A number of the conditions that cause hearing problems in our patients can’t be reversed which is quite frustrating for our hearing specialists. Damage to the tiny, sensitive hair cells of the inner ear is among the more prevalent reasons for hearing loss. The work of these hair cells is to vibrate in response to sound waves. What we think of as hearing are the translations of these vibrations into electrical impulses which are sent to and interpreted in the brain.
The sensitivity of these tiny hair cells enables them to vibrate in such a manner, and thus enables us to hear, but their very sensitivity makes them very fragile, and susceptible to damage. Infections, certain medications, aging or exposure to loud sounds (resulting in noise-induced hearing loss/NIHL) are all potential sources of damage. The hair cells in human ears can’t be regenerated or “fixed” after they have become damaged or destroyed. Therefore, hearing professionals and audiologists have to deal with hearing loss technologically, using hearing aids
or cochlear implants.
If humans were more like chickens or fish, we would have other options. That may sound like an odd statement, however it is true, because – unlike humans – some fish and birds can regenerate inner ear hair cells, and thus regain their hearing once it has become lost. To name a couple such species, zebra fish and chickens have been shown to have the ability to spontaneously replicate and replace inner ear hair cells that have become damaged, thereby regaining their full functional hearing.
Could hearing loss in humans be reversed? Glimmers of hope are appearing from the groundbreaking research of the Hearing Restoration Project (HRP), but the research is preliminary and no useful benefits for humans have yet been established. Financed by a non-profit organization called the Hearing Health Foundation, this research is currently being conducted in 14 different laboratories in the U.S. and Canada.Working to identify the molecules that allow the replication and regeneration in some animals, HRP scientists hope to find some way to stimulate human hair cells to do the same.
This work is slow and demanding. Scientists need to sift through the many molecules active in the regeneration process – some of which support replication while others inhibit it. But their hope is that if they can isolate the compounds that enable this regeneration process to happen in avian and fish cochlea, they can find a way to enable it to happen in human cochlea. The HRP researchers are taking a divide and conquer approach to achieve their joint goal. While some labs work on gene therapies others focus on approaches using stem cells.
Our entire team extends to them our best wishes and hopes for a great success, because absolutely nothing would delight us more than being able to completely cure our clients’ hearing loss.