It has been estimated that over 7 million Americans aged twelve and older have severe to profound hearing loss in at least one ear. Up until the 1980’s, those with severe to profound hearing loss had no effective treatment options for their disability. But in 1985, the FDA approved the first cochlear implant, the Nucleus CI22, for commercial use. The cochlear implant has since been proven to be a successful option. As of December 2019, over 183,000 cochlear implants have been implanted in children and adults.
What Is a Cochlear Implant?
A cochlear implant is a complex hearing device used by individuals with moderately-severe to profound hearing loss. It includes both external and internal components that work together to directly stimulate the auditory nerve. Direct stimulation of the auditory nerve produces sounds that can be recognized by a person as speech, music, alarms, knocking, or other noises.
Who Needs a Cochlear Implant?
Cochlear implants are recommended for children and adults whose hearing loss and speech recognition do not benefit from traditional hearing aids.
Cochlear implants are a lifetime commitment. Therefore, cochlear implants are only advised for patients who have a strong desire to be a part of the hearing world. They must be committed to the training, or rehabilitation, required with cochlear implants.
Both young children and adults can improve their quality of life with the use of cochlear implants.
Cochlear Implants for Children
Babies who are born deaf can experience normal speech development after getting a cochlear implant and participating in aural rehabilitation (a type of “listening” therapy). A child with a severe to profound hearing loss in both ears, or auditory neuropathy spectrum disorder, may be a candidate for a cochlear implant. Children who are born deaf can receive a cochlear implant around 10-12 months of age. The sooner the child is implanted, the greater success they will have with normal language development. Contact your audiologist to find out if a cochlear implant is right for you or your child.
Cochlear Implants for Adults
Adults who get cochlear implants should be able to understand spoken communication and rely less on lip reading following consistent aural rehabilitation. In a small minority of people, specifically adults who were born deaf and have little experience with sound, cochlear implants may not help with speech understanding.
How Does a Cochlear Implant Work?
The cochlear implant consists of five main components:
- Microphone
- Processor
- Transmitter
- Receiver
- Electrode array
The microphone, processor, and transmitter are the external parts of a cochlear implant. The receiver and electrode array are the internal parts that are implanted during surgery. Each component and its role are discussed below.
Microphone and Processor
The microphone and processor are usually housed together in a plastic case that rests on the outer ear, much like a behind-the-ear hearing aid. There are other styles of cochlear implants in which the microphone and processor are housed with the transmitter and held in place on the side of the head. This style is bulkier and not as discreet as the behind-the-ear style of cochlear implant, but it is easier to manage and less likely to cause discomfort to the ear. Consult an audiologist for guidance on which style is best for you.
The role of the microphone, as predicted, is to pick up sounds and pass them to the processor. The processor sorts all the sounds into different frequency “channels” and then converts the information into digital signals. Finally, the processor sends the digital signals to the transmitter (also known as the transmitting coil).
Transmitter
The transmitter receives the digital signals from the processor and passes them on to the receiver, which is implanted underneath the skin. The transmitting coil is held in place against the head by a magnet on the receiver.
Receiver
The receiver on a cochlear implant is often referred to as the stimulator or the internal processor. It is surgically implanted underneath the skin alongside the head. The first job of the receiver is to collect the digital signals from the transmitter. Next, the receiver changes the digital signals, which have been sorted into frequency “channels” by the external processor, into electrical impulses. Lastly, the receiver will pass the electrical impulses on to the electrode array via a small wire.
Electrode Array
The electrode array on a cochlear implant features 12 to 22 electrodes placed along a small wire. This thin wire is inserted into the cochlea during surgery. Electrical impulses from the receiver are sent down the wire and to the various electrodes. The job of each electrode is to stimulate a different region of the cochlea. Electrical impulses that correspond to higher frequency sounds are sent to electrodes in the outer region of the cochlea. Electrical impulses that correspond to lower frequency sounds are sent to electrodes in the inner region of the cochlea. The auditory nerve picks up the signals as they are transmitted to the cochlea.
What to Expect During Cochlear Implant Surgery
Cochlear implant surgery is an outpatient procedure conducted in a hospital or clinic. The surgery typically lasts two to four hours. During the surgery, the internal components (receiver and electrode array) of a cochlear implant are put in place. The surgery is performed while the patient is under general anesthesia, and the steps taken during the procedure are as follows:
- A one-inch incision is made directly behind the ear. A small section of hair may be shaved away from the incision site beforehand.
- The skin is opened to the mastoid bone.
- A “subperiosteal pocket” is created for the receiver to lay along the skull.
- The surgeon then cuts a small “round window” through the mastoid bone.
- The surgeon identifies the facial nerves and creates an opening between them to the cochlea.
- A tiny hole is made in the cochlea.
- The receiver is placed under the skin and into the “subperiosteal pocket.”
- The electrode array is then slowly fed into the cochlea.
- The “round window” to the cochlea is closed.
- The incision site is closed.
Recovery
After surgery, a bandage is wrapped around the head to protect the incision site. The patient is then taken to a recovery room to wait while the general anesthesia wears off. Patients are discharged the same day as the surgery, usually after two hours of observation. Normal activities are allowed to resume a few days after surgery, with special precaution taken for the surgical site.
Activation
Activation of the cochlear implant takes place two to four weeks after surgery. In a separate visit to the audiologist, the cochlear implant will be turned on and checked for functionality. The patient will continue to visit the audiologist multiple times over the next year to fine-tune the cochlear implant. The patient will also need to attend rehabilitation sessions with a therapist in order to acclimate themselves to the sounds heard through the cochlear implant.
Risks
As with any surgical procedure, risks can occur. The risks are rare, but may include:
- Bleeding
- Inflammation of the membranes surrounding the brain and spinal cord (meningitis)
- Infection at the surgery site
- Tinnitus
- Loss of residual hearing
- Dizziness
- Numbness around the ear
- Changes in taste
- Injury to the facial nerve, which can cause paralysis in the face
- Leakage of spinal fluid
- Risks of general anesthesia
- Failure of cochlear implant
Insurance
Cochlear implants and cochlear implant surgeries are covered by Medicare, Medicaid, the Veteran’s Administration, and over 90% of private insurance companies. For anyone looking into Medicare, Medicare Part B covers the cost of one or two cochlear implants. To qualify, the audiologist, health care provider, and implant supplier must all participate in Medicare. The cost that you will still be responsible for is a 20% co-pay and the deductible.
Rehabilitation
The success of a cochlear implant relies heavily on the rehabilitation that occurs after surgery, called aural rehabilitation. For children, rehabilitation begins immediately after the cochlear implant is activated. For adults, rehabilitation does not start until a month after the implant is activated. Rehabilitation is the time in which patients begin to understand the sounds that they can now hear through the cochlear implant. The process lasts at least one year and typically consists of weekly sessions. Some topics that are addressed during these sessions are as follows:
- The cochlear implant and how it works
- New sounds and what they represent
- New sounds and where they are coming from
- Music
- The difference between sounds and speech
- How to improve one’s own speech
FAQ’s
Is the cochlear implant surgery considered to be major brain surgery?
No. Cochlear implant surgery is not considered to be major brain surgery. The surgery is a simple, outpatient procedure that lasts two to four hours. The patient is placed under general anesthesia while one small cut is made behind the ear to insert the implant.
Will a cochlear implant restore hearing back to normal?
No, a cochlear implant does not fully restore hearing back to normal. It can take months for a patient to interpret the sounds from a cochlear implant and to learn what the sounds represent. Nonetheless, patients are eventually able to understand speech, recognize where sounds are coming from, listen to music, and much more.
Can a cochlear implant be removed?
Yes. In some situations, a cochlear implant may need to be removed. Examples include failure of or damage to the internal components. In addition, one may need an upgrade to the internal components. In any case, surgery would have to be repeated to remove and replace the device.
Are cochlear implants safe for MRI’s?
An MRI should be avoided if alternative imaging techniques (i.e., CT scans and x-rays) can be used. However, an MRI can be safely performed if necessary. Patients typically undergo a binding procedure beforehand in which technicians will bandage the site of the magnet on the cochlear implant. Symptoms experienced during an MRI include mild to moderate discomfort and warmth at the location of the magnet.
Can I fly with a cochlear implant?
You can safely fly in an airplane one to two weeks after surgery. This timeline can vary depending on the surgeon’s recommendations. You are advised to carry your cochlear implant identification card, since the metal in the implant will set off metal detectors.
Are cochlear implants waterproof?
The external components (microphone, processor, and transmitter) are designed to be water-resistant but not waterproof. If you truly want your external components to be waterproof, they must be sealed in special waterproof cases. Unless you have purchased a waterproof case for your cochlear implant, avoid swimming or showering with the external components.
Can a cochlear implant treat tinnitus?
Yes, cochlear implants have been shown to relieve tinnitus in some cases, as a form of neuromodulation. However, the treatment of tinnitus is neither the primary goal of a cochlear implant nor can it be guaranteed.
Will I need one or two cochlear implants?
Research has shown that two cochlear implants are beneficial for improved speech recognition and development. Having a cochlear implant in both ears is called binaural implantation. Binaural implantation can also be helpful for localizing where sounds are coming from. Someone may not be a candidate for binaural implantation if the structures of the cochlea in one ear are malformed. Your cochlear implant professional team will determine if you are a good candidate for binaural implantation. If not, bimodal hearing may be recommended, which is a cochlear implant in one ear and a hearing aid in the other ear. Bimodal hearing can also be beneficial for speech understanding and localization.
How much does a cochlear implant cost?
The cost of a cochlear implant, by itself, can range from $6,000 to $9,000. However, the cost of the cochlear implant is generally included in the cost of the surgery. The total cost for surgery and all necessary office visits can range from $50,000 to $100,000 without medical insurance. With insurance, the cost can range from $1,000 to $50,000. The price will vary depending on the co-pay, deductible, and maximum-out-of-pocket set by your insurance company.
Conclusion
Cochlear implants are a viable treatment plan for individuals with moderately-severe to profound hearing loss. With successful rehabilitation, a person can:
- Communicate with friends and family
- Rely less on lip reading or sign language
- Hear their own voice
- Hear music, alarms, knocking, and other everyday sounds
- Watch TV without closed captioning
In conclusion, most patients report a significant improvement with their quality of life. To find out if a cochlear implant is right for you or your child, contact your audiologist.
Sources
- Centers for Disease Control and Prevention. “Data and Statistics About Hearing Loss in Children.” https://www.cdc.gov/ncbddd/hearingloss/data.html. Accessed Mar. 13, 2022.
- Goman, Adele M. et. al. “Prevalence of Hearing Loss by Severity in the United States.” American Journal of Public Health, vol. 106, no. 10, Oct. 2016, pp. 1820-22. https://doi.org/10.2105/AJPH.2016.303299.
- Hearing Sol. “Cochlear Implant Cost.” https://www.hearingsol.com/help/cochlear-implant/cost/. Accessed Mar. 13, 2022.
- Hearing Sol. “Cochlear Implant History.” https://www.hearingsol.com/help/cochlear-implant/history/. Accessed Mar. 13, 2022.
- John Hopkins Medicine. “Cochlear Implant Frequently Asked Questions.” https://www.hopkinsmedicine.org/otolaryngology/specialty_areas/cochlear-implant-center/faq.html. Accessed Mar. 11, 2022.
- Mayo Clinic. “Cochlear Implants.” https://www.mayoclinic.org/tests-procedures/cochlear-implants/about/pac-20385021. Accessed Mar. 11, 2022.
- National Institute on Deafness and Other Communication Disorders. “Cochlear Implants.” https://www.nidcd.nih.gov/health/cochlear-implants. Mar. 24, 2021. Accessed Mar. 11, 2022.
- Pacific Hearing Services. “Cochlear Implants.” https://www.pacifichearing.com/services/cochlear-implants/. Accessed Mar. 13, 2022.
- U.S. Drug and Food Administration. “What is a Cochlear Implant?” https://www.fda.gov/medical-devices/cochlear-implants/what-cochlear-implant. Updated Feb. 4, 2018. Accessed Mar. 13, 2022.
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