A cochlear implant is an implantable device to help restore hearing. So there are
different types of hearing loss. Most of it involves the inner ear. And the cochlear implant
consists of several different parts. There is an external part that's worn partially
behind the ear, perhaps like you might -- or like a behind-the-ear hearing aid. It has
a separate wire with a little coil. The coil communicates to an internal device we place
under the skin behind the ear. The internal device then has a wire that goes into the
inner ear itself, into the cochlea, and then we can directly electrically stimulate the
hearing nerve. This allows us to bypass much of the damaged part of the cochlea, or inner
ear. Most people that have hearing loss will have loss of the outer hair cells or inner
hair cells or other structures in the inner ear. And the cochlear implant allows us to
bypass all those structures, go straight to the hearing nerve, and restore some degree
of hearing. So once a decision has been made to proceed with a cochlear implant, a surgery
is done in a hospital under general anesthesia, so completely asleep. Typically it takes anywhere
from 1-2 hours of surgery time, and most patients are able to go home the same day of surgery
or perhaps stay overnight one night. It's an incision made behind the ear. It's about
3-4 centimeters. We open up the bone behind the ear, which is the mastoid bone. That takes
us down to where the inner ear is. We place the main part of the device underneath the
skin behind the ear and then make about a 1-millimeter opening into the cochlea itself
and thread the electrode array into the inner ear. We then do some testing during surgery
to make sure the device is functioning appropriately and that we're stimulating the hearing nerve
and then some stitches. The cochlear implant is a complicated device, and it requires a
multidisciplinary team of professionals to gain the maximal performance of the device.
It's not an operation or a procedure where you come in one day, you have it done, you
flip a switch, and automatically you hear again. The device needs to be programmed,
there's a learning phase where the brain learns to interpret the sound, and the surgery itself
has some nuances. And so the whole evaluation process, the implant process, the post-operative
care and the programming requires a good team effort: the audiologists, surgeons like myself,
in the case of children, professionals that work with the schools or educational audiologists,
speech and language pathologists. And Mayo Clinic has a comprehensive team of experts
with a lot of experience in placing and taking care of people that have cochlear implants.
We have a number of ongoing research projects with respect to cochlear implants. There's
a whole host of questions that everyone's trying to answer. For example: Is one cochlear
implant enough or are people better off with two cochlear implants? We're born with two
ears, we hear better with two ears, but in the past a lot of people only had one cochlear
implant. Now we're implanting a second device in many adults, and it's really our preferred
process to implant two implants from the beginning in children. So we're looking at the outcomes
of that. And then another big area of interest, a very big area of interest, is preservation
of the hearing that people do have. In the past, when we put a cochlear implant in, we
would usually lose all of the remaining hearing in that ear. Some people have some useful
hearing, particularly in the low tones. With the newer devices, advances in surgical technique,
we're able to preserve some of that residual hearing. And then there's a group of devices
that are designed specifically to preserve the hearing, called short electrodes or hybrid
electrodes, and the idea there is you have a cochlear implant for electric hearing. But
in addition, you can wear a conventional hearing aid on the same side and so that's a big area
of research.