New hearing-loss drugs face tough proof ahead

new hearing-loss – From social isolation to heart disease and dementia, hearing loss is increasingly tied to major health outcomes. This week’s reporting centers on what researchers can’t yet promise—and what’s moving, fast: an FDA-approved gene therapy for congenital deafness,

In a soundproof booth, the smallest uncertainty feels heavy. You press a button because you think you heard a faint electronic tone, then you wait for the next one—straining, second-guessing, afraid you’ll fail the test.

Hearing loss can begin quietly, but its consequences don’t stay small. Otologist Justin Golub at Columbia University in New York says the condition—once treated as a routine inconvenience of age—has become a major public health issue. It’s strongly linked to risks ranging from dementia to cardiovascular disease. And after years when there were no drugs that could restore lost hearing. a new wave of treatments is pushing into the pipeline.

The first step, though, is getting the diagnosis right. Hearing loss can be defined by the quietest sound someone can detect—roughly 20 to 25 decibels. about as loud as a ticking watch. The causes come in three main forms. Conductive hearing loss happens when sound waves can’t reach the inner ear because of a blockage; earwax build-up and infections are common causes and can often be cleared relatively easily.

Sensorineural hearing loss (SNHL) is the most common type. It comes from damage to the inner ear—either the cochlea or the nerve pathways from the cochlea to the brain. Age is a frequent driver. but so are genes. underlying diseases. noise damage. and pharmaceuticals toxic to the inner ear. especially a class of antibiotics called aminoglycosides.

The third category is auditory neuropathy spectrum disorder (ANSD), where the brain’s processing of sound goes awry. Both SNHL and ANSD are irreversible, though they can be alleviated with technology or therapy.

This isn’t just a personal problem. Over 1.5 billion people—almost a fifth of the global population—are living with some form of hearing loss. according to the World Health Organization. The WHO’s first-ever World Report on Hearing, published in 2021, found that around half of people over 65 have difficulty hearing. Prevalence doubles with every decade of life. and by age 70. about two-thirds of people can’t hear as well as they used to.

The outlook is grim enough to spur urgent medicine. The WHO predicts that by the end of this decade, 1.9 billion people will be hard of hearing. By 2050, that number rises to 2.5 billion—about a quarter of the world’s population. At least 700 million people will be affected enough to need a hearing aid. cochlear implant. or other intervention such as learning sign language or lip-reading.

What happens next isn’t limited to the ears. The most immediate effect many people describe is social isolation and loneliness. Julie Beadle at Simon Fraser University in Vancouver. Canada. says even mild hearing loss can push people into becoming socially disengaged. Multiple studies have shown the same outcome. and a recent review found that uncorrected hearing loss often leads to a significant withdrawal from social activities. Hearing loss can also make work and study harder, lower self-esteem, and feel exhausting. All told, social isolation and loneliness increase the risk of death from any cause by about a third.

If isolation doesn’t do it first, cardiovascular disease might. Iris Otero-Luis at the University of Castilla-La Mancha in Cuenca. Spain. led a research review earlier this year that examined research on the link between hearing loss and cardiovascular disease. The review concluded that many known cardiovascular risk factors—including obesity. type 2 diabetes. high blood pressure. imbalances in blood lipids. and metabolic syndrome—are also risk factors for hearing loss.

A Singapore study led by Woei Shyang Loh found that people with hearing loss have a 38 per cent higher risk of cardiovascular disease, with risk rising as hearing loss becomes more severe. One study in China found participants with the worst hearing were 76 per cent more likely to have a stroke.

There’s an important caution embedded in those numbers: hearing loss doesn’t necessarily cause cardiovascular disease. Otero-Luis says the most likely explanation is that both may be consequences of the same underlying problem. Cardiovascular disease often involves damage to small blood vessels, and that damage may also disrupt how the inner ear works. Oxidative stress and inflammation may play a role too, though the mechanism remains unclear.

The same “two sides of the same coin” idea may also explain why asymmetric hearing loss is tied to higher stroke risk: it can reflect localized damage to blood vessels in one side of the brain and inner ear. Shaojie Li at Peking University in Beijing argues that this could be useful—an early warning sign that helps people get cardiovascular care sooner. Other linked outcomes include falling over. a leading cause of injury and injury-related death worldwide. and mental health problems such as depression.

The dementia connection is among the most debated, and it lands at the heart of the current medicine push. A 2024 Lancet commission on dementia prevention, intervention and care identified 14 known risk factors, including hearing loss. Over the past decade. five major studies have found a significant association between hearing loss in older age and subsequent dementia. with increased risk ranging from 28 per cent to 139 per cent. In one of the most recent analyses, each 10 decibel increase of hearing loss increased dementia risk by 16 per cent.

The commission concluded that 7 out of 100 dementia cases are caused by hearing loss and could be prevented.

But not everyone agrees with the scale. Last year. a team led by Séverine Sabia at INSERM and Paris City University in France looked specifically at whether hearing loss around age 50 is an even bigger dementia risk factor. given that those people would live longer with impaired hearing. The study did not find that pattern. “There is an association. but it’s not as strong as previously thought. ” says team member Marcos Daniel Machado-Fragua. now at the Spanish National Centre for Cardiovascular Research in Madrid. That analysis put the increased risk at about 10 per cent.

Sabia’s INSERM colleague Archana Singh-Manoux offered a reason the numbers might look larger in older groups. She points to reverse causation: in people in their 70s—who are often losing hearing due to the early stages of dementia—changes in the brain can affect hearing before obvious cognitive deficits appear. “Pre-clinical dementia causes changes in the central nervous system. it affects hearing. so those results are open to what we call reverse causation. which is the disease itself affecting what you think is a risk factor. ” she says.

Even a 10 per cent increase is still meaningful, though the exact explanation remains contested. The Lancet commission proposed several contenders: hearing loss can lead to social isolation. loneliness and depression—risk factors on their own. Another possibility is that the brain becomes chronically overloaded by processing sounds. forcing cognitive strain that leads to brain shrinkage and dementia. A third is brain shrinkage driven by reduced sensory stimulation. A final possibility is that hearing loss is simply another symptom that appears before cognitive decline.

For now, the people living with hearing loss are watching the science for one clear answer: can it be reversed?

One major signal came with the US Food and Drug Administration’s recent approval of a treatment for a form of congenital deafness called DFNB9. The gene therapy is called Otarmeni and was developed by Regeneron Pharmaceuticals in New York state. It addresses a mutation responsible for profound hearing loss from birth. Otarmeni won’t help many people—only a few thousand worldwide have DFNB9—but Golub calls it proof of principle that gene therapies can be delivered to the correct part of the inner ear and restore hearing. “It’s exciting because we finally have an example of a biological treatment for hearing loss.”.

That success is already shaping research aimed at later-life hearing loss. One effort based at the University of New South Wales in Sydney. Australia. is developing a gene therapy to enhance cochlear implant performance. The genes are delivered during implant installation and are meant to stimulate production of two growth factors—neurotrophin-3 and BDNF—that promote neuron survival. The therapy has completed phase II and is moving into phase III. Chief investigator Gary Housley says the results have yet to be published but appear promising. adding. “The regeneration occurs very rapidly. ” and that the findings bode well for better hearing. He also says the delivery system could eventually be used for standalone gene therapy without a cochlear implant.

Stem-cell strategies are also underway. Degeneration of the spiral ganglion neurons—which connect the cochlea to the auditory nerve—is a leading cause of SNHL. Those neurons don’t regenerate on their own. but they can be coaxed by implanting stem cells called otic neural progenitors. Earlier this year. a company called Rinri Pharmaceuticals based in Sheffield. UK. received clearance to run a clinical trial of a therapy delivered alongside a cochlear implant. A US rival, Lineage Cell Therapeutics in Carlsbad, California, has something similar in early-stage testing.

Then there are chemical compounds designed to protect or regenerate inner-ear parts breaking down in age-related hearing loss. These drugs have a history of failure: since 2023. three promising ones were dropped after not performing well enough in clinical trials. One of the failures. from Audion Therapeutics. was described as close—Golub says it suggested the drug might work if tweaked. Two other compounds remain in phase II clinical trials: Ebselen from Sound Pharmaceuticals in Seattle. Washington. and Paliroden from Cilcare in Montpellier. France. “It’s impossible to forecast when we’ll actually have a drug but. yeah. I think there’s potential. ” Golub says.

While drug treatments remain uncertain, there are things people can do now. Diet matters. Foods rich in antioxidants. vitamin B9 (folate). omega-3 fatty acids. and magnesium have been found to be protective of the inner ear. Last year. a team at Rush University in Chicago reported that people who eat healthily—particularly the DASH (dietary approaches to stop hypertension) diet—have a reduced risk of hearing loss and slower cognitive decline once it starts.

And there is already a device that many people associate only with hearing better. Hearing aids are being tested for cognitive outcomes too. Ten years ago. researchers at Johns Hopkins Bloomberg School of Public Health in Baltimore. Maryland. began the world’s first clinical trial to see whether hearing aids can slow cognitive decline and dementia in older adults with hearing loss. The results were published in 2023 and suggested benefit in some circumstances. Overall effects weren’t statistically significant. but among a subgroup—people more susceptible to dementia because they were older. less educated. less wealthy. more likely to smoke. and had more underlying health conditions—hearing aids substantially slowed cognitive decline.

There are dissenting views. Singh-Manoux’s team at Paris City University also analyzed whether hearing aid use protected against dementia and found it didn’t. “Wearing a hearing aid isn’t going to mitigate the risk of dementia,” she says. Still, she insists the purpose is broader than cognition. “Hearing aids are important for people to remain connected to life. to remain connected to friends. to remain connected in conversations. to manage their day-to-day life.” Golub says the same applies to cochlear implants. which can vastly improve quality of life for people with severe or profound hearing loss.

The most practical advice, across disagreements about percentages and mechanisms, is straightforward: get tested. Golub says people shouldn’t ignore early signs of losing hearing. “My main advice would be, don’t ignore it. Go and see an audiologist. find out exactly what your level of hearing loss is and then you can make a decision about what to do about it.” Hearing test apps for smartphones are also available and increasingly good. he adds.

In that booth. the test ends with a result that is both reassuring and a warning: the narrator reports very mild hearing loss at two middle frequencies in the left ear. It’s described as age-related. and “nothing to worry about – yet.” Still. the message lands like the room’s silence—something to keep track of closely.

The science is moving. from gene therapy approvals to phase II and phase III studies. and it’s clear why people are watching so closely. But the stakes aren’t only about what hearing can be restored. They’re about what hearing loss can take from the rest of the body—and about how quickly medicine can catch up before that happens.

hearing loss sensorineural hearing loss auditory neuropathy spectrum disorder gene therapy Otarmeni DFNB9 cochlear implants stem cells spiral ganglion Ebselen Paliroden hearing aids dementia risk cardiovascular disease Lancet commission on dementia