How do hearing aids work?

Overview:

• What can hearing aids do for you?
• How do modern hearing aids work? 
• Why hearing aids do more than simply "make things louder"
• Other technological aids
• The history of the hearing aid

What can hearing aids do for you?

Hearing and understanding are to some extent abilities that we have to learn. If hearing loss means that certain high-frequency sounds, for example, are no longer forwarded to the brain, then the brain gradually forgets how to interpret these sounds. It literally forgets how to hear. Part of the hearing spectrum gets lost.

Hearing aids work by amplifying or increasing the volume of sound.

A microphone picks up sound, such as a piece of music, and converts it into an electrical signal and the volume is increased by the amplifier within the hearing aid. A receiver then changes the electrical signal back into sound which is sent into the ear. The hair cells in the inner ear convert the sound vibrations into nerve signals which are picked up by the brain, mimicking natural hearing.

If sounds in certain frequencies are no longer forwarded to the brain then the brain gradually forgets how to interpret these sounds. Hearing aids will pick up sounds your brain has't processed in a while. It can take time to get used to this – up to 12 weeks depending upon your hearing loss, which is why it is important to persevere with hearing aids, and to stay in contact with your hearing care professional with any concerns or questions you may have.

One of the functions of hearing aids is to act as a kind of "trainer"; for the brain in order to regain lost hearing. Soft and high-pitched tones can be audible once more and specific sounds and shades of meaning can be distinguished.

How do modern hearing aids work?

Modern hearing aids are now powerful computers, which, thanks to the latest technology, can be perfectly adapted to individual needs. As well as being extremely comfortable to wear, they also come in attractive designs. These modern medical devices are now available at affordable prices.

They are usually made up of three main components: A microphone, a processor, and a loudspeaker. The microphone picks up sounds, or acoustic signals, from the environment and transmits them to the processor. The processor amplifies the sounds and converts them into electrical signals. The loudspeaker, or receiver, transmits the signals to the wearer's ear. The sound is released there and can once again be clearly perceived by the wearer.

To allow hearing aid wearers to enjoy problem-free hearing, hearing aids specifically amplify sounds that are important for communication and reduce disruptive sounds. This process is fully automatic in modern hearing aids.Discover additional features in modern hearing aids.

Why hearing aids can do more than simply “make things louder”

Impaired hearing means more than simply hearing less well. It also means difficulties in understanding. Noises differ with respect to tone, with some being more shrill or some more buzzing. Certain sounds are typically perceived as unpleasant, or even painful. In such cases, „making things louder“ is not the right way to help people hear better again.

Determining the right volume

Technology for amplifying sound signals is vital. People with impaired hearing can only hear sounds above a certain volume, meaning these sounds must be louder than for those with good hearing. However, if everything were to be made louder, a noise such as a police siren would be absolutely unbearable. This is why hearing aid adjustment is used to determine the hearing aid wearer's discomfort threshold. This threshold represents the sound level beyond which sounds are perceived as unpleasant. For most people with normal hearing, this value is around 100 decibels (dB), although the values vary according to the individual.

Background noise and exact frequency ranges

In addition to general volume, a hearing aid must amplify the specific frequencies that the wearer can no longer hear very well. Digital hearing aids, which are now state-of-the-art technology, are able to compensate hearing loss in various frequency ranges in a precise and targeted way.

The real challenge – for both technology and humans – is to filter out background noise. During conversations in busy restaurants, for example, even people with normal hearing rely on some very complex processing mechanisms to single out a friend's voice. Modern hearing aid technologies feature special functions that significantly improve speech comprehension in such difficult situations.

In order to cope with difficult situations, modern devices also feature various hearing programs for different hearing contexts, such as restaurants or listening to music. Hearing aids also have several frequency channels, making it possible to adapt sound amplification individually to the wearer's needs. Background noise and unpleasant feedback whistling can also be suppressed.

Other technological aids

Many behind-the-ear models have a T-loop (telecoil) or induction loop. This is useful during telephone calls as it transfers the speech signals from the telephone directly to the ear. This significantly improves sound quality and speech comprehension. With a telecoil, induction systems, such as those installed in meeting rooms, theaters, or churches, can be used without any additional devices. This allows speech to be received directly via the hearing aid, while disruptive background noise is filtered out.

Hearing aids with Bluetooth are able to receive speech and music wirelessly from other Bluetooth-enabled audio sources (mobile phones or TV sets) over short distances. In some cases, a small, additional device (streamer) is required, which is positioned between the devices to transfer the signals.

Today, there are also apps that can be used to control the hearing aid via a smartphone. This means the hearing aid can be controlled wirelessly.

Our expert audiologistsare happy to show you the latest models and advise you on which is best suited to you.

If you are unsure whether or not you need a hearing aid, you might be interested in our free hearing test. If the test confirms that your hearing is impaired, we recommend you visit one of our branches or talk to your ENT doctor.

The history of the hearing aid

Once used exclusively by royal eavesdroppers, hearing aid use has only become popular in the last 200 years. Few people are aware that the first hearing aid for which a patent was registered was worn by Queen Alexandra of England in 1901.