Laserdopplervibrometrische Schwingungsmessungen am menschlichen Trommelfell nach Stapesfixierung*

Stasche, N.; Baker, Alan R. H.; Hj, Foth; Huthoff, Christian; Hörmann, K.

doi:10.1055/s-2007-997151

Cited by 8 publications

(8 citation statements)

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“…With an established model, it will be easier to plan and perform experiments to get the required information. As newer experiments show, meaningful data may also be derived from in vivo experiments [Stasche et al, 1994;Rodriguez et al, 1997].…”

Section: Methodsmentioning

confidence: 99%

Measurements of Ossicular Vibrations in the Middle Ear

Schön

Müller²

1999

Audiol Neurotol

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The vibrations of the ossicles were measured with a laser Doppler vibrometer in temporal bone specimens. The data contradicted the generally accepted view that the malleus and incus rotate about a fixed axis. The vibrations of the ossicles show a more complex pattern and, consequently, a more sophisticated model is needed to portray the behaviour of the middle ear in a satisfactory manner. But in turn models with many degrees of freedom make the identification process a very difficult task. This dilemma can be resolved if the system is divided into subsystems of less complexity where each subsystem can be studied in an appropriate manner. The excitation by electrostatic forces, as applied in this study, seems to be a powerful tool to make possible a study of parts of the ossicular chain.

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Section: Methodsmentioning

confidence: 99%

Measurements of Ossicular Vibrations in the Middle Ear

Schön

Müller²

1999

Audiol Neurotol

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“…Experimentelle Schwingungsmessungen am Trommelfell wurden erstmals von v. Békésy [1] mittels einer kapazitiven Sonde, später von Gilad et al [10], Gummer et al [13,14] mit der Mössbauer-Methode, von Tonndorf und Khanna [25] holographisch, von Brenkman et al [2] mit einem SQUID-Magnetometer und durch Hüttenbrink [16] mit der direkten Röntgenvergrößerungstechnik durchgeführt. Stasche et al [21,22] untersuchten am Felsenbein die Eignung der LDV als Hilfsmittel zur objektiven Mittelohrdiagnostik. Stasche et al [21,22] untersuchten am Felsenbein die Eignung der LDV als Hilfsmittel zur objektiven Mittelohrdiagnostik.…”

Section: Laservibrometrieunclassified

Laservibrometrie

Jorge¹,

Zenner²,

Hemmert³

et al. 1997

HNO

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A complete battery of audiometric methods is required for the differential diagnosis of different hearing disabilities (including puretone audiometry, impedance, stapes reflex, speech audiometry, brainstam evoked response audiometry, otoacoustic emissions, etc.). In many cases, a comprehensive diagnosis is not possible. Here we describe a new technique based on a laser-Doppler vibrometer that has the potential for non-invasive diagnosis not only middle ear disease but also cochlear pathologies. Disturbance of cochlear function can be ascertained because the input impedance of the cochlea acts as a mechanical load on the middle ear and therefore influences motion of the umbo. In the present study vibration of the umbo and eardrum were measured with a commercially available laser-Doppler vibrometer coupled directly into a standard surgical microscope. The use of the microscope allowed non-invasive measurements of vibrations without having to introduce reflecting material onto the tympanic membrane. Sound pressure was measured with a calibrated probe microphone placed near the tympanic membrane. The displacement response and the specific acoustic impedance of the umbo were calculated from the velocity and sound pressure measured. For normal hearing subjects, the amplitude of the umbo's displacement for frequencies from 0.1 kHz to 1 kHz was 1 nm at 60 dB SPL and decreased with a slope of 6 dB/octave for frequencies between 1 and 5 kHz. A strong correlation was found between the specific acoustic impedance of the umbo and hearing thresholds for hearing-impaired subjects (having otosclerosis or sensorineural hearing losses). The frequency response of the umbo proved to be a means for evaluating the function of both the middle ear and the cochlea under pathological conditions. The measurement technique described is also suitable for intraoperative investigation of the frequency response of the opened middle ear, as well as for the in situ frequency response of partial and total ossicular replacement prostheses.

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“…The most modern technology employs a laser Doppler vibrometer (LDV) to measure eardrum vibrations in human subjects (20,(23)(24)(25)(26)(27)(28)(29)(30). The LDV is a heterodyne interferometer where the instantaneous frequency of the interferometric signal is shifted in direct proportion to the velocity of the vibrating object (31,32).…”

mentioning

confidence: 99%

“…Stimulus levels of 60 dB SPL produce umbo displacements of Ϸ1 nm below 1 kHz (20,(23)(24)(25)(26)(27)(28)(29)(30). However, vibration measurements of Ͻ1 nm on the eardrum are difficult to perform in human subjects because the poor signal-to-noise ratio (SNR), due to poor optical reflection and extraneous noise such as heart beat, breathing or swallowing, necessitates inordinately long averaging times.…”

mentioning

confidence: 99%

Distortion product otoacoustic emissions measured as vibration on the eardrum of human subjects

Dalhoff

Ţurcanu

Zenner

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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It has previously not been possible to measure eardrum vibration of human subjects in the region of auditory threshold. It is proposed that such measurements should provide information about the status of the mechanical amplifier in the cochlea. It is this amplifier that is responsible for our extraordinary hearing sensitivity. Here, we present results from a laser Doppler vibrometer that we designed to noninvasively probe cochlear mechanics near auditory threshold. This device enables picometer-sized vibration measurements of the human eardrum in vivo. With this sensitivity, we found the eardrum frequency response to be linear down to at least a 20-dB sound pressure level (SPL). Nonlinear cochlear amplification was evaluated with the cubic distortion product of the otoacoustic emissions (DPOAEs) in response to sound stimulation with two tones. DPOAEs originate from mechanical nonlinearity in the cochlea. For stimulus frequencies, f 1 and f2, with f2/f1 ‫؍‬ 1.2 and f 2 ‫؍‬ 4 -9.5 kHz, and intensities L1 and L2, with L1 ‫؍‬ 0.4L2 ؉ 39 dB and L 2 ‫؍‬ 20 -65 dB SPL, the DPOAE displacement amplitudes were no more than 8 pm across subjects (n ‫؍‬ 20), with hearing loss up to 16 dB. DPOAE vibration was nonlinearly dependent on vibration at f 2. The dependence allowed the hearing threshold to be estimated objectively with high accuracy; the standard deviation of the threshold estimate was only 8.6 dB SPL. This device promises to be a powerful tool for differentially characterizing the mechanical condition of the cochlea and middle ear with high accuracy.cochlea ͉ hearing loss ͉ laser interferometer ͉ middle ear

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Laserdopplervibrometrische Schwingungsmessungen am menschlichen Trommelfell nach Stapesfixierung*

Cited by 8 publications

References 0 publications

Measurements of Ossicular Vibrations in the Middle Ear

Measurements of Ossicular Vibrations in the Middle Ear

Laservibrometrie

Distortion product otoacoustic emissions measured as vibration on the eardrum of human subjects

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