For those with a cochlear implant, the idea is to essentially bypass the ear altogether, as it is too damaged.
Who Needs a Cochlear Implant?
The reason that most people don’t need a cochlear implant is that modern hearing aids are very versatile. Hearing aids currently on the market are powerful enough to easily provide proper amplification for severe hearing losses. They are also sophisticated enough to provide a clear signal in most environments. But they do have their limitations. And that is where cochlear implants come into play.
Simply put, hearing aids can only get so loud. If a person’s hearing is beyond the output limit of the hearing aid, they will not benefit. Particularly for those with profound hearing losses, cochlear implants are the best solution. Because of the way cochlear implants function, which will be discussed more in the next section, they are not subject to the same output limits as hearing aids. Thus, they can provide audibility for any degree of loss.
The other factor is clarity. Some people may have a hearing loss that fits within the output range of a hearing aid, but be completely unable to understand speech. For example, a person may have a moderate to severe hearing loss, but only 30% word recognition. So even though the hearing aid makes it easier for them to hear the sound, speech still sounds garbled and unintelligible. It’d be like listening to a loud, fuzzy radio. Again, this type of patient would benefit greatly from a cochlear implant, as studies show it can help to significantly improve speech understanding. The bottom line is that if a patient no longer benefits from appropriately fitting hearing aids, they become a cochlear implant candidate.
How Does a Cochlear Implant Work?
When a soundwave approaches the ear, it is funneled down the ear canal to the eardrum. The eardrum vibrates in a specific pattern, which moves the bones in the middle ear (ossicles). The ossicles then vibrate the fluid in the cochlea, which is the organ of hearing. The vibrating fluid stimulates the sensory cells in the cochlea, which then generate an electrical impulse for the auditory nerve. This is how we hear. However, if the sensory cells or nerve are damaged, this prevents the signal from appropriately reaching the brain, which causes hearing loss.
For those with a cochlear implant, the idea is to essentially bypass the ear altogether, as it is too damaged. Instead, an electrode array is inserted into the cochlea, stimulating the auditory nerve directly. A processor connects to the implant via magnet, collecting and modifying the sound much like a hearing aid would. There is no acoustic signal, so output limit is not a concern. The signal does not have to travel through the ear, so there is not as much distortion. Cochlear implants are also convenient to use, with some being rechargeable and many being Bluetooth enabled. They can also come with accessories, just like hearing aids, making them an elegant solution for those most in need.
What are the Qualifications?
In contrast to hearing aids, determining cochlear implant candidacy involves many factors. First, of course, is the hearing exam itself. Candidates must have a certain degree of hearing loss and speech recognition ability of 40% or less. Your audiologist will know the specific numbers. But you must also be a good candidate for surgery. While receiving a cochlear implant is a quick out-patient procedure that is safe at any age, the surgeon must still verify that it is safe to perform the surgery and that there are no anatomical anomalies that would prevent placement. The other big factor is social support. You will need somebody to take care of you during the surgery and while recovering. There are also multiple follow up appointments with the audiologist, which are necessary for successful outcomes.
Cochlear implants are a wonderful invention that can vastly improve the quality of life for those who receive them. Always feel free to discuss the option with your audiologist if you feel it may be right for you. FBN
By Jeff Lane, Au. D.
Trinity Hearing Center is located at 1330 N. Rim Dr., Suite B in Flagstaff. For more information, visit the website at TrinityHearing.net. Jeff Lane is a doctor of audiology with a passion for improving the lives of others. Dr. Lane may be reached at 928-522-0500 or at audio@trinityhearing.net.
