A sheet of hair cells might be able to amplify sounds
by making use of the general mechanism of active hair bundle
movement, which is probably the principal amplifier
of non-mammalian cochleae and is also relevant for the
normal mammalian organ of Corti [52–54]. Further challenges
will involve integrating the replacement hair cells
into the micro mechanical cochlear apparatus, which, after
the degeneration of the organ of Corti, would not be capable
of effectively conducting mechanical force to stereociliary
bundles. It will be of interest to investigate whether
developing stem-cell-derived sensory epithelia couple with
the tectorial membrane, a structure that, when absent or
detached from cochlear hair cells, leads to a substantial
increase of the threshold of hearing [55,56].