Bone Anchored Hearing Aids (Baha)

15 04 2008

I asked Lyn, Chair of Baha Users Support and Honorary member of The Baha Professionals Group, about her Baha hearing aids. Here she very helpfully explains what a Baha is and how it differs from an air conduction aid – which I’m guessing most of us wear as the BTE (Behind the ear) is what I see most people wearing.

For me, having Bahas means the difference between having no useful hearing, to having hearing that “is” useful.

Putting my Bahas in on in the morning is like opening double windows to sound.

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Like all aids they have their limitations, the range of sound is not “normal” but it enables me to communicate mostly effectively, assisting my lipreading.

I see my bilateral Bahas as offering me “effective” hearing for longer than I would otherwise have it, as my nerve hearing is now failing on one side. I cannot use any other type of hearing aid.

My middle ear parts don’t work, the middle ear consists of the ear drum and the little bones behind it. So the chain of sound is broken, there is nothing to carry the sound from the outer ear to the inner nerve part of the ear.

The Bahas are sound processors which attach to an abutment (socket) behind my ears. The abutment is held on to the skull by a tiny 4mm titanium screw fitted into the bone. A 40 minute minor surgical procedure, usually a day case job under local anaesthetic (for most adults).

The Baha can be used as a regular bone conduction aid in children from a few weeks, or attached to an elasticated material headband called a Softband.

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This enables use from an early age without causing any deformity of the young bones, as happens with the usual headband type. The implant can be fitted when the child’s skull is mature enough.

The sound processors pick up sound, convert it to vibrations (as would normally happen with the middle ear parts), the vibrations are carried to the skull bone via the abutment and tiny titanium implant screw.

Bone is an efficient conductor of vibrations, and the vibrations are carried directly to the cochlea (inner nerve part of the hearing mechanism).

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Some people can be profoundly deaf conductively (due to middle ear problems) but can have perfectly working nerve hearing parts. So the Baha is a very effective “middle ear bypass”. The better the cochlea function the better the benefit from the Baha. Only an assessment by audiologists trained in Baha can tell if a person is suitable and can benefit – the Baha is available on the NHS, though the funding is very inconsistent round the UK!

It can also help people who are single sided deaf, even if their deaf ear is nerve deaf (as in post acoustic neuroma surgery). The Baha enables sound to be picked up on the deaf side, and the vibrations are heard in the working nerve on the opposite side of the head, offering a “sense” of bilateral hearing.

Mostly the Baha is fitted to people who can benefit, and who are unable to use air conduction aids.

This could be due to deformities of middle or outer ear parts, or in many cases due to middle ear disease / infection where there is damage to the little bones and no hope of reconstruction surgically (as in stapedectomy).

Also people with middle ear disease / infections can have their problems made worse by blocking off the ear canal with air conduction ear moulds.

I personally could only wear my air conduction aid for 20 minutes before the middle ear would start weeping. So I kept it in my handbag, and only put it in when I “really” needed it…. because of the middle ear destruction the air conduction aid did not offer me very effective hearing anyway.

Now my Bahas offer me 24/7 optimal hearing. Hearing that is consistent, even if I have middle ear infections.

Thank you for “listening”. Lyn.

* Pictures courtesy of Cochlear, the manufacturer of the Baha.

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9 responses

15 04 2008
Candy

So are you saying the baha gives you more hearing than regular hearing aids?

Is the surgery anything like C.I.?

I have moderate to severe hearing loss and with my aids, I can hear pretty much everything except for certain sounds like letter “s” or “z” and so on.. Would Baha benefit me more?

16 04 2008
Jarom M.

I have known few people who had BAHA but they ended up get implanted with cochlear implant because they complained of repetive infections around the screw that stick out of head. I personally won’t benefit from it since I am profound deaf and have implants on both sides. I know that my implant center do BAHA but they rarely do it and I was told that my surgeon prefer not to do that procedure.

16 04 2008
Sarah

You’ve been tagged at my blog
http://speakuplibrarian.blogspot.com

16 04 2008
Lyn

You will only be considered for a baha if you are unable to benefit from air conduction aids (for reasons mentioned in my write up), and are able to benefit from the baha. The surgeon, as mentioned, is minor, nothing like that with surgery for CI.

The CI is for those who have cochlears which do not work effectively enough for them to benefit from other types of aids, but who have functioning hearing nerves which would carry electrical impulses from the cochlears to the brain if the cochlears functioned effectively. The CI directly stimulates the cochlea to effectively “magnify” the electrical impulses so that they are strong enough to be carried on the hearing nerve to the brain.

The Baha is for another type of hearing loss caused by middle ear problems, and requires at least one cochlear to be functioning at a level sufficient for a person to be able to benefit.

Two different aids, two different types of deafness which they are used for.

It isn’t considered an “alternatative choice” to air conduction aid. For those of us who have it, it is the “only” option.

They are not fitted when the issue is one of sound quality, only if for some reason you are unable to use air conduction aids and could benfit from the Baha.

There are many air conduction aids available now, so if you do not have what you feel is good enough sound quality with what you have, you possibly need to be reassessed to see if another make would help you better.

Or, it might be that your aids need re-tuning, which can happen when there is an ongoing deterioration with hearing.

I hope this clarifies.

Good luck. 😉

16 04 2008
Lyn

Hi Jerome. Those people were possibly borderline with their cochlea function. Usually the baha will be fitted to people who have air conduction aids but keep getting infections. What can happen their cochlea function may continue to deteriorate, getting to a point where the baha will no longer help them. (There is a powerful version of the baha which has a body worn microphone, this is used in people who have middle ear disease which is made worse by wearing ear moulds, but who need strong aided hearing). There is a point beyond which the baha will not help, and the cochlear implant will.

I believe that fairly recently the criteria for considering CI has changed a lot, whereas before the loss had to be very great before CI was considered, they are fitting it to people who still have some cochlea function…. I am not completely sure, so do check out a site related to CI for exact information.

I have only ever had one “bad” infection in one of my implant sites, in 9 years. Ongoing infection is rare, and will depend on various things. But people in general good health, and able to care effectively for their abutment sites, should be OK. 🙂

21 04 2008
Abbie

I always wondered how the BAHA worked and what the sound quality was, I am glad you posted this!. Does the external part clip right up the against the head or is there a space?

21 04 2008
Lyn

Hi Abbie. There is clearance between the sound processor and the scalp. This is so the sound processor can vibrate freely. If it is too close it will affect sound quality and there will be feedback.
I can get the tip of my little finger between my sound processors and my scalp, so not a “huge” distance.
Sound quality will mainly depend on how good a person’s inner ear parts work.
My right cochlea is not working so good these days, and the sound quality I get from my right Baha alone is very much poorer than the quality I get with my left sound processor alone.
My left cochlea works really well, top class hearing!! But ironically my left has been profoundly conductive deaf (because of canal and middle ear deformity) from birth, so the cochlea has only been in use for the past 9 years since my first implant which I had put that side.
My theory is that my right “better” ear, being more used throughout my life, has “worn out”, plus the cochlea may now finally be suffering damage from my middle ear disease too.
I am going to ask for my audiologist to consider trying a more powerful sound processor on my right. He suggested it might help bring the sound quality up on that side for me. But funding in our Trust is not brilliant (better than it was….but) so I won’t hold my breath. I’d rather the money be used for someone who needs a Baha, rather than to upgrade me just yet if the money isn’t there. I can get by single sided baha, after spending my first 39 years SSD! 😀

29 04 2008
acoustic neuroma

[…] what a Baha is and how it differs from an air conduction aid – which I??m guessing most of us wehttps://funnyoldlife.wordpress.com/2008/04/15/bone-anchored-hearing-aids-baha/Tiny skull vibrations producing device highly beneficial for hearing impaired New KeralaWashington, […]

10 07 2010
jinky

It seems you spend a lot of time for this blog. I’ll keep reading your blog to keep up with you. :_)

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