What key function does a cochlear implant have compared to a hearing aid?

A cochlear implant functions by bypassing the inner ear and directly stimulating the auditory nerve. This is crucial for individuals with severe or profound sensorineural hearing loss who do not benefit significantly from conventional hearing aids. Unlike hearing aids, which amplify sound to the remaining functional hair cells in the cochlea, cochlear implants convert sound signals into electrical impulses that are sent straight to the auditory nerve. This process facilitates the perception of sound even when the inner ear has been damaged or is non-functional.

The other options describe functionalities that do not accurately characterize cochlear implants. For instance, amplifying sound through the inner ear is a primary function of hearing aids, not cochlear implants. While external auditory devices can enhance sound, they do not directly stimulate the auditory nerve as cochlear implants do. Lastly, bone conduction devices focus on transmitting sound vibrations through the skull to reach the inner ear, which is a different approach than what cochlear implants utilize.