Our hearing

Our hearing is the only one of our senses that is constantly active – even when we sleep.

Our hearing is important

Our everyday situation and quality of life can be affected by hearing loss. 

What we hear constantly supplies us with vital information, as well as helping us experience emotions and recall memories. Our hearing is important in many ways.

Not to mention the sound of music, of children laughing, of caring words whispered by a loved one, the sound of birds, of autumn leaves, waves at the beach or the cracking sounds of a a fire.

How our hearing works

We have two ears and a brain to hear with. And for a good reason.

Natural hearing
A healthy hearing system can recognise both low sounds (a double-bass or traffic) and high (a violin or the twittering of birds). In technical terms, that means frequencies between around 20 and 20,000 Hertz. What’s more, it can process very quiet sounds (the buzzing of a mosquito) and extremely loud sounds (a jet engine starting). This equates to volumes between 0 and more than 120 decibels.

Understanding speech
Our brain is particularly adept at understanding language, which it can cope with in all its various facets and in every situation. Whether we are sitting in a café, on the phone or in a lecture, our brain filters out a flood of irrelevant sounds to concentrate on those that we need to hear. It is thanks to this facility that we are able to focus on a single instrument in a symphony orchestra, or participate in intimate conversations in a noisy environment.

Spatial hearing
Our brain hears sounds 360 degrees around the head – at every angle around our head. Our brain can differentiate between front and back, up and down. This lets us tell where a sound is coming from, how big a room is or whether there is an obstruction in the area.

How we hear

The anatomy of hearing

"Hello"

Auditory
canal
Eardrum
Hammer
Anvil
Stirrup
Eardrum
Nerve fibres
Cochlea
Back

The brain

Once impulses are sent to the breain, it processes the data so that we can select waht is relevant to the situation and follow it.

The inner ear

Processing begins in the inner ear and sound waves are transformed into electrical impulses. The snail-shaped cochlea is filled with fluid, sound waves cause this fluid to move and the movement is picked up by the sensory cells which send the electrical impulses to your brain.

The middle ear

Three tiny bones and the eardrum make up the middle ear. The hammer, the anvil and the stirrup. The stirrup is actually the smallest bone in your body. They work together to amplify sound waves.

The outer ear

Ever wondered why an ear is shaped as it is? The shape of your ear ensures that sound waves are captured and directed through the auditory cancl into your eardrum.

The brain works hard

Many people find it challenging to follow conversations in some places, like in a noisy restaurant. This is because speech is made up of a large number of different sounds, put together in very rapid flow. Our brain constantly prioritises and organises all these sounds for us.

When it comes to hearing, it may come as a surprise to learn that the brain works harder than the ears. This is why in noisy environments, such as in a crowded restaurant, it can be very frustrating just trying to follow conversation. Even people with no hearing loss can find this challenging. Ordinarily your brain will be able to sort through all information you apply your attention to through a cognitive process: Put simply, the brain organises the sound environment, selects the desired source and follows it. For people with hearing loss, however, the brain has to work much harder to make sense of sound because the input it receives from the ears is softer, less detailed, and/or unclear.

Some sounds are heard better than others
The high-pitched consonant sounds like f, s and t are easily drowned out by louder, low pitched vowel sounds like a, o and u. This results in a person with hearing loss complaining that they can hear that others are talking, but not what they are saying.

What is hearing loss

If the ear is exposed to loud sounds over time, the tiny sensory cells and fibres of the inner ear can become damaged. This can lead to permanent hearing loss.

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