Restoration of middle-ear input in fluid-filled middle ears by controlled introduction of air or a novel air-filled implant

Ravicz, Michael E.; Rosowski, John J.

doi:10.1016/j.heares.2015.06.012

Cited by 3 publications

(1 citation statement)

References 54 publications

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“…We filled the entire mastoid cavity with fluid in order to achieve the maximum conductive loss observed in those studies, across all frequencies. A similar set of experiments in human cadaveric temporal bones showed that umbo velocities are reduced to the greatest degree at high frequencies (>1 kHz) when the ear is completely filled with fluid (10), and that this reduction may be reduced by re-introduction of air into the middle ear cavity (25). These reports suggest that changes in umbo velocity are directly related to the proportion of the middle ear filled with fluid.…”

Section: Discussionmentioning

confidence: 96%

Intracochlear Pressures in Simulated Otitis Media With Effusion: A Temporal Bone Study

Alhussaini

Hartl²,

Benichoux

et al. 2018

Otology &Amp; Neurotology

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Simulating effusion leads to a frequency-dependent reduction in intracochlear sound pressure levels consistent with audiological presentation and prior reports. Results reveal that intracochlear pressure measurements (PSV and PST) decrease less than expected, and less than the decrease in PDiff. The observed decrease in umbo velocity is greater than in the differential intracochlear pressures, suggesting that umbo velocity overestimates the induced conductive hearing loss. These results suggest that an alternate sound conduction pathway transmits sound to the inner ear during effusion.

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Section: Discussionmentioning

confidence: 96%

Intracochlear Pressures in Simulated Otitis Media With Effusion: A Temporal Bone Study

Alhussaini

Hartl²,

Benichoux

et al. 2018

Otology &Amp; Neurotology

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Modelling the effect of round window stiffness on residual hearing after cochlear implantation

Elliott

Verschuur

2016

Hearing Research

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Preservation of residual hearing after cochlear implantation is now considered an important goal of surgery. However, studies indicate an average post-operative hearing loss of around 20 dB at low frequencies. One factor which may contribute to post-operative hearing loss, but which has received little attention in the literature to date, is the increased stiffness of the round window, due to the physical presence of the cochlear implant, and to its subsequent thickening or to bone growth around it. A finite element model was used to estimate that there is approximately a 100-fold increase in the round window stiffness due to a cochlear implant passing through it. A lumped element model was then developed to study the effects of this change in stiffness on the acoustic response of the cochlea. As the round window stiffness increases, the effects of the cochlear and vestibular aqueducts become more important. An increase of round window stiffness by a factor of 10 is predicted to have little effect on residual hearing, but increasing this stiffness by a factor of 100 reduces the acoustic sensitivity of the cochlea by about 20 dB, below 1 kHz, in reasonable agreement with the observed loss in residual hearing after implantation. It is also shown that the effect of this stiffening could be reduced by incorporating a small gas bubble within the cochlear implant.

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Effects of Tympanic Membrane Electrodes on Sound Transmission From the Ear Canal to the Middle and Inner Ears

Hannon,

Lewis

2024

Ear &Amp; Hearing

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Objectives: The first objective of the study was to compare approaches to eardrum electrode insertion as they relate to the likelihood of introducing an acoustic leak between the ear canal and eartip. A common method for placing a tympanic membrane electrode involves securing the electrode in the canal by routing it underneath a foam eartip. This method is hypothesized to result in a slit leak between the canal and foam tip due to the added bulk of the electrode wire. An alternative approach involves creating a bore in the wall of the foam tip that the electrode can be threaded through. This method is hypothesized to reduce the likelihood of a slit leak before the electrode wire is integrated into the foam tip. The second objective of the study was to investigate how sound transmission in the ear is affected by placing an electrode on the eardrum. It was hypothesized that an electrode in contact with the eardrum increases the eardrum’s mass, with the potential to reduce sound transmission at high frequencies. Design: Wideband acoustic immittance and distortion product otoacoustic emissions (DPOAEs) were measured in eight human ears. Measurements were completed for five different conditions: (1) baseline with no electrode in the canal, (2) dry electrode in the canal but not touching the eardrum, secured underneath the eartip, (3) dry electrode in the canal not touching the eardrum, secured through a bore in the eartip (subsequent conditions were completed using this method), (4) hydrated electrode in the canal but not touching the eardrum, and (5) hydrated electrode touching the eardrum. To create the bore, a technique was developed in which a needle is heated and pushed through the foam eartip. The electrode is then thread through the bore and advanced slowly by hand until contacting the eardrum. Analysis included comparing absorbance, admittance phase angle, and DPOAE levels between measurement conditions. Results: Comparison of the absorbance and admittance phase angle measurements between the electrode placement methods revealed significantly higher absorbance and lower admittance phase angle from 0.125 to 1 kHz when the electrode is routed under the eartip. Absorbance and admittance phase angle were minimally affected when the electrode was inserted through a bore in the eartip. DPOAE levels across the different conditions showed changes approximating test-retest variability. Upon contacting the eardrum, the absorbance tended to decrease below 1 kHz and increase above 1 kHz. However, changes were within the range of test-retest variability. There was evidence of reduced levels below 1 kHz and increased levels above 1 kHz upon the electrode contacting the eardrum. However, differences between conditions approximated test-retest variability. Conclusions: Routing the eardrum electrode through the foam tip reduces the likelihood of incurring an acoustic leak between the canal walls and eartip, compared with routing the electrode under the eartip. Changes in absorbance and DPOAE levels resulting from electrode contact with the eardrum implicate potential stiffening of eardrum; however, the magnitude of changes suggests minimal effect of the electrode on sound transmission in the ear.

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Restoration of middle-ear input in fluid-filled middle ears by controlled introduction of air or a novel air-filled implant

Cited by 3 publications

References 54 publications

Intracochlear Pressures in Simulated Otitis Media With Effusion: A Temporal Bone Study

Intracochlear Pressures in Simulated Otitis Media With Effusion: A Temporal Bone Study

Modelling the effect of round window stiffness on residual hearing after cochlear implantation

Effects of Tympanic Membrane Electrodes on Sound Transmission From the Ear Canal to the Middle and Inner Ears

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