Hearing loss

Published by Bupa’s Health Information Team, X.
 
This factsheet is for people who have hearing loss, or who would like information about it.
 
Hearing loss can be temporary or permanent and can affect all age groups. Ageing, ear infections and loud noises can all cause hearing loss.
 
 
How the ear works
About hearing loss
Symptoms of hearing loss
Causes of hearing loss
Diagnosis of hearing loss
Treatment of hearing loss
 

How the ear works

About hearing loss

Hearing loss affects around two out of 10 adults in the UK. Most of these people are over 60 and have lost their hearing gradually as part of the natural ageing process. Around seven in 10 people over 70 in the UK have some degree of hearing loss. However, hearing loss can also happen at a younger age.
 

Sound and the ear

Your ear consists of three parts: the outer ear, middle ear and inner ear.
 
The outer ear is the visible part of your ear. It collects sound waves, which travel down your ear canal to your eardrum. The sound waves cause your eardrum to vibrate. This vibration is passed on to your middle ear, which consists of three small bones called ossicles. The ossicles amplify and conduct the vibrations to your inner ear.
 
Your inner ear contains the cochlea and the auditory nerve. The cochlea is full of fluid and contains tiny hair cells. Vibrations cause the hair cells in your cochlea to move. Movement of these hair cells produces electrical signals that travel along the auditory nerve to your brain, where they are converted into meaningful information, such as language or music.  
 

Types of hearing loss

There are two main types of hearing loss.
 

• Conductive hearing loss – this is caused when sound can’t move freely from your outer ear to your inner ear.
• Sensorineural hearing loss – this happens when there is damage to the pathway between your inner ear and your brain.

 
You may have a combination of conductive and sensorineural hearing loss – this is known as mixed hearing loss.
 
You may have hearing loss in one ear only (unilateral) or both ears (bilateral).
 

Symptoms of hearing loss

 
In adults, hearing loss may be very gradual, for example in age-related hearing loss. You may start to notice you find it difficult to hear and understand people when you're in a noisy place. Hearing loss can also be very sudden, for example if it’s caused by a viral infection of the inner ear. Some people find that their hearing loss is associated with a continual ringing in their ears (tinnitus).
 
Depending on what is causing your hearing loss, you may also have some other symptoms, such as earache and discharge from your ears, if you have an infection.
 
Hearing loss can affect speech and language development in children.
 
If you, or your friends and family, think that your hearing is getting gradually worse, you should see your GP. If you have sudden hearing loss in one or both ears, you should seek immediate advice, as treatment may need to be started very quickly.
 

Causes of hearing loss

Conductive hearing loss

The following are possible causes of conductive hearing loss.

• Middle ear infection. This is particularly common in children.
• Glue ear (a build up of fluid in your middle ear). This is also common in children.
• Blockage of your outer ear, usually caused by a build up of wax.
• Otosclerosis – bone growth in the middle ear, which makes the ossicles of your middle ear harden and become less able to vibrate.
• Perforated (pierced) eardrum, which can be caused by an untreated ear infection, a head injury or from poking something in your ear.

 
The causes of conductive hearing loss can often be treated, so it’s usually only temporary.
 

Sensorineural hearing loss

Most hearing loss is thought to be sensorineural. It happens when the hair cells within your cochlea are damaged. The following are some possible causes.
 

• Age-related hearing loss (presbycusis) – a natural decline in your hearing due to damage that occurs to your cochlea as a part of the ageing process.
• Regular exposure to loud noises, for example if you work in a noisy place or listen to a lot of loud music.
• Certain infections such as rubella, measles or meningitis.
• Meniere's disease – a condition that affects your inner ear, causing dizziness and tinnitus, as well as leading to hearing loss.
• Certain medicines, such as some strong antibiotics.
• Certain cancer treatments, such as chemotherapy and radiotherapy.
• Acoustic neuroma – is a benign (non-cancerous) tumour that affects your auditory nerve.
• Cholesteatoma – a benign skin growth behind your eardrum.
• An injury to your head.

 
Sensorineural hearing loss is usually permanent, as once the hair cells in your cochlea are damaged, they can’t be repaired.

 
Diagnosis of hearing loss

 
Your GP will ask you about your symptoms and examine you. He or she may also ask you about your medical history.
 
Your GP may perform a hearing test, or he or she may refer you to either an otolaryngologist (a doctor who specialises in ear, nose and throat disorders), an audiologist (a specialist in hearing) or an audiovestibular physician (a doctor who specialises in hearing, balance and communication
problems).
 
You may have the following tests.
 

• Whispered speech test. Your doctor will whisper a combination of numbers and letters from behind you and ask you to repeat the combination to check if you can hear anything. He or she will test each ear separately.
• Tuning fork test. Different tuning forks can be used to test your hearing at a variety of frequencies. They can also help determine the type of hearing loss you have.
• Pure tone audiometry. You will be asked to wear a set of headphones attached to a machine called an audiometer. The audiometer produces sounds of different volumes and frequencies, and you will be asked to indicate when you hear the sounds in the headphones. The level at which you can’t hear the sound of a certain frequency is known as your threshold.

 
If your hearing loss has a sensorineural cause, a number of other tests can be performed to pinpoint where the problem lies.
 

• Otoacoustic emissions. This test is used to measure your cochlear function by recording signals produced by the hair cells.
• Auditory brainstem response. This test measures the activity of your cochlea, auditory nerve and brain when a sound is heard.

 
If your doctor thinks your hearing loss is due to an acoustic neuroma or cholesteatoma, you may need to have an MRI scan of your head.

Treatment of hearing loss

Self-help

You may find it easier to hear and understand people if you:
 

• make sure there is light on the face of the person you’re talking to, so you can see their lips moving
• sit close to the person you’re talking to
• sit so that your better ear is close to the person you’re talking to

Medicines

If you have a bacterial infection of your middle ear, it can sometimes be treated with antibiotics. Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.
 

Non-surgical treatments

If your outer or middle ears are blocked by ear wax or fluid caused by an ear infection, a nurse will be able to remove the blockage with a syringe after it has been softened.
 
If there is no cure for your hearing loss, for example if it’s caused by ageing, a hearing aid for one or both of your ears may help. Hearing aids can work for both conductive and sensorineural hearing loss. Many different types of hearing aid are available, and your audiologist will advise you as to which type best suits your needs.
 

Surgery

If you have a large perforation of your ear, you may need to have surgery to repair it.
 
An acoustic neuroma can be removed with surgery or treated with radiotherapy. Ossicles affected by otosclerosis can sometimes be treated with surgery.
 
If a hearing aid doesn’t help (eg, in profound deafness), your doctor may suggest you have a cochlear implant. This is a device that turns sounds into electrical signals, which directly stimulate your auditory nerve, allowing you to hear.