Frequency characteristics of the middle ear

Abstract

For 68 temporal bones, frequency curves for the round window volume displacement have been measured for a constant sound pressure at the eardrum. Phase curves were measured for 33 of the specimens. The levels averaged amplitude curve is approximately flat below 1 kHz, where the round window volume displacement per unit sound pressure at the eardrum is 6.8 X 10(-5) mm3/Pa, and falls off by about 15 dB/oct at higher frequencies. For the 20 ears having the largest sound transmission magnitude at low frequencies, the corresponding amplitude curve is displaced about 5 dB towards higher levels. The phase of the round window volume displacement lags the eardrum sound pressure phase. In average for 33 temporal bones, the phase lag increases from zero at the lowest frequencies to pi near 2 kHz and to about 1.5 pi at 10 kHz.

Hearing threshold for pure tones above 20 kHz

“…Frequency characteristics of the middle ear have been studied and the amplitude at the stapes is known to fall off by 12 to 15 dB/octave above 1 kHz [21][22][23][24]. In these studies, however, no reliable data are presented above 10 kHz, probably because the signal to noise ratio also falls off at high frequencies.…”

Identifying Mechanisms Behind the Tullio Phenomenon: a Computational Study Based on First Principles

“…Our results show that the dominant mechanisms relate to the pathoanatomy of the patient. Measurements of the stapes motility U s /p s indicate that the stapes oscillates at the largest velocity amplitudes for sound stimuli between approximately 800 Hz and 2 kHz (Kringlebotn and Gundersen 1985;Huber et al 2001;Chien et al 2009). According to predictions for the fluid fraction ϕ by Kim et al (2013), a larger percentage of the stapes-induced flow enters the vestibular ducts at lower frequencies, whereas higher sound frequencies favor a stimulation of the cochlear ducts.…”

“…Here, ϕ is defined as the percentage of the stapes-induced flow which enters the cochlear scalae (the rest enters the vestibular system). This is incorporated into a lumped lever arm model (Grieser 2015, p. 29) with which we can compute the vestibular perilymph velocity amplitudes U p [m/s] as a function of the frequency f and the sound pressure level SPL measured in the ear canal, (Kringlebotn and Gundersen 1985) as well as in vivo (Huber et al 2001;Chien et al 2009) in human ears for harmonic sound stimuli.…”

“…1). Using patient-specific data from Kringlebotn and Gundersen (1985) on the human stapes motility U s / p s (Chien et al 2009, Fig. 10, "Human cadaveric") and incorporating predictions on the pathological fluid fraction ϕ (Kim et al 2013, Fig.…”

“…(21) of the soundinduced steady streaming velocity in the endolymph can be used to approximate the corresponding eye velocities α t . In order to reflect physically reasonable anatomical conditions, we use the frequency-dependent stapes motility measurements U s /p s from Kringlebotn and Gundersen (1985) in combination with numerical predictions on the fluid fraction ϕ by Kim et al (2013), using Eq. (1).…”