Digital hearing aids have been available for almost 30 years. By converting the sounds collected by the microphone into ‘bits’ of information we are able to manipulate and control the amplified sound to a much greater extent compared to older analogue technology.
Initially the focus was to enable more accurate hearing aid fittings by breaking the amplified sound into distinct ‘bands’ of pitches from low to high. Each band can be separately adjusted for their response to soft, medium and loud noises leading to a very accurate ‘fit’ for a given hearing loss. Advances in the control of feedback or whistling of hearing aids using ‘phase inversion’ to cancel out the noise meant that hearing aids could be made much lighter with fittings that didn’t completely block up the ear canal.
Over time the list of features that have been added to digital hearing aids has got longer and longer. Noise management, directional microphones, Bluetooth, impulse noise reduction, wind noise reduction and expansion (which suppresses very quiet noises). More recently we have hearing aids that can cancel out echo’s, reduce car noise and even help to recover speech sounds in area’s where there is no remaining hearing (frequency compression).
Are very accurate fittings and noise management all that modern hearing aids can do? The latest hearing aids also offer something more. Very rapid and accurate categorisation of the type of sounds around the wearer can allow the hearing aid to automatically switch to settings idealised for each scenario e.g. speech in noise, music, one to one etc. Binaural signal processing allows the hearing aids to work in synchrony with each other to ensure you are always getting the clearest speech sound.
Sitting above all of the features is the hearing aids’ signal processing strategy. This is the really where some of the latest hearing aids have taken large strides in improving their performance. Like a conductor in an orchestra the signal processor makes millisecond decisions to coordinate and select all of the above features (and more) to ensure the clearest possible hearing in every situation. Every manufacturer has a different strategy for this:
- Resound call theirs Surround Sound which mimics the natural function of the ear, helping the user to hear all the sounds around them whilst also enhancing speech.
- Oticon have Brainhearing. This is designed to take some of the mental effort of listening from the user and let the hearing aid do some of the work
- Phonak use Autosense 3.0 and VoiceStream technology to deliver the clearest speech signal to both ears simultaneously
- Unitron have SoundNav 3.0 and Spatial Awareness which helps to accurately place sounds in their proper orientation in relation to the wearers head
Hearing loss is very complicated and listening preferences can be very individual. This means that different strategies can be more or less effective for different people. Your Audiologist will always try to ensure they select the appropriate manufacturer and strategy for your needs. If you don’t get on well with your selected hearing aids however you may well benefit more from the processing strategy of a different brand.
Developing these strategies takes a long time and a great deal of research to ensure they are going to be effective. Manufacturers periodically release new platforms that run on purpose built microchips. These are getting faster and more accurate all the time. When these new platforms such as Phonak’s Marvel 2.0 and Resound’s Quattro are released several models are developed. Not everyone needs all of the features of the new device. In order to make it affordable several models are released at different ‘Technology Levels’. The lower the level of technology the fewer features of the new platform the hearing aid has. This allows patients to choose the features that matter to them and not overpay for some features they may never benefit from.
At Novus Hearing we understand this which is why we have an active hearing aid trial programme. Book in for your free hearing assessment and leave with better hearing! Ask about our two week diagnostic trials that help you choose which technology level is right for you.