Cochlear implants are small, implantable devices that restore hearing perception to those who do not benefit from wearing conventional hearing aids. While the conventional hearing aids amplify sounds, the cochlear implant bypasses impaired inner ear structures and stimulate the hearing/auditory nerve. As of December 2012, approximately 324,000 people worldwide have received cochlear implants. The Georgetown Cochlear Implant Program offers some of the most advanced options in auditory rehabilitation including bilateral cochlear implants, hybrid and other hearing preservation devices and approaches.
Learn more about cochlear implants and if cochlear implants are right for you or a loved one.
- What is a cochlear implant and how does it work?
- What is the difference between hearing aids and cochlear implants?
- Who is a candidate for cochlear implants?
- How much do cochlear implants cost?
- What is the process of receiving cochlear implants?
- What should I expect after I get cochlear implants?
- What are the risks and complications of cochlear implants?
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What is a cochlear implant and how does it work?
A cochlear implant is an electronic device that is partially implanted surgically into the cochlea, the hearing organ of the inner ear. It uses electrical current to bypass damaged or missing portions of the inner ear and stimulates remaining hearing nerve fibers. A microphone, processor, and transmitter are worn externally to control the implanted internal device.
As seen in the photo:
- The sound processor (A) captures sound and converts it into digital code.
- The sound processor transmits the digitally coded sounds through the coil (B) to the implant (C) just under the skin.
- The implant converts the digitally coded sound to electrical signals and sends them along the electrode array, which is positioned in the cochlea.
- The implant's electrodes stimulate the cochlea's hearing nerve fibers, which relay the sound signals to the brain to produce hearing sensations.
The use of cochlear implants for the treatment of moderate to profound hearing loss is a revolutionary treatment and has been called one of the single most effective health interventions of our time.
As seen in the photo:
- Sound waves enter the ear canal and contact the ear drum (tympanic membrane).
- After the ear drum picks up the sound, it transmits sound through the three ear bones, known as the hammer (malleus), anvil (incus), and stirrup (stapes). The stirrup passes the vibrations to the inner ear fluids within the cochlea.
- Fluid waves travel through two and a half (2 ½) turns of the cochlea and stimulate the cochlear sensory organ, hair cells.
- The hair cells are tuned to respond to the wide range of frequencies or pitches of the original sound waves, initiating signals within their corresponding hearing/auditory nerve endings prior to sending them to the brain.
Implants vs. Hearing Aids
Hearing is a complex process that originates in the cochlea: the organ of hearing that is located inside the temporal bone of the skull. The cochlea contains thousands of microscopic sensory cells that work much like the keys on a piano. Each sensory cell, called a hair cell, is organized and tuned to match a specific pitch. In a normal hearing person, these sensory cells respond to acoustic/sound information in the environment and translate it into a neurological code that is transmitted through the hearing nerve to the brain where understanding of the sound happens. If any of these sensory cells do not work properly, the information that arrives in the brain will be distorted and incomplete. The listener may have difficulty understanding what is said.
In the presence of hearing loss, when the sensory hair cells are permanently damaged and/or missing, incomplete and distorted sound arrives at the brain. Hearing aids only make sounds louder and can compensate for partially damaged hair cells, but they cannot overcome significant and permanent hair cell damage.
A cochlear implant is not a hearing aid. Instead it is a neural prosthesis that helps to provide hearing to people with moderate to profound hearing loss by bypassing the damaged sensory cells of the cochlea for individuals that obtain little or no benefit form sound amplification by hearing aids. The patient’s traditional means of hearing “acoustic hearing” is then replaced with “electric hearing” through the cochlear implant.
Who is a candidate for cochlear implants? (Criteria)
With technical advances in cochlear implant technology, the minimal criteria have been evolving, the following is the current criteria for adult and child cochlear implant candidates:
The Food and Drug Administration (FDA) has approved the use of cochlear implants for children who meet the specified criteria:
- Children at least 9 months of age
- Children with severe-to-profound hearing loss
- Children who are healthy enough to have the surgery
- Children whose families are motivated to follow through with auditory verbal rehabilitation therapy and full time device use
- Younger children:
- No benefit from well-fitted hearing aids that are worn all of the time, and
- No progress or change in speech and language development
- Older children:
- Unable to understand at least 30% of the words with listening only tests
Patient expectations can be a sensitive and critical issue to address both pre-operatively and post-operatively with not only the patient undergoing the surgery but with the patient's family and friends. Post-operative outcomes for cochlear implant recipients can take many recognizable forms, including sound awareness (known as detection) at the most basic level to open-set speech recognition (referring to the patient’s ability to identify what is said without prior knowledge of what the word or sentence choices are) in noise.
When a seemingly simple head cold led to hearing loss, professional bicyclist John Anderson says he “became a pedestrian.” But Dr. Michael Hoa and cochlear implants got him back on the road.
The amount of benefit that a patient perceives is largely dependent on his/her past hearing history and exposure to amplification and spoken language. Patients who developed spoken language prior to the onset of significant hearing loss are routinely identified as post-lingually deafened. A patient with this hearing background is different from a patient whose primary means of communication is through sign language or other forms of manual and visual communication. Patient's who rely on sign language are often described as being pre-lingually deafened, meaning that the hearing loss preceded his/her development of spoken language. Post-lingually deafened adult patients tend to have better outcomes than pre-lingually deafened adult patients after cochlear implantation. In those pre-lingually deafened pediatric patients implanted early in their development (12-24 months), outcomes with cochlear implants may be equivalent to those of post-lingually deafened pediatric patients. After this early period, post-lingually deafened pediatric patients tend to have better outcomes than pre-lingually deafened pediatric patients after cochlear implantation.
Research has shown auditory verbal therapy and speech-language rehabilitation to be viable means for improving speech perception outcomes for most cochlear implant recipients. Referral for these services is optional for each patient and can be discussed with your audiologist and speech-language pathologists we are supportive of this decision. Both post-lingual as a well as pre-lingual patients can be excellent candidates for cochlear implantation, and we review each patient as a unique and separate case. Cochlear implantation is a life-changing experience and we believe in serving all of our patients to the best of our knowledge and expertise.
Cochlear Implant Process
The surgery takes approximately 2 to 3 hours to perform. The majority of patients go home the same day of surgery. Further surgical details will be discussed with your physician.
The surgical placement of cochlear implants has been performed for over 40 years. Newer implant designs and surgical techniques allow us to place these devices with very few complications and excellent cosmetic results.
The procedure is performed in a day surgery unit with most patients going home the same day. General anesthesia is administered in the operating room, and a small amount of hair behind the ear is shaved, if necessary. An incision is made in the crease behind the ear, which makes the scar very inconspicuous once it has healed. A pocket is created under the skin to accommodate the internal receiver-stimulator portion of the implant. This part of the implant has a very flat design so that it will not produce a noticeable deformity. An opening is then made into the air-filled bone called the mastoid. This mastoidectomy allows us to access the cochlea without disturbing the ear canal or eardrum. A very small opening is made into the cochlea, and the implant electrode is threaded in as far as possible. Most cochleas can accommodate the complete electrode unless there is a cochlear abnormality, which may result in a partial insertion. The incision is closed with hidden absorbable stitches that do not require removal. A mastoid dressing is placed on the ear and remains in place for 1-2 days. Patients usually leave the hospital 2-3 hours after surgery is completed. Pain is mild-to-moderate for 1 to 2 days and can be controlled with oral pain medicines. Some patients experience imbalance for a few days after surgery, but this resolves within the first week. Patients are seen in the office 1 week after surgery to check the incision. Most patients are able to return to work or school at that point. The initial activation of the device and placement of the external equipment is performed 4 weeks after surgery. Once healed there is practically minimal visible evidence of the implant’s presence. The incision can tolerate water 3 days after surgery. Sports and strenuous exercises should be suspended for 3 weeks. After that, there are no activity restrictions.
Cochlear implants are extremely reliable. It is expected that a patient will never need to have their implant replaced. Less than 1% of implants have malfunction that requires replacement. Thankfully, if necessary, implants can be surgically replaced without losing any hearing performance. This also means that in the future patients can be upgraded to newer technology if warranted by the expectation of improved performance.
Cochlear implant activation usually takes place 4 weeks after surgery. At that time, the patient will be fitted with the external parts of the device, which requires programming of the external speech processor by the cochlear implant audiologist. During this process, the patient will begin to hear their first sounds generated by the implant. That day you will have the processor programmed and leave the office with the implant functioning. This is the beginning of learning to hear with the implant. If indicated, you will schedule Auditory-Verbal Therapy to begin sometime after this visit.
The programming of the external speech processor is a procedure that must be repeated one week later and then periodically thereafter. The reason for this is because the implant system must be programmed to suit each individual's needs. Each patient's tolerance of sound improves with time. Therefore, the implant stimulation level can be adjusted to suit each patient’s needs. The implant team is committed to work with the implant recipient as long as it is necessary to ensure optimal benefit from the device.
Cochlear implantation and its benefit to individuals with moderate to profound hearing loss is a well-documented medical procedure. Medicare along with most major, private insurance companies recognize its significant benefit and medical necessity and typically offer 80-100% coverage of the costs of the surgery and the implant system. Once candidacy for the process has been determined and a surgery date established, the MedStar Georgetown University Hospital Department of Otolaryngology will work with your insurance on your behalf to obtain an authorization for the cochlear implant surgery. Every patient's medical coverage is unique, which can affect the overall cost of the surgery. The MedStar Georgetown Department of Otolaryngology-Head and Neck Surgery will work with you with regards to financing. We will discuss your individual insurance plan and your potential out-of-pocket expenses associated with the surgery.
Selecting a Device
With three cochlear implant companies manufacturing reliable FDA approved devices, flexibility exists among the available technology to make the “best” choice for each and every patient. We work equally with all three cochlear implant devices and are equipped to service and program implant from these companies: Cochlear Corporation, MED-EL Corporation, and Advanced Bionics Corporation.
The ultimate decision-making process includes the collaboration of the patient's desires with the recommendations of the implant team (surgeon, audiologist, family). All three implant manufacturers have a long-standing history of building and creating reliable speech processors that offer strong patient performance. They are committed to the functioning of the device for the lifetime of the patient. These manufacturers are constantly seeking to improve the existing technology so as to offer new options to patients while ensuring back-compatibility to the internal devices that may have been implanted years earlier.
With most advances, newer, sleeker and more efficient processing units become available which means that the upgrade process is understood and supported by the companies as well as insurance providers. A variety of accessories and features come with each of these implants and information on these options will be provided to the patients by the audiology. You will discuss your personal needs with your audiologist to determine the best implant system to meet the demands of your lifestyle.
Regarding patient preference, we encourage patients to obtain literature from all implant manufacturers as well as visit the company websites online to gain more information about device technology, before engaging in the selection process. We are comfortable with all manufacturers and are willing and able to accommodate patient preferences.
Abnormal cochlear or external ear anatomy will be assessed via CT and/or MRI scan. The surgeon may have advice and valuable input about a specific internal receiver, which may work best with the patient’s anatomy. In the end, this could influence the external wearing options for the patient.
Examples of external components from the 3 manufacturers are seen below:
Risks and Complications
- Loss of natural (or residual) hearing in implanted ear
- Greater chance for infection around the brain and spinal cord (known as meningitis)
- Facial nerve stimulation resulting in involuntary facial twitching
- Swelling (inflammation) / Pushing or thrusting out (extrusion) of device
- Soreness, redness, breakdown of skin in area around device
- Failure of implanted device, sometimes requiring reimplantation
- Numbness / tenderness around the ear
- Injury to the facial nerve / facial paralysis (facial drooping)
- Taste Change (dry mouth or metallic taste in mouth)
- Leak of inner ear fluid (perilymph) or fluid that surrounds the brain (cerebrospinal fluid)
- Dizziness or Vertigo
- Ringing in the ears (tinnitus)
- Local complications such as blood/fluid collection or infection at or near surgery site
- Rashes (skin reactions)
- Post-surgery pain, scarring, bleeding, and infection
- Risks associated with being put to sleep or general anesthesia (problems with the heart, lungs, kidneys, liver and brain due to general anesthesia)
Meningitis is a possible, albeit very rare, complication of cochlear implantation. However, when present it can cause serious consequences.
Meningitis is an infection of the lining of the surface of the brain. Early symptoms of meningitis include fever, irritability, lethargy and loss of appetite in infants and young children. Older children and adult may also manifest headaches, stiff neck, nausea, vomiting, and confusion or alteration in consciousness. Physicians are encouraged to consider a diagnosis of meningitis in cochlear implant patients when such symptoms exist and to begin appropriate treatment as soon as possible.
The unusual occurrence of meningitis can be decreased even further through the use of appropriate vaccination. We recommend vaccinations for patients with cochlear implants. If you have not received a vaccination recommendation sheet, please ask our office staff. If you have any issues regarding this issue, please contact your physician.
Based on CDC recommendations, all persons with cochlear implants should receive age-appropriate pneumococcal vaccination with 13-valent pneumococcal conjugate vaccine (PCV13/Prevnar13), 23-valent pneumococcal polysaccharide vaccine (PPSV23) (Pneumovax®23), or both according to the Advisory Committee on Immunization Practices (ACIP) schedules for person at high risk.
Because the rate for pneumococcal meningitis is higher in children with cochlear implants and Streptococcus pneumoniae is the most common pathogen causing bacterial meningitis in cochlear implant recipients of all ages with meningitis of known etiology, CDC recommends the following for persons who have or are scheduled to receive a cochlear implant:
- Children aged <2 yrs with cochlear implants should receive PCV13, as is universally recommended; children with a lapse in vaccination should be vaccinated according to the catch– up schedule issued.
- Children aged 2 to 5 yrs with cochlear implants who have not received PCV13 should be vaccinated according to the high-risk schedule; children with a lapse in vaccination should be vaccinated according to the catch-up schedule for persons at high risk issued after the PCV13 shortage resolved (3.4). Children who have completed the PCV13 series should receive PPSV23 ≥8 weeks after vaccination with PCV13 (3).
- Persons aged 5-64 years with cochlear implants should have one dose of PCV13 followed 8 weeks later by PPSV23
- Persons planning to receive a cochlear implant should be up-to-date on age appropriate pneumococcal vaccination ≥2 weeks before surgery, if possible.
- Adults (age 19 years and older) who have NOT had any prior pneumococcal vaccinations need one dose of PCV13 followed 8 weeks later by PPSV23. A PPV23 booster is required at age 65 years. Adults (age 19 years and older) who have had prior vaccination only with PPV23, now also need one dose of PCV13 to be given 12 months after their PPSV23 shot.
Meningococcal Cochlear Implants and Vaccination Recommendations: Information for Public | CDC
The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website. www.cdc.gov
- CDC, Pneumococcal vaccination for cochlear implant recipients. MMWR 2002;51;931.
- Reefhuis J, Honein MA, Whitney CG, et al. Risk of bacterial meningitis in children with cochlear implants, USA 1997-2002. N Engl J Med 2003;349:433-43.
- U.S. Food and Drug Administration, Public Health web notification: cochlear implant recipients may be at greater risk for meningitis.
- CDC. Preventing pneumococcal disease among infants and young children: recommendations for the Advisory Committee on Immunization Practices. MMWR 2000:49(No. RR-9)
- CDC. Use of Vaccines to Prevent Meningitis in Persons with Cochlear Implants. Updated June 19, 2015. Available at http://www.cdc.gov/vaccines/vpd-vac/mening/cochlear/dis-cochlear-gen.htm
- American Academy of Otolaryngology-Head and Neck Surgery
- American Cochlear Implant Alliance
- AG Bell Association
- American Speech-Language-Hearing Association
- Cochlear Implant Patient Information Packet
- Hearing Loss Association of America
- Hearing Journey
- MRI Safety for Cochlear Implant Patients
Cochlear Implant Manufacturers: