Deafness Discovery Showed Inner Ear Hair Cells Regenerated

Editor: Conventional wisdom for quite some time has been that most mammals do not regenerate cochlear hair cells. Now it turns out that may not be true. Here's a story on hair cell regeneration from the Olathe News. Reprinted with permission.

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By Leonard Hall

An interesting medical discovery found the small bundle of hair cells in the inner ears of rats are naturally being replaced every two days. The discovery was announced by the National Institute on Deafness and other Communication Disorders.

This discovery may explains why so many people suffer temporary hearing loss or ringing in the ear after exposure to loud noises for two days and then fully recover their hearing. The report stated that there are many antennae called sterocila that make up the sensory component of the ear hair cells.

During loud noise exposure, the sterocila makes bending movements causing critical damages to the sterocila cells. The research found that the damaged portion of the sterocila is replaced within 2 days.

The research shows how the human inner ear survives to keep working after encountering substantial damage due to loud noise exposure. Before this discovery, many researchers thought that temporary hearing loss did not involve the hair cells but the base of the hair cells where swelling occurred.

The key question is why some people suffer permanent hearing loss after extended exposure to loud noise when other people do not lose any hearing? The researchers said that genetic, environmental and age factors are involved.

It is now believed that continuous exposure to loud noise will cause irreversible damage to the inner hair cells regenerative ability to replace the hair cells.

The discovery may lead to more medical research on whether new hair cells can be produced [or whether] stem cells can be implanted to replace those permanently damaged. Apparently, this may lead to major medical advance to allow doctors to implant hair cells to replace those hair cells that were permanently damaged.

There may be an option of hair cell implants in the future to restore or replace the permanent damaged hair cells to restore hearing. Perhaps in ten years, hair cell implants will be common as kidney or heart transplants to provide hearing for those people with hearing loss.

(Leonard Hall writes columns on the deaf community and can be reached at Legalnetwk@aol.com.)