> Rough guess based on the price of regular, high-end "in-the-ear-canal" hearing aids. This guess completely missed the point. Cochlear implants are not audio

> Rough guess based on the price of regular, high-end "in-the-ear-canal" hearing aids. This guess completely missed the point. Cochlear implants are not audio amplifiers like hearing aids are. They must convert sound into electrical impulses which are sent more or less directly at the user's sense organ, via a relatively dumb implant. Now, on the one hand you could say, "yeah well that's just a Fourier transform" but that would also miss the point. A cochlear implant only creates impulses at a limited discrete set of points, and the way those points map to frequencies is not going to obey a nice consistent function. This means the processor must be programmable to adjust the mapping of desired frequency (which may not be the input frequency) to electrodes, which already puts us into needing a rather fancier microprocessor than a hearing aid needs. Moreover, the limited set of frequencies causes a massive loss of signal-to-noise ratio. The processor has to compensate for this intelligently filtering the sound to make the result useful. For example, it may need to detect and filter background noise. It is not really even attempting to replicate natural hearing because that's impossible; it may be more helpful to think of it hijacking the user's aural sense to do something almost totally different with it, but staying just close enough to natural hearing that the brain has a fighting chance of making sense of the inputs.