Hearing Aids: How Do They Work?

Sorry, what did you say?
Sorry, what did you say?

Hearing loss affects many of us, regardless of age, and it’s important to understand exactly what we mean when we’re talking about them. To understand more about how they work, take a quick look at our guide. If you’re worried about your own hearing, book a hearing test – Amplifon offer free tests across the UK.

The ear

The ear has two basic functions: hearing and balancing. In this guide we’ll just be focusing on hearing. Here’s a quick step-by-step guide on how we hear with healthy ears:

• Sound vibrations in the air are first received by the ear canal, otherwise known as the outer ear. These funnel down to the ear drum, which in turn vibrates.
• This moves the small bones in the middle ear – the hammer, anvil and stirrup – causing the vibrations to amplify.
• The stirrup is connected to the cochlea in the inner ear, which is filled with liquid and lined with tiny hairs connected to the auditory nerve.
• The vibrations are transferred into waves in the liquid, which move the hairs.
• This movement is picked up by the auditory nerve, and signals are sent to the brain to interpret into the sounds that we can hear.

Hearing aids

Hearing aids, generally speaking, work by bypassing a certain stage in the hearing process, depending on the specific problem. A common issue that causes hearing loss is the deterioration of the hair cells in the cochlea, preventing higher-pitched signals from reaching the brain – this happens in most people as we get older. Other causes include acoustic trauma, when a sudden loud noise or prolonged exposure to loud noises causes the cochlea to become inflamed; and conductive hearing loss, which is when sound is blocked and cannot pass into the inner ear, either because the eardrum is damaged or the middle ear bones are less able to transmit and amplify sound.

Digital hearing aids, the most popular type, use a microphone and amplifier to transmit stronger waves into the cochlea, so that the small hairs are more likely to pick them up. They contain a silicon chip which constantly processes sound, converting it into the appropriate volume and cleaning it up to provide the wearer with a clear, audible sound impression. They can distinguish which sounds need to be enhanced, and which are irrelevant, allowing the wearer to hear what is going on without having to adjust it often.

Analogue hearing aids are older, and not very often used these days – they are quite primitive in comparison to digital aids, but still very impressive. They pick up the sound using a microphone, amplify it and feed it into the ear, but they need to be adjusted manually to pick up different types of sound – for example at different volumes or different pitches.

Because hearing aids work by amplifying sound, they cannot help people whose ability to hear has been permanently damaged. They are also unable to restore a person’s hearing back to full capacity. However, they are ideal for people who are slowly losing their hearing due to natural deterioration, and are priceless for older people who may otherwise find themselves losing touch with the world.


Leave a comment