Hearing and hearing loss facts

The Hearing Research Group works together on several interrelated projects aimed at discovering how sound is processed by our ear and perceived by the brain. We use this research to develop methods to create diagnostic tools and therapeutic interventions to prevent or cure hearing loss and deafness.

MRC festival 2016

What is sound?

Sound is a form of mechanical vibration that travels through air, liquids and solids. The sound of leaves rustling in the breeze and the roar of a jet engine travelling through the air at about 760 miles per hour. Sound travels faster and more effectively in water, which allows whales to sing to each other across oceans. Sound travels even faster through solid materials like railway tracks.

Why do we need to hear?

Language is a defining feature of human culture and the ear is best adapted for receiving human speech. Our brain uses the different positions and asymmetric shapes of our two outer ears to create 3D maps of the soundscape around us and we integrate this with our other senses to provide information about the pleasures (e.g. music) and dangers of the external world. The social isolation caused by hearing loss can be a deeply distressing human experience.

How do we hear?

The sound of a name travels inside the ears to a coiled structure in the inner ear called the cochlea, where sensory cells can detect incoming vibrations of less than a millionth of a millimetre. The cells convert these vibrations into tiny electrical signals a billion times smaller than those used to charge, for example, a mobile phone. These tiny electrical signals are perceived by the brain as loudness, pitch and a host of other features that enable it to reconstruct the name and to place it amongst all the memories associated with that name. This analysis is so complex that more of the brain is devoted to the sense of hearing than to any other sensory system.

Human ear anatomy

Facts about hearing

  • In the UK there are 11 million people with hearing loss.
  • 50,000 of those are children.
  • 40% of people over the age of 50 have hearing loss.
  • 71% of people over the age of 70 have hearing loss.
  • It is estimated that by 2035 there will be around 15.6 million people with hearing loss across the UK – that is one in five.

Hearing loss in children

  • Children experience difficulties in learning and talking.
  • They will often ask you to repeat yourself.
  • They do not answer when being called.
  • They may often talk very loudly.

Hearing loss in adults

  • Adults can find it hard to follow a conversation in noisy places or on the phone.
  • They will also ask people to repeat themselves multiple times.

Types of hearing loss

  • Genetic-induced hearing loss: caused by mutations or deletion of genes.
  • Noise-induced hearing loss - caused by repeated exposure to loud sound. This occurs because the sensitive hair cells inside the cochlea become damaged.
  • Ototoxic drug associated hearing loss - caused by, for example, aminoglycoside antibiotics and some anti-cancer drugs.
  • Age-related hearing loss - develops as a result of getting older.

What is hearing loss?

Hearing loss is when you are partially or completely unable to hear sound in one or both of your ears.

How is hearing loss treated?

Currently, the only therapeutic options to ameliorate hearing loss are hearing aids and cochlear implants. While beneficial, they are unable to restore important features of hearing such as the ability to appreciate music and to understand speech in a noisy environment.

Cochlear implant

What can you do?

Hearing damage is irreversible, but you can help prevent the damage by

  • Avoiding repeated exposure to very loud noise
  • Wearing headphones for short periods of time
  • Don’t stay too close to speakers
  • Wearing earplugs when exposed to loud noise
  • Identifying the early signs and symptoms