Scientists examine how to reverse hearing loss
Roughly one-third of senior adult citizens suffer from moderate hearing loss. With more people choosing to attend live concerts without the use of ear protection, and with more emphasis on volume than on clarity, that number of people detrimentally effected by sound will likely increase. However, according to a new study reported by the Atlantic, we might be able to reverse the effects of hearing loss.
As the Atlantic explains the matter, "We owe our hearing to a tiny field of swaying cilia deep in the skull. Four rows of hair cells sprout in the snail-shaped cochlea of the inner ear, which is filled with fluid. Sound vibrations cause them to bend, opening pores that activate electrical signals bound for the brain. We are born with 15,000 hair cells in each ear, but unlike skin or other cell types, they do not turn over or replenish themselves. Loss of these hair cells over time accounts for much of the age-related hearing loss around the world, as well as that caused by too much loud noise. A loud sound can permanently bend or physically prune a fragile hair cell, rendering it ineffective."
This does not ring true for all animals, however. While animals like birds and reptiles have "notch inhibitor" class molecules, which stimulates regrowth in sensory hair cells after destruction of hearing, humans and other mammals do not, which is why our hearing loss is currently more permanent. This new study suggests that a treatment could potentially act as the missing notch inhibitor and cause the lost hair cells to regrow and multiply in a semi-natural state.
The article explains, "Each hair cell responds best to a particular frequency of sound — they are arranged in order of frequency along the cochlea — so scientists can pinpoint the effect of these new cells on hearing. When regenerated hair cells were then grown in the cochlea of mice, the pitches corresponding to their placement were better detected by the animals."
In 2013, Dr. Albert Edge led a team of researchers to grow and regenerate hair cells in the cochlea of mice, which allowed the rodent to increasingly detect different kinds of sounds. The team noticed the similarities between the side effects of dementia treatment and in treating deafness, which brought them to testing the mice's response -- which proved successful.
Dr. Edge's company Audion Therapeutics is moving forward with this method by planning the same attempt on humans. They are using compounds developed by pharmaceutical company Eli Lilly and are teaming up withFrequency Therapeutics for the human clinical trials to develop the treatment, using either a tube or piece of foam in the middle ear to similarly stimulate the regrowth of hair cells that were once damaged by sound in the human ears.
Projects like these have no proposed trajectory of time or success, and may take years to see developments in the theory. However, we're moving in the right direction, and hopefully those who spent their early years scoping out the rail closest to the bass amp will be able to hear again one day. Though, you should still always take care of your ears!