Human inner ear cochlea in a long line modeling

Abstract

In this paper was presented a little overview of the study of the cochlea of the human inner ear. More than 6% of the people have hearing problems. Early diagnosis of hearing disorders allows to prevent deterioration or loss of hearing. Researching the cochlea construction occurres for centuries. The basic theories of the transmission and transformation acoustic signal in the cochlea were analyzed such as Helmholtz theory, Rutherford’s "telephone theory", Evald and Harst standing waves theories and Bekesy’s theory. The last one theory is the most proven theory, despite this it has a lot of questions, which is need to be answered. Also it was shown general methods of modeling human cochlea such as hydromechanical and electric models. Hydromechanical modeling show that there are resonant processes on the basilar membrane while applying sinusoidal excitation signal to the membrane’s input window. The most informative data about the attenuation of the excitation signal during running wave transmission can be obtained using electrical modeling. This models give a clear idea about the transfer and transformation of the acoustic signal in cochlea. It was analyzed the features of modeling human inner ear cochlea in a long line and spiral presentation. We considered the cochlea curvature influence on the hearing in wave propagation along the channel. The functional meaning of cochlea coils attracted researchers in different areas and at different times. For a long time it was believed that spiral form does not affect on hearing and it was showed by physical and mathematical models However statistics indicate a strong correlation between the number of spiral coils and low frequency hearing thresholds. Wave energy remains constant while waves of basilar membrane passing along the cochlea channel due to slow resize of cochlea including curvature. Since the wave energy is constant, it can be argued that the average value of the cross-section is also constant. The curvature creates a radial gradient in liquid pressure. The cochlea’s curvature increases the radial displacement in the basilar membrane caused by redistribution of wave energy density across the width of the channel. Due to difficulties in modeling cochlea considering all the parameters in a spiral form the modeling was presented like a long line. In this work is showed an idealized schematic representation of the cochlea of the human inner ear. Ref. 17, fig. 3.

Keywords

References

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Copyright (c) 2018 Сергій Анатолійович Найда, Валерія В. Безродна (Автор)