Oticon’s latest hearings aid is called Oticon More and builds upon its predecessor the very successful Oticon Opn S. Opn introduced the Open Sound Navigator platform on their Velox chip designed to preserve the sound scape naturally to support the way our brains Orientate, Focus and Recognise sounds. They then introduced the Velox S platform that added Open Sound Optimiser ™purported to be a “pro-active” feedback cancelling system that could very quickly cancel feedback (annoying whistles and squeaks) within 90ms-1.
New Oticon More hearing aids contain their latest Polaris ™ Chip platform which give you a a clear, complete and balanced sound scene with acoustic richness and finer details. This supports the Oticon Brain Hearing™ philosophy of making it as effortless as possible for your brain to make sense of sound.
Oticon research showed that by preserving the sound scape naturally and rapidly attenuating competing noise “between words” they can improve speech intelligibility and reduce listening effort to a greater extent than conventional approaches taken by other hearing aid manufacturers.
How Hearing Loss Effects the Brain
Oticon continues to further their research into how the brain makes sense of sound and develop their hearing aids to best to support these brain processes. They patented the term Brain Hearing ™ to describe these processes and has been the foundation of their research for more than 30 years. The philosophy is that hearing happens in the Brain. It is not a simple sense but a very complex cognitive process. We know that hearing loss is not just a loss of audibility but also comes with a loss of speech understanding and creates distortion problems especially in noisy situations. This is because hearing loss impacts the quality of the sound the brain has to work with.
Our brains are plastic and do adapt to this lower quality of information or under-stimulation, however there are ramifications and consequences. The listener has to work harder to make sense of sound. Hearing loss therefore can be described as a bio-psycho-social problem. Biological in that we know there’s a change to biological function, but also Psycho-Social changes in that untreated hearing loss can lead to a change in a persons’ behaviour. Such as avoidance of environments where you know you’ll have difficulties hearing such as social gatherings or any competing noise environments. Such avoidance behaviours can lead to a sense of social isolation. This can lead to depression and in the long run accelerated cognitive decline.
Providing the Brain with the right types of Amplification.
Oticon’s ultimate goal is make it as easy as possible for the brain to make sense of sound. Extensive research has enabled Oticon to bring to market a unique combination of technologies that all work to reduce listening effort and provide the right conditions for the brain. In spite of modern chip sets and sound processing technologies available today, the brain can still be considered to be the most sophisticated sound processor that exists. This is because the brain has the ability to navigate in simple environments as well complex environments with many different types of sounds being present. It can choose where and when to focus and which sounds to attend. It can choose to push some sounds into the background whilst focusing on which sounds are relevant. This happens seamlessly as the sound situation changes. Important for both social activities as well as for safety.
New Scientific Discoveries:
It is believed that the brain needs access to all sounds and not just speech to work in a natural way. According to Oticon research there are two auditory cortex sub-systems with different functions that are always working together to make sense of sound. Overall hearing ability can depend on how well they work together. These two systems are the Orient sub-system and the Focus sub-system. The Orient system is constantly scanning all surrounding sounds to make a complete picture of the sound scape. Whilst the Focus system is supporting us to determine which sounds we actually focus on whilst determining which sounds we push into the background. We know these subsystems exist based on measurements from new scientific and imaging techniques techniques including Magneto-Encephalography (MEG), Deep Electrodes (EcoHG/sEEG), Electro Encephalography (EEG). Two independent studies have shown the existence of these two sub systems within the Auditory cortex of the brain.
The Orient Sub-System of Neural Sound Processing
The Orient stage of sound processing within the brain is considered crucial in creating a full sound scene representation within the brain to then identify what it wants to focus on. This decision can only be as good and as accurate as the information that is delivered to the Orient sub-system itself. In this earlier stage of sound processing the entire sound scene is being represented in the brain. The Orient system needs to receive a good neural code to create a good auditory overview and separate sounds out to determine what’s going on in the surroundings. It also creates an auditory foreground and background and starts to identify what to focus on and listen to. It provides the brain with the best conditions on which to focus on and listen to.
The Focus Sub-System of Neural Sound Processing
In the focus sub-system which is a later stage of sound processing, only the sounds that the listener attends to is strongly represented in the brain. This allows us to focus on a point of interest, form auditory objects out of the different sound characteristics available. Allows us to focus our attention on the sounds we want to attend to whilst filtering out unwanted or irrelevant sounds. These systems work continuously together to maintain our focus on what is presently most important. Although we can maintain focus on a particular sound the brain intentionally distracts itself four times a second checking in on the rest of the environment sound scene. This allows us to switch attention if something more important suddenly appears in the sound scene.
The Workload on the Brain
When these systems are working well together it frees up other cognitive processes to work optimally. One can more easily recognise other sounds, store and recall information and perform executive functioning such as being able to respond to what is taking place or been said.
Irrespective of the quality of the signal the brain is receiving it will always try to match it with information stored in its long-term memory. It does this to make meaning of the sound. Clear sensory information makes for easier matches and more effortless conversation. However, when the sound is changes or distorted the sensory information is no longer clear. This can result from hearing loss and competing noise. The brain cannot as easily match the acoustic information with information stored in the long-term memory and so making sense of the sound requires a lot more effort. Selective attention allows our Auditory system to effectively filter out sounds and even enhance our perception of sounds of interest which is called Sustained Attention. Our ability to focus in on something for a longer period of time. These two sub-systems help us separate out sounds and focus in on what we are interested in. To gather meaning of what’s heard also need to recognise sounds which make use of available working memory in the brain and extract meaning. Also requires working with other important cognitive capacities such as attention switching, ,memory recall. Also other senses play a role at this level of processing including visual input. These higher cognitive processes also influence the Orient and Focus stages.
Hearing Loss makes it more difficult to Orient & Focus:
Hearing loss resulting from changes in the cochlear result in a loss of spectral and temporal resolution diminishing the quality of the neural code being delivered. The ability to selectively switch attention is also slowed down. The increased cognitive load to follow results in less capacity left over.
Oticon indicates that studies are showing the brain needs full access to the sound scene to prioritise what it attends to and what it filters out. Attention is more like a filter that takes in all available sensory input and prioritises what is being attending to and processed and what is filtered out. Oticon argue that conventional hearing aid technology uses a focus approach including the use of directional microphone systems, speech reduction and gain reduction methods of feedback elimination and indicates such methods restrict information being delivered to the brain and does not help form a complete sound scene therefore does not best support the way the brain naturally processes sound. Oticon indicates that inadequate treatment of a hearing problem in turn results in a brain problem. Consequences of untreated hearing loss include; 1. Increased listening effort, 2. Increased Cognitive Load, 3. Re-organised brain functionality, 4. Accelerated cognitive decline, 5. Accelerated brain volume shrinkage.
Brain problems can therefore turn into life problems. Risk of dementia is from untreated hearing loss is increased 5 fold for severe hearing loss. Associations between hearing loss and balance disorders.
Research indicates that all these conditions associated with untreated hearing loss are modifiable risk factors that are potentially reversible. A study showed that approximately 40% of dementia cases can be explained by modifiable risk factors. Livingston et al. showed in 2017 that in mid-life hearing loss represented the greatest modifiable risk factor in onset of dementia being 8%. Even at mild levels hearing loss has been documented increase the risk of developing dementia in the long term and the worse the hearing loss the increased likely hood of dementia.
Do Hearing Aids Make a Difference?
A longitudinal study by Elaine et al. over 25 years using 3,777 participants found an increased risk of dementia with those that had a self-reported hearing problem. There was found to be no increased risk for those using hearing aids. Research seems to indicate hearing loss is a risk factor that increases the likely hood of onset of dementia even though it’s hard to isolate with so many variables that can affect the individual.
How does Today’s Hearing Aids Support the Brains natural processing?
Ideally a hearing aid should be working with the brain. There are four key areas a hearing aid should provide 1. Access to the full sound scene (So the brain can Orient and not miss out in important sounds 2. Handle sound very precisely and noise sources accurately 3. Provide optimal audibility; Throughout the day through appropriate amounts of amplification in both Static and Dynamic environments with good sound quality. 4. Flexibility to preserve changing speech cues in Dynamic listening environments
Need to deliver audible, clear and comfortable sounds in all situations. “More of the Sound Scene is More”
Key Brain Hearing Features that are limited to high end Oticon Hearing Aids are;
- Open Sound Navigator ™ Provides 360 degree’s access to all sounds, speakers & balances the sound sources.
- Open Sound Optimiser ™ Pro-active feedback cancelling system that is about maintaining optimal gain all day
- Speech Guard Lx which is Oticon’s adaptive compression system which preserves rich speech details and cues.
- Super Shield
- Noise Reduction Lx
The benefits of these technologies have been documented for users over the years using a number of studies that all use objective and acknowledged research methods.
To determine the effectiveness of Oticon’s Open Sound Navigator System an EEG Study was performed at Eriksholm using a 64 Channel Electrode array to measure brain activity in the representation of a primary and secondary speaker. With Open Sound Navigator switched on there was shown to be a 10% stronger EEG signal with the speaker in focus and 95% more EEG activity with a secondary talker and a reduction of background “babble noise” by 50%. This means sounds are better organised in the brain allowing the user to choose which speaker they want to listen to and background sounds are less disturbing allowing for social participation.
In summary Oticon claim to develop their hearing aids from a brain first perspective working with the brain rather than against it. This approach will continue to guide their development into the future. Key points are that the brain needs; 1. access to the full sound scene to work in a natural way. 2. There are two sub-systems that work together being the Orient and Focus sub-systems. 3. A good neural code is essential for making senses of sounds. 4. Conventional technology does not optimally support the brains natural processes. 5. A hearing problem can lead to brain problems which can turn into life problems. Hearing aids must provide the full sound scene to provide a quality neural code to optimise speech understanding and reduce listening effort even in competing noise environments.