More interesting basic research on how hair cell regeneration works. Action on hearing loss has a nice article summarising the result. Or take a look at the journal article. Short summary: Birds do it, fishes also (where "it" means regenerate hair cells, of course...). So they looked at what genes are active when hair cells regenerate vs. when they don't, by killing the cells in chicks and look at what happens during regeneration. This way they were able to identify two molecular pathways that are active during regeneration. They then took a look at zebra-fish, which have hair cells on the outside to sense water movements. They then killed of those cells and treated half the fish with a drug that blocks the molecular pathway in question. Result: those fishes didn't regenerate their hair cells as well as the untreated fishes. So, this makes me wonder - maybe the cure is to stick one of those in your ear.