| 1. |
- Dobrev, Ivo, et al.
(författare)
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Influence of stimulation position on the sensitivity for bone conduction hearing aids without skin penetration
- 2016
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Ingår i: International Journal of Audiology. - : TAYLOR & FRANCIS LTD. - 1499-2027 .- 1708-8186. ; 55:8, s. 439-446
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study explores the influence of stimulation position on bone conduction (BC) hearing sensitivity with a BC transducer attached using a headband. Design:(1) The cochlear promontory motion was measured in cadaver heads using laser Doppler vibrometry while seven different positions around the pinna were stimulated using a bone anchored hearing aid transducer attached using a headband. (2) The BC hearing thresholds were measured in human subjects, with the bone vibrator Radioear B71 attached to the same seven stimulation positions. Study sample: Three cadaver heads and twenty participants. Results: Stimulation on a position superior-anterior to the pinna generated the largest promontory motion and the lowest BC thresholds. Stimulations on the positions superior to the pinna, the mastoid, and posterior-inferior to the pinna showed similar magnitudes of promontory motion and similar levels of BC thresholds. Conclusion: Stimulations on the regions superior to the pinna, the mastoid, and posterior-inferior to the pinna provide stable BC transmission, and are insensitive to small changes of the stimulation position. Therefore it is reliable to use the mastoid to determine BC thresholds in clinical audiometry. However, stimulation on a position superior-anterior to the pinna provides more efficient BC transmission than stimulation on the mastoid.
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| 2. |
- Dobrev, Ivo, et al.
(författare)
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Sound wave propagation on the human skull surface with bone conduction stimulation
- 2017
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Ingår i: Hearing Research. - : ELSEVIER SCIENCE BV. - 0378-5955 .- 1878-5891. ; 355
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Tidskriftsartikel (refereegranskat)abstract
- Background: Bone conduction (BC) is an alternative to air conduction to stimulate the inner ear. In general, the stimulation for BC occurs on a specific location directly on the skull bone or through the skin covering the skull bone. The stimulation propagates to the ipsilateral and contralateral cochlea, mainly via the skull bone and possibly via other skull contents. This study aims to investigate the wave propagation on the surface of the skull bone during BC stimulation at the forehead and at ipsilateral mastoid. Methods: Measurements were performed in five human cadaveric whole heads. The electro-magnetic transducer from a BCHA (bone conducting hearing aid), a Baha (R) Cordelle II transducer in particular, was attached to a percutaneously implanted screw or positioned with a 5-Newton steel headband at the mastoid and forehead. The Baha transducer was driven directly with single tone signals in the frequency range of 0.25-8 kHz, while skull bone vibrations were measured at multiple points on the skull using a scanning laser Doppler vibrometer (SLDV) system and a 3D LDV system. The 3D velocity components, defined by the 3D LDV measurement coordinate system, have been transformed into tangent (in-plane) and normal (out-of-plane) components in a local intrinsic coordinate system at each measurement point, which is based on the cadaver heads shape, estimated by the spatial locations of all measurement points. Results: Rigid-body-like motion was dominant at low frequencies below 1 kHz, and clear transverse traveling waves were observed at high frequencies above 2 kHz for both measurement systems. The surface waves propagation speeds were approximately 450 m/s at 8 kHz, corresponding trans-cranial time interval of 0.4 ms. The 3D velocity measurements confirmed the complex space and frequency dependent response of the cadaver heads indicated by the ID data from the SLDV system. Comparison between the tangent and normal motion components, extracted by transforming the 3D velocity components into a local coordinate system, indicates that the normal component, with spatially varying phase, is dominant above 2 kHz, consistent with local bending vibration modes and traveling surface waves. Conclusion: Both SLDV and 3D LDV data indicate that sound transmission in the skull bone causes rigid body-like motion at low frequencies whereas transverse deformations and travelling waves were observed above 2 kHz, with propagation speeds of approximately of 450 m/s at 8 kHz. (C) 2017 Elsevier B.V. All rights reserved.
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| 3. |
- Maier, Hannes, et al.
(författare)
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Consensus Statement on Bone Conduction Devices and Active Middle Ear Implants in Conductive and Mixed Hearing Loss
- 2022
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Ingår i: Otology and Neurotology. - : Lippincott, Williams & Wilkins. - 1531-7129 .- 1537-4505. ; 43:5, s. 513-529
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, several options are available to treat patients with conductive or mixed hearing loss. Whenever surgical intervention is not possible or contra-indicated, and amplification by a conventional hearing device (e.g., behind-the-ear device) is not feasible, then implantable hearing devices are an indispensable next option. Implantable bone-conduction devices and middle-ear implants have advantages but also limitations concerning complexity/invasiveness of the surgery, medical complications, and effectiveness. To counsel the patient, the clinician should have a good overview of the options with regard to safety and reliability as well as unequivocal technical performance data. The present consensus document is the outcome of an extensive iterative process including ENT specialists, audiologists, health-policy scientists, and representatives/technicians of the main companies in this field. This document should provide a first framework for procedures and technical characterization to enhance effective communication between these stakeholders, improving health care.
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| 4. |
- Prochazka, Lukas, et al.
(författare)
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Novel Fabrication Technology for Clamped Micron-Thick Titanium Diaphragms Used for the Packaging of an Implantable MEMS Acoustic Transducer
- 2022
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Ingår i: Micromachines. - : MDPI. - 2072-666X. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Micro-Electro-Mechanical Systems (MEMS) acoustic transducers are highly sophisticated devices with high sensing performance, small size, and low power consumption. To be applied in an implantable medical device, they require a customized packaging solution with a protecting shell, usually made from titanium (Ti), to fulfill biocompatibility and hermeticity requirements. To allow acoustic sound to be transferred between the surroundings and the hermetically sealed MEMS transducer, a compliant diaphragm element needs to be integrated into the protecting enclosure. In this paper, we present a novel fabrication technology for clamped micron-thick Ti diaphragms that can be applied on arbitrary 3D substrate geometry and hence directly integrated into the packaging structure. Stiffness measurements on various diaphragm samples illustrate that the technology enables a significant reduction of residual stress in the diaphragm developed during its deposition on a polymer sacrificial material.
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| 5. |
- Roosli, Christof, et al.
(författare)
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Intracranial Pressure and Promontory Vibration With Soft Tissue Stimulation in Cadaveric Human Whole Heads
- 2016
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Ingår i: Otology and Neurotology. - : LIPPINCOTT WILLIAMS & WILKINS. - 1531-7129 .- 1537-4505. ; 37:9, s. E384-E390
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Tidskriftsartikel (refereegranskat)abstract
- Hypothesis:Intracranial pressure and skull vibrations are correlated and depend on the stimulation position and frequency.Background:A hearing sensation can be elicited by vibratory stimulation on the skin covered skull, or by stimulation on soft tissue such as the neck. It is not fully understood whether different stimulation sites induce the skull vibrations responsible for the perception or whether other transmission pathways are dominant. The aim of this study was to assess the correlation between intracranial pressure and skull vibration measured on the promontory for stimulation to different sites on the head.Methods:Measurements were performed on four human cadaver heads. A bone conduction hearing aid was held in place with a 5-Newton steel headband at four locations (mastoid, forehead, eye, and neck). While stimulating in the frequency range of 0.3 to 10kHz, acceleration of the cochlear promontory was measured with a Laser Doppler Vibrometer, and intracranial pressure at the center of the head with a hydrophone.Results:Promontory acceleration and intracranial pressure was measurable for all stimulation sites. The ratios were comparable between all stimulation sites for frequencies below 2kHz.Conclusion:These findings indicate that both promontory acceleration and intracranial pressure are involved for stimulation on the sites investigated. The transmission pathway of sound energy is comparable for the four stimulation sites.
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