How do digital hearing aids work?
The most basic function of a hearing aid is to amplify sound. Digital hearing aids, which have only been around since late 1990’s, offer such a natural and rich sound due to their ability to be configured to better match a wearer’s unique pattern of hearing loss.
Older hearing devices only amplified hearing in two channels – high-pitched sounds (treble) and low-pitched sounds (base). Modern hearing aids separate sound into numerous frequency bands (up to 48 bands) and then amplify each band by the amount required to restore normal hearing levels at that band.
The whistling sound (feedback) that many hearing aid users encountered with older hearing aids was both uncomfortable and embarrassing. This feedback was caused when a hearing aid’s microphone picked up amplified sound emitted from the hearing aid.
Sound travels in waves with distinct wave patterns. Digital hearing aids detect the wave shape of frequencies causing the feedback. They then apply a mirror of that wave to counteract it within fractions of a second. So, there will be no annoying and embarrassing whistling from your hearing aid.
Improvements in feedback management have enabled hearing aid manufacturers to develop devices allow more natural sound through the ear canal.
Previously, wearers of hearing aids would complain of a “talking in a barrel” sensation, like you can experience when using your fingers to block your ears and listening to the sound of your own voice.
Open-fit hearing aids have very thin tubes that enter the ear canal and smaller cases that rest behind the ear, making them barely visible. Additionally, hearing aids that sit within the ear canal can now have greater ventilation.
The end result is hearing aids offering more comfort and clarity.
Older hearing aids amplified all sounds equally – whether the source of the sound is a conversation or background noises (e.g. traffic, air-conditioners, crowds). This led to discomfort and made it harder for wearers to follow conversations in difficult environments.
Modern hearing aids can actually tell the difference between speech and background noise and do this individually for every frequency band. The hearing aid then amplifies the speech sounds and reduces the amplification of background noise.
Wearers can now enjoy the results of noise management – greater listening comfort and clarity.
People with hearing loss can find following conversations in a noisy place a tremendous struggle.
Logically, most conversations are with people who we are facing, while distracting background noise will come from the sides and behind us.
Digital hearing aid can now pinpoint the location of sounds. They do this by using multiple microphones and gauging the difference in time that sounds is received by each microphone – even though microphones are only a few millimetres apart! The hearing aid then provides greater amplification to sounds coming from in front of the wearer and less to sound coming from the sides and behind.
Directional microphones can be extremely beneficial in difficult situations like restaurants and are the most important feature in terms of improving wearers’ abilities to follow conversations in noisy environments.
Different listening environments often call for different settings within hearing aids in order to maximise their effectiveness. For example, when listening to music, the user would prefer to turn off features that may misinterpret elements of the music as noise. When in a quiet room, a wearer will not need the benefit directional microphones and noise reduction to the same extent they would in a crowd at the football.
Advanced hearing aids allow the user to change the settings by pressing a small button on the device. The most advanced hearing aids will even listen to the environment and change the hearing aids settings automatically, without the wearer needing to touch or think about their hearing aids.
Wearers are increasingly looking for solutions to improve their ability to use their hearing aids more effectively in partnership with their mobile phones, digital radio, plasma televisions and personal stereos (e.g. Smart Phones, iPads, Tablets).
In response, manufacturers have developed streamers that connect wireless devices to the user’s hearing aid. The benefit is that this delivers improved performance in terms of speech intelligibility and sound quality as signals from the external devices are streamed directly into the hearing aid, without background noise and the need for the hearing aid to first process a sound signal.
Smart Phones now performing the task or wireless streamers
Up until 2014, someone wanting to connect their hearing aids wireless to their phone, tablet or music player would have been required to purchase an optional wireless streamer with their hearing aids. Now, since the launch of the ground-breaking ReSound LiNX, it is possible to have your smartphone (iPhone) manage these tasks. So wearers can manage streaming and functions such as volume and program settings from an easy to use App on their phone or iPad.
We were born with two ears for a reason: it helps with sound location and provides much clearer ‘stereo quality’. Advanced features such as directional microphones are far more effective when applied with two hearing aids.
For these reasons, Australian Audiology strongly recommend that our clients are fitted with hearing aids in each ear affected by hearing loss, as this will lead to a vastly improved benefits and client satisfaction.
If you would like to arrange a discussion with one of our hearing care professionals to discuss hearing aids and how they could benefit you, please call us on 1300 864 3275 or use the contact form found here.