Roughly one-third of senior citizens suffer from moderate hearing loss. With more people choosing to attend live concerts without ear protection and with more emphasis on volume than clarity, the number of people affected 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, “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. While animals like birds and reptiles have “notch inhibitor” class molecules, which stimulate regrowth in sensory hair cells after destruction of hearing, humans and other mammals do not. This 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 rodents to increasingly detect different kinds of sounds. The team noticed similarities between the side effects of dementia treatment and treating deafness, which prompted them to test 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 with Frequency Therapeutics for 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 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 it’s important to always take care of your ears!