Investigation of Tympanic Membrane Influences on Middle-Ear Impedance Measurements and Simulations

Sackmann, Benjamin; Warnholtz, Birthe; Sim, Jae Hoon; Burovikhin, Dmitrii; Dalhoff, Ernst; Eberhard, Peter; Lauxmann, Michael

doi:10.1007/978-3-030-23132-3_1

Cited by 2 publications

(6 citation statements)

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“…The geometry of the tympanic cavity is simplified by using plane side walls. The volume of the cavity is 9 × 10 -7 m 3 according to TB 24L in [18], which was used to validate the FE model [14]. The aditus ad antrum acts as a bottleneck connecting the air volume in the mastoid cells and the tympanic cavity.…”

Section: Finite Element Modelmentioning

confidence: 99%

“…The model was further validated on impedance measurements from Voss et al [18] and compared to their published mean and standard deviation of normal TBs and an individual TB with removed TM, both with a sealed tympanic cavity. To match the TB measurements and the experimental conditions of Voss et al [18] to the model from Lauxmann [21], the Youngs modulus of the pars tensa in Sackmann et al [14] was reduced from 4 MPa to 3.2 MPa, the ear canal length was shortened to the experimental conditions of the reference, the local TM thickness values were adapted slightly as shown in Fig. 3 as well as Sackmann et al [14] and the size and boundary conditions of the tympanic cavity were changed [14].…”

Section: Finite Element Modelmentioning

confidence: 99%

“…To match the TB measurements and the experimental conditions of Voss et al [18] to the model from Lauxmann [21], the Youngs modulus of the pars tensa in Sackmann et al [14] was reduced from 4 MPa to 3.2 MPa, the ear canal length was shortened to the experimental conditions of the reference, the local TM thickness values were adapted slightly as shown in Fig. 3 as well as Sackmann et al [14] and the size and boundary conditions of the tympanic cavity were changed [14]. The METF of the model in Sackmann et al [14] was assured to stay within the standard throughout all these modifications for the here investigated frequency range 0.2-4 kHz.…”

Section: Finite Element Modelmentioning

confidence: 99%

“…The METF of the model in Sackmann et al [14] was assured to stay within the standard throughout all these modifications for the here investigated frequency range 0.2-4 kHz. Therefore, the effect on METF should be reproduced appropriately in this study and acoustics of the ear canal and cavity should also be reproduced appropriately, as this model reproduces the effects of intact and removed tympanic membranes well as showed in Sackmann et al [14].…”

Section: Finite Element Modelmentioning

confidence: 99%

“…This study aims to investigate how the size and location of a TM perforation influence the middle ear transfer function (METF), which is the ratio between the stapes pistonlike displacement and the acoustic ear canal sound pressure. We also used a preexisting Finite Element (FE)-model of the middle ear [12][13][14] to test TM perforation effects. Analysis of the movement of individual middle ear structures in the FE-model allowed us to test causal relationships between middle ear pathology and altered ossicular movements.…”

Section: Introductionmentioning

confidence: 99%

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The impact of tympanic membrane perforations on middle ear transfer function

Bevis

Sackmann

Effertz

et al. 2021

Eur Arch Otorhinolaryngol

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Purpose Injury or inflammation of the middle ear often results in the persistent tympanic membrane (TM) perforations, leading to conductive hearing loss (HL). However, in some cases the magnitude of HL exceeds that attributable by the TM perforation alone. The aim of the study is to better understand the effects of location and size of TM perforations on the sound transmission properties of the middle ear. Methods The middle ear transfer functions (METF) of six human temporal bones (TB) were compared before and after perforating the TM at different locations (anterior or posterior lower quadrant) and to different degrees (1 mm, ¼ of the TM, ½ of the TM, and full ablation). The sound-induced velocity of the stapes footplate was measured using single-point laser-Doppler-vibrometry (LDV). The METF were correlated with a Finite Element (FE) model of the middle ear, in which similar alterations were simulated. Results The measured and calculated METF showed frequency and perforation size dependent losses at all perforation locations. Starting at low frequencies, the loss expanded to higher frequencies with increased perforation size. In direct comparison, posterior TM perforations affected the transmission properties to a larger degree than anterior perforations. The asymmetry of the TM causes the malleus-incus complex to rotate and results in larger deflections in the posterior TM quadrants than in the anterior TM quadrants. Simulations in the FE model with a sealed cavity show that small perforations lead to a decrease in TM rigidity and thus to an increase in oscillation amplitude of the TM mainly above 1 kHz. Conclusion Size and location of TM perforations have a characteristic influence on the METF. The correlation of the experimental LDV measurements with an FE model contributes to a better understanding of the pathologic mechanisms of middle-ear diseases. If small perforations with significant HL are observed in daily clinical practice, additional middle ear pathologies should be considered. Further investigations on the loss of TM pretension due to perforations may be informative.

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Section: Finite Element Modelmentioning

confidence: 99%