Human temporal bones versus mechanical model to evaluate three middle ear transducers (original) (raw)
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Anatomical study of the human middle ear for the design of implantable hearing aids
Auris Nasus Larynx, 2006
Objective: To generate anatomical data on the human middle ear and adjacent structures to serve as a base for the development and optimization of new implantable hearing aid transducers. Implantable middle ear hearing aid transducers, i.e. the equivalent to the loudspeaker in conventional hearing aids, should ideally fit into the majority of adult middle ears and should utilize the limited space optimally to achieve sufficiently high maximal output levels. For several designs, more anatomical data are needed. Methods: Twenty temporal bones of 10 formalin-fixed adult human heads were scanned by a computed tomography system (CT) using a slide thickness of 0.63 mm. Twelve landmarks were defined and 24 different distances were calculated for each temporal bone. Results: A statistical description of 24 distances in the adult human middle ear which may limit or influence the design of middle ear transducers is presented. Significant inter-individual differences but no significant differences for gender, side, age or degree of pneumatization of the mastoid were found. Distances, which were not analyzed for the first time in this study, were found to be in good agreement with the results of earlier studies. Conclusion: A data set describing the adult human middle ear anatomy quantitatively from the point of view of designers of new implantable hearing aid transducers has been generated. In principle, the method employed in this study using standard CT scans could also be used preoperatively to rule out exclusion criteria. #
Otology & Neurotology, 2006
Hypothesis: To assess the feasibility of a new, active middle ear device in temporal bones (TB). Background: This device is designed for patients with mixed hearing loss subsequent to chronic middle ear infection, surgery, or trauma. This Bell-Vibroplasty is built from a VIBRANT MED-EL Vibrant Soundbridge and a Kurz Bell titanium partial ossicular replacement prosthesis. Methods: In three fresh TBs, healthy and reconstructed middle ears were analyzed by means of laser Doppler interferometry. The sound transmission properties of a partial ossicular replacement prosthesis and a passive and an active Bell-Vibroplasty were compared with healthy middle ear function. Results: The measurements provided reliable results with small standard deviations and good signal-to-noise ratios.
Testing a Method for Quantifying the Output of Implantable Middle Ear Hearing Devices
Audiology and Neurotology, 2007
This report describes tests of a standard practice for quantifying the performance of implantable middle ear hearing devices (also known as implantable hearing aids). The standard and these tests were initiated by the Food and Drug Administration of the United States Government. The tests involved measurements on two hearing devices, one commercially available and the other home built, that were implanted into ears removed from human cadavers. The tests were conducted to investigate the utility of the practice and its outcome measures: the equivalent ear canal sound pressure transfer function that relates electrically driven middle ear velocities to the equivalent sound pressure needed to produce those velocities, and the maximum effective ear canal sound pressure. The practice calls for measurements in cadaveric ears in order to account for the varied anatomy and function of different human middle ears.
The Floating Mass Transducer for External Auditory Canal and Middle Ear Malformations
Otology & Neurotology, 2011
The indications for the Med-El Vibrant Soundbridge, currently limited to patients with sensorineural hearing loss and normal middle ear function, have been extended to include patients with conductive or mixed hearing loss because of severe acquired or congenital ossicular chain defects. Patients with congenital aural atresia have combined malformations of the external auditory canal and the middle ear, often accompanied by severe mixed hearing impairment. Long-term results of traditional surgical techniques for treatment of congenital aural atresia show a persistent air-bone gap in most patients, suggesting that new and better techniques for hearing rehabilitation in these patients would be of value. This study demonstrates that placement of the floating mass transducer of the Med-El Vibrant Soundbridge on the round window (RW) allows optimal amplification and enables the restoration of good hearing in these patients. Study Design: Retrospective case review. Setting: Tertiary referral center. Patients: The study population comprised 12 patientsV5 adults and 7 childrenVwith severe external auditory canal and middle ear malformations. The patients were either judged not to be candidates for air conduction hearing aids or declined bone conduction and Bone-Anchored Hearing Aids. Intervention: RW implantation. Main Outcome Measures: Pure-tone threshold and speech understanding. Results: Significant improvements were observed in pure-tone threshold and speech understanding immediately after surgery and at follow-up intervals ranging from 12 to 48 months. No complications or instances of device extrusion were observed in these patients. Conclusion: The results suggest that RW implantation offers a viable and improved treatment option for patients with severe mixed hearing loss and congenital malformation of the outer and middle ear.
Middle Ear Transducer: Long Term Stability of the Latest Generation T2
BioMed Research International
Objectives/Hypothesis. Comparing long term stability of the Middle Ear Transducers (MET) of the 1st generation T1 (Otologics LLC) with the current generation T2 (Cochlear Ltd.) in all our clinical cases with standard incus coupling. Study Design. Retrospective chart review. Methods. 52 ears implanted with a MET device between 2008 and 2016 were analyzed retrospectively. All patients suffered from sensorineural hearing loss and the actuator was coupled to the body of the incus (standard coupling). 23 ears were implanted with the transducer T1 (Otologics LLC) between 2008 and 2011 and 29 ears were implanted with the current transducer T2 since 2011 (Otologics LLC/Cochlear Ltd.). Latest available in situ and bone conduction (BC) thresholds were exploited for a follow-up period of up to 7 years after first fitting. Long term stability of coupling and actuator performance was evaluated by tracking differences between in situ and BC thresholds. Results. In the T1 group, 9 out of 23 implan...
A New Implantable Middle Ear Hearing Device for Mixed Hearing Loss
Otology & Neurotology, 2006
Hypothesis: To assess the feasibility of a new, active middle ear device in temporal bones (TB). Background: This device is designed for patients with mixed hearing loss subsequent to chronic middle ear infection, surgery, or trauma. This Bell-Vibroplasty is built from a VIBRANT MED-EL Vibrant Soundbridge and a Kurz Bell titanium partial ossicular replacement prosthesis. Methods: In three fresh TBs, healthy and reconstructed middle ears were analyzed by means of laser Doppler interferometry. The sound transmission properties of a partial ossicular replacement prosthesis and a passive and an active Bell-Vibroplasty were compared with healthy middle ear function. Results: The measurements provided reliable results with small standard deviations and good signal-to-noise ratios.
Bio-medical materials and engineering, 2014
Since the 1980's, various types of implantable hearing aids using unique means for delivering acoustic power to the inner ear have been developed. Recently, implantable hearing aids that stimulate the round window by the middle ear transducer have received great attention because it reduces loading effect at the ossicular chain. In this study, we have implemented a direct install 3-pole type EM transducer in round window niche for implantable middle ear hearing aid. The 3-pole type EM transducer consists of two permanent magnets and three coils and exhibit structural features that minimize leakage flux, thereby permitting high efficiency and low magnetic field interference. The stapes velocity was measured using a laser Doppler vibrometer in response to the round window stimulation from the transducer. To verify the usefulness of the 3-pole type EM transducer, we compared the stapes vibration characteristics produced by the transducer and those from a sound source. The magnitude...
Auris Nasus Larynx, 2009
To demonstrate the safety and efficacy of the Otologics Carina Middle Ear Transducer for treatment of mixed hearing loss through a case report. A Carina fully implantable device with the MET transducer for conductive applications was implanted in a 48-year-old woman suffering from right mixed hearing loss (mean PTA loss: 80 dB). A facial recess approach was used to access the middle ear. Sclerotic tissue obliterated the stapes footplate so the approach selected was to place the transducer directly on the round window. The mounting bracket was placed on the mastoid and the prosthesis was advanced toward the round window until the Otologics surgical software indicated contact. Effective stimulation of the cochlea was confirmed intraoperatively by ABR monitoring. Postoperative unaided PTA thresholds were unchanged after surgery. When the implant was activated, the mean PTA functional gain was 39 dB. The capability of the Carina MET Ossicular stimulator to provide appropriate gain relative to the degree of hearing loss indicates that the device offers a viable treatment option for mixed hearing loss. However, these promising initial results establish the need for future work on two fronts: (1) further studies are needed including a greater number of patients to confirm these preliminary results; (2) a long term follow-up must be carried out to detect any possible cochlear adverse effects on the cochlea, in particular on the basilar membrane.