The all-electric ear

From an engineering perspective, the human ear can be viewed as an elaborate signal-processing device, converting variations in air pressure into electrical signals on the auditory nerve. This signal conversion is effected in two distinct stages: a mechanical-mechanical conversion in the middle ear, and a mechanical-electrical conversion in the inner ear, or cochlea. Some 3000 patients throughout the world have received cochlear implants. The author shows how, through the direct electrical stimulation of the cochlea, such implants can restore a degree of hearing to profoundly deaf people