What is the advantage of a cochlear implant?

We put this question to Karen Steel:

Karen: - Cochlear implants are usually used for people who have very severe or profound hearing impairment where a hearing aid isn't very much use to you because you don't have enough hearing left. Whereas hearing aids are used for a different group of people, a much larger population of people who have mild or a moderate hearing impairment where amplifying what they can hear is of benefit to them. Basically, that's what a hearing aid does - It amplifies the sound.

Chris - Because the cochlear implant (invented in Australia a little while back) is a series of electrodes that directly stimulates the nerves that connect the cochlea to the brain, whereas the hearing aid is relying on putting bigger vibrations in to the ear, to make the hair cells vibrate a bit more.

Karen - That's right. The hearing aid doesn't do anything biologically to your inner ear and your sensory hair cells are still there and doing the best they can. But the cochlear implant is actually placed inside your ear, so it involves surgery and it's quite likely to damage the natural hearing ability that you might have because it directly stimulates the nerve endings.