Are otoacoustic emissions high-frequency extended modes?

Sound induces surface waves along the cochlea's basilar membrane, mostly in well-known localized modes, which are sharply peaked in position. However, in recent computational work, we found another novel set of collective low-frequency "extended modes". While the full system is analytically intractable, we can construct a linearized version with the same mode structure, showing that these two types of modes are qualitatively distinct. We then examine how irregularities in the cochlea's spatial stiffness profile affect these extended modes, allowing them to appear at higher frequencies, and explore them as a source of otoacoustic emissions.