Article by Hearing Partners, contributed by Lim Chu Hong, Clinical Support Audiologist at Hearing Partners
Cochlear implants are medical devices designed to bypass damaged parts of the ear and directly stimulate the auditory nerve. Each device consists of 2 main components – a receiver that is surgically implanted into the skin and a sound processor worn behind the ear.
Cochlear implants are generally recommended when hearing aids prove to be insufficient. These implants allow individuals with severe to profound hearing loss to perceive sound and have been proven to enhance speech perception and overall quality of life for users.
Read on as we share more about how cochlear implants work, the process of getting them and the risks involved. We’ll also touch on the differences between cochlear implants and hearing aids.
Who Is Suitable for a Cochlear Implant?
The suitability for cochlear implants is determined by a hearing care professional, such as an audiologist, based on the results of a hearing test.
Generally, individuals who have severe to profound hearing loss and have not benefited from hearing aids are considered suitable candidates for cochlear implants. They also mustn’t have any medical condition that would prevent them from undergoing surgery.
Children, as young as 6 to 12 months old, and adults can receive cochlear implants. To find out if you or your loved one is a suitable candidate, you’re recommended to speak to a hearing care professional.
How Cochlear Implants Work
A cochlear implant consists of 2 main components – an external processor and an internal receiver. This is how the components work together to help users hear:
- The small microphone found in the external processor captures sounds from the user’s surroundings.
- The microphone transmits these sounds to the speech processor.
- The sounds are filtered and coded by the processor before being sent to a transmitting coil.
- The transmitting coil will send the codes across the skin to the internal receiver.
- The codes will be converted into special electronic signals by the internal receiver and sent to specific electrodes. Each electrode is designed to deliver sounds in different loudness and pitches.
- The electrodes will subsequently stimulate the appropriate auditory nerve, which sends messages to the brain to help the user make sense of the sounds initially captured by the microphone.
Process of Getting Cochlear Implants
If you’re a suitable candidate for a cochlear implant, you may want to understand the process of getting one. Here are the general steps:
Step 1: Medical assessment
A detailed medical assessment with a hearing care professional is required to help determine your suitability for cochlear implants. The assessment will typically include the following:
- Hearing tests, speech tests, and occasionally balance tests
- Physical examination to evaluate your health and anatomy
- Magnetic resonance imaging (MRI) or computerised tomography (CT) tests of the skull to assess the condition of your cochlea and inner ear structure
Once the tests have been completed, your hearing care professional will advise you on the most suitable type of cochlear implant for your hearing needs. After making a decision, the next step is surgery.
Step 2: Surgery
For the surgery, general anaesthesia will be administered. The surgeon will make a minor incision behind your ear and create a small hole in your mastoid bone for the internal receiver. Next, a small incision will be made in your cochlea to insert the electrode.
Once the components have been successfully inserted, the surgeon will close the holes with stitches. On average, the surgery will last approximately 2 hours.
After the surgery, you may experience feelings of dizziness or nausea, or some discomfort in the area where the device was implanted. These sensations are temporary and users often return home on the day of the surgery.
Step 3: Activation of implant
Approximately 3 weeks after the surgery is completed, you’ll meet your hearing care professional to activate the device. The session will last 2 – 3 hours and involves:
- Checking the components of the device to ensure that they’re functioning well
- Adjusting the sound processor setting according to your needs and comfort level
- Identifying the sounds that you’re able to hear
At the same time, your hearing care professional will instruct you on the proper care and usage of the cochlear implant. Follow-up sessions will also be scheduled to check on the device and ensure that it’s functioning at its best.
Step 4: Post-operative therapy
With cochlear implants, speech and ambient sounds may differ from your memory. Your brain will require a period of acclimation, where it’ll learn to recognise sounds through the device. As such, post-operative therapy is crucial in helping you enjoy the best listening outcomes possible.
Risks of Getting Cochlear Implants
As with any type of surgery, there are certain risks of getting cochlear implants. They include:
- Loss of residual hearing
Cochlear implants can sometimes result in the loss of remaining hearing in the implanted ear.
- Meningitis
Meningitis is the inflammation of the protective membranes surrounding the brain and spinal cord. This condition, while uncommon, can occur after cochlear implant surgery. To reduce the chances of this condition, vaccinations are often given to users before the surgery.
- Device failure
This is an uncommon complication that may occur post-surgery. In such situations, the internal device may be faulty and require replacement.
Other rare complications may include:
- Bleeding
- Dizziness and balance problems
- Facial paralysis
- Infections
- Leakage of spinal fluid
- New or worsened tinnitus
- Taste problems
Difference Between Cochlear Implants and Hearing Aids
While both cochlear implants and hearing aids are designed to help those experiencing hearing loss hear their surroundings, there are several differences:
| Hearing Aids | Cochlear Implants | |
| Purpose | Promote hearing by amplifying sounds | Promote hearing through electrical stimulation |
| Type and severity of hearing loss | ● Mild to profound hearing loss
● Conductive or sensorineural hearing loss |
● Moderate to profound hearing loss
● Sensorineural hearing loss |
| Speech understanding | ● Fair or poor
● Able to understand at least 50% of the words spoken during the test |
● Fair to poor
● Able to understand 50% or less of the words spoken during the test |
| Time to adapt to the device | 2 weeks or more | 6 to 12 months |
| Where the device is worn | Inside or behind the ear | Surgically implanted and behind the ear |
| Surgery | Not required | Required |
| Risk | Little to no risk | Low to moderate risk |
Enjoying a Better Quality of Life With Cochlear Implants
Cochlear implants can greatly benefit those with severe to profound hearing loss by enhancing their ability to recognise environmental sounds, listen in noisy environments and follow conversations. They can also improve sound localisation abilities and reduce signs of tinnitus, creating a better overall quality of life.
If you think that you or your loved one can benefit from cochlear implants, speak to your hearing care professional today!
