title: Generation place of the long- and short-latency components of transient-evoked otoacoustic emissions in a nonlinear cochlear model.
abstract: Time-domain numerical solutions of a nonlinear active cochlear model forced by click stimuli are analyzed with a time-frequency wavelet technique to identify the components of the otoacoustic response associated with different generation mechanisms/places. Previous experimental studies have shown evidence for the presence of at least two components in the transient otoacoustic response: A long-latency response, growing compressively with increasing stimulus level, and a shorter-latency response, characterized by faster growth. The possible mechanisms for the generation of the two components are discussed using the results of the numerical simulations. The model is a one-dimensional (1-D) transmission line model with nonlinear and nonlocal active terms representing the anti-damping action of the "cochlear amplifier." The dependence on the stimulus level of latency and level was measured for the different components of the response. The generation mechanisms/places of the different components were identified by varying the stimulus level and by turning off the cochlear roughness in well-defined cochlear regions. The results suggest that reflections from roughness coming from basal regions of the cochlea may give a relevant contribution to the early otoacoustic response, whereas nonlinear mechanisms seem to produce a much smaller additional contribution.
authors.affiliation: Physics Department, University of Roma Tor Vergata, Via della Ricerca Scientifica, 1, 00133 Roma, Italy. arturo.moleti@roma2.infn.it
authors.forename: Arturo
authors.initials: A
authors.lastname: Moleti
authors.forename: Adnan Mohsin
authors.initials: AM
authors.lastname: Al-Maamury
authors.forename: Daniele
authors.initials: D
authors.lastname: Bertaccini
authors.forename: Teresa
authors.initials: T
authors.lastname: Botti
authors.forename: Renata
authors.initials: R
authors.lastname: Sisto
mesh_terms: D001489:Basilar Membrane / Q000502:physiology; D003051:Cochlea / Q000502:physiology*; D003198:Computer Simulation; D018072:Hair Cells, Auditory, Outer / Q000502:physiology; D006801:Humans; D017711:Nonlinear Dynamics; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D010046:Oval Window, Ear / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*; D013018:Sound Spectrography