Wave model of the cat tympanic membrane

Abstract

In order to better understand signal propagation in the ear, a time-domain model of the tympanic membrane (TM) and of the ossicular chain (OC) is derived for the cat. Ossicles are represented by a two-port network and the TM is discretized into a series of transmission lines, each one characterized by its own delay and reflection coefficient. Volume velocity samples are distributed along the ear canal, the eardrum, and the middle ear, and are updated periodically to simulate wave propagation. The interest of the study resides in its time-domain implementation--while most previous related works remain in the frequency domain--which provides not only a direct observation of the propagating wave at each location, but also insight about how the wave behaves at the ear canal/TM interface. The model is designed to match a typical impedance behavior and is compared to previously published measurements of the middle ear (the canal, the TM, the ossicles and the annular ligament). The model matches the experimental data up to 15 kHz.

Forward and reverse transfer functions of the middle ear based on pressure and velocity DPOAEs with implications for differential hearing diagnosis

“…The 14-ms value derived from human subjects is very close to the value that we obtained from the guinea-pig model. In differences between the expected and observed values in guinea pig can be accounted for by interspecies differences in propagation speed, which in turn depends on TM curvature, inclination to the ear canal and material anisotropy (Fay et al, 2006;Parent and Allen, 2007). With respect to the second assertion, it is clearly incorrect to equate one-way propagation delay in the forward direction to overall propagation delay in the forward direction (Parent and Allen, 2010).…”

“…In contrast to guinea pig (Sec. 3.3), for human C B [5.5 mF in Zwislocki (1962)] is larger than the acoustic compliances of the malleus (0.32 mF) and annular ligament (0.16 mF), both calculated from Parent and Allen (2007). 9 Therefore, pathological changes in C M and/or C C are expected to be detectable in f-TF.…”

Slow dynamics of the amphibian tympanic membrane

“…While the overall bullfrog TyM motion is complex, we propose a relatively simple model to capture its essential features. Consider the TyM as a distributed segment of transmission line (e.g., [12]) connecting the air to the ossicles (and subsequently the inner ear). At frequencies where the characteristic impedance of the transition (i.e., air-to-TyM, TyM-to-ossicle) is well-matched, a slow-traveling wave behavior will dominate.…”

An Analysis of the Acoustic Input Impedance of the Ear

“…Previous studies of the acoustic input impedance of the ear include lumped element models of the human middle ear (e.g., Kringlebotn 1988;Moller 1961;Zwislocki 1962), experimental studies of the middle ear of human temporal bones (e.g., O'Connor and Puria 2008;Voss et al 2000), experimental studies of human ears (e.g., Farmer-Fedor and Rabbitt 2002;Kringlebotn 1994;Margolis et al 1999;Moller 1965;Rabinowitz 1981;Voss and Allen 1994), and models and experimental studies of animal ears (e.g., Huang et al 2000;Lynch et al 1994;Parent and Allen 2007). Prior to 1981, experimental studies of the acoustic input impedance of the ear in humans were limited to about 1.5 kHz, the ear canal treated as an acoustic compliance (Rabinowitz 1981).…”