This study explores the phenomenology of distortion products in nonlinear cochlear models, predicting their amplitude and phase along the basilar membrane. The existence of a backward-traveling wave at the distortion-product frequency, which has been recently questioned by experiments measuring the phase of basilar-membrane vibration, is discussed. The effect of different modeling choices is analyzed, including feed-forward asymmetry, micromechanical roughness, and breaking of scaling symmetry. The experimentally observed negative slope of basilar-membrane phase is predicted by numerical simulations of nonlinear cochlear models under a wide range of parameters and modeling choices. In active models, positive phase slopes are predicted by the quasi-linear analytical computations and by the fully nonlinear numerical simulations only if the distortion-product sources are localized apical to the observation point and if the stapes reflectivity is unrealistically small. The results of this study predict a negative phase slope whenever the source is distributed over a reasonably wide cochlear region and/or a reasonably high stapes reflectivity is assumed. Therefore, the above-mentioned experiments do not contradict "classical" models of cochlear mechanics and of distortion-product generation.

Sisto, R., Moleti, A., Botti, T., Bertaccini, D., Shera, C. (2011). Distortion products and backward-traveling waves in nonlinear active models of the cochlea. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, 129(5), 3141-3152 [10.1121/1.3569700].

Distortion products and backward-traveling waves in nonlinear active models of the cochlea

MOLETI, ARTURO;BERTACCINI, DANIELE;
2011-01-01

Abstract

This study explores the phenomenology of distortion products in nonlinear cochlear models, predicting their amplitude and phase along the basilar membrane. The existence of a backward-traveling wave at the distortion-product frequency, which has been recently questioned by experiments measuring the phase of basilar-membrane vibration, is discussed. The effect of different modeling choices is analyzed, including feed-forward asymmetry, micromechanical roughness, and breaking of scaling symmetry. The experimentally observed negative slope of basilar-membrane phase is predicted by numerical simulations of nonlinear cochlear models under a wide range of parameters and modeling choices. In active models, positive phase slopes are predicted by the quasi-linear analytical computations and by the fully nonlinear numerical simulations only if the distortion-product sources are localized apical to the observation point and if the stapes reflectivity is unrealistically small. The results of this study predict a negative phase slope whenever the source is distributed over a reasonably wide cochlear region and/or a reasonably high stapes reflectivity is assumed. Therefore, the above-mentioned experiments do not contradict "classical" models of cochlear mechanics and of distortion-product generation.
2011
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/07 - FISICA APPLICATA (A BENI CULTURALI, AMBIENTALI, BIOLOGIA E MEDICINA)
Settore MAT/08 - ANALISI NUMERICA
English
Con Impact Factor ISI
Active models; Analytical computations; Basilar membranes; Classical model; Cochlear model; Cochlear regions; Distortion product; Feed-Forward; Micro-mechanical; Negative phase; Negative slope; Nonlinear numerical simulation; Observation point; Phase slope; Quasi-linear
Sisto, R., Moleti, A., Botti, T., Bertaccini, D., Shera, C. (2011). Distortion products and backward-traveling waves in nonlinear active models of the cochlea. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, 129(5), 3141-3152 [10.1121/1.3569700].
Sisto, R; Moleti, A; Botti, T; Bertaccini, D; Shera, C
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/37557
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