Hearing Restored in Mammals By Researchers
At one time it was believed that once we had damaged our hearing by listening to loud rock music or being exposed to other loud sounds there would be no way to repair it, and such individuals would be condemned to wear hearing aids later on in life.
Now for the first time there may be hope for restoring hearing in such cases of hearing loss. So far the following procedure has only been performed on mice, but researchers are hopeful they will eventually be able to restore noise-damaged human ears too.
The part of the ear that was the focus for this research was the cochlea, which is the shell shaped inner portion of the ear responsible for our hearing. In the cochlea there are hair cells that translate sound into electrical impulses from which the brain can discern what the sounds are.
Once these cells are damaged the body cannot repair them on its own; thus sensorineural hearing damage (hearing loss caused by loud sounds, infections, toxins, etc.) was assumed to be permanent. This distinguishes mammals from fish and birds which are able to repair their own cochlear hair cells.
Later in life many are subject to hearing aids or cochlear implants in order to help partially restore of their hearing. Since sensorineural hearing loss is the most common type of hearing problem, these are commonplace. However, such solutions only allow the patient to recover some of their hearing and do not fix the underlying issue of ear damage.
Researchers used a medicine that when combined with stem cells from the inner ear results in hair cell restoration – applying this drug to the cochlea of mice resulted in hair cell restoration, and subsequently a partial regaining of hearing ability.
Therefore, the potential findings in a human context are twofold. Firstly, hair cells can be restored, and secondly hair cell restoration results in regained hearing ability – researchers hope that these findings may represent a big step forward in fighting a major root cause of deafness.