A cochlear implant is a surgically implanted artificial inner ear or cochlea. The implant uses a thin metal coil to electronically stimulate the hearing nerve, bypassing a damaged or deformed cochlea. In contrast, a hearing aid simply amplifies sound and sends it through the malfunctioning cochlea to the hearing nerve. In many cases an implant will provide an improvement in the use of sound far beyond what a hearing aid can provide, but implants do not restore normal hearing. It does, however, allow for the perception of sound "sensation."