Cochlear implants
What is a cochlear implant?
A cochlear implant is a hearing implant that bypasses the damaged hair cells in the inner ear and transmits signals directly to the brain via the auditory nerve.
Cochlear implants (also known as CIs) make it possible for people to hear sounds even if they have damaged hair cells in the inner ear and have a severe or a profound sensorineural hearing loss.
Parts of a cochlear implant
A cochlear implant consists of two parts. The external part consists of a sound processor / audio processor and an antenna and sits behind the ear. The internal part is a receiver that sits under the skin behind the ear. The receiver has an array attached to it which on the other end has a series of electrodes which are placed in the inner ear (the cochlea).
How does a cochlear implant work?
A cochlear implant works in the following way:
- The sound processor / audio processor captures and digitises sounds.
- The antenna transmits the digitised signals from the sound processor / audio processor to the receiver.
- The receiver transforms the digital signals into electronic signals.
- The electronic signals are sent via the array into the inner ear.
- On the array, there are electrodes that correspond to different signal frequencies.
- The electrodes stimulate the auditory nerve that finally sends signals to the brain.
In this way, a cochlear implant bypasses the damaged hair cells in the inner ear and sends signals directly to the brain via the auditory nerve. It captures sounds and converts them to electronic signals that are sent to the brain.
Who can benefit from a cochlear implant?
Cochlear implants are relevant for people with a severe to profound sensorineural hearing loss who do not benefit from the sound amplification of hearing aids and where this amplification has little or no effect. A cochlear implant can also be used as treatment for a unilateral severe sensorineural hearing loss, if the cochlea in the inner ear is intact.
People who can benefit from cochlear implants normally have damaged or no hair cells in the inner ear and therefore cannot detect sound properly.
It is important to note that cochlear implants do not restore hearing to the same level as a person without a hearing loss even though very good results can be achieved.
Both adults and children
Both adults and children with severe or profound sensorineural hearing loss can benefit from cochlear implants. Infants can get cochlear implants and benefit from them as early as from the age of around 1 year.
One or two cochlear implants?
Hearing with two ears is always better than hearing with just one. Hearing with both ears makes it possible to better localise sound, aids speech understanding in noisy environments and allows stereo perception of sound. Listening with two ears also normally requires less mental effort than hearing with just one ear.
Even if in such cases two cochlear implants are recommended, many people still unfortunately can only get one cochlear implant due to reimbursement/cost reasons.
Surgery and activation
A cochlear implant is implanted during a surgical procedure, usually performed under general anaesthesia. Nowadays, the surgery is a standard procedure and normally takes one to two hours. The cochlear implant is normally activated and adjusted some weeks after the surgery. Later on, additional adjustments are typically made.
Rehabilitation
After the activation of the cochlear implants, the brain must learn to capture, recognise and interpret the different sounds. This is called rehabilitation. Rehabilitation involves training in different ways and it may take some time before a person becomes accustomed to hearing and understanding sounds with cochlear implants.
Candidate for cochlear implants?
If you think you may benefit from cochlear implants, you should start by contacting an ENT-doctor or an audiologist.
Other types of implants:
Bone conduction devices
Middle ear implant
Auditory Brainstem Implant (ABI)