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Explore Types of Hearing Technology in more detail :

Hearing Implants

Hearing implants are surgically implanted devices – and comparatively recent developments, with ongoing developments.

Cochlear implants
Cochlear implants were developed to be used when hearing aids were not powerful enough to manage the level of hearing loss. Unlike hearing aids, they require a surgical procedure: they bypass the damaged cochlea and provide electrical stimulation directly to the auditory nerve. While cochlear implants were highly controversial when work began on mainstream implantation in the 1980’s and 1990’s, now the majority of profoundly deaf children in developed countries have implants, and increasingly adults. For summary of development of implantation in children see Deaf Education: changed by cochlear implantation [52] and for adults see Adult Cochlear Implantation: evidence and experience [48]. For more general information and literature on cochlear implants, please download the Cochlear Implant information sheet on The Ear Foundation website page - Cochlear Implant Information SheetFor more information on cochlear implants, please visit The Ear Foundation website page - Cochlear Implants. This diagram illustrates the levels of hearing to be considered for implantation:


The inner part, or receiver, is surgically implanted in the mastoid bone, behind the ear, and electrodes inserted directly to the cochlea, or inner ear. The outer part consists of a microphone which collects the sound, processor which converts the sound into electrical signals which are passed to electrodes which are in the cochlea. These signals then pass up the auditory nerve to the auditory brain. See above right picture (courtesy of Cochlear).

Cochlear implants have transformed the communication, linguistic and educational outcomes for deaf children and communication, confidence, employment and quality of life outcomes for adults (refs). They have been shown to be cost-effective in both children and adults.

Electro-acoustic implants now combine the benefits of cochlear implant and hearing aid technology for those who have useful low frequency hearing.

For a video on how the cochlear implant works, please visit this Oticon Medical website page. For useful information, resources and opportunities to ask questions about cochlear implants, please visit Sounding Board.  

Other implantable devices
Other implantable devices such as bone conducting implants, middle ear implants, and brain stem implants have been developed for specific issues. Please visit this British Cochlear Implant Group (BCIG) website page which has a useful summary of other implantable devices. This diagram illustrates the range of implants and the hearing losses they address (picture source: Cochlear):

 
Bone Conducting Hearing Implants
Bone conducting hearing implants (BCHI), sometimes called bone-anchored hearing aids (BAHA), are also surgically implanted or can be used on a soft band on the head with children. The sound processor picks up sound, converts them into vibrations, and sends them to the implant sitting in the bone behind the ear, through the skull bone, directly to the inner ear. This bypasses any problems in the ear canal or middle ear. BCHI devices are suitable for those with permanent or longstanding conductive hearing loss, single sided deafness or mixed (conductive with sensorineural component) hearing loss and for those who lack an ear canal (picture source: Cochlear). For more information on bone conduction hearing implants, please visit The Ear Foundation website page - Bone Conducting Hearing Implants and please download our information sheet on The Ear Foundation website page - Bone Conducting Hearing Implant Information Sheet.
 
          

Middle Ear Implants
Middle Ear Implants (MEIs) are implantable devices that are used when someone has a conductive or mixed hearing loss. MEIs are only suitable for patients unable to wear conventional hearing aids. The device is surgically implanted in the middle ear and then transmits sounds to the cochlea (inner ear). MEIs are typically used with an external audio processor which is worn behind the ear and held in place by a magnetic connection across the skin. For further information on middle ear implants, please visit this MED-EL website page and this BCIG website page websites.

Auditory Brainstem Implants
If the auditory nerve is damaged or absent then neither a hearing aid or a cochlear implant will provide any benefit. An Auditory Brainstem Implant (ABI) stimulates the auditory brainstem directly, and is placed in the brainstem itself. It is highly specialised and only a few centres offer this system. For further information on auditory brainstem implants, please visit this Hearing Link website page.

For research around cochlear implants, bone conducting hearing implants and assistive listening devices, please visit The Ear Foundation - Research page and see the section on Research across the Lifespan.