WHAT IS A COCHLEAR IMPLANT?
A cochlear implant is an electronic device that is partially implanted surgically into the cochlea, the hearing organ of the inner ear. The microphone, processor, and transmitter are worn externally.
Cochlear implants detect sounds via an ear level microphone that conveys these sounds to a wearable sound processor. The processor converts these sounds to tiny digital impulses that provide hearing sensations to the user. Some of the newest sound processors are small enough to fit behind a person’s ear. The electronic impulses from the processor are sent to a coil (half- dollar sized) worn externally behind the ear over the implant. The coil sends an FM signal to the implant receiver, located completely under the scalp.
The implant then directs these sound impulses to an array of tiny electrodes within the cochlea (inner ear). In these signals are information about the frequency and loudness of speech and other sounds. The responses to these signals are then conveyed along the auditory nerve to the cortex of the brain where they are interpreted as sound.
The sound processing units must be specially fitted for their users. Audiologists specially trained in programming these devices usually do this. Programming sound processors involves measurement of the individual’s sensitivity to the electronic impulses. Other sound quality such as pitch also may be assessed. These responses are used to customize each person’s implant system so that sound is as clear and comfortable as possible for them. Quite remarkably, some deafened patients are able to communicate on the telephone the first day. Modern multichannel implants can provide very high levels of sound recognition to many recipients.
COCHLEAR IMPLANT SURGERY
Cochlear implant surgery frequently is conducted on an outpatient basis. After surgery, it generally takes three to five weeks for the incision to heal. Once healed, the implant recipient is fitted with the other components and the system is programmed to provide appropriate levels of stimulation.
Some patients with tinnitus (ringing in the ears) find that it is reduced after surgery, although it is not the goal of the surgery to reduce or eliminate tinnitus.
WHO BENEFITS FROM COCHLEAR IMPLANTS?
The patient likely to receive the most benefit from a cochlear implant is one who acquires profound deafness after developing verbal language skills and who is implanted within a few years of onset of deafness.
Others who may benefit include:
Adults with severe to profound or profound sensorineural hearing loss (“nerve deafness”) in both ears, who receive limited benefit from hearing aids.
Children with a profound sensorineural hearing loss in both ears, who receive little or no useful benefit from hearing aids.
Patients who have no existing medical conditions that would prevent them from having a surgical procedure.
Patients who have the support of friends and family.
Patients who want to be part of the hearing world.
Children who can be enrolled in an educational program that stresses auditory and oral language development.
Patients who are willing and able to make a time commitment of up to one year for the necessary rehabilitation process.
CONSIDERING A COCHLEAR IMPLANT?
If you think you may benefit from a cochlear implant, here is a comprehensive list of questions to ask when selecting your cochlear implant center.
General Questions for the Implant Team
- Who are the members of the implant team? (Should include: surgeon, audiologist, speech pathologist, psychologist, educator/educational liaison).
- How many different makes of cochlear implants are available in the USA?
- How long has each device been on the market? How many adults/children have these devices?
- Are these all approved by the FDA?
- Which implants are currently still in the investigational stages? (i.e. going through clinical trials
- What are the advantages and disadvantages of selecting a device that has/has not been approved by the FDA?
- Is additional follow-up testing required for an investigational device?
- What is the newest technology available in the cochlear implant market?
- How adaptable is each of the available cochlear implants to improvements in technology? (i.e. newer processing strategies, smaller component parts, etc.)
Does your team recommend a hearing aid trial of at least 6 months prior to commencing the cochlear implant evaluation?
What evaluation procedures are required before implantation? (i.e. Audiological tests: behavioral and electrophysiological, speech/language assessment, cognitive evaluation, otological evaluation, CT Scan, educational assessment)
Does the behavioral audiological assessment include speech perception testing?
Does the psychological or audiological evaluation include an assessment of expectations of benefit from the cochlear implant?
If you use total communication, is at least one member of the team able to communicate in sign language?
What is the audiologist’s personal experience with cochlear implants? How many years has he/she worked with implants?
How many workshops/training courses on cochlear implants has the audiologist attended? How many within the last two years?
Is the audiologist certified by one or more of the implant companies to rehabilitate cochlear implant recipients?
How many cochlear implant operations has the surgeon performed on adults/children?
Which devices has the surgeon implanted in adults/children?
What preparation for surgery does the center provide? (i.e. tour of hospital)
What physical restrictions are placed on the child in the weeks immediately post surgery?
What special precautions need to be taken when playing contact sports with a cochlear implant?
The Mapping Process
Which implants does the audiologist have the most experience with?
How many adults/children has he/she mapped?
What techniques does the audiologist use to validate mapping? (i.e. Ling 6 Sounds, ESP, Speech Tracking, etc.)
What experience has the audiologist with coupling assistive devices to the cochlear implant? (i.e. FM auditory trainers)
Does the center have a loaner stock of spare processors, microphones, coils, cords, etc.?
How easy is it to obtain replacement parts for each implant? (i.e. What is the center’s policy on scheduling emergency appointments?)
What is the repair warranty and loss/damage policy on each implant?
How often should you expect to have to replace cords, batteries, and other component parts?
What equipment costs and/or follow-up costs are not covered by insurance?
How easy is it to upgrade the external equipment when new things become available?
How many days does your center schedule for initial stimulation of the device? (2 to 3 sessions is usual)
How often are follow-up visits scheduled? (i.e. at one month, three months, six months, one year, eighteen months, two years, annually)
What follow-up tests are conducted to document progress with the cochlear implant? (i.e. speech/language evaluation, speech perception tests, etc.)
How many follow-up visits are covered by insurance?
What rehabilitation therapy is offered on site at the center?
What level of support are you, the parent/family/caregiver able to provide post implantation?
Are you able and willing to reinforce recommendations at home?
Are you able to support spoken English as the primary language of instructions at home to facilitate maximum success with the cochlear implant?
Have you discussed the cochlear implant with your child? Is he/she motivated to receive an implant? (for the older child)
Are you aware of the debate over cochlear implantation among the deaf community?
Have you talked with other cochlear implant recipients and their families?