Expert: Harriet Jacobster, Au.D. - 5/3/2008

Question
There are a few websites of information of bone-conduction that says it helps you hearing safe, and i have the websites with me, please let me know what you think.

http://en.wikipedia.org/wiki/Bone_conduction

http://cgi.ebay.com/Bone-Conduction-Headphone-Alljoy-AG110_W0QQitemZ320224976133...

Answer
Hi Max,
Before I address these websites, maybe I should explain a bit how we hear.  Sound enters our ears through the ear canals and set the eardrum into vibration.  The eardrum in turn sets the three bones in the middle ear into vibration which then set the fluid in the inner ear in motion.  Think of thowing a pebble into a lake...you see all the ripples.  Now, in the inner ear are nerves that are stimulated by the ripples of the fluids.  These nerves sway back and forth and translate these movements into electrical impulses.  These impulses are then sent to the auditory nerve up to the brain and that is how we hear.  When we listen to loud sounds, the damage is 99% done to the nerves in the inner ear...the louder the sounds, the more these nerves bend back and forth until they finally break. Occasionally... and very occasionally...is the eardrum, or the middle ear bones, affected or damaged by loud noise. The bone conduction headphone bypasses the eardrum and the bones BUT still sends loud sounds to the inner ear which still can overstimulate the inner ear nerves.  Therefore, using these phones will still cause hearing loss.
Hope this helps.
Harriet B. Jacobster, AuD
Board Certified Doctor of Audiology