Hearing technology manufacturers and BIHIMA members explain the role of hearing devices in preventing cognitive decline…
The growing body of research showing that hearing loss changes brain function and can even contribute to cognitive decline has confirmed a theory the hearing health community has held for years. The smoking gun was a recent study in the Lancet which demonstrated that hearing loss is the leading modifiable risk factor in developing dementia, listed above other factors such as smoking and brain injury.
Furthermore, increasing evidence is now beginning to reveal that hearing devices can be a vital part of the solution. A 25 year study at of the University of Bordeaux, for example, is often cited as substantiating the claim that hearing technology needs properly investing in as, if not a silver bullet, a vital shot in the arm in the fight against dementia, a disease which affects about 47 million people globally, a figure projected to triple by 2050.
Hearing technology experts are working on how to speak into this growing public health crisis and raise awareness of the effectiveness of their products in preserving brain health. Thomas Behrens, Director of Oticon’s Centre for Applied Audiology Research, explains that, “To really make it tangible, we need to ask what kind of hearing aid intervention should we be recommending? Firstly, hearing aids need to be cognition-friendly, so in other words use signal processing strategies that minimize cognitive load and are well-fitted to the individual, so the person will feel a substantial benefit in the most important listening environments, which will motivate a consistent use pattern, which should be above six hours per day.
Keeping socially active
“A study by Glick & Sharma 2020 shows that consistent use of hearing aids that were fitted according to best practice led to more normal brain structure (according to the simple measures they were using). However, their findings are consistent with listening being less cognitively demanding, so cognitive capacity is freed up, for instance, in working memory, so it is not occupied making sense of sound, but has residual capacity for storing and remembering things as needed for being socially active.
“When taking a broader look at the literature, as well as the Lancet commission on dementia, it is because hearing aids help people stay socially active that is the most likely way hearing aids help keep the brain fit, which gives users the double benefit of hearing aids – that they get short term benefit from improved communication with friends and family and longer term improvements in cognitive health.”
Even if the exact mechanisms explaining why hearing aids help to limit cognitive decline are not yet clear, there is certainly consensus among the hearing technologists that one of the factors is in reducing the strain on the brain. Oliver Townend, Lead Audiologist at Widex, explains that their strategy has been to focus on delivering the most natural sound possible in order to support unlaboured, effortless hearing. “Effortless hearing requires that all the natural nuances of input sounds are captured accurately. This includes information in the frequency, intensity (including intensity changes and relative intensities between ears), and temporal domains. Without expert handling of input sounds, this information is easily distorted and lost. But by preserving as much of these natural nuances as possible, we aim to provide as much needed information to wearers as possible to achieve effortless hearing. This allows successful communication — with greater ease and confidence — in many more daily listening situations. But addressing cognitive decline through natural sound can only be delivered through careful and deliberate choices in hearing aid design.”
Achieving natural sound quality is also seen as one of the ingredients necessary for getting people to wear their hearing devices for longer periods of time, another important aspect in preserving brain health. In order to achieve this, Thomas Behrens explains, hearing aid signal processing needs to do certain things: “to amplify sound in all situations throughout the day – not only in static environments (where some traditional technologies have problems) but also in dynamic environments when people are out and about or if they use headwear or are close to reflective surfaces. We also need to amplify different sound levels differently, achieving global compression of input levels without the side-effects of traditional compression that changes the waveform in a way that may make it difficult for people to separate sounds.
“Finally, we must provide help systems for noisy environments that are fast enough at following changes in typical sound environments, so they can reduce the level of disturbing noise sources around the user and remove noise in the natural pauses that occur in speech. If these three areas are customized to the needs of the individual and follow-up ensures that the user is experiencing benefit in the key listening situations, then that is the best recipe for providing the best short term and long term hearing health benefits from hearing aids.”
Natural first fit to prevent rejection
Dr. Donald Hayes, Director of Audiology, Unitron, agrees that “regular hearing aid use amongst hearing impaired seniors is the thing which minimizes the impact of cognitive decline by providing consistent adequate stimulation to the auditory system. In other words, getting people to wear their hearing aids is key. People are most likely to consistently wear hearing aids that sound natural out of the box. By defining a first fit starting point that sounds as natural as possible at the listener’s preferred listening level we avoid rejection due to poor sound quality during the trial period. This encourages regular use while the instrument slowly modifies its gain in the background over a period of weeks, taking advantage of the listener’s auditory plasticity, to quickly reach target gain equal to an industry standard such NAL-NL2 or DSL 5.0. This automatic adaptation ensures listener compliance reducing the risk of cognitive decline.”
Hearing technology company, Starkey, has used additional features to encourage consistent use of their products. “We’ve developed products and associated apps to “gamify” physical and cognitive activity as expressed in the user application to motivate people to use their hearing aids twelve or more hours daily, wear them in diverse acoustic listening environments, and engage in frequent conversations with other humans as frequently as possible,” explains Dr Dave Fabry, Chief Innovations Officer at Starkey.
However, Laurel Christensen, Chief Audiology Officer at GN Hearing, believes more effort needs to be invested further back in the consumer journey, in generating wider public awareness and appeal: “We know that only 17% of people who could benefit from wearing a hearing aid currently use one, as many find them unacceptable, too difficult to use or ineffective. We’re making hearing aids more acceptable to users, breaking down the stigma with great design, comfort, ease of use, and the most natural sound quality, individualization instead of one size fits all, designing our hearing aids to be sleeker and more attractive to wear with the aim of looking more like fashionable consumer products.”
Candy on ears for the eye
Erik Harry Høydal, Senior Audiology Expert, Signia agrees that the way to leverage the power of hearing technology in combatting cognitive decline is in generating a wider public mindset shift, moving from simply preventing adverse health consequences to augmenting human performance. “Looking at statistics of when people choose to get hearing aids, I think it’s fair to say we haven’t been very successful in getting out the message that people should start using hearing aids earlier in life. At this time when people are more focused on their health and wellbeing our message should resonate better. We realized we needed to do something drastic to convince people to wear hearing aids before a certain age, and have invested a lot in new, appealing form factors as well as features aimed at surpassing human capabilities. There’s something fundamentally more appealing to people about a device that goes beyond even normal hearing — a product that’s more than just a medical device compensating for loss. Psychologically, it’s easier to adopt the former than the latter.
“Functionality, features, convenience, and design — they all need to reflect what people would expect and want from a desirable product, instead of screaming ‘medical product’ or ‘old age’. It’s time to not just sugar the pill, but also to create eye candy that people will truly crave. There is a current trends toward optimizing one’s health and reaching for enhanced human performance meaning that digital devices of any kind — including hearing aids — that help people perform better in social gatherings, follow lectures more clearly, remember more, and maintain a healthy brain will be desirable. Who would want to miss out on so much? We should expect increasing technological advancements that take us from pure compensation to actual enhancement of our natural capabilities.”
The British Irish Hearing Instrument Manufacturers Association (BIHIMA) represents in the UK and Ireland the world’s leading hearing instrument manufacturers. We work in partnership with other professional, trade, regulatory and consumer organisations within the health care and charitable sectors. Our goal is to raise awareness of the benefits of hearing well, making available the very latest in hearing technology aligned to consumer and hearing healthcare priorities to enhance the lives of those affected.
This BIHIMA feature was published in the November 2020 issue of Audio Infos UK.
 World Health Organization (2020) Deafness and hearing loss. Factsheet. https://www.who.int/news-room/fact-sheets/detail/deafness-and-hearing-loss. Accessed July 2020.