Cochlear Implant Information

How Normal Hearing Works

Outer Ear - Sound is directed into to ear by the visible outer portion, called the Pinna, and travels down the ear canal.

Middle Ear - Sound waves then hit the eardrum causing it and the three small bones behind it to vibrate.

Inner Ear - The inner ear is filled with fluid and contains thousands of sound receptors known as hair cells. Once sound enters the cochlea, the fluid is sent into motion causing these hair cells to sway or shear.

Hearing Nerve - Thousands of nerve pathways transmit sound information from the hair cells up to the hearing centers of the brain.

How Does a Cochlear Implant Work?

A cochlear implant bypasses the damaged cochlear hair cells and uses electrical impulses to stimulate the auditory nerve.  The goal is to restore sound detection and enable speech recognition.

• The microphone in the headpiece collects sound and sends it to the speech processor.
   
• The speech processor converts the sound using a coding strategy compatible with the electrodes.
   
• The signal is then sent back to the headpiece.
   
• The headpiece transmits the signal via radio waves across the skin to the internal component of the implant.
   
• The internal component delivers the signal to the electrode array that is implanted in the cochlea.
   
• The electrodes stimulate the hearing nerve with electrical impulses.

How are hearing aids different?

Hearing aids are designed to make sound louder.  Just making sound louder won’t provide much usable hearing for a severely damaged ear.

A cochlear implant doesn’t make sounds louder – it stimulates the ear directly, bypassing the damaged part of the ear.  Sound is sent directly to the hearing nerve.  This sound stimulation can provide a range of benefits from simple sound detection, to speech understanding without lip-reading.