Forward- and reverse-traveling waves in DP phenomenology: Does inverted direction of wave propagation occur in classical models?

Abstract

Recent basilar-membrane (BM) vibration experiments show that the phase slope of the distortion product (DP) in the cochlear region in which a backward-traveling wave is expected is negative, which is typical of a forward-traveling wave, according to the predictions of quasi-linear approximate solutions of classical 1-D transmission-line cochlear models. This phase behavior has been interpreted as suggesting a strong deviation from the "classical" models of the otoacoustic emission (OAE) generation and transmission. In this paper, the DP phase inversion phenomenon is approached from a conservative point of view. The DP phase is calculated in a classical cochlear model. The main conclusion is that deviations from the classical model are not necessary to account for the observed phase behavior. © 2011 American Institute of Physics.