Cochlear Implant: Information on Initial Fitting and Cochlear Implant Surgery

The cochlear implant consists of two main parts: the speech processor, which is worn externally on the ear, and the implant itself, which is located under the skin behind the ear. The microphone picks up sound and converts it into digital signals. These signals are transmitted through the skin to the implant via a transmission coil with a magnet—the so-called subcutaneous implant then relays the signals to the receiving coil. From there, an electrode array with stimulation electrodes delivers the electrical stimulation directly to the electrodes in the cochlea, stimulating the remaining functional hair cells as well as the auditory nerves. The auditory nerve transmits these impulses to the brain, creating the first auditory impressions.

Similar to a hearing aid, the externally worn processor picks up sound waves from the environment. Cochlear, Med-El, and other manufacturers offer various systems that differ in design and technology but all operate on the same basic acoustic principle. The hearing outcome depends heavily on the auditory pathway and the quality of postoperative care. The implant’s function is regularly monitored and adjusted as needed.

In cases of bilateral hearing loss, bilateral cochlear implantation may also be advisable under certain circumstances to improve directional hearing and speech comprehension in everyday situations.

The surgery to insert the cochlear implants is performed by a specialist at an ear, nose, and throat (ENT) clinic. This specialist should have extensive experience in specialized microsurgery of the ear.

The basic therapy following the surgery must also be provided in specialized multidisciplinary centers through collaboration among

• physicians,
• speech-language pathologists, and
• audiologists

.

A cochlear implant, on the other hand, is used when conventional hearing aids no longer provide sufficient benefit—particularly in cases of hearing loss caused by damage to the auditory nerve. For a cochlear implant to function, an intact auditory nerve is necessary. Its function is first checked before implantation using a promontory test. 

A cochlear implant can then benefit

• people with total hearing loss and
• people with residual hearing who have not been able to achieve satisfactory results with various types of hearing aids

benefit from a cochlear implant.

Patients may have been deaf from birth or may have become deaf later in life.

The earlier a cochlear implant is inserted, the more beneficial it is. In cases of total hearing loss that occurred a very long time ago, a very long rehabilitation period is necessary. The benefit of the cochlear implant may also be so minimal that patients still rely on lip-reading.

For children born deaf, the implants should be implanted within the first few years of life. However, (except in exceptional cases) a monitoring period of approximately 6 months precedes the procedure. During this time, medical professionals assess the effectiveness of hearing aids and early intervention—that is, alternative treatment options.

Although the surgery to insert cochlear implants is technically demanding, it is associated with few complications. It carries no greater risks than middle ear surgery.

Even during the implantation of the inner-ear prosthesis, several measurements are taken that are necessary for adjusting the speech processor. Once the wound has healed, the speech processor must be adjusted to the patient’s individual needs.

Basic postoperative therapy, which includes, among other things,

• speech therapy,
• training in the use of the cochlear implant, and other measures

, begins no earlier than four weeks after the operation. This is followed by follow-up therapy.

Follow-up visits, which are usually conducted on an outpatient basis, are very frequent at first. Starting six months after the initial adjustment of the cochlear implant system, two to six follow-up visits per year are still required. These visits must be continued for the rest of the patient’s life.

The cochlear implant opens up the world of hearing to those affected—often just a few months after surgery