For those of you who don’t know about a bone conduction implant or system we’ve put together this article to help you learn about bone conduction and show the differences between each one.
When considering a bone conduction hearing system, there are a few main designs that have their own benefits or weaknesses—the best way to find out which one is right for you is by understanding how they all work.
How Bone Conduction Works
A bone conduction system is designed for someone whose outer or middle ear cannot send sound waves to the functioning inner ear; this is called mixed or conductive hearing loss.
Here’s where the outer and middle ear are located:
It gets around this blockage by vibrating the bones of the skull. These tiny vibrations can’t be felt, and they send sound waves to the hearing organ, the cochlea. This makes it possible for someone with a mixed or conductive hearing loss, or SSD, to be able to hear.
Most bone conduction systems vibrate the temporal bone because it’s the bone which is closest to the inner ear.
This is where the temporal bone is:
Types of Bone Conduction Implants and Systems
There are a few different ways that you can vibrate the temporal bone:
- Bone conduction headbands send vibrations through the skin to the temporal bone and are completely external.
- Bone anchored hearing aids (BAHA) vibrate a metal screw that’s drilled into the bone. The audio processor either vibrates a screw that goes through the skin, or is magnetically attached to a metal screw that’s under the skin.
- Bone conduction implants are implanted into the bone and completely under the skin. An audio processor is held to the implant with a magnet, and sends sound information to it with wireless signals.
The BONEBRIDGE is this third option, and here’s why we believe it’s the best design:
The 3 Reasons for BONEBRIDGE’s Sound Quality
1. A Smaller, Lighter Processor
Because the part of the BONEBRIDGE that vibrates the bone is entirely under the skin, the external audio processor can be thin and light. It needs only a battery and the computer chip which converts sound waves into the wireless electrical signals.
The newest BONEBRIDGE audio processor, SAMBA, is only 10 mm tall and weighs 9 g with the battery.
That means it’s not just nicer to wear, but you can wear it longer—up to 50% longer. 1
2. Under the Skin, or Through the Skin?
A small and light audio processor isn’t the only reason to want an implant that’s under the skin. It also makes for more comfortable hearing.
The alternatives are a headband which can be uncomfortable and cause the skull bones to deform,2 or a BAHA with its abutment and complication rates that average 23.9%.3 With BONEBRIDGE the skin heals completely and the implant is totally hidden. The audio processor is held onto the skin by magnetic attraction that can be secure enough to keep it from falling off while not so tight as to cause discomfort—it’s similar to how a cochlear implant uses its magnet.
3. Active Bone Conduction
And since it has the implant under the skin, it sends sound vibrations directly into the bone. This doesn’t just make hearing more comfortable, it makes for better hearing quality.4
The skin above the temporal bone varies between 2–8 mm,5 which means that when using a headband or BAHA you have to vibrate all of this skin even before sound waves get to the bone. The skin reduces the loudness of higher-pitched sounds and therefore distorts the sound. This means the BONEBRIDGE is both more efficient, because it vibrates the bone directly, and sounds better.4
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- Average wearing time in the BONEBRIDGE clinical study was 10.6 hrs/day. For the Baha Attract an average wearing tim of 7 hrs was reported (Cochlear product presentation, LION Broadcast, 10 December 2013)
- Raicevich, G., Burwood, E., Dillon, H. (2008) Taking the Pressure Off Bone Conduction Hearing Aid Users. The Australian and New Zealand Journal of Audiology. 30(2): 113-8. DOI: 10.1375/audi.30.2.113.
- Hobson, J.C., Roper, A.J., Andrew, R., Rothera, M.P., Hill, P., & Green, K.M. (2010) Complications of bone-anchored hearing aid implantation. The Journal of Laryngology & Otology. 124(2): 132-136. doi: 10.1017/S0022215109991708.
- Håkansson, B., Eeg-Olofsson, M., Reinfeldt, S., Stenfelt, S., & Granström, G. (2008) Percutaneous versus transcutaneous bone conduction implant system: a feasibility study on a cadaver head. Otology & Neurotology 29(8): 1132-9. doi: 10.1097/MAO.0b013e31816fdc90.
- Taghavi, H. (2014) The Bone Conduction Implant (BCI) Preclinical Studies, Technical Design and a Clinical Evaluation (Doctoral thesis, Chalmers University of Technology, Goteborg, Sweden) Retrieved from http://publications.lib.chalmers.se/records/fulltext/193305/193305.pdf.