Cochlear Implants

What are Cochlear Implants?

Cochlear implants are an advanced medical technology used to treat hearing disabilities in people, mostly children. This involves using a small audio processor placed behind the ear and an implant placed inside the person’s inner ear, hence connecting directly to the natural hearing system. It is surgically placed in the ear to provide sound stimulation by replacing the typical hearing process with electrical signals. In turn, it stimulates the auditory nerve, and the brain receives the signals and interprets the sounds. A cochlear implant may be placed in one ear or both ears, depending on how severe the hearing loss is, especially for infants and young children still learning how to speak. 

What are the types of cochlear implant technique?

There are two major types and they include:

• The Traditional Cochlear Implant

This is also called “standard mastoidectomy,” which has been in use for over 40 years and involves the use of an incision made behind the ear in order to access the mastoid bone and gain access into the middle ear and also the inner ear.

• The Hybrid Cochlear Implant

This is a new technique employed by surgeons in order to reduce blood loss and injury to surrounding tissues and also save much time and early recovery. The hybrid implant is quite small and is not placed as deeply as the traditional one; however, its frequency for detecting sounds is very high. 

How do Cochlear Implants work? 

The device can pick up sound waves and converts them into electrical impulses that cause a cochlear stimulation to give signals to the auditory nerve, which in turn, signals the brain, which interprets these electrical signals as sounds. The device consists of two parts, namely the audio processor and the implant that is placed surgically at the inner ear. The audio processor is placed with a microphone and worn behind the ear. This enables it to pick sounds and transmit those sounds to the implant inside the ear. Hearing through a cochlear implant is quite different from the natural process of hearing but can immensely help hearing and speech improvement. 

What are the pros and cons of a cochlear implant?

As every other foreign implant is introduced into the body, the pros and cons of cochlear implants are existent. First, looking at the benefits of the device, the following can be considered the pros:

• Hearing becomes easier and almost at a normal level.
• The person finds it easier to pick up sounds of different types.
• They have better control of the voice after the implants.
• A better understanding of speech.

They are quite safe. However, there may be some risks associated with them. The risk of cochlear implants may include the following:  

• Bleeding and infection.
• Nerve damage could affect the sense of taste and cause facial paralysis.
• Dizziness and balance issues may arise.
• Continuous ringing in the ear.
• Fluid leaking into the brain.
• Meningitis.
• Loss of residual hearing.
• Failure of the device and infection of the brain membrane.

What are the criteria for cochlear implants?

The eligibility of a person for a cochlear implant can be based on certain factors such as severe to profound hearing loss in both ears, hearing loss that cannot be treated using hearing aids, inadequate development of the auditory nerve or skills, no medical history or underlying disease that could impair the implant, etc. 

What are the pediatric criteria for cochlear implants?

The pediatric criteria are listed below:

• Children at least 12 months of age and older
• Children with severe to profound hearing loss
• Children who are fit for the procedure
• Young children who have no progress or change in speech and language development [1].
• Older children who are unable to understand at least 30% of the words. 

How much do Cochlear Implants cost? 

The cost of a cochlear implant depends majorly on the brand to be used, the age of the patient, complications during surgery, and the hospital performing the surgery. The device alone costs approximately 8000 USD to 15000 USD. At Anavara, we help people connect with professional doctors across the globe who are specialists with many years of experience at an affordable and friendly cost.  

Preparation for Cochlear Implants

While preparing for a cochlear implant, avoid taking certain medications and inform the doctor of the medications they are taking. Avoid eating and drinking for a few hours before the implant. The doctor will also give the guidelines to the patient regarding how to prepare depending on their medical record and what is suitable for the body system. 

Cochlear Implants Procedure

Before the Procedure

The patient will be examined by the doctor, and the extent of their hearing loss will be determined. Then the medical history of the patient will be examined for any underlying disease condition which could affect the cochlear implantation. The patient is advised to go through some hearing tests such as an audiogram, a hearing aid trial, and tests to evaluate the structures of the middle and internal ear. The patient will be taken to the lab and some scans, such as computerized tomography scan, x-ray, magnetic resonance imaging, etc., to see the shape of the cochlea. These tests are also done to check if there is any growth in the cochlea, which could have resulted from any infection such as meningitis, as this could interfere with the cochlear implant. The patient will also need to undergo a psychological test to check their ability to cope with the implant.

During the Procedure

A cochlear implant normally lasts for approximately 2hours. This procedure involves the administration of anesthesia so that the patient doesn’t feel pain during the surgery. The patient will be administered drugs and other fluids that will help keep them stable intravenously while their vital signs will be closely monitored. A part of the scalp will be shaved for the implantation of the cochlear implant, an incision will be made behind the ear in order to access the mastoid bone, and a drill will be made into the inner ear. Then an electrode is placed inside, and the incision is sutured (stitched) back. The cochlear implant activation will only be made when the incision is completely healed, which could take about four weeks after the surgery. 

After the Procedure

 After the surgery, the patient will be kept in the hospital and closely observed for a day or two, while in some cases, the patient might get discharged after a few hours of close observation. The surgery is not painful, and most people can return to their normal daily activity after 2 to 3 days. The patient might need to learn to adapt to hearing with the implant as there might be changes in balance canal function. In adults, there might be a feeling of dizziness, and they will experience the surgery, which could last for a week or more.

Cochlear Implants Stimulation and Activation

In order to activate the cochlear implant, the sound processor will be adjusted, the components checked to make sure they are working, and the device will be set so that the patient can hear to the best of their ability. 

What is the success rate of cochlear implants? 

The result encountered in cochlear implants changes according to individual differences. It might be influenced by factors such as age when the hearing was lost and the time interval between hearing loss and cochlear implant. It is generally best for children and has a relatively high success rate compared to other surgeries. With proper and adequate adjustment to the lifestyle after the surgery, one could enjoy a beautiful life with fewer complications over the years.

What Kind of Long-Term Maintenance Is Needed? 

Since it is a device, there is a need to properly care for and maintain it, ensuring that the device is always in good working condition. Maintenance steps include: 

• Changing the microphone protector at least every three months.
• Cleaning the sound processor regularly with a soft dry cloth.
• Removing and storing the sound processor in storage when sleeping.
• Ensuring to charge the batteries of the sound processors and always carry spare batteries.

FAQ

References

1. https://www.medstarhealth.org/services/cochlear-implants
2. https://medlineplus.gov/ency/article/007203.htm
3. https://emedicine.medscape.com/article/857242-overview#a13