Cochlear implants

What are cochlear implants?

A cochlear implant is a medical device that mimics the natural hearing function of the inner ear. Unlike hearing aids, which simply amplify sound, cochlear implants bypass the damaged part of the inner ear and send electrical signals directly to the hearing nerve. Since cochlear implants stimulate the hearing nerve directly, sound can be heard more clearly than what some people experience with hearing aids.

Who can they benefit?

Cochlear implants are a good solution for people with moderate to profound hearing loss in both ears who no longer get much or any benefit from hearing aids.

What do they look like?

A cochlear implant system has two parts: an external sound processor and an internal cochlear implant.

The external sound processor looks much like a Behind-the-Ear hearing aid and is worn on the ear. Attached to the processor is a small coil which transmits signals from the sound processor to the internal implant. The coil is held in place next to the skin with a small magnet.

The internal cochlear implant is placed behind the ear and just under the skin by the implant surgeon. Attached to the implant is a tiny electrode array, with as many as 22 electrode contacts in the array. The surgeon inserts the electrode array into the snail-shaped cochlea in the inner ear.

There are two types of sound processor: behind-the-ear and off-the-ear.

Behind-the-ear (BTE)

A BTE sound processor looks much like a BTE hearing aid and is worn on the ear. Attached to the processor is a small coil, which transmits signals from the sound processor to the internal implant. The coil is held in place next to the skin with a small magnet. An example of a BTE sound processor is the Cochlear™ Nucleus^® 7 Sound Processor.

Off-the-ear (OTE)

An OTE sound processor is an all-in-one unit that also contains the coil and magnet. An example of an OTE sound processor is the Cochlear Kanso™ Sound Processor.

What else should I know?

Hearing aids vs cochlear implants

Although hearing aids can help most people with hearing loss, they can’t help everyone. This is because even the most powerful and advanced hearing aids simply make sounds louder, not necessarily clearer. By directly stimulating the hearing nerve, cochlear implants allow for clearer sounds and better overall hearing than is possible with hearing aids.

Cochlear implants can help when hearing aids are no longer enough, and they also deliver fast improvements. A Cochlear-funded study showed that adult cochlear implant users demonstrated, on average, more than 60 per cent improvement at three months and more than 70 per cent improvement at 12 months in quiet post-implantation when compared to their pre-operative hearing aid performance.¹ Another user study showed that adults with cochlear implants understand sentences on average almost seven times better than they could with hearing aids.²

Unlike hearing aids, cochlear implants are also typically covered by most private and government health insurance plans.

A treatment for ‘nerve deafness’

A cochlear implant can help both adults and children with severe to profound sensorineural hearing loss - a condition that is commonly incorrectly referred to as ‘nerve deafness’. Most people who have been told they have nerve deafness actually suffer from damage to the cochlea, not the hearing nerve. If you have been told you have nerve deafness, a cochlear implant may be an option for you because it bypasses the damaged part of the ear and stimulates the hearing nerve directly.

How cochlear implants work

1. The microphone in the external sound processor picks up sound from the environment and turns it into a digital signal.

2. The external sound processor then sends this digital signal through the coil and across the skin (via radio frequency) to the internal cochlear implant system.

3. The internal cochlear implant system changes the digital information into electrical signals and sends them to an electrode array that sits gently inside your hearing organ (cochlea or inner ear).

4. The electrical signals stimulate the hearing nerve, thus allowing the brain (and the cochlear implant user) to “hear” sound.

What to expect

Reconnecting with the world of sound with a cochlear implant is a huge and exciting journey, and it’s one that you need to fully participate in. Knowing what to expect at each step of the process will help you to get the most out of your implant and better tackle any challenges you encounter along the way. It’s important to have realistic expectations about what you may hear on activation, and to know that your first year of rehabilitation is vital to the long-term success of your cochlear implant. During this year, you will work closely with your audiologist and other hearing and speech specialists to fine-tune your implant and learn how to listen and communicate again.

Cochlear implants – after surgery

You will need to wait up to three to six weeks for the incision site to heal before the external parts of your system can be fitted and activated. Once the swelling is gone, you will meet with your audiologist to have your sound processor, programmed and activated.

Cochlear implants - activation

At your activation session, your audiologist will fit the sound processor and other external parts of your implant. You won’t be able to hear sounds from the implant until it is switched on - a moment many people with cochlear implants describe as a huge breakthrough on their hearing journey. However everyone is different, and your first perception of speech and sounds will depend on the degree of your hearing loss and how long you have been living with it. Most cochlear implant users say that the sound changes over time and gets better with consistent daily use.

Once the implant is activated, your audiologist will test your hearing and make adjustments where necessary. During this session your audiologist will also instruct you on how to best use and care for your device and discuss what will be involved in your rehabilitation program.

Cochlear implants - rehabilitation

Activation is just the start of your entry into the world of sound and daily practice is an important part of the cochlear implant process as you need time to adjust to the new way of hearing sound. You may also undergo aural rehabilitation with a team of hearing and speech specialists, which may include audiologists, speech-language pathologists, educators, surgeons, medical specialists, psychologists and counsellors.

Your rehabilitation program will involve developing new listening skills through daily activities such as reading aloud to yourself and with family and friends, listening to audio books while reading along, and listening to easily recognisable songs. If you have been without hearing for a long time, you may also need an auditory development program to help you recognise speech and environmental sounds and develop new listening and communication techniques.

Your willingness to undergo aural rehabilitation and experience new sounds is crucial to how successful your implant is. A family member should also learn how to operate your sound processor and be included in your training program whenever possible.

Your cochlear implant is for life, so you will continue to visit your audiologist for annual check-ups and for adjustments and reprogramming to meet your changing hearing needs and lifestyle. As a cochlear implant user, you will also have the chance to upgrade your sound processor as the technology advances.

Learn about Cochlear Nucleus 7 Sound Processor

View Cochlear support resources

Before the operation, the patient will be given a general anesthetic, after which some hair is shaved from behind the ear.

The operation takes place in theatre and will take between two and five hours to complete.

The patient will wake up with a large bandage on his head, which will be taken off the next day.

Recovery

Recovery after the operation is variable but most patients feel better very quickly. Most patients do not suffer significant pain after the operation.

The patient is required to check into the ward the day before surgery and he will remain in hospital for one to two nights after the surgery.

It is recommended that the patient take two weeks rest at home.

Once the hair has grown back and the scar has healed, the only evidence of the operation will be a small bump just behind the ear.

Risks and side effects

A cochlear implant operation carries the same slight risk as other ear surgery.

The patient, however, should be aware of the following possible side effects:

• The risks associated with having a general anesthetic.
• Temporary dizziness and/or temporary disturbance of balance.
• Temporary increase in tinnitus.
• Numbness in area of scar.
• A risk of infection.
• Facial nerve bruising: This nerve running near the site of surgery is carefully monitored throughout the operation. This ensures that bruising of the facial nerve is highly unlikely.

Post operation

• While the patient is on the ward one of the nursing staff will show him how to wash his face whilst at the same time protecting the scar area.
• He is encouraged to wait a minimum of two weeks after surgery before washing his hair. It is needed to keep the wound dry and to be very gentle with that area for the first month.
• After the first month, the patient can treat the wound as normal and if he is a keen swimmer he can restart then. Flying should be avoided for four weeks following surgery.
• If required the patient will be given painkillers on the ward and some to take home.
• The surgeon will generally use dissolvable stitches, which do not need to be removed. The area around the scar, including part of the patient ear, will be numb and sensation will slowly return over a period of six months.

Precautions:

The patient is advised to avoid all activities that might cause a blow to the head, e.g., football and boxing as these could potentially cause damage to the implant.

Also, He is advised against doing such activities as scuba diving as the pressure changes involved in deep water diving could damage the implant.