About Bone Conduction Devices

WHAT ARE BONE CONDUCTION DEVICES?

The reason we have an ear canal and an ear drum and hearing bones is to convert the sound vibrations in air into vibrations in the fluid inside the inner ear (the cochlea). The nerve endings of the hearing nerve then pick up these sound vibrations and send the information to the brain.

The other way that the fluid inside the cochlear can be made to vibrate is by BONE CONDUCTION. The bony outer wall of the cochlea is part of the skull bone. If you can make the skull vibrate then you will make the fluid inside the cochlea vibrate. If the skull vibrates at the same frequency as sounds or speech then the fluid in the cochlea will vibrate at those frequencies and the nerve endings will detect those vibrations.

HOW DO YOU MAKE THE BONE VIBRATE?

A bone conductor hearing aid will take sound in through its microphone and then make the casing of the device vibrate at the same frequencies. If the device is then pressed against the bone it will make the skull bone vibrate at those frequencies. You will not feel these vibrations.

A very important principle of BONE CONDUCTION:

It does not matter where on the skull you attach your vibrating device because the vibrations will find their way to BOTH inner ears (cochleas)

From this it follows that:

If you have only one working cochlea the vibrations will find that good cochlea and you will be able to hear through it.

WHAT BONE CONDUCTION DEVICES ARE AVAILABLE?

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BONE CONDUCTION HEARING AIDS?

These aids are attached to either a band which presses the aid firmly against the side of the head or the aid can be concealed in the arm of reading glasses.

These aids can be very effective but in order to work well the aid needs to be pressed hard against the skull. Most people find that this is very uncomfortable and are unable to wear the aid for more than an hour or two before needing to take it off.