Questions and Related Information
You probably have a lot of questions related to your child's hearing loss and cochlear implants in general. Here are some frequently asked questions, and answers that will hopefully make you feel more comfortable about choosing an implant for your child.
What are the different types of hearing loss?
There are three types of hearing loss: conductive, sensorineural, and mixed.
Conductive hearing loss affects the outer or middle ear. Simply stated, this type of loss is a result of a physical blockage or non-moving part (that should be moving), that prevents sound from being conducted (or transferred) into the ear to be heard.
Sensorineural hearing loss affects the inner ear or the parts beyond (like the auditory nerve). This type of loss is a result of damage to the cochlea, its hair cells, or the transmission of messages along the auditory pathway (the path sound takes from the ear to the brain). This prevents sound from being detected by the ear and/or interpreted by the brain.
Mixed hearing loss is some combination of conductive and sensorineural.
You should talk to your child's audiologist more about his or her specific type of hearing loss and what that means for your child.
What are the different degrees of hearing loss?
Hearing loss can be classified as mild, moderate, moderate-severe, severe, or profound. Each degree has a minimum and maximum decibel level. The degrees of loss are as follows:
Normal 0-15 dB
Slight 16-25 dB
Mild 26-40 dB
Moderate 41-55 dB
Moderately Severe 56-70 dB
Severe 71-90 dB
Profound 91+ dB
Not every hearing loss falls perfectly into one degree, so it's not uncommon if your child has a loss that "slopes," "falls," or "rises" from one degree to another or among multiple degrees of loss. Sometimes, losses might be within the same degree at all but one frequency (called a "notch" or "cookie bite" loss).
With each increasing degree of hearing loss comes new challenges, such as environmental and speech sounds that cannot be heard. Generally speaking, the greater the degree of loss, the less is heard.
You should talk to your child's audiologist more about his or her specific degree of loss and what that means for your child.
Who is eligible for a cochlear implant?
The FDA has set the following criteria in place for children receiving cochlear implants:
1. Children ages 12-24 months with a profound sensorineural hearing loss bilaterally (in both ears) who have shown limited benefit from the use of hearing aids.
2. Children ages two years and older with a severe to profound hearing loss bilaterally who have shown limited benefit from the use of hearing aids.
3. Children who have had meningitis, regardless of age or hearing aid use. These children are at risk for ossification (hardening) of the bony part of the cochlea, which can make implantation more difficult.
If you are interested in learning more about FDA guidelines, information is available on the FDA website.
You should talk to your child's audiologist more about his or her eligibility for a cochlear implant.
How does a cochlear implant work?
A cochlear implant is a device that has two main parts, one internal and one external.
The external part of the device includes a speech processor, a microphone, a battery or battery rack, a cable, and a coil. The microphone collects sound, which the external processor then converts into digital information. This information is sent up the cable to the coil which transmits the information across the skin to the internal part of the device.
The internal part of the device is comprised of a receiver/simulator and an electrode array. The receiver/stimulator converts the digital information into electrical signals and sends them to the electrode array which is situated inside the cochlea. The electrical signals stimulate the auditory nerve and the information travels up the auditory pathway to the brain, where the sound is perceived.
The cochlear implant works by retrieving sound and delivering it directly to the auditory nerve, bypassing the damaged hair cells of the cochlea that cause the hearing loss.
You should talk to your child's audiologist and explore the cochlear implant manufacturer websites to better understand how each specific device functions.
How are cochlear implants and hearing aids different?
The biggest difference between hearing aids and cochlear implants is what they do to sound. Hearing aids work to amplify sound, basically just making it louder. Cochlear implants work to convert sound into electrical impulses and stimulate the auditory nerve directly, providing access to sound to people for whom hearing aids cannot provide adequate benefit.
One important thing to remember is that hearing aids and cochlear implants are assistive devices, not corrective devices. They can help overcome the effects of hearing loss, but they do not actually fix the loss. Getting a cochlear implant will not reverse your child's hearing loss, but will help give them access to sounds they cannot hear without an implant.
Cochlear implants aren't appropriate for every type of hearing loss. Some people use a hearing aid on one ear and a cochlear implant on the other. You should talk to your child's audiologist about the most appropriate use of assistive listening devices for your child.