Quantitative validation of cochlear models using the Liouville-Green approximation

This article is devoted to the question of whether linear and passive models of the cochlea can mimic the recently observed sharply tuned data of basilar membrane vibration. The model equations are solved by means of an asymptotic approach, the Liouville-Green approximation, which is adequate for quantitative comparisons with experimental data. The conclusions are: (i) the older, mildly tuned basilar membrane responses can be matched very well by means of linear, passive models; (ii) the newer, sharply tuned data cannot be matched satisfactorily by linear, passive modelling. Hence, this study supports the view that the cochlea must contain an active mechanical filter which manifests itself at the level of BM vibration.