Analysis of design parameters of round-window stimulating type electromagnetic transducer by a nonlinear lumped parameter model of implanted human ear

<abstract> <p>Round-window stimulating transducer is a new solution to treat mixed hearing loss. To uncover the factors affecting the round-window stimulation's performance, we investigated the influence of four main design parameters of round-window stimulating type electromagnetic transducer. Firstly, we constructed a human ear nonlinear lumped parameter model and confirmed its validity by comparing the stapes responses predicted by the model with the experimental data. Following this, an electromagnetic transducer's mechanical model, which simulates the floating mass transducer, was built and coupled to the human ear model; thereby, we established a nonlinear lumped parameter model of implanted human ear under round-window stimulation and verified its reliability. Finally, based on this model, the influences of the four main design parameters, i.e., the excitation voltage, the electromechanical coupling coefficient, the support stiffness, and the preload force, were analyzed. The results show that the change of excitation voltage does not alter the system's natural frequency. Chaotic motion occurs when the electromechanical coupling coefficient is small. Meanwhile, the stapes displacement appears to increase firstly and then decrease with the increase of the electromechanical coupling coefficient. The increase of the support stiffness enlarges the resonance frequency of the stapes displacement and reduces the stapes displacement near the resonance frequency, deteriorating the transducer's hearing compensation at low frequency. The preload force can improve the transducer's hearing compensation performance in mid-high frequency region.</p> </abstract>

Management of Residual Hearing with Cartilage Conduction Hearing Aid after Lateral Temporal Bone Resection: Our Institutional Experience

Background: There is no guideline for hearing compensation after temporal bone resection. This study aimed to retrospectively analyze surgical cases with reconstruction for hearing preservation after temporal bone malignancy resection and propose a new alternative to compensate for hearing loss. Methods: We retrospectively reviewed the medical records of 30 patients who underwent lateral temporal bone surgery for temporal bone malignancy at our institution and examined their hearing abilities after surgery. Result: The hearing outcomes of patients with an external auditory meatus reconstruction varied widely. The mean postoperative air–bone gap at 0.5, 1, 2, and 4 kHz ranged from 22.5 dB to 71.25 dB. On the other hand, the average difference between the aided sound field thresholds with cartilage conduction hearing aid and bone conduction thresholds at 0.5, 1, 2, and 4 kHz ranged from −3.75 to 41.25. More closely located auricular cartilage and temporal bone resulted in smaller differences between the aided sound field and bone conduction thresholds. Conclusions: There is still room for improvement of surgical techniques for reconstruction of the auditory meatus to preserve hearing after temporal bone resection. The cartilage conduction hearing aid may provide non-invasive postoperative hearing compensation after lateral temporal bone resection.

Reading Comprehension

Much has been written about the components that contribute to reading success, such as vocabulary knowledge, phonological awareness, orthographic knowledge, syntax, and inference and integration skills. But much less is known about how these skills contribute to reading comprehension in learners who are deaf or hard of hearing (DHH). With the spread of universal hearing screening of newborns, and the new generation of technologies in hearing compensation (i.e., digital hearing aids and cochlear implants [CIs]), the prospects for children with hearing loss with regard to successful reading comprehension should be substantially improved. However, despite these developments, reading and writing often remain a challenge for DHH children. The chapter begins with a summary of the skills required for successful comprehension in typically hearing readers, and then considers what we know about reading comprehension in DHH children. It concludes with a discussion of where researchers should be focusing their future investigations in order to serve educators and learners most effectively.

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

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.

Tool Development for Human Audible Spectrum Compensation

Communication relies on good understanding. Humans relate to each other through visual, audible and tactile communication. It is imperative that the audible communication message reaches the receiver in good conditions, in order to keep a healthy, smooth and understandable speech. There are some disturbances in human speech and communication when hearing damage is present. Nowadays, hearing loss is a frequent injury, caused by noise pollution, daily stress or noisy workplaces. Yet, it can be treated by several ways. This project consists in developing a tool that captures the emitter's voice audible spectrum, filters the noise and other frequencies, and compensates the message, enabling the listener/receiver understanding. The purpose of this research is not aimed to substitute nor compete with hearing aids in the market, which are well-developed, certified and prescribed by Otorhinolaryngology clinicians. The focus of this study is to identify the issues of human hearing loss and to develop an algorithm for hearing compensation by using filtering techniques in a simulated environment applied to a hearing model.

Transducer Type and Design Influence on the Hearing Loss Compensation Behaviour of the Electromagnetic Middle Ear Implant in a Finite Element Analysis

Several types of electromagnetic transducer for the middle ear implants (MEIs) have been developed as an alternative to conventional hearing aids for the rehabilitation of sensorineural hearing loss. Electromagnetic transducer type and design are thought to have a significant influence on their hearing compensation performance. To investigate these effects, a middle ear computational model was constructed based on a complete set of microcomputerized tomography section images of a human ear. Its validity was confirmed by comparing the model predicted motions with published experimental measurements. The result shows that the eardrum driving transducer (EDT) is superior to the floating mass transducer (FMT) in hearing compensation when the transducer mass is small but inferior to the FMT when the mass gets bigger. The incus body driving transducer (IBDT) is the most ineffective type of transducer for hearing compensation. Moreover, the masses of the EDT and the FMT decrease the transducer performance mainly at higher frequencies: the greater the transducer mass, the lower the displacement of the stapes excited by these transducers. On the other hand, the IBDT driving rod stiffness decreases transducer's performance severely at low frequencies and its adverse effect on transducer performance increases with the decrease of the stiffness of the IBDT driving rod.