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.
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.
The BAHA got three components:
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.
Human 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.
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.
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.
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 .
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.
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.