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Cochlear Implants at Mayo Clinic

Posted by @shawnbishop, Nov 4, 2011

Dr. Colin Driscoll, a Mayo Clinic Ear, Nose and Throat surgeon discusses Mayo Clinic’s minimally invasive approach to cochlear implants and efforts to preserve existing hearing. For more information on cochlear implants, click here:

The following is a transcript of Dr. Driscoll’s video.

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. Theres an external part thats worn partially behind the ear, 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 in to 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 the inner ear. Most people that have hearing loss will have a 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. Once the decision has been made to proceed with a cochlear implant, the surgery is done in a hospital, under general anesthesia, so completely asleep. Typically takes anywhere from one to two hours surgery time and most patients are able to go home the same day as surgery or perhaps stay overnight one night. So an incision made behind the ear, its 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 one 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 were stimulating the hearing nerve then some stitches.
A cochlear implant is a complicated device and it requires a multi-disciplinary team of professionals to gain the maximal performance of the device. Its not an operation or 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, theres a learning phase where the brain learns to interpret the sound and the surgery itself has some nuances so the whole evaluation, the implant process, the post-operative care and the programming requires a good team effort, the audiologist, 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 respects to cochlear implants. Theres a whole host of questions that everyones trying to answer, for example, is one cochlear implant enough or are people better off with two cochlear implants. Were born with two ears, we hear better with two ears, but in the past a lot of people only had one cochlear implant. Now were implanting a second device in many adults and its really our preferred process to implant two implants from the beginning in children so that the very young children born without hearing loss often have two implants right from the state. So were 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, so with the newer devices, advances in surgical technique, were able to preserve some of that residual hearing. Then theres 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 convention hearing aid on the same side and so thats a big area of research.


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