Hearing Aids May Lead to Lower Rates of Dementia, Depression, and Anxiety

Hearing Aids May Lead to Lower Rates of Dementia, Depression, and Anxiety

 

According to a report, hearing Aids May Lead to Lower Rates of Dementia, Depression, and Anxiety

 

This article appeared September 2019 in the Hearing review

 

Older adults who get a hearing aid for a newly diagnosed hearing loss have a lower risk of being diagnosed with dementia, depression, or anxiety in the following three years, and a lower risk of suffering fall-related injuries, than those who leave their hearing loss uncorrected, a new study finds. A summary of the study’s findings were published on the University of Michigan’s website.

Devon hearing

Yet only 12% of those who have a formal diagnosis of hearing loss actually get the devices—even when they have insurance coverage for at least part of the cost, the study shows. It also reveals gaps in hearing aid use among people of different racial and ethnic backgrounds, geographic locations, and genders.

The findings, made by a University of Michigan team using data from nearly 115,000 people over age 66 with hearing loss and insurance coverage through a Medicare HMO between 2008 and 2016, are published in the Journal of the American Geriatrics Society.

Unlike traditional Medicare, Medicare HMOs typically cover some hearing aid costs for members diagnosed with hearing loss by an audiologist.

Elham Mahmoudi, MBA, PhD, the U-M Department of Family Medicine health economist who led the study, says it confirms what other research has shown among patients studied at a single point in time—but the new findings show differences emerging as time goes on.

Ear wax removal Honiton

“We already know that people with hearing loss have more adverse health events, and more co-existing conditions, but this study allows us to see the effects of an intervention and look for associations between hearing aids and health outcomes,” she says.

“Though hearing aids can’t be said to prevent these conditions, a delay in the onset of dementia, depression, and anxiety, and the risk of serious falls, could be significant both for the patient and for the costs to the Medicare system.”

Long-term Tracking

Mahmoudi and her colleagues at the U-M Institute for Healthcare Policy and Innovation looked at anonymous insurance data to perform the study, and looked at the data for each person with hearing loss one year before their diagnosis, and three years after, so they could see only newly diagnosed dementia, depression, anxiety, and fall injuries.

They intend to keep studying further data from this population, to see if the differences in health outcomes continue beyond three years.

The study shows that men with hearing loss were more likely to receive a hearing aid—13.3% compared with 11.3% of women. Only 6.5% of people of Latino heritage received a hearing aid for their hearing loss, compared with 9.8% of African-Americans and 13.6% of whites.

Nearly 37% of people with hearing loss who lived in the north-central part of the country, as designated by the Census Bureau, used a hearing aid, compared with just 5.9% of people in the mountain states.

Differences in Diagnosis

When the researchers looked at the path that patients who received hearing aids took over three years, compared with those who didn’t get the devices, significant differences emerged.

In all, the relative risk of being diagnosed with dementia, including Alzheimer’s disease, within three years of a hearing loss diagnosis was 18% lower for hearing aid users. The risk of being diagnosed with depression or anxiety by the end of three years was 11% lower for hearing aid users, and the risk of being treated for fall-related injuries was 13% lower.

The study also confirms previous studies’ findings that people with hearing loss had much higher rates of dementia, depression, and fall injuries than the general population.

The reasons for this are complicated, and can include loss of social interaction, loss of independence, loss of balance, and less stimulation to the brain. Some researchers also believe that the loss of nerve impulses from the ear to the brain, and loss of cognitive ability leading to dementia, could be part of the same ageing process.

What’s to Come

The study only included individuals who billed their insurance company for part of the cost of their hearing aid, Mahmoudi notes. The coming of FDA-approved over-the-counter hearing aids in 2020 for people with mild to moderate hearing loss could make the devices much more accessible for many people.

But those new devices could also complicate researchers’ ability to study the effects of hearing aids on other health outcomes, if people don’t use insurance coverage and researchers can’t tell if they have one.

“Correcting hearing loss is an intervention that has evidence behind it, and we hope our research will help clinicians and people with hearing loss understand the potential association between getting a hearing aid and other aspects of their health,” says Mahmoudi.

She notes that Medicaid in the state of Michigan is now covering hearing aid testing, fitting, and purchase, since a policy change in 2018, and that it will be important to study impacts in this population as well.

In addition to Mahmoudi, the new study’s authors are IHPI statisticians Tanima Basu, MS and Neil Kamdar, MA, and IHPI members Kenneth Langa, MD, PhD, Michael M. McKee, MD, MPH, Phillip Zazove, MD, and Neil Alexander, MD. Langa and Alexander are professors in the U-M Department of Internal Medicine; McKee and Zazove are assistant professor and chair, respectively, of the U-M Department of Family Medicine. Langa also holds faculty positions in the U-M Institute for Social Research and the VA Ann Arbor Center for Clinical Management Research.

Original Paper: Mahmoudi E, Basu T, Langa K, et al. Can hearing aids delay time to diagnosis of dementia, depression, or falls in older adults? Journal of the American Geriatrics Society. 2019. DOI: https://doi.org/10.1111/jgs.16109

Source: University of Michigan, Journal of the American Geriatrics Society

Even the Queen wears hearing aids

Even the Queen wears hearing aids

 

As reported in many outlets this week, the Queen was seen wearing hearing aids for the very first time in public.

This is proof if there has ever been proof that everyone will suffer from hearing loss at some time in their life. It really isn’t such a big deal to wear hearing aids as the Queen has shown. Be brave and get back into conversation with your family, friends or work colleagues.

Devon hearing centre

 

Watch our video here to see what types of hearing aids there are and what they look like. Today you can customise certain hearing aids to make them look on trend.

Honiton hearing centre

 

If you feel that your hearing isn’t the same as it once was ( it really does suffer as we get older) and would like a short hearing test then we can help. Once we know the results we can help if there is any hearing loss and recommend a solution for you.  It could be that you have ear wax build up and if that is the case its a simple cleaning of the ear! Click here to see how ear wax removal is done using Microscution.

Exeter hearing centre, Honiton hearing centre, Ear wax, ear wax removal, Devon,

Exeter hearing centre Devon

 

You can read an article on the Queens hearing aid here

Starkey’s Livio AI Featured in ‘TIME’s 100 Best Inventions of 2019′ List

Starkey’s Livio AI Featured in ‘TIME’s 100 Best Inventions of 2019′ List

 

The Honiton hearing centre are excited to learn that Starkey’s Livio AI has featured in the ”Time’s 100 Best.

 

Starkey Hearing Technologies announces that Livio AI, “the world’s first multi-purpose hearing aid,” has earned a place on TIME’s 100 Best Inventions of 2019 in the accessibility category. This list is said to “highlight inventions that are making the world better, smarter, and even a bit more fun.”

Starkey Livio AI hearing aid

Starkey Livio AI hearing aid.

TIME uses a multi-step process to assemble the annual list. Contenders from around the world are evaluated on key factors, including originality, effectiveness, ambition, and influence. The result: One hundred groundbreaking inventions that are changing the way we live, work, play, and think about what’s possible, according to Starkey’s announcement.

Honiton Hearing centre

Livio AI  features integrated sensors and artificial intelligence, providing what the company says is “superior sound quality and the ability to track both body and brain health.” By providing direct monitoring of physical and cognitive activity, including fall alerts and transcription features, Livio AI helps raise awareness about the connection between treating hearing loss and reducing health risks, like cognitive decline and heart disease.

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“I’d like to thank TIME for this incredible recognition. We are humbled and proud to be on this list and in the company of other innovative companies that are truly making the world a better place,” said Starkey President Brandon Sawalich. “I’m grateful to the entire Starkey team for its relentless dedication to helping people hear better, so they can live better. Thank you for continuing to push us to break technological boundaries and transform hearing health as we know it.”

The new issue of TIME, featuring Starkey and Livio AI, goes on sale November 22.

Source: Starkey Hearing Technologies 

New Signia hearing aids announced

Signia Introduces Xperience Platform with Motion Sensor Technology

A post by the Honiton hearing centre

The new Pure 312 X hearing aid: a discreet personalized hearing aid with direct streaming.

The new Pure 312 X hearing aid: a discreet personalised hearing aid with direct streaming.

Signia, a brand of WS Audiology A/S, has launched Signia Xperience, a new platform that reportedly introduces the world’s first combination of advanced acoustic sensors with a built-in motion sensor. Signia Xperience hearing aids are designed to provide a complete analysis of the wearer’s dynamic soundscape, allowing for automatic adjustments between sounds in front of and all around the wearer for a personalised listening experience.

Devon hearing Company

Many hearing aid wearers have an active lifestyle and are always on the go—yet, current hearing aids don’t always keep up relative to hearing in noise. Existing hearing aids are sometimes unable to adapt to diverse listening environments as the wearer moves around. The Signia Xperience platform, built upon YourSound technology, was developed to fill this crucial gap and respond to rapid changes in the wearer’s environment.

YourSound Technology

Patricia (Tish) Ramirez, AuD

Patricia (Tish) Ramirez, AuD

With the new YourSound technology, Signia Xperience hearing aids can identify more variables from the environment than ever before and ensure they know what is important at every moment, according to the company. They also include a built-in motion sensor to take into consideration how the wearer’s movement affects their hearing in each situation. In a conversation with The Hearing Review, Signia Vice President of Clinical Education & Professional Relations Tish Ramirez, AuD, provided information about how the system can identify soundscapes in dynamic listening situations, and then intelligently apply omni-directional, directional, and narrow-band microphone technology in addition to advanced processing algorithms to improve the signal-to-noise ratio (SNR) in changing acoustic environments. For example, she described a “cocktail party” scene where a listener might wish to walk through the party and hear the “omni” environment, then stop to chat and enjoy a one-on-one conversation where narrow-band directionality might be engaged, but also benefit from detection of important noises in back (eg, a waiter asking if you need something) as the hearing aid adjusts accordingly.

East Devon hearing aids and Ear Wax Removal

In essence, the new Signia Xperience is designed to enable wearers to continuously benefit from the proper amount of frontal focus, says Dr Ramirez, while still being able to hear relevant speech from other directions, like when running in a park with friends or walking down a busy street. Although inertial sensors have been employed in other hearing aids, Dr Ramirez says this is the first time these sensors have been employed for addressing SNR, ambient modulation, own-voice features, and more, enhancing the hearing aid’s speech-in-noise performance in a wider variety of acoustic settings.

The three key features of YourSound technology are:

  • Acoustic-motion sensors for a complete analysis of each wearer’s dynamic soundscape;
  • Dynamic Soundscape Processing for natural sound and speech from any direction, in any situation—even when moving, and
  • Own Voice Processing (OVP™) for a natural sounding own voice.

YourSound technology is delivered by the powerful Signia Xperience chip. It includes 80% more transistors and 7 times the memory of the previous Signia Nx chip, while being 60% smaller. As a result, the first two hearing aids on the platform, the Pure® 312 X and the Pure® Charge&Go X, are smaller yet more powerful than their predecessors.

A New Sound and New Look for Pure 312 X

Available now, the Pure 312 X includes all the benefits of the Signia Xperience platform in a new, appealing design created in collaboration with hearing care professionals and hearing aid wearers. With long-lasting exchangeable batteries, plus an optional telecoil (available in December), this high-performing receiver-in-canal (RIC) hearing aid is said to deliver a more personal hearing experience, with a clean, ergonomic design. Pure 312 X also has Bluetooth® connectivity for effortless streaming of phone calls, music, and TV audio.

New Features for Pure Charge&Go X

Pure Charge&Go X combines all advantages of the Signia Xperience platform with lithium-ion rechargeability and full Bluetooth (BT) connectivity.

Pure Charge&Go X combines all advantages of the Signia Xperience platform with lithium-ion recharge-ability and full Bluetooth (BT) connectivity.

Exeter hearing aids

Coming in November, Pure Charge&Go X is a RIC with Bluetooth connectivity that combines the advantages of the Signia Xperience platform with lithium-ion recharge-ability. With 20% more charging capacity and 16% smaller than the previous Pure Charge&Go Nx, wearers benefit from a slim device that can support a long wear time even with streaming, says Signia.

Pure Charge&Go X features a rocker switch for easier adjustments and comes with a new inductive charger with a lid to protect the hearing aids as they charge. The charger also works as a dehumidifier and is designed to fit custom ear molds.

The new charger will be backward compatible to existing rechargeable Signia devices, and also affords a 30-minute fast-charge that can give wearers 6 hours of operation.

The Signia App: Three Apps in One

The Signia app provides hearing aid wearers with everything they need for a personalized wearing experience, including remote control, remote support, and audio streaming.

The Signia app provides hearing aid wearers with everything they need for a personalised wearing experience, including remote control, remote support, and audio streaming.

Sidmouth Hearing aids

Along with these two new products, the Signia Xperience introduces a new app. The Signia app combines the three existing Signia apps—the myHearing app for remote telecaretouchControl app (for non-BT), and myControl app(for BT aids)— into one unified environment to meet every user’s needs, including:

  • Providing wearers with direct support from a hearing care professional;
  • Remote control so the wearer can personalise their hearing experience, and
  • Easy management of streaming accessories to fully enjoy phone calls, music, and TV.

Available in S-Demos. As with the Signia Nx, the new hearing aids will also be available for hearing care professionals in models that can be demonstrated to patients on a timed-trial basis.

Additional information about the Signia Xperience platform can be found at: https://pro.signiausa.com/signia-xperience/

New custom hearing aids Devon

New custom hearing aids Devon

New custom hearing aids Devon at the Honiton hearing centre near Exeter

 

 

New custom hearing aids Devon are now available at the Honiton hearing centre. Hearing aids have transformed the way people live and work in recent technology advances. Today hearing aids can be tailored to an individual like never before.  The days of plain analogue amplification of every noise in the room or outdoors have pretty much gone.  The latest digital hearing aids are so clever that they can in most instances only increase the level of the frequency loss and not any other frequency making the hearing aids more uncomfortable sonic wise.

Hearing aids Devon

Here at Honiton hearing we know what how to get the best from your new hearing aids. After a comprehensive hearing test we will know what level of hearing loss you maybe experiencing.  With this knowledge we then can decide what type of hearing aid you may need to make your hearing a lot better.  Once we have this information we can then go onto tailoring the actual aid. New to the market are hearing aids that sit in the ear canal and are now more powerful in helping you hear far better than the traditional over the ear type. This is new and exciting times fro hearing aids. Colin Eaton is an expert audiologist at Honiton and will gladly take you through the process of getting your hearing back on track.

Below is a press release explaining how the new in ear hearing aids have advanced. It’s an interesting read!

 

Please call or book an appointment with Sam on reception to start your journey back to hearing again.

 

 

Honiton Hearing News:

 

Great Sound in Miniature: GN Hearing Introduces New Custom-crafted Hearing Aids

Logo
Aug. 30, 2019 11:00 UTC

BALLERUP, Denmark–(BUSINESS WIRE)– GN Hearing, the global leader in hearing aid connectivity, today launched a suite of new custom-crafted hearing aids. The new portfolio packages the industry renowned ReSound LiNX Quattro™ technology – a brilliant experience with Layers of Sound, great speech intelligibility even in noisy situations, and excellent streaming – into discreet custom-crafted hearing aids. While taking up as little space as possible in the ear canal, users will benefit from an impressive listening experience.

Tiverton hearing aids

Great hearing is in high demand. Not only are 466 million people around the world living with disabling hearing lossi, ReSound LiNX Quattro has also seen a positive reception in the market, which has led to the launch of new custom hearing aids for this popular model. The new custom-crafted hearing aids can enrich people’s lives with all the qualities of hearing, such as socializing, learning, and working optimally. In addition, each hearing aid is designed to fit exactly to the ear canal of every individual user, using a 3D scanner and advanced personalized modelling. Sitting discreetly in the ear canal, the design can also bring extra confidence to the user.

Exeter hearing aids

ReSound LiNX Quattro is a clear number one for streaming. In an independent study, streaming music and speech from an iPhone was top-rated for ReSound LiNX Quattro compared to other hearing aidsii. Users can benefit from using the new small and discreet custom-crafted hearing aids for taking calls and streaming their favorite music and TV shows. They can also stream sound directly to the hearing aids from an iPhone with no need for intermediate devices and the hearing aids are built for direct Android™ streaming, tooiii.

“ReSound LiNX Quattro has been very well received by people with hearing loss. We are dedicated to bringing the technological benefits to more users, who prefer wearing their hearing aids discreetly in the ear canal,” said Jakob Gudbrand, President and CEO of GN Hearing. “These technological wonders in miniature are truly personalized and custom-crafted to fit each person’s hearing, yet with the brilliant experience with Layers of Sound and excellent streaming that people appreciate.”

Four new options are available: the first Completely-in-Canal (CIC) 2.4 GHz wireless hearing aid for direct streaming, high-quality In-the-Canal (ITC) and In-the-Ear (ITE) models, and the industry’s only Mic-in-Helix (MIH) hearing aid. Each custom-crafted hearing aid comes in five skin-tone colors to ensure that they are personal and discreet for every user.

Browse the ReSound customs portfolio.

The new custom-crafted hearing aids are now also available in the Beltone AmazeTM collection.

Hearing aids Tiverton

Hearing aids Tiverton

 

Hearing aids Bath, at the Honiton hearing centre.

 

 

The best hearing aids around Tiverton, Devon, are to be found at the Independent hearing centre called Honiton hearing centre. Colin Eaton, lead audiologist and owner, is a truly independent hearing centre selling premium hearing aids and conduct ear wax removal either by the traditional water irrigation (ear syringing) method, or using Micro-Suction.

Hearing aids Tiverton, Devon

Hearing aids are now a lot smaller than they once were. If you feel that your hearing isn’t what is once was and maybe struggling in loud environments, busy restaurants or just cant seem to pick up what sometimes is said, having a hearing test will see what is happening with your hearing. Once the hearing test has been completed we can discuss what the next path would be. It could be that your hearing is fine and all you need is your ears cleaning of any excess ear wax. if however, you are suffering from hearing loss, then we would discuss how slight or how severe that hearing loss is and show you what is currently on the market that would help your hearing back to something it once was. Colin Eaton is an ear wax removal specialist.

Hearing aids, Honiton, Devon

You will be amazed at how small some hearing aids really are. Some are so small you just cannot see them at all as they sit inside your ear canal. These are for slight hearing loss only, but if that is all you have it would really help to gain your confidence in social gatherings knowing that you can be part of the conversation again.No more lip reading to catch what someone said.

If you live near or in Tiverton, Devon, or surrounding areas and would like to really get your hearing back to something it once was, call or pop in to make an appointment. We are here to help and to make your life once more an enjoyable hearing experience. The Honiton hearing centre.

Ear wax removal, Devon hearing aids,

Honiton hearing centre Devon now stock the latest digital hearing aids from Phonak

Ear wax removal near Tiverton Devon

Ear wax removal near Tiverton Devon

 

Ear wax removal near Tiverton Devon is available at the Honiton hearing centre. If you are suffering from excessive wax build up in the ear or ears we can come to your aid. Using Microsuction or the traditional irrigation technique, (some call it ear syringing), it only take a few mins to painlessly  remove excess ear wax. Please click here to see how Micro-Suction works via our new online video.

To see how ear syringing works please click here. 

If you live in Tiverton area then contact us for Ear wax removal near Tiverton Devon

Honiton hearing centre also conduct lots of other ear related issues such as hearing tests, dispensing the very latest digital hearing aids along with hearing aid servicing and setting up of new hearing aids after you purchase them. If you need any of our services please book in using our online booking calendar or call Sam on reception.

 

Honiton hearing news:

Philips Hearing Aids Introduced by Demant

Published on 

Philips-Hearing-Aids-Honiton-Hearing-Devon

Honiton hearing Devon

Demant, Copenhagen, Denmark, has announced the introduction of Philips branded hearing aids to the global hearing aid market, according to a press release from the company. A new player, the Philips brand is entering the hearing healthcare market with a complete range of premium hearing aids, accessories, and applications to best serve hearing aid users. Demant states Philips Hearing Solutions will quickly become a trusted brand with hearing care providers and users, as it has great potential around the world to present unique opportunities for hearing care professionals in an ever-evolving market.

In August, Demant  announced a licensing agreement with Philips, which is headquartered in Eindhoven, The Netherlands, to bring Philips-branded solutions to the hearing healthcare market.  Demant (formerly William Demant Holding) is the parent group of Oticon, Sonic, and Bernafon hearing aids, as well as Oticon Medical.

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“Based on a shared vision of improving the lives of people through innovative healthcare this new cooperation will not only change the way we see hearing healthcare, but also widen the definition of hearing healthcare, supporting healthier lifestyles and active aging,” said Spencer Ramsey, Senior Director of Brand Licensing, Philips, in the press statement. “Combining Demant’s world-leading hearing aid technology with Philips’ global brand presence in healthcare, the cooperation will enrich the hearing healthcare experience.”

The new premium Philips hearing aids—named Philips HearLink—are now available for hearing care professionals in selected countries. The look and feel of the Philips HearLink hearing aids is designed to cater to today’s baby boomer generation with design and usability developed for this expanding market. Philips HearLink users will benefit from connectivity between their hearing aids and the devices they use in their everyday life, such as smartphones and televisions. The hearing aids will reportedly be manufactured by Demant using the Velox-S and Velox platforms, and will be available in a complete range of styles, including RICs, BTEs, ITCs, CICs, and IITs.

Demant President Søren Nielsen provided an overview of the Oticon Opn S and Opn Play at an investor and media presentation.

Søren Nielsen

“The Philips hearing aids will provide users with an innovative, future-proof hearing solution,” says Demant President & CEO Søren Nielsen. “We live in an age where user engagement and digital services are shaping the future of healthcare technology. More and more people are conscious of taking control of their own personal healthcare and are using electronic devices to do so. In this light, Philips Hearing Solutions offers new and exciting premium solutions alongside Philips’ healthcare ecosytem, which will attract interest and generate significant benefits to users, ultimately supporting our valued customer base of hearing care professionals.

Tiverton ear wax removal at the Honiton Hearing centre

“With this partnership, we take connected hearing healthcare to the next level and offer new and exciting solutions within integrated healthcare services to the benefit of both professionals and people suffering from a hearing loss,” continued Nielsen. “Health, caring, and innovation are cornerstones in the vision of both Demant and Philips, which makes the partnership a great match for the future. Furthermore, it will strengthen and add value to both companies’ ambition to improve people’s lives.”

The Philips brand is something of a “back to the future moment” for more seasoned dispensing professionals. Philips was a well-known hearing aid brand in the 1990s, and the company embarked on a technical collaboration with Telex then exited the market just before the turn of the new century when Beltone purchased Philips’ hearing aid technology. The Hearing Review published numerous news and technical articles about Philips technology in the 90s.

Traditionally, hearing aid branding has not played a large role in hearing healthcare; MarkeTrak 9 suggested that less than half of hearing aid users (43%) could identify the brand of their device. However, many experts in the industry believe this is due to change, as more consumers are expected to enter the market and there is continued competition and aggressive marketing among dispensing chains, pharmacies, mass merchandisers, and online retailers. The Philips brand brings with it one of the world’s best known and trusted healthcare and consumer electronics brands.

For further information about Philips Hearing Solutions and a full presentation of the Philips HearLink product range, visit: hearingsolutions.philips.com

Honiton hearing centre, Devon

Honiton hearing centre, Devon

 

 

Honiton hearing centre caters for all types of hearing loss and ear wax removal. Colin Eaton, the lead audiologist at the Keynsham hearing centre has over 15 years audiology expertise to make sure his clients get the best hearing result no matter what the hearing issues are.

Ear wax removal is available by appointment and a limited amount of out of hours appointments are available but please call Sam on reception if you require out of hours.

Comprehensive hearing tests are also available. Please make sure that any ear wax issues are clear before you take the test, if you need ear wax removing prior the test please call reception and make this clear to Sam that you will need ear wax clearing first.

If you are confused on what hearing aids are for and for what type of hearing loss, please watch our new video here that explains why so many different types of hearing aids there are.

 

Honiton hearing centre, News

Researchers Restore Hearing via Gene Therapy in Deaf Mouse Model

Published on 

In collaboration with the universities of MiamiColumbia, and San Francisco, scientists from the Institut Pasteur, InsermCNRSCollège de FranceSorbonne University, and the University of Clermont Auvergne have managed to restore hearing in an adult mouse model of DFNB9 deafness, a hearing disorder that represents one of the most frequent cases of congenital genetic deafness, Institut Pasteur announced on its website. Individuals with DFNB9 deafness are profoundly deaf as they are deficient in the gene coding for otoferlin, a protein which is essential for transmitting sound information at the auditory sensory cell synapses. By carrying out an intracochlear injection of this gene in an adult DFNB9 mouse model, the scientists successfully restored auditory synapse function and hearing thresholds to a near-normal level. These findings, published in the journal PNAS, open up new avenues for future gene therapy trials in patients with DFNB9.

Honiton hearing centre Devon

The left panel is a schematic representation of the human ear. Sound waves are collected by the outer ear made up of the pinna and ear canal. The middle ear, composed of the eardrum and ossicles, transmits sound waves to the inner ear, which features the cochlea – the hearing organ responsible for transmitting auditory messages to the central nervous system. The right panel shows an immunofluorescence image of the auditory sensory epithelium within an injected cochlea. The inner hair cells have been stained for otoferlin in green. Otoferlin is detected in almost all of these cells. The inset is a high magnification area showing an inner hair cell that has not been transduced. © Institut Pasteur

The left panel is a schematic representation of the human ear. Sound waves are collected by the outer ear made up of the pinna and ear canal. The middle ear, composed of the eardrum and ossicles, transmits sound waves to the inner ear, which features the cochlea – the hearing organ responsible for transmitting auditory messages to the central nervous system. The right panel shows an immunofluorescence image of the auditory sensory epithelium within an injected cochlea. The inner hair cells have been stained for otoferlin in green. Otoferlin is detected in almost all of these cells. The inset is a high magnification area showing an inner hair cell that has not been transduced. © Institut Pasteur

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Over half of nonsyndromic profound congenital deafness cases have a genetic cause, and most (~80%) of these cases are due to autosomal recessive forms of deafness (DFNB). Cochlear implants are currently the only option for recovering hearing in these patients.

Adeno-associated viruses (AAVs) are among the most promising vectors for therapeutic gene transfer to treat human diseases. AAV-based gene therapy is a promising therapeutic option for treating deafness but its application is limited by a potentially narrow therapeutic window. In humans, inner ear development is completed in utero and hearing becomes possible at approximately 20 weeks of gestation. In addition, genetic forms of congenital deafness are generally diagnosed during the neonatal period. Gene therapy approaches in animal models must therefore take this into account, and gene therapy efficacy must be demonstrated following a gene injection when the auditory system is already in place. In other words, therapy must reverse existing deafness. The team led by Saaïd Safieddine, a CNRS researcher in the Genetics and Physiology of Hearing Unit (Institut Pasteur/ Inserm) and coordinator of the project, used a mouse model of DFNB9, a form of human deafness that represents 2-8% of all cases of congenital genetic deafness.

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DFNB9 deafness is caused by mutations in the gene coding for otoferlin, a protein that plays a key role in transmitting sound information at the inner hair cell synapses. Mutant mice deficient in otoferlin are profoundly deaf as these synapses fail to release neurotransmitters in response to sound stimulation, despite the absence of detectable sensory epithelial defects. DFNB9 mice therefore constitute an appropriate model for testing the efficacy of viral gene therapy when it is administered at a late stage. However, as AAVs have limited DNA packaging capacity (approximately 4.7 kilobase (kb)), it is difficult to use this technique for genes whose coding region (cDNA) exceeds 5 kb, such as the gene coding for otoferlin, which has a 6 kb coding region. The scientists have overcome this limitation by adapting an AAV approach known as dual AAV strategy because it uses two different recombinant vectors, one containing the 5’-end and the other the 3’-end of the otoferlin cDNA.

A single intracochlear injection of the vector pair in adult mutant mice was used to reconstruct the otoferlin coding region by recombining 5′ and 3′-end DNA segments, leading to long-term restoration of otoferlin expression in the inner hair cells, and then restored hearing.

Honiton hearing centre, Devon

The scientists have therefore obtained initial proof of the concept of viral transfer of fragmented cDNA in the cochlea using two vectors, showing that this approach can be used to produce otoferlin and durably correct the profound deafness phenotype in mice.

The outcomes achieved by the scientists suggest that the therapeutic window for local gene transfer in patients with DFNB9 congenital deafness could be wider than thought, and offers hope of extending these findings to other forms of deafness. These results are the subject of a patent application filed.

Hearing aids Tiverton, Devon

In addition to the institutions mentioned in the first paragraph, this research was funded by the French Foundation for Medical Research, the European Union (TREAT RUSH), and the French National Research Agency (EargenCure and Lifesenses LabEx).

Original Paper: Akil O, Dyka F, Calvet C, et al. Dual AAV-mediated gene therapy restores hearing in a DFNB9 mouse model. PNAS. 2019. DOI: https://doi.org/10.1073/pnas.1817537116

Source: Institut Pasteur, PNAS

Image: Institute Pasteur