Types of hearing implants

A cochlear implant is a small electronic device that can help a patient with severe hearing problems to gain access to everyday sounds and the sound of speech.

The implant consists of an internal and external part. The internal part consists of an electronic package, a magnet and an electrode array. The external component is called a speech processor, this is worn behind the ear and connects to the implant via a magnet on the head.

The processor picks up the sound and converts this into digital information which is transmitted to the internal implant. The implant array is positioned within the cochlea. Along the length of the implant are tiny electrical contacts called electrodes. Each electrode can give small electrical pulses to a specific part of the cochlea. This triggers the auditory nerve and gives a sensation of sound. This then allows the person to have perception of sound and better understanding of speech.

Watch: How Cochlear Implants Work (opens in a new tab)

Who is suitable for a Cochlear implant?

This service is provided for both children and adults with a significant hearing loss and receive limited benefit from hearing aids. A cochlear implant may be suitable for those with either a congenital or an acquired hearing loss. Candidacy will depend on many factors: the two most import are specified by the national “NICE” criteria and determine the funding, these are the level of hearing loss and the extent to which the hearing loss effects speech understanding. In addition there are several factors such as the anatomy of the ear and general medical health.

Candidates with a profound hearing loss in the high frequencies, but aidable low frequency hearing may be suitable for Electro-Acoustic Stimulation (EAS). EAS combines the electric stimulation from a cochlear implant with an acoustic component from a conventional hearing aid.

For more information on the above please refer to our referral section.

Possible outcomes using a Cochlear implant

All implant users have different experiences of sound through their Cochlear implants. An implant is able to give you access to sound, which your brain has to be trained to recognise. Adapting to the sound can take time and effort. It takes training and practice for sounds to be interpreted.

The factors below influence how well you/your child will do with the Cochlear implant:

• Age at implantation
• Onset and duration of deafness
• Educational setting and mode of communication
• Additional disabilities
• Commitment by the user
• Local support (family and professionals)

A Cochlear implant may help with:

• Hearing sounds in the environment
• Hearing speech in quiet situations
• Improving the ease of listening
• Improved hearing in background noise
• Increased access to sounds in music
• For children implanted at an early age, an implant may aid development of oral speech and listening skills
• Monitoring the pitch and volume of your own voice
• Using the telephone

A Bone Conduction Implant delivers sound via direct bone conduction to the inner ear, effectively bypassing the outer and middle ear. The term Bone Anchored Hearing Aid (BAHA) was used historically to describe bone conduction implants, however the term BAHA refers to a specific type and brand of bone conduction implant. A Bone Conduction Implant relies on a working cochlea to send sound to the brain. There are several bone conduction implants which may be suitable; each works in a different way. They all have a surgically inserted fixing point anchored to the skill and an external processor. The external processor converts the sound energy into mechanical movement of the implanted anchor. The fixture vibrates in the skull and so that the natural bone conduction (transmission) of sound to the cochlea can bypass the non-functioning outer or middle ear.

Who is suitable for a bone conduction implant?

Candidates may include those:

• With hearing problems in the outer or middle ears.
• Those who are unable to wear conventional hearing aids due to ear infections or skin problems.
• Those who are unable to wear conventional hearing aids due to ear abnormalities such as bony growths in the ear canal, a very narrow ear canal, or difficulty wearing ear moulds due to previous ear surgery.
• Single sided deafness.

Possible outcomes using a bone conduction implant

A bone conduction implant may help with:

• Reducing the risk of ear infections or skin problems
• Hearing without occluding ear moulds
• Hearing sounds in the environment
• Hearing speech
• Monitoring the volume of your own voice
• Lip reading
• Using the telephone
• Enhanced music appreciation

More information on the above is available on the referral section

A middle ear implant is implanted in the middle ear and mechanically stimulates the inner ear. It is designed for candidates who are unable to use hearing aids for medical reasons. The middle ear implant system consists of two main parts: an internal and an external part.

The internal part is implanted during the surgical procedure. It consists of:

• A receiver package, including a magnet
• An internal component which is attached in the middle ear either to one of the bones in the middle ear, or attached near to the round window of the cochlear

The external part is called the processor. It picks up sound from the environment, and transmits the signal across the skin to the implanted receiver. It uses a magnet to hold in position. The internal component adds extra movement to the natural hearing pathway. The sound is transmitted into the cochlea along this pathway.

Who is suitable for a Middle Ear Implant?

Candidates may include those:

• With hearing problems in the outer, middle or inner ears
• Those who are unable to wear conventional hearing aids due to certain types of ear infections, skin problems or ear mould allergies
• Those who are unable to wear conventional hearing aids due to ear abnormalities such as bony growths in the ear canal or a very narrow ear canal

Possible outcomes using a middle ear implant

• Reducing the risk of ear infections or skin problems
• More natural sound quality
• Lack of feedback
• Absence of occlusion
• Less distortion

What is an Auditory Brainstem Implant?

Auditory Brainstem Implants are designed for those with a profound hearing loss who are not able to use a cochlear implant. The auditory brainstem implant uses technology similar to that of the cochlear implant but instead of electrical stimulation within the cochlea, it stimulates the cochlear nucleus in the brainstem.

An auditory brainstem implant consists of two parts, an internal and external part.

The internal part is known as the electrode array or implant. It is inserted surgically, usually under general anaesthetic. It consists of a receiver package with a magnet, placed under the skin above the ear; and an electrode array, placed in the brainstem.

The external part is known as the sound processor. It is worn behind the ear and consists of a sound processor with a microphone to pick up sounds and cable and circular coil held on the head by a magnet, which enable sounds to be transferred to the electrode array.

Who is suitable for an auditory brainstem implant?

An auditory brainstem implant may be suggested when the hearing nerve is absent or damaged. An auditory brainstem implant can give some access to sound as it bypasses the nerve of hearing and takes the sound signal directly to the brainstem.

This may apply to:

• Some cases of acoustic tumours.
• Some people diagnosed with NF2.
• Those born without a hearing nerve.

Possible outcomes using an auditory brainstem implant

All implant users have different experiences of sound through their implants. The degree of benefit cannot be guaranteed. It is a difficult task to position the auditory brainstem implant (ABI) on the brainstem exactly to deliver sound. It is possible that there is no hearing sensation at all from the auditory brainstem implant. In other cases the response is within a narrow range so that sounds are not well differentiated. People listening with an auditory brainstem implant are very likely to need to lip-read as well. It takes time to adjust to the sound perceived through an auditory brainstem implant.

An auditory brainstem implant may help with:

• Hearing sounds in the environment
• Monitoring the pitch and volume of your own voice
• Lip reading: using sound alongside lip patterns to understand speech

More information on the above is available in our referral section.