Hearing Damage Self Healing

Gene therapies could soon repair hearing damage. But the most effective approach would be to avoid noise – especially that from headphones.

A gene involved in half of all hereditary hearing disorders

Noise is not the only reason for hearing damage. Also carried over middle ear infections, viruses, and above all hereditary diseases can lead to hearing loss. “Studying such hereditary diseases helps us understand how hearing damage occurs,” Müller said.

For example, that the gene “connexin 26” in the inner ear plays an important role in converting sound into a nerve impulse. It is, therefore “the most frequently associated” gene with the disease in humanity: “50 percent of all hereditary cases of hearing damage can be traced back to a change in this one gene.” When we hear, the air vibrations of sound are transmitted through the eardrum to the fluid in the cochlea of the inner ear, where the sensory cells for perceiving sounds are located.

“If you wind up the cochlea, it looks like a piano – the sensory cells for perceiving high-pitched sounds are at one end and for low-pitched sounds at the other.” Depending on the pitch, the fluid in the inner ear presses on the hearing organ’s “keys,” called hair cells. They convert the mechanical signals of the sound into electrical signals that are transmitted to the brain.

Impaired hearing is the most common sensory disorder in humans

The World Health Organization (WHO) even considers hearing loss a pandemic, a worldwide problem that also has an economic dimension: In the U.S. alone, $50 billion is spent annually to correct hearing problems. In Europe, around 71 million people are currently affected by hearing loss. Almost half of them are older than 75. However, about one billion people worldwide are at risk of early hearing loss. ” This has partly to do with headphones,” said neuroscientist and hearing expert Ulrich Müller of Johns Hopkins University last week during a lecture at the “flagship store” of headphone manufacturer Sennheiser at Berlin’s Tauentzien as part of a new lecture series “Mittelstand meets Science.”

15000 hair cells per ear – enough for a lifetime

For this to happen, however, hair cells must be intact. And per ear, a person is born with only about 15,000 of these sensitive cells. “If they die, they are lost forever; people cannot regenerate them,” says Müller. And noise damages the cells so much that 10 percent of all hearing damage in adults can be attributed to it. “Even the sound you have in your ear the day after a rock concert is a sign that the connections of hair cells and nerve cells are disrupted,” Müller said.

 

Meanwhile, knowledge about the hearing process and the cells and genes involved is leading to new therapeutic approaches – for example, in regenerative medicine. Here it is already possible to grow hair cells in the laboratory and also in animal experiments. But mimicking these processes in the human ear is “still utopia at the moment,” Müller said. Companies like Frequency Therapeutics, however, are already trying to stimulate hair cell regeneration with drugs.

Can I restore my hearing to 100% with a hearing aid?

No. A hearing aid is an aid, like a pair of glasses, for example. Hearing systems are constantly being developed further and research benefits from the experiences of hearing-impaired people. Of course, there are also people who can understand almost everything again with a hearing aid and thus achieve practically 100%.