Bilateral Cochlear Implants
Boys Town National Research Hospital offers cochlear implantation of both ears, in addition to single-side implant surgery. Bilateral implantation may be an option for individuals who are cochlear implant (CI) candidates or current CI recipients who already have one ear implanted. There are two options for bilateral cochlear implantation:
Simultaneous implantation - both ears are implanted in the same surgery. With this option, patients only have to be in the hospital once and only go under anesthesia once. This option is much less expensive than having two separate surgeries. Simultaneous implantation is a particularly good option for individuals recently deafened by meningitis because the disease can cause bone to grow and fill in the cochlea, which can make it extremely difficult or impossible for an implant to be inserted at a later date.
Sequential implantation - the CIs are placed during two separate surgeries. The time interval between the first and second surgery can range from weeks to years. This option is common for individuals who received their first CI years ago and would like to experience binaural hearing and/or benefit from newer technology in the second ear. This option is also common for people who don't want to be completely without sound or "off the air" for any length of time. Those recipients continue to use a hearing aid in the non-implanted ear during the healing period between surgery and the initial programming session. Once the first ear's speech processor has been programmed and the recipient has acclimated to the sound, then the second ear is implanted.
Why Should I Consider Bilateral Cochlear Implantation?
Hearing is normally accomplished with two ears. We are born with two ears and our brains are wired to receive input from both ears. It is the standard of practice in audiology to provide hearing aids for both ears (particularly for children), so it has been suggested that it should also be the standard of practice to provide two CIs.
Better localization and understanding speech in noise. Having two ears allows us to determine where sounds come from (localization), and it helps with understanding speech in background noise. Current research on bilateral cochlear implantation has shown a wide range in recipients' performance on these two particular tasks. In general, bilateral CI recipients tend to be able to localize better and understand speech in noise better with two CIs than with one.
Better sound quality, less listening effort, and other benefits. Benefits of bilateral implants appear to extend beyond sound localization and hearing in noise. Many bilateral implant recipients report better sound quality/clarity, more acoustical balance, greater ease in following group conversations, and less fatigue at the end of the day. A team of researchers at Boys Town National Research Hospital is currently investigating the benefits that children and adults receive from two CIs. The most important finding so far is that children with two CIs are much more confident to engage in group conversation and to stay in those conversations. This has very important implications for socialization in deaf children. Additionally, parents report improvements in their child's behavior with bilateral CIs.
Never being without sound. In the unfortunate event that external equipment breaks (e.g., a cord, processor, headset) or the internal device fails, having a second implant means that the recipient never has to go without sound. This is an important consideration for adults who cannot afford to miss work because they can't hear or for children who would otherwise miss out on learning opportunities in daily life or at school.
What are the Potential Disadvantages of Bilateral Cochlear Implantation?
Cost. In addition to the increased costs associated with surgery and a second internal device, the costs associated with maintaining hardware (cords, cables, batteries, speech processors, service agreements/extended warranties, etc.) is doubled with two CIs. There is also added cost for clinical services due to the extra time needed for programming two speech processors.
Loss of residual hearing. One of the biggest risks of CI surgery is the loss of any remaining acoustic hearing. Although advances have been made in implant design and surgical technique, loss of residual hearing following implantation is still common. Acoustic hearing can be useful for better sound quality and music enjoyment, so some individuals prefer to have only one ear implanted and use a hearing aid in the opposite ear to maintain some acoustic hearing. This of course is not an issue for candidates who do not benefit from hearing aids.
Future technological advances. Some people want to "save" the other ear for future technological advances. One problem with this is that research has shown that lack of auditory input causes the neural pathways in the auditory system to slowly die back (atrophy). If the neurons atrophy, then the CI won't have much to stimulate and the recipient will get little benefit from the implant. Therefore, hearing aid use is highly recommended if an individual is considering waiting for implantation at a much later date. Other things to consider are: (1) Re-implantation is done with a high success rate in the event that old technology needs to be replaced with new technology, (2) CI manufacturers are building extra capabilities into their internal devices so that upgrades only need to be made to the external speech processor instead of having another surgery to replace the internal device, and (3) advances in hair cell regeneration have been slow to evolve and won't help for some causes of deafness (for example, where certain structures in the cochlea are malformed or missing).
Who Is a Candidate for Bilateral CI Surgery?
The same candidacy criteria for single-sided cochlear implant surgery apply to bilateral implant surgery.
Will Insurance Pay for Bilateral Cochlear Implantation?
Insurance coverage for bilateral CIs has been sporadic. Some insurance companies will pay, some won’t, and some will pay only after an initial denial has been appealed (sometimes more than once). The cochlear implant manufacturers have resources to assist implant centers with insurance approvals/appeals for bilateral CIs. There are some resources available to assist candidates in this process:
What Do Other People With Bilateral CIs Have to Say?
The following websites contain personal accounts of bilateral cochlear implantation from the recipient's perspective. Boys Town National Research Hospital and the Lied Learning and Technology Center for Childhood Deafness and Vision Disorders is in no way affiliated with or responsible for the information contained in the following websites: