Intracochlear sound pressure measurements in guinea pigs

Dancer, A.; Franke, R.

doi:10.1016/0378-5955(80)90057-x

Cited by 129 publications

(93 citation statements)

References 5 publications

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“…The impedance, primarily resistive, was quite similar to our result in gerbil. The impedance was found using nonsimultaneous pressure and velocity measurements in chinchilla (Ruggero et al 1990) and guinea pig (Dancer and Franke 1980). Merchant et al (1996) and Aibara et al (2001) reported human cochlear input impedance measured in fresh temporal bone.…”

Section: Cochlear Input Impedance In the Literaturementioning

confidence: 99%

Simultaneous Measurements of Ossicular Velocity and Intracochlear Pressure Leading to the Cochlear Input Impedance in Gerbil

Rochefoucauld

Decraemer

Khanna

et al. 2008

JARO

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Recent measurements of three-dimensional stapes motion in gerbil indicated that the piston component of stapes motion was the primary contributor to intracochlear pressure. In order to make a detailed correlation between stapes piston motion and intracochlear pressure behind the stapes, simultaneous pressure and motion measurements were undertaken. We found that the scala vestibuli pressure followed the piston component of the stapes velocity with high fidelity, reinforcing our previous finding that the piston motion of the stapes was the main stimulus to the cochlea. The present data allowed us to calculate cochlear input impedance and power flow into the cochlea. Both the amplitude and phase of the impedance were quite flat with frequency from 3 kHz to at least 30 kHz, with a phase that was primarily resistive. With constant stimulus pressure in the ear canal the intracochlear pressure at the stapes has been previously shown to be approximately flat with frequency through a wide range, and coupling that result with the present findings indicates that the power that flows into the cochlea is quite flat from about 3 to 30 kHz. The observed wide-band intracochlear pressure and power flow are consistent with the wide-band audiogram of the gerbil. Keywords: middle ear, cochlea, stapes, powerAbbreviations: SV -scala vestibuli; EC -ear canal; PF -pars flaccida; LPI -long process of the incus; PLP -plate of the lenticular process of the incus; CAPcompound action potential; SPL -sound pressure level; CT -computed tomography; BM -basilar membrane; BF -best frequency; TM -tympanic membrane; PUR -power utilization ratio; MEE -middle ear efficiency List of Symbols: U s -stapes volume velocity (mm 3 /s); V s -stapes velocity (mm/s); A fp -effective footplate area (mm 2 ); Z c -cochlear input impedance; Z Eradiation impedance looking out the external ear from the TM; Z T -middle ear input impedance (Pa s/m 3 = N s/m 5 ); P -Power; P ME -middle ear power (W); P sv -SV pressure; P EC -EC pressure (Pa)

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Section: Cochlear Input Impedance In the Literaturementioning

confidence: 99%

Simultaneous Measurements of Ossicular Velocity and Intracochlear Pressure Leading to the Cochlear Input Impedance in Gerbil

Rochefoucauld

Decraemer

Khanna

et al. 2008

JARO

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“…opening the scala tympani, rather than the scala vestibuli) and at the other end of the cochlea (the base, rather than the apex), where any effects on the cochlea's hydrodynamics should be minimized by the presence of the round window (cf. Dancer & Franke 1980;Nedzelnitsky 1980;Olson 1998). Indeed, the recent studies of Narayan et al (1998;Ruggero et al 2000) can be used to prove that the effects of opening the basal turn's scala tympani are negligible from a sound processing point of view: these authors recorded tuning curves from individual auditory nerve fibres in the same preparations that they used to make BM recordings from, and found neural tuning which was indistinguishable from normative data (collected from perfectly intact cochleae).…”

Section: Do 'Fast' Responses Exist In the Intact Cochlea?mentioning

confidence: 99%

An experimental study into the acousto-mechanical effects of invading the cochlea

Dong

Cooper

2006

J. R. Soc. Interface.

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The active and nonlinear mechanical processing of sound that takes place in the mammalian cochlea is fundamental to our sense of hearing. We have investigated the effects of opening the cochlea in order to make experimental observations of this processing. Using an optically transparent window that permits laser interferometric access to the apical turn of the guineapig cochlea, we show that the acousto-mechanical transfer functions of the sealed (i.e. near intact) cochlea are considerably simpler than those of the unsealed cochlea. Comparison of our results with those of others suggests that most previous investigations of apical cochlear mechanics have been made under unsealed conditions, and are therefore likely to have misrepresented the filtering of low-frequency sounds in the cochlea. The mechanical filtering that is apparent in the apical turns of sealed cochleae also differs from the filtering seen in individual auditory nerve fibres with similar characteristic frequencies. As previous studies have shown the neural and mechanical tuning of the basal cochlea to be almost identical, we conclude that the strategies used to process low frequency sounds in the apical turns of the cochlea might differ fundamentally from those used to process high frequency sounds in the basal turns.

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“…The pressure difference thus drives auditory transduction. Dancer and Franke (1980) and Lynch et al (1982) demonstrated that the differential sound pressure measured in the guinea pig and cat, respectively, closely follows that of the cochlear microphonic measured in a similar location. Voss et al (1996) also showed that the pressure difference between the oval and round windows is the stimulus that produces cochlear responses in the cat.…”

Section: Introductionmentioning

confidence: 99%

Differential Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones

Nakajima

Dong

Olson

et al. 2008

JARO

175

226

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We present the first simultaneous sound pressure measurements in scala vestibuli and scala tympani of the cochlea in human cadaveric temporal bones. The technique we employ, which exploits microscale fiberoptic pressure sensors, enables the study of differential sound pressure at the cochlear base. This differential pressure is the input to the cochlear partition, driving cochlear waves and auditory transduction. In our results, the sound pressure in scala vestibuli (P SV ) was much greater than scala tympani pressure (P ST ), except for very low and high frequencies where P ST significantly affected the input to the cochlea. The differential pressure (P SV − P ST ) is a superior measure of ossicular transduction of sound compared to P SV alone: (P SV −P ST ) was reduced by 30 to 50 dB when the ossicular chain was disarticulated, whereas P SV was not reduced as much. The middle ear gain P SV /P EC and the differential pressure normalized to ear canal pressure (P SV − P ST )/P EC were generally bandpass in frequency dependence. At frequencies above 1 kHz, the group delay in the middle ear gain is about 83 μs, over twice that of the gerbil. Concurrent measurements of stapes velocity produced estimates of cochlear input impedance, the differential impedance across the partition, and round window impedance. The differential impedance was generally resistive, while the round window impedance was consistent with compliance in conjunction with distributed inertia and damping. Our technique of measuring differential pressure can be used to study inner ear conductive pathologies (e.g., semicircular dehiscence), as well as non-ossicular cochlear stimulation (e.g., round window stimulation and bone conduction)-situations that cannot be completely quantified by measurements of stapes velocity or scala vestibuli pressure by themselves.

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Intracochlear sound pressure measurements in guinea pigs

Cited by 129 publications

References 5 publications

Simultaneous Measurements of Ossicular Velocity and Intracochlear Pressure Leading to the Cochlear Input Impedance in Gerbil

Simultaneous Measurements of Ossicular Velocity and Intracochlear Pressure Leading to the Cochlear Input Impedance in Gerbil

An experimental study into the acousto-mechanical effects of invading the cochlea

Differential Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones

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