Wyniki wyszukiwania - BazTech

1

Bone conduction stimulation of the otic capsule: a finite element model of the temporal bone

Borkowski Paweł, Marek Piotr, Niemczyk Kazimierz, Lachowska Magdalena, Kwacz Monika, Wysocki Jarosław

Acta of Bioengineering and Biomechanics

|

2019

|

Vol. 21, no. 3

75--86

EN

Bone conduction stimulation applied on the otic capsule may be used in a conductive hearing loss treatment as an alternative to the bone conduction implants in clinical practice. A finite element study was used to evaluate the force amplitude and direction needed for the stimulation. Methods: A finite element model of a female temporal bone with a precisely reconstructed cochlea was subjected to a harmonic analysis assuming two types of stimulation. At first, the displacement amplitude in the form of air conduction stimulation was applied on the stapes footplate. Then the force amplitude was applied on the otic capsule in the form of bone conduction stimulation. The two force directions were considered: 1) the primary direction, when a typical opening is performed during mastoidectomy, and was coincident with the axis of an imaginary cone, inscribed in the opening, and 2) the direction perpendicular to the stapes footplate. The force amplitude was set so that the response from the cochlea corresponded to the result of air conduction stimulation applied on the stapes footplate. Results: The amplitude and phase of vibration and the volume displacement on the round window membrane were considered as well as vibrations of the basilar membrane, spiral lamina, and promontory. Conclusions: The cochlear response was comparable for the two types of stimulation. The efficiency of bone conduction stimulation depended on the force direction. For the primary direction, the force was a few times smaller than for the direction perpendicular to the stapes footplate.

2

Analysis of a dynamic response of the cochlea using fluid-structure interaction model

Kamieniecki K., Piechna J., Borkowski P.

Engineering Transactions

|

2016

|

Vol. 64, iss. 4

573--579

EN

A one-dimensional (1D) model of the cochlea of the inner ear has been built and validated against the previously built three-dimensional (3D) fluid-structure interaction (FSI) model of the cochlea. The 1D model has been used to assess the influence of the round window impedance on the pressure distribution in the cochlea. It was shown that high impedance, which enables compression reflection pressure wave at the round window, leads to the biggest pressure difference between the scala vestibule and the scala tympani in the cochlea, which may lead to a stronger excitation of the basilar membrane.

3

On the place code for pitch: a psychophysiological paradox in the classical concept

Zwislocki J. J.

Archives of Acoustics

|

2007

|

Vol. 32, No. 3

447--454

EN

The place of maximum excitation in the cochlea has been believed to be the code for the pitch of tones since mid 19-th century. More recent physiological experiments have revealed that, in a healthy cochlea, the maximum is displaced gradually toward the cochlear base (input) as the sound pressure is increased, whereas the pitch remains practically constant. This paradox suggests that the maximum excitation may not be the adequate code for the pitch after all. In the presence of hearing loss of cochlear origin, the pitch appears higher than normal. As the sound pressure level is increased, it changes gradually back to normal. By contrast, the maximum of cochlear excitation in the presence of cochlear damage, although displaced toward the cochlear base, remains independent of sound pressure level. In both situations, normal and pathological, the apical cut off of cochlear excitation depends on the sound pressure level in the same way as does the pitch. Could the cut off be the adequate place code for the pitch?