Author: Dolly Bhargava, M. Spec. Ed.

Some students with a severe to profound sensorineural hearing loss may be using appropriate hearing aids but are not receiving much benefit from them and are still having difficulty communicating.  Such students may be candidates for cochlear implants.   Selecting a suitable candidate for a cochlear implant involves an evaluation process that takes into consideration factors such as: the student’s age, duration of hearing impairment, speech and language abilities, results from the medical assessment, audiological assessment and psycho-social factors (Chute, 2002, Miyamoto and Kirk, 1998). 

What is a cochlear implant?

photo on implant, provided by courtesy of Cochlear limitedA cochlear implant is an electronic device that is surgically implanted into the cochlea (inner ear) to compensate for the damaged or absent hair cells by directly stimulating the auditory nerve fibers.  The internal cochlear implant is coupled to external components that pick up sounds from the environment (Turnbull, Turnbull, Shank and Smith, 2004).  Dugan (2003) states that “a cochlear implant is not a cure nor does it restore hearing to normal” (p. 77).  Rather, it taps into the retained potential of the hearing pathway, by bypassing damaged hair cells and directly stimulating the functional auditory nerve fibers in the cochlea (Dugan, 2003; Turnbull et. al, 2004). 

A cochlear implant has internal and external parts.  The internal implant consists of an internal receiver coil and a receiver/ stimulator, which is surgically implanted under the skin behind the ear, and electrodes that are inserted into the cochlea.  The external speech processor converts sound waves into a digital code, which is transmitted via a mini radio link to the internal coil.  The receiver/ stimulator then converts the code into electrical currents, which the electrode delivers to the auditory nerve.  The external part consists of a microphone, a speech processor and a transmitter coil (Dugan, 2003; Turnbull et. al, 2004).  The microphone is located on the student’s head, held in place by the pinna.  The speech processor is either worn on the body or is positioned behind the ear.  The external transmitter coil is held in place over the internal receiver coil by a magnet (Downie, 2000).  The external components work together to collect, analyze, process and transmit auditory information to the internal parts to provide the student with sound (Zwolan, 2002).

How Does a Cochlear Implant Work?

1.  How a cochlear implant worksA microphone picks up sound.

2.  Sound is sent from the microphone to the speech processor.

3.  The speech processor analyzes and digitizes the sound into coded signals.   4.  The speech processor is programmed to the student’s hearing needs.

5.  Coded signals are sent to the transmitter.

6.  The transmitter sends the code across the skin to the internal implant.

7.  The internal implant converts the code to electrical signals.

8.  The signals are sent to the electrodes to stimulate the remaining nerve fibres.

9.  The signals are recognized as sounds by the brain, producing a hearing sensation.

Benefits of Cochlear Implants

For most recipients the cochlear implant is able to provide sufficient hearing to stimulate speech and language development, enabling some children to attend mainstream schools and enjoy broader education, employment and social opportunities.

Deaf children’s speaking and hearing success depends on a number of things, including how long they were deaf before receiving any auditory stimulation.  Spencer and Marschark (2003) state that the earlier in life implants are provided, the better the outcome, particularly with spoken communication, literacy and mainstreaming.

According to parents, children with cochlear implants enjoy significant gains in sound awareness, especially of softer sounds, speech understanding, monitoring their own speech and understanding voices without looking at the speaker.  This makes communication a great deal easier and promotes success in communication.

Tips for teachers

  • Cochlear implants will not restore hearing to “normal”.  In other words the student will not immediately start understanding all the sounds that they are hearing.  Once a student has been fitted with a cochlear implant he or she must undergo extensive audition based speech and language therapy to learn how to interpret the new sounds effectively (Pagliano, 2005).

  • It is important to remember that each student is unique, and outcomes will differ from student to student.  A variety of factors (such as degree of hearing loss, type and amount of auditory and speech intervention before and after cochlear implantation, motivational factors) will affect how much and how quickly the student will benefit from the cochlear implant.

  • Please refer to the strategies discussed in the Accommodations chapter, as they are still relevant when communicating with the student who has a cochlear implant.  For example, facing the student when interacting, speaking clearly and monitoring background environmental noise and light are critical for successful communication.