Auditory System Hearing Testing Impairments Cochlear Implants

Individuals who are profoundly hard of hearing or deaf may derive minimal benefits from a hearing aid. These individuals may choose to use manual communication, or they may decide to get a cochlear implant. A cochlear hearing implant allows the brain to process sound, even when the auditory system is profoundly compromised.

Cochlear Implants - Hearing Impairment

Cochlear Implant Components

Cochlear implants contain several components, which work together to transmit sound information from the environment to the auditory nerve:

  • Microphone: Picks up environmental sounds, including speech
  • Sound or speech processor: Analyzes and arranges sound information
  • Transmitter: Transmits signals to the internal receiver
  • Receiver: Receives signals from the transmitter and creates electrical impulses
  • Electrode array: The strip of electrodes inserted into the cochlea. Receives electrical impulses from the receiver, and stimulates the auditory nerve (which sends messages to the brain).

The microphone, sound/speech processor and transmitter are external components of the cochlear implant. The transmitter is implanted under the skin, and the electrode array is implanted inside the cochlea.

How Does a Cochlear Implant Work?

A cochlear implant allows individuals who are deaf or profoundly hard of hearing to experience sound from the world around them. However, hearing implants do not create or restore normal hearing. Rather, they send signals that simulate hearing to the brain via the auditory nerve. Cochlear implants vary in the number of electrodes, or channels, contained in the electrode array. The higher the number of channels, the greater number of frequencies can be stimulated on the auditory nerve, and the more nuanced a person’s perception of sounds will be.

Hearing Training After Cochlear Implant Surgery

Hearing, and especially understanding speech, does not come immediately or naturally when you get a cochlear implant. After you have had time to heal from the implant surgery, you must have the implant turned on and “mapped.” During mapping sessions, your audiologist tests for appropriate loudness levels, and makes necessary adjustments. Individuals will need training in order to learn to process speech after cochlear implant.

Cochlear Implants: A Difficult Choice

Cochlear implants are a controversial course of treatment for deaf and hard of hearing individuals. Like any surgical procedure, risks and benefits are involved. Improvement can be slow, particularly for children who have never used a sense of hearing. General anesthesia during surgery poses a certain level of risk as well. However, many individuals think the benefits, including being able to interact through spoken communication with hearing peers and being able to use a phone, outweigh the risks.

Some members of the Deaf community are opposed to cochlear implants. Many deaf individuals are part of Deaf culture, using sign language to communicate and embracing deafness as a part of who they are. For some people who are culturally Deaf, cochlear implants are seen as appropriate for certain individuals. However, many vehemently oppose cochlear implants, particularly for children, who are too young to make educated decisions for themselves on this difficult topic.

Resources

Food and Drug Administration (n.d.). Cochlear implants. Retrieved February 4, 2010, from Food and Drug Administration Web site: http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/ImplantsandProsthetics/CochlearImplants/ucm062823.htm.

Martin, F.M.