External portions of a cochlear implant A microphone hooked around the boy’s ear picks up sound waves and sends signals to an auditory processor. The auditory processor converts the signals into electrical pulses, suitable for stimulating the cochlea, and sends those pulses up the cable to a transmitter fastened to the boy’s head above and behind his ear. The transmitter sends the pulses through the skin to a receiver implanted in his skull, and from there the pulses are sent by thin wire electrodes to stimulate appropriate sets of auditory neurons in the cochlea of the inner ear.
Life in View/Science Source