There are two types of sound processing in hearing aids – Analogue & Digital.
Analogue – In analogue instruments, sound is processed as an electrical signal by a microphone.
Analogue sound is like making a photocopy: the sound is registered and you get an overall picture, but the actual processing is like recopying a photocopy – it can only be done to a certain extent because it causes a deterioration of the original imprint. Analogue hearing aids have now on the whole been replaced by their newer, smaller, faster and more effective digital counterparts.
Digital – Rather than using an electrical signal the sound waves are encoded as a series of binary numbers that measure its pitch and volume at a given instant in time. Basically they are bits of data that are manipulated by a digital microcomputer inside the hearing aid. Processing the sound bit by bit is much more precise and accurate. This unique technology separates the incoming sound in to bands and processes each band independently so that the hearing aid can be programmed by a computer to be frequency specific and match the specific needs of an individual.
Overall, the technology keeps sounds within a comfortable range for the listener, whilst maintaining a clear and natural sound quality. It can automatically adjust to changing environments. Digital technology also provides far superior performance in background noise. It is important to remember that it is not possible to eliminate background noise, however they are able to recognise background noise and maintain a better signal to noise ratio enabling the user to hear better in that environment.
A digital signal can be repeated endlessly without affecting the overall quality providing a clearer more accurate sound. It is like making copies of a scanned image: each copy is a perfect duplicate of the original.
Modern hearing aids are programmable, meaning that the amplification can be precisely fine tuned to match an individual’s prescription.
There are many different hearing aid styles, sizes and levels of technology that can be tailor made to meet one’s particular needs and requirements regardless of the type or level of hearing loss.
Hearing aid technology is always evolving. Here is a summary of some of the technology that is available today:
● Individual channels – Separates the sound signal into different frequency specific sections for processing. This allows the hearing aid to be customised across the different frequencies to better replicate an individual’s prescription, giving a more precise sound experience and speech intelligibility.
● Directional Microphones – This enables the wearer to have preference to sounds from particular directions (i.e front, sides or from behind – depending on the need and situation). This ultimately has the effect of improving speech understanding in background noise.
● Automatic volume control -This keeps the sound at a comfortable level, never too loud; never too soft – reducing the need for fiddly controls.
● Digital noise reduction – This determines whether the signal contains unwanted noise and reduces the level of noise if present. This generally means increased listening comfort by reducing the
annoying background noise.
● Speech detection -This enables the hearing aid to detect when speech is present which again helps especially in complex listening situations or when background noise is present.
● Sound Smoothing -This feature smoothes sudden impulse/impact noises such as cutlery, dishes clattering etc, which makes for a less stressful and more comfortable listening environment.
● Feedback management – Basic feedback management systems reduce the overall amplification of a hearing aid to stop the whistling which can affect the sound quality, whereas more advanced
systems reduce or eliminate whistling without affecting the overall amplification, whilst maintaining clarity.
● Wind noise reduction – Reduces the annoyance of wind blowing across the microphones – enabling better listening comfort for outdoor use.
● Binaural processing – This is where left and right hearing aid exchange data wirelessly and coordinate their functions. The information is processed and the individual settings are adjusted to the specific auditory situation, which ultimately improves speech perception, particularly in loud environments. In addition, if the volume is adjusted on one side, the other aid automatically adjusts as well. This also applies to other functions such as noise reduction and individual programs etc. The hearing aids therefore work together as one complete system rather than two independent devices.
● Tinnitus management – The ability to provide an effective management tool for reducing the effects of tinnitus using soothing tones and / or noise.
● Self learning – Gradually over time the hearing aids learn from manual adjustments made by the wearer adapt automatically. This gives greater personalisation and a more accurate individual fitting.
● Bluetooth Connectivity – High speed, echo free connectivity to external devices such as the television or stereo, mobile phones, telephones ,remote controls and other bluetooth devices. This means no more needing to take your hearing aid out when you answer the telephone. You are able to hear these peripheral devices directly through your hearing aids in true stereo, at your preferred volume without disturbing others around you, so no more arguments over the volume on TV. All of the advances in technology go some way to help put you back in control of your life again.