◽  
Output Characteristics ◽  
Temporal Bones

AbstractAcoustic hearing aids generate amplified sound in the ear canal, and they are the standard of care for patients with mild to moderate sensorineural hearing loss. However, because of their limited frequency bandwidth, gain, and feedback, there is substantial room for improvement. Active middle ear implants, which directly vibrate the middle ear and cochlea, are an alternative approach to conventional acoustic hearing aids. They provide an opportunity to improve sound quality and speech understanding with amplification rehabilitation. For floating-mass type and direct-rod type (DRT) middle ear transducers, a differential floating-mass transducer (DFMT) and a tri-coil bellows transducer (TCBT), respectively, were fabricated to measure the output characteristics in four human temporal bones. Both were fabricated to have similar output forces per unit input and were placed in four human temporal bones to measure their output performances. The TCBT resulted in higher output than did the DFMT throughout the audible frequency range, and the output was more prominent at lower frequency ranges. In this study, we showed that DRT was a more effective method for round window stimulation. Because of its frequency characteristics and vibration efficiency, this implantation method can be utilized as a driving solution for middle ear implants.

Round window application of an active middle ear implant (AMEI) system in congenital oval window atresia

2015 ◽  
Vol 136 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Shouqin Zhao ◽  
Shusheng Gong ◽  
Demin Han ◽  
Hua Zhang ◽  
Xiaobo Ma ◽  
...  
Keyword(s):  
Middle Ear ◽  
Round Window ◽  
Oval Window ◽  
Active Middle Ear Implant ◽  
Middle Ear Implant

Acoustic stimulation on the round window for active middle ear implants

2018 ◽  
Vol 97 ◽  
pp. 171-177 ◽  
Author(s):  
Kiwoong Seong ◽  
Kyuyup Lee ◽  
Sunil Puria ◽  
Jin-Ho Cho
Keyword(s):  
Middle Ear ◽  
Round Window ◽  
Acoustic Stimulation ◽  
Middle Ear Implants

Interposed Cartilage as a Precaution against Extrusions of Ceramic Ossicular Replacement Implants

1987 ◽  
Vol 96 (2) ◽  
pp. 207-209 ◽  
Author(s):  
Christoph Zöllner
Keyword(s):  
Middle Ear ◽  
Ossicular Chain ◽  
Oxide Ceramic ◽  
Small Disk ◽  
Middle Ear Implant ◽  
Ossicular Replacement ◽  
Middle Ear Implants ◽  
Aluminum Oxide Ceramic ◽  
Postoperative Observation

Since 1980 we have used middle ear implants of aluminum oxide ceramic in some reconstructions of the ossicular chain. We had opportunities to examine 108 ears (91 patients); the longest period of postoperative observation was 4 years. Follow-up examinations showed that the rates of extrusion and liability to extrusion can be reduced by interposing a small disk of autologous cartilage and perichondrium. Moreover, interposing cartilage tends to improve audiometric results. On the basis of our study, we strongly recommend the interposition of a disk of autologous cartilage and perichondrium between the middle ear implant and eardrum when an Al2O3 implant is used.

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