Cochlear Implants
A cochlear implant (CI) is a surgically implanted electronic device that provides a sense of sound to a person who is profoundly deaf or severely hard of hearing. The cochlear implant is often referred to as a bionic ear. Unlike hearing aids, the cochlear implant does not amplify sound, but works by directly stimulating any functioning auditory nerves inside the cochlea with an electric field. External components of the cochlear implant include a microphone, speech processor and an RF transducer or primary headpiece coil. A secondary coil is implanted beneath the skull's skin and inductively coupled to the primary headpiece coil. The headpiece coil has a magnet by which it attaches to another magnet placed on the secondary coil often beside the cochlear implant. The implant relays the incoming signal to the implanted electrodes in the cochlea. The speech processor allows an individual to adjust the sensitivity of the device. The implant gives recipients additional auditory information, which may include sound discrimination fine enough to understand speech in quiet environments. Post-implantation rehabilitative therapy is often critical to ensuring successful outcomes.
For Whom
The cochlear implants are useful for those who have lost their hearing sensations later in life and cannot benefit from hearing aids. It can also be of immense aid to young children who are deaf.This implant helps them cope and also learn day to day speech and understanding of language. Some children with congenital hearing disorders may also need cochlear implants.
The Implant
The cochlear implant is a small, complex electronic device that can help to provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing. The implant consists of an external portion that sits behind the ear and a second portion that is surgically placed under the skin (see figure). An implant has the following parts:
A microphone, which picks up sound from the environment.
- A speech processor, which selects and arranges sounds picked up by the microphone.
- A transmitter and receiver/stimulator, which receive signals from the speech processor and convert them into electric impulses.
- An electrode array, which is a group of electrodes that collects the impulses from the stimulator and sends them to different regions of the auditory nerve.
How does it work
A cochlear implant is very different from a hearing aid. Hearing aids amplify sounds so they may be detected by damaged ears. Cochlear implants bypass damaged portions of the ear and directly stimulate the auditory nerve.Signals generated by the implant are sent by way of the auditory nerve to the brain, which recognizes the signals as sound.Hearing through a cochlear implant is different from normal hearing and takes time to learn or relearn. However, it allows many people to recognize warning signals, understand other sounds in the environment, and enjoy a conversation in person or by telephone.
How is it different from a Hearing Aid
Cochlear implants differ from hearing aids in two important ways:
- Hearing aids simply amplify sounds. A cochlear implant, on the other hand, transforms speech and other sounds into electrical energy that is used to stimulate the hearing nerve in the inner ear.
- Unlike most hearing aids, cochlear implants have both internal and external components. The implant system consists of an external speech processor and headset (worn behind the ear) and an internal, surgically implanted receiver/stimulator package with an electrode array.
Preparation for Surgery
Prior to Surgery
The implant candidate is anesthetized with a general anesthesia.
Preparing for Operation
Some hair is shaved off where the surgery will be done. This is usually a small amount of hair. The area shaved is behind the ear.
Making the Cut
An incision is made and the skin and tissue flap is lifted so that the surgeon can drill into the skull bone behind the ear. A receiver is placed into the drilled-out area and an electrode array is inserted into the cochlea.
Closing Up
The surgical area is closed up with stitches (a small permanent scar may result) and the head is bandaged.
After Surgery
Depending on the length of the surgery and other factors, the patient may either be sent home shortly after surgery or have to stay in the hospital for a short while.
Recovery Period
During the recuperation from the surgery, there may be minimal side effects such as temporary swelling. Side effects are minor if they do occur and are generally temporary: pain, changes in taste, dizziness, inflammation, bleeding, etc. |
