For more than half a century, hearing aids have been the only effective treatment for the millions of Britons struggling with deafness.
Yet they can be unsightly, uncomfortable and, in the eyes of some, label users as ‘old’ before their time.
As of January 2018, scientists are testing new drugs that could banish hearing aids for good for the estimated 900,000 people in Britain with moderate to severe deafness.
Two major clinical trials have started in recent months, which, it is hoped, will produce ground-breaking medicines capable of helping millions who cannot hear properly.
Both studies involve injecting experimental medicines into the ear with the intention of repairing the damage that caused the hearing loss in the first place.
Scientists at University College London’s Ear Institute are taking part in an international trial injecting a drug called a gamma-secretase inhibitor into the ears of 24 patients who have had partial deafness for up to ten years and use a hearing aid.
They believe the drug will restore hearing by stimulating the growth of healthy new ‘hair’ cells deep inside the ear.
In a healthy ear, sound enters the cochlea (a snail-shaped compartment inside the ear) and is picked up by sensory cells that resemble tiny hairs.
These hairs convert sounds into an electrical impulse that can travel along the auditory nerve to the brain.
These hairs can be damaged or destroyed by ageing, loud noise or infection and, until recently, it was thought it was impossible to regenerate them.
But laboratory tests at the Massachusetts Eye and Ear Infirmary in Boston in 2013 found that injecting gamma-secretase inhibitors into a type of cell called a progenitor cell led to the growth of healthy new hair cells. Progenitor cells are a form of stem cell that, unlike most stem cells, cannot develop into almost any form of body tissue.