Hearing impairment, or deafness, is when your hearing is affected by a condition or injury. Some people are born with a hearing loss while others may develop it as they get older.

Most commonly, hearing loss happens with age or is caused by loud noises.

Action on Hearing Loss (formerly the Royal National Institute for the Deaf) estimates that there are more than 10 million people in the UK with some form of hearing loss.

How hearing works

Sound waves enter your ear and cause your eardrum to vibrate. These vibrations are passed to the three small bones (ossicles) inside your middle ear.

The ossicles amplify the vibrations and pass them on to your inner ear where tiny hair cells inside the cochlea move in response to the vibrations and send a signal through the auditory nerve to the brain.  

Types of hearing loss

There are three main types of hearing loss:

• conductive hearing loss – where sounds are unable to pass from your outer ear to your inner ear, often as the result of a blockage such as earwax, glue ear or a build-up of fluid due to an ear infection, a perforated ear drum or a disorder of the hearing bones
• sensorineural hearing loss – the sensitive hair cells either inside the cochlea or the auditory nerve are damaged, either naturally through ageing, or as a result of injury
• mixed hearing loss – it is possible to get both types of hearing loss at the same time

Read more about what causes hearing impairment.

Levels of hearing loss

The level of hearing loss can be defined as mild, moderate, severe or profound. The level of hearing loss in an individual is determined by performing a hearing test to discover the quietest sound which that person can hear.

Some ear problems may not necessarily cause hearing loss, such as tinnitus, which is the sensation of a ringing or buzzing sound in the ear.

Read more about the symptoms of hearing loss.

How can I check if I have a hearing problem?

If you think that you or your child may have hearing problems, see your GP. They will check your ear for any problems, such as earwax or a perforated eardrum (a hole or tear in the eardrum).

Your GP may refer you to an audiologist (hearing specialist) or an ENT surgeon for further tests, including tuning fork tests and Pure Tone Audiometry.

Hearing tests are routinely carried out on newborn babies within the first few weeks to try and identify any hearing problems. This is known as the Newborn Hearing Screening Programme (NHSP).

You might also wish to visit the Action for Hearing Loss website for an online hearing test.

Read more about diagnosing hearing loss.

Treating hearing loss

The way hearing impairment is treated depends on the type of hearing loss and how severe it is.

In cases where there is sensorineural damage, there are several options that may help to improve a person’s ability to hear and communicate. These include:

• digital hearing aids, available through the NHS
• middle ear implants – surgically implanted devices suitable for some people who are unable to use hearing aids 
• cochlear implants – small hearing devices that are surgically implanted inside the ear for people who find that hearing aids are not powerful enough
• sign language, such as British Sign Language (BSL)

For people with conductive hearing loss there is often the possibility of improving their hearing with an operation or a device such as a Bone Anchored Hearing Aid (BAHA). This will often be discussed with an ENT surgeon who will diagnose the cause and offer treatment.

Read more about treating hearing loss.

You may also wish to find services for hearing impairment and deafness support.

Preventing hearing loss

It isn't always possible to protect a person’s hearing if they have an underlying condition that causes hearing loss.

However, there are several things you can do to reduce the risk of hearing loss from loud, consistent noise. This includes not having music or the television on at a very loud volume at home and using ear-protection at loud music events or in noisy work environments.

See your GP if there are signs of an ear infection, such as a high temperature (fever), flu-like symptoms, severe earache or hearing loss.

Read more about preventing hearing impairment.

Hearing impairment can be present at birth or it can develop at a later stage during childhood or adulthood.

The symptoms of hearing impairment will vary depending on what is causing it. Hearing loss can gradually develop over time, especially hearing loss related to noise exposure and age.

It can develop more rapidly when related to earwax, ear infection or disease in the middle ear.

People who wake up with a sudden loss of hearing in one ear or lose the hearing in one ear within a couple of days should see their GP as a matter of urgency, as early treatment may help.

Some hearing-related conditions can have symptoms other than hearing loss. For example, the condition tinnitus has symptoms such as continuous or intermittent ringing, hissing, whistling or buzzing noises.

Hearing impairment in children

Babies are routinely screened within the first few weeks of their birth as part of the Newborn Hearing Screening Programme (NHSP). Read more about how hearing impairment is diagnosed.

However, there are signs you can watch out for in your child which may suggest that you should see your GP to arrange another hearing test.

Signs in babies

You should consider seeing your GP if you notice that your baby or toddler:

• is not startled by loud noises
• does not turn to the source of a sound while under four months old
• does not say single words by the time they are one year old
• notices you when they see you but not when you call their name
• hears some sounds but not others

Signs in children

You should consider seeing your GP if you notice your child:

• is delayed in learning to talk, or they are not clear when they speak 
• often asks you to repeat yourself 
• often talks very loudly
• often turns up the volume of the TV so that it is very loud

Read more about your child's development from their birth to five years old.

Levels of hearing impairment

There are four different levels of hearing impairment, which are defined by the quietest sound that you are able to hear, measured in decibels (dB). These are described below.

Mild deafness

If you are mildly deaf, the quietest sound that you can hear is between 25 to 39dB. Mild deafness can sometimes make following speech difficult, particularly in noisy situations.

Moderate deafness

If you are moderately deaf, the quietest sound that you can hear is between 40 to 69dB. You may have difficulty following speech without using a hearing aid.

Severe deafness

If you are severely deaf, the quietest sound that you are able to hear is between 70 to 89dB. People who are severely deaf usually need to lip-read or use sign language even with the use of a hearing aid.

Profound deafness

If you are profoundly deaf, the quietest sound that you can hear is 90dB or more. People who are profoundly deaf can often benefit from a cochlear implant. Other forms of communication include lip reading and sign language

Read more about treating hearing impairment, including different types of hearing aids and sign language.

Age and loud noises are the most common causes of hearing impairment.

Age-related hearing loss

Age is the biggest single cause of hearing impairment. Hearing impairment that develops as a result of getting older is often known as age-related hearing loss or presbycusis.

Most people begin to lose a small amount of their hearing when they are 30 to 40 years old. This hearing loss increases as you get older. By the age of 80 most people will have significant hearing impairment.

Age-related hearing loss occurs when the sensitive hair cells inside the cochlea gradually become damaged or die. As your hearing starts to deteriorate, high-frequency sounds, such as female or children’s voices, may become difficult to hear. It may also be harder to hear consonants, such as the letters s, t, k, p and f. This can make understanding speech in background noise very difficult.

Acoustic trauma

Another common cause of hearing loss is damage to the ear from loud noises. This is known as acoustic trauma and it can occur when part of the delicate inner structure of the ear becomes damaged. After prolonged exposure to loud noises, the cells inside the spiral part of the cochlea become inflamed.

The loudness of the noise and the length of time that you are exposed to it are important factors in acoustic trauma. If you are exposed to loud noises over a long period of time, you are more likely to develop acoustic trauma.

In particular, people who are at risk of developing acoustic trauma include those:

• who work with noisy equipment, such as pneumatic drills or compressed-air hammers
• who work in environments where there is loud music, such as nightclub staff
• who listen to music at a high volume through headphones

If you are at risk of developing acoustic trauma, you may want to read more about how to prevent hearing impairment.

Conductive hearing loss

Conductive hearing loss occurs when sounds are unable to pass into the inner ear. This is usually due to a blockage, such as having too much ear wax, or from a build-up of fluid caused by glue ear or an ear infection.

However, conductive hearing loss can also be caused by:

• a perforated eardrum – where the eardrum is torn or has a hole in it
• otosclerosis – an abnormal growth of bone in the middle ear which causes the inner hearing bone (the stapes) to be less mobile and less effective at transmitting sound

Sensorineural hearing loss

Sensorineural hearing loss occurs if the sensitive hair cells inside the cochlea (the coiled, spiral tube inside the inner ear) are damaged, or as a result of damage to the auditory nerve (the nerve that transmits sound to brain). In some cases, both may be damaged.

There are many different causes of sensorineural hearing loss, including:

• age-related hearing loss (presbycusis)
• genetic hearing loss – some people may be born deaf or become deaf over time due to a genetic abnormality, although there is not always a family history
• prolonged exposure to loud noises (acoustic trauma) which causes damage to the inner ear
• viral infections of the inner ear, such as mumps or measles
• viral infections of the auditory nerve, such as mumps or rubella
• Ménière's disease – where a person suffers with vertigo (spinning dizziness), hearing loss which can come and go, tinnitus and a feeling of blockage in the ear
• acoustic neuroma – a non-cancerous (benign) growth on or near the auditory nerve
• meningitis – an infection of the protective membranes that surround the brain and spinal cord
• encephalitis – inflammation (swelling) of the brain
• multiple sclerosis – a neurological condition that affects the central nervous system (the brain and spinal cord)
• stroke – where the blood supply to the brain is cut off or interrupted

Cytotoxic medication (chemotherapy), which is often used to treat cancer, and certain antibiotics such as Aminoglycosides can also damage the cochlea and the auditory nerve, causing sensorineural hearing loss.

See your GP if you are having problems with your hearing. If you are unsure whether you have hearing problems, answering the following questions can be a guide:

• Do you have difficulty hearing over the telephone?
• Do you have difficulty listening when more than one person in the room is talking?
• Do other people complain about the volume of your music or television?
• Do you have to concentrate quite hard to understand the other person when you are having a conversation?
• Do you often miss the sound of the doorbell or the phone ringing?
• Do you often get confused about the direction a sound is coming from?
• Do you regularly have to ask people to repeat themselves?
• Do the voices of women and children seem harder to understand?
• Do you work in a noisy environment?
• Does it seem as though everyone is mumbling?
• Do you often misunderstand what people are saying?
• Can you sometimes hear a hissing, rushing or ringing sound?
• Has someone close to you suggested that you may have a hearing impairment?

You should visit your GP if you answer yes to most of these questions. Your GP will examine your ears and carry out some simple hearing tests.

You might also wish to visit the Action for Hearing Loss website for an online hearing test.

Ear examination

During an ear examination, an instrument with a light at the end called an auriscope (or otoscope) is used to look for anything abnormal including:

• a blockage caused by earwax, fluid or an object
• an ear canal infection
• a bulging ear drum – indicating that there is infection inside the middle ear
• fluid behind the ear drum, known as glue ear
• a perforated ear drum – a hole in the eardrum
• a collapsed ear drum
• skin collected in the middle ear (cholesteatoma)

Your GP will ask you if you have any pain in your ear and when you first noticed the hearing loss.

Referral to a specialist

Your GP may refer you to an ear, nose and throat (ENT) specialist or an audiologist (a hearing specialist). The specialist will carry out further tests to help determine what is causing your hearing loss and recommend the best course of treatment.

Some of the hearing tests that you may have include:

• a tuning fork test (may be performed by your GP)
• a pure tone audiogram, which tests air conduction hearing and bone conduction hearing 
• a speech audiogram 

These tests are described below.

Tuning fork test

A tuning fork is a Y-shaped, metallic object. When tapped, it produces sound waves at a fixed pitch. It is usually used for tuning instruments. The hearing specialist will tap the tuning fork on their elbow or knee to make it vibrate and they will then hold it next to your ear. This will indicate whether you can hear sounds that are transmitted through air vibrations.

The specialist may also hold the tuning fork against the bone behind your ear (mastoid). This will help to determine your level of hearing when the sound waves are transmitted to your inner ear through the bone.

Audiometry test

This is sometimes known as Pure Tone Audiometry and includes testing both air conduction and bone conduction.

Air conduction

During the air conduction part of the test you will wear earphones that are attached to a machine. Sounds of different tones and volumes will be played through the earphones. You will be asked to indicate whether you have heard them by raising your hand or pressing a button.

The audiologist may also check how well you are able to hear words that are spoken at different volumes. After listening to the words, you will be asked to repeat what you have heard.

Bone conduction

The bone oscillator test determines how well you are able to hear sounds that are transmitted through the bone rather than the air. It is similar to the tuning fork test but instead of a tuning fork, an instrument called a bone oscillator is placed against the bone behind your ear (mastoid) to determine your level of hearing through the bone. This is testing how well the nerve part of your hearing works.

Newborn Hearing Screening Programme (NHSP)

It is not easy to identify hearing loss in young babies because they are too young to know that something is wrong. Screening a baby’s hearing soon after they are born means that any hearing loss can be identified early.

After your baby is born, they will be given a number of routine health checks, including a hearing test. The test is part of the NHS Newborn Hearing Screening Programme (NHSP), and it will be carried out within the first few weeks of your baby's birth.

A test that is commonly used to check a baby’s hearing is the otoacoustic emissions (OAE) test. The test involves inserting a tiny probe just into the outer ear. If possible, it will be carried out while your baby is asleep.

The probe emits small sounds and checks for a corresponding "echo" from the ear, which is known as an otoacoustic emission. If there is no response, it does not necessarily mean that your child has a hearing impairment, although further tests will be needed to determine the cause.

About 15% of newborn babies will need further testing and one to two babies in every thousand will have some level of hearing loss in one or both ears.

How hearing impairment is treated will depend on the underlying cause of the condition. For people with sensorineural hearing loss, the condition is permanent.

This is because once the sensitive hair cells in the cochlea (the coiled, spiral tube inside the inner ear) are damaged, they cannot be repaired and remain damaged for the rest of a person’s life.

However, if your hearing is impaired, various treatment methods can improve your quality of life. Some are discussed below.

You may also wish to find services for hearing impairment and deaf support.

Hearing aids

If you have a hearing impairment, you may be able to wear a hearing aid. A hearing aid does not cure a hearing impairment, but it increases the volume of sound entering your ear so that you may be able to hear things more clearly.

A hearing aid is an electronic device that consists of:

• a microphone
• an amplifier
• a loudspeaker 
• a battery

Modern hearing aids are very small and discreet and can be worn inside your ear. The microphone picks up sound which is made louder by the amplifier. Hearing aids are fitted with devices that can distinguish between background noise, such as traffic, and foreground noise, such as conversation.

Hearing aids are not suitable for everyone. For example, they may not be effective if you have profound hearing impairment. Your GP or audiologist (hearing specialist) will be able to advise you about whether a hearing aid is suitable for you.

If a hearing aid is recommended for you, an audiologist will take an impression of your ear so that the hearing aid will fit you perfectly. The hearing aid will be adjusted to suit your level of hearing impairment. You will also be shown how to use and care for it.

After your hearing aid has been fitted, you will have a follow-up appointment three months later.

NHS hearing aids

In the UK, both analogue and digital hearing aids are commonly used. Most hearing aids that are prescribed through the NHS are now digital.

Instead of having moving parts, digital hearing aids contain a very small computer that processes sounds. This enables the hearing aid to be programmed to suit different environments, such as a small quiet room or a large, noisy workshop.

Digital hearing aids that are available through the NHS are usually the behind-the-ear (BTE) type. This type of hearing aid is described below along with other types.

Behind-the-ear (BTE) hearing aids

Behind-the-ear (BTE) hearing aids usually have an earmould which sits inside your ear. The rest of the hearing aid is connected to the earmould and lies behind your outer ear.

Some types of BTE hearing aids have two microphones that enable you to listen to sounds in the general vicinity or to focus on sounds that are coming from a specific direction. This can be particularly useful in noisy environments.

In-the-ear (ITE) hearing aids

In-the-ear (ITE) hearing aids are like an earmould. They fill the area just outside your ear canal and fill the opening of your ear canal. The working parts of the hearing aid are either located in a small compartment that is attached to the earmould or inside the earmould itself.

In-the-canal (ITC) hearing aids

In-the-canal (ITC) hearing aids fill the outer part of the ear canal and are just visible.

Completely in-the-canal (CIC) hearing aids

Completely in-the-canal (CIC) hearing aids are even smaller and less visible than ITE hearing aids. However, they may not be recommended if you have severe hearing loss.

Body-worn (BW) hearing aids

Body-worn (BW) hearing aids have a small box containing the microphone. The box can be clipped to your clothes or you can put it inside a pocket. A lead connects the box to an earphone which delivers sound to your ear.

Bone conduction hearing aids

Bone conduction hearing aids are recommended for people with conductive hearing loss or for those who can't wear a more conventional type of hearing aid. Bone conduction hearing aids vibrate in response to the sounds going into the microphone.

The part of the hearing aid that vibrates is held against the bone behind the ear (mastoid) by a headband. The vibrations pass through the mastoid bone to the cochlea and are converted into sound in the usual way. They can be very effective but can be painful to wear for long periods.

Bone Anchored Hearing Aids (BAHA)

A bone anchored hearing aid requires an operation. A pedestal is screwed into the bone behind the ear and sticks through the skin to allow a hearing aid to be clipped on and off the pedestal. It is worn during the day and removed at night.

Unlike a bone conduction hearing aid it is not uncomfortable to wear and it is used for patients with conductive hearing loss, or in some patients who have no hearing in one of their ears.

Middle Ear Implants

These are surgically implanted devices which attach to the hearing bones and make them vibrate. They are suitable for people who can't use a hearing aid but have hearing loss at a level where a bone anchored hearing aid would not help.

CROS/BiCROS

CROS hearing aids are recommended for people who only have hearing in one ear. They work by picking up sounds from the side that does not have hearing and transmitting them to the ear that is able to hear.

BiCROS hearing aids work in a similar way to CROS hearing aids and may be useful for people who do not have any hearing in one ear and have limited hearing in the other ear. This type of hearing aid also makes sounds louder.

Disposable hearing aids

Disposable hearing aids are sometimes recommended for people who have mild to moderate hearing loss. The battery inside a disposable hearing aid usually lasts for about 10 weeks, after which time the hearing aid is thrown away and replaced. Disposable hearing aids cost around £26 a month and are usually only available privately.

Cochlear implants

Cochlear implants are small hearing devices that are fitted behind your ear during surgery. They have an external sound processor and internal parts including a receiver coil, an electronics package and a long wire with electrodes on it (an electrode array). The electrode array is fed into the cochlea and stimulates the hearing nerve. The processor takes in sound, analyses it and then converts it to signals which are transmitted along the electrode array into the cochlea. This means that cochlear implants are only suitable for people whose hearing nerves are functioning normally.

A cochlear implant is sometimes recommended for adults or children who have profound sensorineural hearing loss in both ears which is not helped by hearing aids. 

Both ears are usually implanted for children whereas adults are often only able to have one cochlear implant.

Before a cochlear implant is recommended, you will be assessed to find out whether it will help improve your hearing. During the assessment, any disabilities or communication problems that you have will be taken into consideration, which may mean that the usual hearing tests are not suitable.

If a cochlear implant is recommended, it will be inserted into your ear (or both ears) during an operation and will be switched on a few weeks later.

There are currently around 10,000 people in the UK with cochlear implants and the number is increasing each year.

British Sign Language (BSL)

Sometimes, hearing impairment can affect your speech as well as your ability to understand other people. Many people with a hearing impairment learn to communicate in other ways instead of, or as well as, using spoken English.

For people who experience hearing loss after they have learnt to talk, lip-reading can be a very useful skill. Lip-reading is where you watch a person’s mouth movements while they are speaking in order to understand what they are saying.

For people who are born with a hearing impairment, lip-reading is much more difficult. Those who are born with a hearing impairment often learn sign language, such as British Sign Language (BSL), which is a form of communication that uses hand movements and facial expressions to convey meaning.

BSL is completely different from spoken English and has its own grammar and syntax (word order). Other types of sign language include Signed English and Paget Gorman Signed Speech.

More information about BSL is available on the website of Action on Hearing Loss.

The ears are fragile structures that can be damaged in many ways, and it is not always possible to prevent many of the health conditions that affect a person’s hearing.

The risk of your hearing being damaged by loud noises depends on how loud the noises are and how long you are exposed to them. Experts agree that continued exposure to noise at or above 85dB (similar to a lawn mower or loud traffic) can, over time, cause hearing loss.

However, by following the advice below it is possible to reduce your risk of acoustic trauma (hearing loss from loud noise).

• Don't have your television, radio or music on too loud. This is particularly important if you have young children in the house because their ears are more delicate than an adult’s. If you can't have a comfortable conversation with someone who is two metres (about 6.5ft) away from you, turn the volume down. You shouldn't have dull hearing or ringing in your ears after listening to music.
• Use headphones that block out more outside noise, rather turning up the volume. You can buy add-ons for your existing headphones that block out more outside noise.
• Use ear protection equipment such as ear muffs or ear plugs if you work in a noisy environment, for example a pub, nightclub, a garage workshop or on a building site.
• Use ear-protection equipment at loud concerts and at other events where there are high noise levels, such as motor races.
• Don't insert objects into your ears or your children’s ears. This includes fingers, cotton buds, cotton wool and tissue.
• Be aware of the symptoms of common causes of hearing loss, such as ear infections (otitis media) and Ménière's disease
• Visit your GP if you or your child are experiencing hearing problems.

Read more tips to protect your hearing.

Susan is a community mental health nurse helping deaf people with mental illnesses. She talks about how attitudes to deafness have changed and says deafness need not stop you from having a successful career.

Millie’s hearing started deteriorating when she was a child. She talks about learning to cope with the hearing loss and shows that it hasn't stopped her doing what she wants to in life, including dancing.