Cochlear Implant Systems

How does normal hearing work?

In order to understand how a cochlear implant works, it is helpful to have a basic understanding of how normal hearing works. With normal hearing, 

  1. The outer ear collects sound waves as the waves pass through the air and sends it down the ear canal.
  2. The sound waves cause the eardrum and the three tiny ear bones to vibrate. This vibration is passed down the chair of ear bones to the cochlea.
  3. The vibration causes the tiny little hair cells in the cochlea to move, which sends electrical signals to the hearing nerve.
  4. The signal travels up the hearing nerve to the brain where it is interpreted as sound.


Photo courtesy of Cochlear Americas

In the cross section of the cochlea (seen below), it shows how the bones in the middle ear vibrate the tiny hairs of the sensory cells in the inner ear. These vibrations are then converted to an electrical signal that is sent through the hearing nerve into the brain.
Picture courtesy of Advanced Bionics

How does a cochlear implant work?

A cochlear implant consists of both surgically implanted components and an externally worn speech processor.

  1. Sounds are picked up by the microphone of the speech processor, which analyzes sound and turns it into coded signals.
  2. The coded signal is sent across the skin to the internal device where it is converted into electrical signals. 
  3. The electrical signals are sent down the electrode array which has been implanted inside the cochlea.
  4. The signals from the array stimulate the nerve fibers of the auditory nerve directly and are recognized by the brain as sound.

Each person with a cochlear implant perceives the electrical signals / sounds differently. Therefore, the external speech processor is programmed to meet each patient's hearing needs.


Pictures courtesy of Cochlear Americas

external_cochlearExternal Speech Processor
internal_cochlearInternal Device

What cochlear implant systems are available?

A cochlear implant system consists of an internally implanted electrode array, and an external speech processor. Currently, there are three manufacturers that offer cochlear implant devices approved by the Federal Drug Administration (FDA). All three companies have excellent implant systems. The OHSU Cochlear Implant Program offers patients a choice between all three device options. More information on these systems can be found at the web sites listed below:

Cochlear Americas:

Advanced Bionics:

MedEl Corporation:

Additional Resources

For Parents and Families:

How to make an appointment

 If you are interested in setting up a cochlear implant consultation, please contact our secretaries:

Phone: 503 494-5171