Intracranial Pressure and Promontory Vibration With Soft Tissue Stimulation in Cadaveric Human Whole Heads

Röösli, Christof; Dobrev, Ivo; Sim, Jae Hoon; Gerig, Rahel; Pfiffner, Flurin; Stenfelt, Stefan; Huber, Alexander

doi:10.1097/mao.0000000000001121

Cited by 20 publications

(20 citation statements)

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“…Even if BC sound is transmitted in the bone of the skull, the outer and middle ear may contribute to the final auditory perception (Stenfelt et al 2002;Stenfelt et al 2003). However, the main distinction between AC and BC sound is that BC sound has a dominant sound power transmission through the skull bone (Eeg-Olofsson et al 2008;Stenfelt and Goode 2005a;Eeg-Olofsson et al 2013), the soft tissues, or the interior of the skull (Sim et al 2016;Roosli et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Chang

Kim

Stenfelt

2018

Biomech Model Mechanobiol

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Bone conduction (BC) sound is the perception of sound transmitted in the skull bones and surrounding tissues. To better understand BC sound perception and the interaction with surrounding tissues, the power transmission of BC sound is investigated in a three-dimensional finite-element model of a whole human head. BC sound transmission was simulated in the FE model and the power dissipation as well as the power flow following a mechanical vibration at the mastoid process behind the ear was analyzed. The results of the simulations show that the skull bone (comprises the cortical bone and diploë) has the highest BC power flow and thereby provide most power transmission for BC sound. The soft tissues was the second most important media for BC sound power transmission, while the least BC power transmission is through the brain and the surrounding cerebrospinal fluid (CSF) inside the cranial vault. The vibrations transmitted in the skull are mainly concentrated at the skull base when the stimulation is at the mastoid. Other vibration transmission pathways of importance are located at the occipital bone at the posterior side of the head while the transmission of sound power through the face, forehead and vertex is minor. The power flow between the skull bone and skull interior indicate that some BC power is transmitted to and from the skull interior but the transmission of sound power through the brain seem to be minimal and only local to the brain-bone interface.

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Section: Introductionmentioning

confidence: 99%

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Chang

Kim

Stenfelt

2018

Biomech Model Mechanobiol

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“…However, in a study by (Roosli et al, 2015) where the intracranial sound pressure and cochlear promontory vibration were measured in cadaver heads, there were little difference in the ratio between promontory motion and intracranial pressure for different stimulation positions as the mastoid and the eye. Consequently, that study indicates that the BC responses at eye stimulation is equally likely to be due to bony vibrations as the stimulation directly on the mastoid bone.…”

Section: Relative Importance Of the Five Componentsmentioning

confidence: 99%

“…Recently, intracranial sound pressure measurements was presented by Roosli et al (2015). In that study, the intracranial sound pressure during BC stimulation was measured at the center of four skulls with a hydrophone.…”

Section: Contribution From the Skull Interiormentioning

confidence: 99%

“…2. The data in Roosli et al (2015) are only presented for frequencies above 300 Hz so the computation of this contributor is only done for frequencies between 0.3 and 10 kHz.…”

Section: Contribution From the Skull Interiormentioning

confidence: 99%

“…were measured with laser Doppler vibrometers or accelerometers in a specific direction but some measurements were of sound pressure (Aibara et al, 2001;Roosli et al, 2015;Stenfelt et al, 2003b) that has no associated directional sensitivity. All these differences may affect the estimated importance of the contributors.…”

Section: Relative Importance Of the Five Componentsmentioning

confidence: 99%

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Model predictions for bone conduction perception in the human

Stenfelt

2016

Hearing Research

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Five different pathways are often suggested as important for bone conducted (BC) sound: (1) sound pressure in the ear canal, (2) inertia of the middle ear ossicles, (3) inertia of the inner ear fluid, (4) compression of the inner ear space, and (5) pressure transmission from the skull interior. The relative importance of these pathways was investigated with an acousticimpedance model of the inner ear. The model incorporated data of BC generated ear canal sound pressure, middle ear ossicle motion, cochlear promontory vibration, and intracranial sound pressure. With BC stimulation at the mastoid, the inner ear inertia dominated the excitation of the cochlea but inner ear compression and middle ear inertia were within 10 dB for almost the entire frequency range of 0.1 to 10 kHz. Ear canal sound pressure gave little contribution at the low and high frequencies, but was around 15 dB below the total contribution at the mid frequencies. Intracranial sound pressure gave responses similar to the others at low frequencies, but decreased with frequency to a level of 55 dB below the total contribution at 10 kHz. When the BC inner ear model was evaluated against AC stimulation at threshold levels, the results were close up to approximately 4 kHz but deviated significantly at higher frequencies. 3 Highlights• A model for BC simulates the contribution from 5 components.• The inner ear compression and inertia and middle ear inertia are most important.• The contribution from intracranial sound pressure is insignificant at higher frequencies.• The model provides similar BM excitation for AC and BC threshold stimulation up to 4 kHz. KeywordsBone conduction, inner ear model, fluid inertia, inner ear compression, middle ear inertia

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Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones During Bone Conduction Stimulation

Stieger

Guan

Farahmand

et al. 2018

JARO

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Bone conduction (BC) is heavily relied upon in the diagnosis and treatment of hearing loss, but is poorly understood. For example, the relative importance and frequency dependence of various identified BC sound transmission mechanisms that contribute to activate the cochlear partition remain unknown. Recently, we have developed techniques in fresh human cadaveric specimens to directly measure scalae pressures with micro-fiberoptic sensors, enabling us to monitor the input pressure drive across the cochlear partition that triggers the cochlear traveling wave during air conduction (AC) and round-window stimulation. However, BC stimulation poses challenges that can result in inaccurate intracochlear pressure measurements. Therefore, we have developed a new technique described here that allows for precise measurements during BC. Using this new technique, we found that BC stimulation resulted in pressure in scala vestibuli that was significantly higher in magnitude than in scala tympani for most frequencies, such that the differential pressure across the partition-the input pressure drive-was similar to scala vestibuli pressure. BC (stimulated by a Bone Anchored Hearing Aid [Baha]) showed that the mechanisms of sound transmission in BC differ from AC, and also showed the limitations of the Baha bandwidth. Certain kinematic measurements were generally proportional to the cochlear pressure input drive: for AC, velocity of the stapes, and for BC, low-frequency acceleration and high-frequency velocity of the cochlear promontory. Therefore, our data show that to estimate cochlear input drive in normal ears during AC, stapes velocity is a good measure. During BC, cochlear input drive can be estimated for low frequencies by promontory acceleration (though variable across ears), and for high frequencies by promontory velocity.

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Intracranial Pressure and Promontory Vibration With Soft Tissue Stimulation in Cadaveric Human Whole Heads

Cited by 20 publications

References 24 publications

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Simulation of the power transmission of bone-conducted sound in a finite-element model of the human head

Model predictions for bone conduction perception in the human

Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones During Bone Conduction Stimulation

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