Middle ear function and cochlear input impedance in chinchilla

Slama, Michaël C.C.; Ravicz, Michael E.; Rosowski, John J.

doi:10.1121/1.3279830

Cited by 21 publications

(34 citation statements)

References 48 publications

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“…Y C magnitude (Figure 2a) in four ears decreases slowly with frequency, and Y C phase is between 0 and -0.25 cycles, roughly consistent with the minimum phase predicted from the magnitude slope. Y C falls between previous studies [13] (N=6), [3] (N=5).…”

Section: Y C With Forward (Sound) Stimulationsupporting

confidence: 77%

Middle-ear mechanics in chinchilla when stimulated in reverse: Predictions and measurements

Ravicz¹,

Bowers²,

Rosowski³

2018

AIP Conference Proceedings

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Abstract. The properties of the middle ear (ME) when driven from the cochlea ("in reverse") are important for evaluating otoacoustic emissions (OAEs) and may be quite different from middle-ear function with normal ("forward") sound transmission. In chinchilla, a species commonly used for auditory research (especially for noise hazard and OAE studies), we measured ear-canal and inner-ear sound pressures and stapes velocity while stimulating the middle ear with sound or in reverse with an actuator on the round window. We compute (1) admittances at the border between the middle and inner ear: the cochlear input admittance Y C , the load seen by the ME with normal sound transmission, and the reverse middle-ear input admittance , the load the ME exerts on the cochlea for reverse transmission such as OAEs, and (2) a metric of middle-ear function with reverse stimulation: The reverse ME pressure gain between the cochlear vestibule and the ear canal, for different ear canal conditions. The sensitivity of and to changes in ear canal termination provides insight into the effect of ear-canal conditions on OAEs and flexibility in the middle ear, while a comparison of the admittances provides an estimate of power absorption and reflection at the boundary between the middle and inner ear. Measurements support predictions from a middle-ear two-port transmission-matrix model based on measurements with forward stimulation.

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Section: Y C With Forward (Sound) Stimulationsupporting

confidence: 77%

Middle-ear mechanics in chinchilla when stimulated in reverse: Predictions and measurements

Ravicz¹,

Bowers²,

Rosowski³

2018

AIP Conference Proceedings

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“…This absorbed power within the cochlea has been measured in chinchilla (Slama et al, 2010). However, little is known about the magnitude of the internal middle-ear loss and its frequency dependence in the normal-functioning human middle ear.…”

Section: Constant Stimulus-level Proceduresmentioning

confidence: 99%

Specification of absorbed-sound power in the ear canal: Application to suppression of stimulus frequency otoacoustic emissions

Keefe¹,

Schairer²

2011

The Journal of the Acoustical Society of America

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An insert ear-canal probe including sound source and microphone can deliver a calibrated sound power level to the ear. The aural power absorbed is proportional to the product of mean-squared forward pressure, ear-canal area, and absorbance, in which the sound field is represented using forward (reverse) waves traveling toward (away from) the eardrum. Forward pressure is composed of incident pressure and its multiple internal reflections between eardrum and probe. Based on a database of measurements in normal-hearing adults from 0.22 to 8 kHz, the transfer-function level of forward relative to incident pressure is boosted below 0.7 kHz and within 4 dB above. The level of forward relative to total pressure is maximal close to 4 kHz with wide variability across ears. A spectrally flat incident-pressure level across frequency produces a nearly flat absorbed power level, in contrast to 19 dB changes in pressure level. Calibrating an ear-canal sound source based on absorbed power may be useful in audiological and research applications. Specifying the tip-to-tail level difference of the suppression tuning curve of stimulus frequency otoacoustic emissions in terms of absorbed power reveals increased cochlear gain at 8 kHz relative to the level difference measured using total pressure.

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“…The resonant characteristics of the external ear help determine the acoustic energy delivered to the cochlea. The middle ear acts as an impedance-matching device that compensate the transmission 95 loss when sound is introduced to the fluid-filled cochlea [25]. The phenomenon of middle ear muscle contraction (MEMC), known as an autonomic reflex that tightens the muscles of the middle ear, can affect the transfer function of middle ear [26].…”

Section: External Ear and Middle Earmentioning

confidence: 99%

“…The SVTF was defined as the ratio between linear velocity of stapes V S and sound pressure near the TM in the ear canal [25], where the linear velocity V S could be obtained by dividing volume velocity U S by the average footplate area.…”

Section: External Ear and Middle Earmentioning

confidence: 99%

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Auditory fatigue model applications to predict noise induced hearing loss in human and chinchilla

et al. 2017

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Middle ear function and cochlear input impedance in chinchilla

Cited by 21 publications

References 48 publications

Middle-ear mechanics in chinchilla when stimulated in reverse: Predictions and measurements

Middle-ear mechanics in chinchilla when stimulated in reverse: Predictions and measurements

Specification of absorbed-sound power in the ear canal: Application to suppression of stimulus frequency otoacoustic emissions

Auditory fatigue model applications to predict noise induced hearing loss in human and chinchilla

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