A 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. A cochlear implant is not the same thing as a hearing aid. It is implanted using surgery and works differently. There are different types of cochlear implants, but they are often made up of similar parts, such as:
One part of the device is surgically implanted into the bone surrounding the ear (temporal bone). It is made up of a receiver-stimulator, which accepts, decodes, and then sends an electrical signal to the brain.
The second part of the cochlear implant is an outside device. This is made up of a microphone/receiver, a speech processor, and an antenna. This part of the implant receives the sound, converts the sound into an electrical signal, and sends it to the inside part of the cochlear implant.
Who needs a cochlear implant?
Cochlear implants allow a deaf person to receive and process sounds and speech. Although these devices allow sound and speech to be sent to the brain, they do not restore normal hearing. As the understanding of the brain’s hearing (auditory) pathways improves and the technology changes, how people get selected for cochlear implants changes too.
Cochlear implants can be used for children and adults. Candidates may have been born deaf or become deaf after learning to speak. Even children as young as 1 year old are now candidates for this surgery. The criteria may differ between children and adults, but they are based on similar guidelines:
The person should be completely or almost completely deaf in both ears and get almost no improvement with hearing aids. Anyone who can hear well enough with hearing aids is not a good candidate for cochlear implants.
The person needs to be highly motivated. After the cochlear implant is placed, they must learn how to properly use the device.
The person needs to have reasonable expectations for what will occur after surgery. The device does not restore or create "normal" hearing.
Children need to be enrolled in programs that help them learn how to process sound.
To determine if a person is a candidate for a cochlear implant, the person must be examined by an ear, nose, and throat (ENT) doctor (otolaryngologist). People will also need specific types of hearing tests performed with their hearing aids.
This may include a CT scan or MRI scan of the brain and the middle and inner ear.
People (especially children) may need to be assessed by a psychologist to determine if they are good candidates.
How does a cochlear implant work?
Although hearing aids amplify sounds so they can be detected by damaged ears, a cochlear implant is much different. Cochlear implants bypass damaged portions of the ear and directly stimulate the auditory nerve. The generated signals from the implant are sent to the brain by way of the auditory, which then recognizes the signals as sound. Since hearing through a cochlear implant is different from normal hearing, it takes time to learn or relearn. For those who cannot recognize warning signals, understand other sounds in the environment, and understand speech in person or over the phone, this is the best solution.
Advantages of having a cochlear implant include:
Hearing speech at a normal sound level
Understanding speech without having to observe the lips
Being able to hear someone talk on the phone
Hearing music better
Distinguishing different levels of sound
Being able to speak more clearly, so others can understand
What are the risks of cochlear implant surgery?
A cochlear implant is a relatively safe surgery. However, all surgeries pose some risks. Risks are less common now that the surgery is performed through a small surgical cut, but may include:
Wound healing problems
Skin breakdown over the implanted device
Infection near the implant site
Less common complications include:
Damage to the nerve that moves the face on the side of the operation
Leakage of the fluid around the brain (cerebrospinal fluid)
Infection of the fluid around the brain (meningitis)
Temporary dizziness (vertigo)
Failure of the device to work
Abnormal taste
You may be admitted to the hospital overnight for observation. However, many hospitals now allow people to go home on the day of surgery. Your healthcare provider will give you pain medicines and sometimes antibiotics to prevent infection. Many surgeons place a large dressing over the operated ear. The dressing is removed the day after surgery.
How is recovery from a cochlear implant?
After cochlear implant surgery, the patient may experience any of the following side effects:
Pressure or discomfort in the affected ear
Dizziness
Nausea
Confusion or feeling disoriented
Sore throat from the breathing tube
The patient may go home 1-2 days after surgery. After discharge, the doctor will encourage you to:
Keep the bandages on for a specified time.
Schedule an appointment to remove stitches approximately one week after the implant.
Follow instructions on how to care for the stitches, wash your head, and shower, as well as what should your diet be.
Schedule a follow-up appointment to activate the implant approximately 3-6 weeks after the surgery. After 3 weeks of healing, the cochlear implant is activated. Post-implantation therapy is required for the patients to adapt to hearing sounds. The patient will also undergo a hearing test performed by the rehabilitation team as part of the scheduled follow-up appointment process.
A week or more after surgery, the outside part of the cochlear implant is secured to the receiver-stimulator that was implanted behind the ear. At this point, you will be able to use the device.
Once the surgery site is well healed, and the implant is attached to the outside processor, you will begin to work with specialists to learn to "hear" and process sound using the cochlear implant. These specialists may include:
Audiologists
Speech therapists
Ear, nose, and throat doctors (otolaryngologists)
This is a very important part of the process. You will need to work closely with your team of specialists to get the most benefit from the implant.
Conclusion
A cochlear implant (CI) is a remarkable neuroprosthesis surgically implanted to provide sound perception for individuals with moderate-to-profound sensorineural hearing loss. Through therapy, these implants can enhance speech understanding in both quiet and noisy environments. By directly stimulating the auditory nerve, CIs bypass acoustic hearing, allowing recipients to learn to interpret signals as speech and sound. The implant consists of an external sound processor and an internal component with electrodes placed in the cochlea. While challenges remain, many users experience improved hearing and speech perception skills post-implantation, especially when combined with lipreading. These devices represent a significant advancement in improving the quality of life for those with severe hearing loss.
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