Bone Anchored Hearing Aids

AKA BAHA hearing aid


Bone anchored hearing aids uses the bones to conduct the sounds. It vibrates the skull bones which eventually vibrate the inner parts of the ear. This is in contrast to standard hearing aids that are air conducting. They use the regular way of vibrating the air which vibrates the eardrum. The BAHA is in use since 1977.

What’s the big idea?

The big idea is to bypass the external ear and the middle ear. In BAHA you transmit the sounds directly to the inner ear and this is what stimulates the hearing nerves which goes to the brain.

How is it built?

image placeholderBAHA components

The BAHA got three components:

  • Titanium implant. Implanted in the skull, during a fairly simple surgery.
  • Outer abutment. Connects the implant to the hearing processor.
  • Hearing processor. Gets the sounds from the surrounding and translates it into vibrations.

How does it work?

The titanium implant is inserted into the skull bone behind the ear in a surgery. Rich out and feel the bone right behind your ear. This is where the implant is located. The outer  abutment is attached to this titanium implant and the hearing processor is connected to the abutment.

The processor receives the sounds and transforms it into vibrations. The outer abutment conducts the vibrations to the implant. The titanium implant vibrates the bone itself and the cochlea which is the auditory portion of the inner ear. This is the component that enables us to hear.


Who can use BAHA?

image placeholderHuman ear diagram

In normal hearing, the sounds are air-conducted through the hearing canal to the eardrum. The eardrum vibrates the ossicles ,and the sounds are transferred to the inner ear where the hearing actually takes place.

Therefore, people with problems in their outer or middle ear, might have problems using regular hearing aids. You have to use something that will bypass the outer and middle ear and will transfer the sounds directly to the inner ear. Bone anchored hearing aids does exactly that. It vibrates the skull and the vibrations get to the inner ear.


So... On what cases can you use BAHA

  • BAHA can be a good solution if you got conductive hearing loss, meaning, a hearing problem that its origin is a problem either in the outer ear or in the middle ear (unlike problems in the inner ear).
  • BAHA can also help if you got mixed problems. A hearing loss that is caused by problems both on the outer or middle ear and on the inner ear. FDA, by the way, approved usage of BAHA to these types of hearing loss back on 1996.
  • BAHA can also help if you have problems with the ossicles (or if they don’t exist). Ossicles are three tiny bones located in the middle ear. They are part of the hearing process.
  • BAHA is sometimes used if you got chronic diseases in the ear canal. Any hearing aid that includes an earmold might be problematic. It can turn on an infection over and over again. Hearing aids that sits in the canal (CIC, ITC) might be a pbroblem for the same reason. Using BAHA bypasses the ear canal and saves the trouble.
  • Baha is also used if you haven't got parts (or all) of the pinna (auricle). Most hearing aids types use the pinna to stay in place. For this problem, there is another option, to use some more primitive device that vibrates the skull bones. It's a bone vibrator that you wear on the head. It’s not as efficient as the BAHA because the skin doesn’t transfer the vibrations well enough. In addition, the older solutions consider to be not very comfortable.
  • Another case you can use BAHA is if you got a hearing loss only on one side. Hearing loss on one side influences mainly on understanding talking in a noisy environment and on your ability to figure out voices’ location.  That’s because your brain uses the sound from both ears to analyze where is the source of the sound. BAHA helps because it vibrates the skull and vibrations are transferred  to both ears using the skull bones. FDA approved BAHA for this type of hearing loss back on 2002. You can also use CROS hearing aids for this kind of hearing loss. CROS gets the sounds from microphone on both ears and transfers it to the good ear. People usually complain that it is not very comfortable and it is bothering wearing a device on your good ear...

The operation

A short procedure, done under Local or general anesthesia. The surgeon inserts the titanium implant to the bone, just behind the ear. The recovery should take a day or two. After the surgery, it takes a few months till the implant and the bone are fused to one another. Only then you connect the abutment  and start the hearing training.

Dangers

The surgery itself is fairly simple. But like any surgery, there is always a danger for infection due to implanting an object into the skull.

Manufacturers

There are two manufacturers for BAHA, Cochlear and Oticon. Cochlear got the BAHA patent registered on their name so Oticon calls it Bone conducting hearing system. Practically, it’s the same thing. You can tell the difference by the outer processor, Oticon processor is rectangular while the other is shaped like a tear .


Two additional advantages you should take into account

When you use BAHA, you haven't got feedback issues (the annoying high tone you hear if you put a mic next to a speaker).

BAHA keeps your ears free. It saves you the uncomfortably of having something in your ear.


To summarize...

BAHA is good if you got problems in the outer or middle ear that prevents you from using standard hearing aids. BAHA isn’t a simple option. You can’t just walk in to a clinic and get one. On the other hand, in many cases, it’s the only option and there is no reason to be afraid of it.  

   


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