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This factsheet is part of RNID’s hearing aids range. You will find it useful if you are deaf and want to find out about bone conduction hearing aids. We use the term ‘deaf’ throughout to refer to all types of hearing loss.
Read this factsheet to find out:
A conventional hearing aid amplifies sounds (makes them louder) and delivers them to the ear canal through an earmould. The earmould fits into the ear canal closely so that sound from the hearing aid enters the ear. The amplified sounds are then heard through a process known as ‘air conduction’.
When you hear, sound passes along the ear canal to the eardrum making it vibrate. This is what is meant by air conduction. These vibrations are passed to three, small, linked bones in the middle ear. The small bones then carry the vibrations to the inner part of the ear (cochlea) and the fluid within it. Movement in this fluid bends tiny hair cells along the length of the cochlea, generating signals in the auditory nerve. The signals travel along the nerve to the brain, which interprets them as sound.
For more information about how your ears work, see our leaflet The facts: ears and ear problems (opens new browser window).
A bone conduction hearing aid can help you hear like a conventional hearing aid – but it works in a different way. It is especially designed for people who cannot wear a conventional hearing aid.
A bone conduction hearing aid works differently to a conventional hearing aid. It amplifies sounds but the sound is not passed into your ear canal via an earmould. Instead, the aid conducts – or carries – sound through the bone in your skull. This process is known as ‘bone conduction’. You hear when the sound vibrations are transmitted directly from the vibrating part of the bone conduction hearing aid through your skull to the cochlea, missing out the outer and middle ears.
Hearing through bone conduction is not as efficient as hearing through air conduction. However, bone conduction hearing aids are an option for people who cannot use a conventional hearing aid.
A bone conduction hearing aid is suitable for anyone who cannot wear conventional hearing aids in their ear canal because:
Once a bone conduction aid is fitted, people usually find that they have fewer ear infections, less feedback and do not have as sore ear canals as when wearing conventional hearing aids.
Bone conduction hearing aids are also suitable for some people with a conductive hearing loss. Conductive hearing loss occurs when sound is prevented from reaching the inner ear through its normal path, usually because of a blockage or abnormality of the outer or middle ear. Although bone conduction hearing aids can be suitable in these cases, a conventional hearing aid is often best for many people with middle ear problems.
Two main types of bone conduction hearing aid are available:
A traditional bone conduction hearing aid consists of an aid worn on the body and a bone vibrator fitted to a removable headband. The headband holds the vibrating part tightly to your head, so these aids can be uncomfortable to wear and can sometimes give you headaches and sore skin because of the pressure of the headband.
An alternative method is to fit the bone conductor to the arm of a pair of specially strengthened spectacles instead of a headband. There is also a type of aid that has a behind-the-ear hearing aid attached to the headband and bone vibrator.
A traditional bone conduction hearing aid is suitable for adults and children who cannot wear a conventional hearing aid, whether this is a temporary or permanent restriction.
If you have difficulty hearing and suffer from recurrent or chronic ear infections, you should see your GP. If your GP thinks you have a physical problem that needs further investigation, they will refer you to the Ear, Nose and Throat (ENT) department at a local hospital to get your ears checked. You may be advised to try a traditional bone conduction hearing aid. These are available from the NHS, except those that need to be fitted to spectacles.
If you prefer, you can buy a bone conduction hearing aid from a private hearing aid dispenser. For further information about buying hearing aids, see our factsheet, Buying a hearing aid?
(opens new browser window)An alternative to traditional bone conduction aids is a bone anchored hearing aid.
A bone anchored hearing aid (BAHA) consists of a permanent titanium fixture or implant (instead of a removable headband), which is surgically inserted into the part of the skull bone that is behind your ear. The vibrating part (called a ‘percutaneous abutment’) is fitted into the implanted fixture. A small detachable sound processor clips onto the abutment.
Some BAHAs have additional features such as:
BAHAs are not suitable for everyone. You will only be advised to have one if you:
There have also been trials using a BAHA for some people who are severely or totally deaf in one ear.
Some bone diseases, for example osteogenesis imperfecta, may mean that your skull bone is too thin and so a BAHA would not be suitable.
As part of your assessment, you will be given the opportunity to listen with a BAHA test rod, which you will bite onto, attached to a BAHA sound processor. If you hear well using this approach, a BAHA is likely to work for you because sound is conducted more efficiently through the skull than through teeth.
You can get a BAHA free from the NHS, though they are very specialised and are not available in every hospital. This means you may have to travel some distance to get one from a specialised centre. Your GP will refer you to your nearest hospital where you will be assessed to see if a BAHA might be suitable for you. You may then be referred to a specialised centre for further assessment.
BAHAs are surgically implanted. Before surgery, the surgeon will discuss which side would be best for the implant depending on which ear you hear better with. If your hearing is similar in both ears and you drive a lot, it may be better to choose your left or passenger-side ear. Or, it may be better for you to choose the ear you usually use for the telephone.
Surgery is usually carried out in one or two stages, normally under a local anaesthetic and sometimes under general anaesthetic. The standard procedure is to carry out both stages at once in adults and older children. However, this varies from hospital to hospital and depends on the surgeon and other factors. Each stage involves a minor operation that takes about an hour.
In stage one, a 3-4 mm titanium implant is inserted into the mastoid bone, which is the part of the skull directly behind your ear.
If carried out separately, the second stage will be done three or four months after stage one. By this time the titanium implant should have bonded strongly to the skull bone. This is known as ‘osseointegration’. During this stage, the implant will be connected through your skin to a small screw called a ‘percutaneous abutment’. This is the vibrating part, which conducts sound through your skull bone to your inner ear.
About a month after the second stage – or longer if both stages of the operation were done at once – you will be ready to use the sound processor. You will be given an appointment at the hospital. You will be shown how to attach and remove the processor, which can be snapped on and off, how to use the controls on it and how to clean the area around the screw. You must keep this area clean as daily cleaning reduces the risk of infection.
The external parts of the BAHA will need to be replaced every five years – but you won’t normally need to have any more surgery once the BAHA has been implanted successfully.
Remember that a BAHA, like any other hearing aid, will not restore your hearing, but it will improve your hearing in everyday situations.
If you feel you need more help with your BAHA directly from other people who also use a BAHA, you could contact a local BAHA support group. Go to www.baha-users-support.com (external link, opens new browser window) to find your nearest support group.
In the UK, children as young as three can be fitted with a BAHA. Children are more likely to dislodge the titanium implant as they have thinner bone and a more active life than adults do. Occasionally, some surgeons fit two implants in children so that there is a spare in case one fails. A new vibrating part can then be inserted into the spare implant, without further surgery.
For more information about BAHAs for children, contact the National Deaf Children’s Society (NDCS).
NDCS supports all deaf children, young deaf people and their families in overcoming the challenges of childhood deafness.Visit the National Deaf Children Society website (external link, opens new browser window) for more information.
The Patients' BAHA website (external link, opens new browser window) has a range of information about BAHAs including equipment such as loops to use with your BAHA, news, support groups and a discussion forum.
The RNID Information Line (opens new browser window) offers a wide range of information on many aspects of deafness and hearing loss. You can contact us for printed copies of this factsheet and the full range of our information factsheets and leaflets.