About this factsheet

This factsheet is part of RNID's medical range. It is written for people who want to know more about acoustic neuromas.

Read this factsheet to find out:

What is an acoustic neuroma?

An acoustic neuroma is a rare, slow-growing benign tumour that develops on the eighth cranial nerve - the nerve of hearing and balance. It is not cancerous.

The eighth cranial nerve

The eighth cranial nerve has many different names. The part that carries the hearing information may be called:

The part that carries balance information is called the vestibular nerve. Together these parts are called the vestibulo-cochlear nerve or the eighth cranial nerve.

The eighth cranial nerve runs through the bone of the skull, carrying both hearing and balance information from the inner ear to the brain. As it passes through the bone, the nerve runs alongside the facial nerve, which carries information from the brain to the muscles of the face.

All nerves have an insulation layer that is produced by special cells called Schwann cells. Occasionally, these cells can develop into a small swelling. For reasons that are not clear, the vestibular nerve is particularly prone to this process. The resultant swelling is therefore called a vestibular schwannoma, but is more commonly known as an acoustic neuroma.

An acoustic neuroma grows extremely slowly over several years. Eventually it presses on the balance, hearing and facial nerves and can therefore affect the hearing and balance. More rarely, it can cause symptoms in the face. If it becomes very large it can press against the brain, though with modern diagnostic techniques, such large tumours are not seen so often.

An acoustic neuroma is not a life-threatening condition except in very unusual cases where the tumour grows so large that it presses on the brain. As it is non-cancerous, it does not spread around the body. If it is completely removed, it is unlikely to grow back again. 

What causes an acoustic neuroma?

About 5% of acoustic neuromas are caused by a hereditary condition called Neurofibromatosis Type II. People with this type of acoustic neuroma are usually younger and may also get other types of neuromas.

All acoustic neuromas are rare - they affect one in 100,000 people. For 95% of people, they occur spontaneously and the cause is not known.  Most of them are found in people aged 30 to 60 years old.

What are the signs of acoustic neuroma?

How is an acoustic neuroma diagnosed?

Most people with an acoustic neuroma initially visit their GP with symptoms such as hearing loss in one ear, tinnitus in one ear or dizziness. The doctor will send them to the local hospital to an ENT (ear nose and throat) clinic. A consultant takes a medical history and organises hearing tests and possibly balance tests, depending on the symptoms. If these tests suggest the possibility of an acoustic neuroma, an MRI or CT scan is arranged.

MRI scan

An MRI scan sends high frequency radio waves through the body in the presence of a strong magnetic field to produce a picture of the inside of the body. The person being scanned lies flat on a couch, which slides into the scanner. The scanner is very noisy so earplugs or headphones are provided. Modern scanners are fast and scans now take only a few minutes.

CT or CAT scan

People who are not able to have MRI scans - for example, someone with a pacemaker or a metal surgical implant in their head - can have a computerised tomography (CT) scan instead. A CT scan also produces pictures of the inside of the body but does so using x-rays rather than radio waves and a magnetic field. A CT scan is slightly less sensitive than an MRI scan but is still a very accurate investigation. Having a CT scan is quite similar to having an MRI scan except that the scanner is much quieter.

How is an acoustic neuroma treated?

If you are diagnosed with an acoustic neuroma, your treatment will depend on a number of things, including:

As acoustic neuromas grow very slowly, there is no need to rush into a decision regarding treatment. It is best to consider all the options carefully and discuss them in detail with the surgeon or radiotherapist. All treatments are carried out in specialist centres and most people have to travel for their treatment. These treatments include:

Observation

If the acoustic neuroma is very small and it is not causing any symptoms, it may just be carefully monitored over a period of time with further MRI or CT scans. This generally means having a scan once every one to two years.

Microsurgery

Microsurgery is the best treatment for most people with an acoustic neuroma. In almost all cases, the tumour can be completely removed and no further treatment will be needed.

A number of surgical techniques are used for the removal of an acoustic neuroma. The technique used depends on:

Even when the acoustic neuroma has been removed completely, it could grow back again, though this is very rare. Most acoustic neuroma surgeons recommend having one or two MRI scans after surgery.

Radiotherapy

Radiotherapy involves using carefully controlled doses of radiation to damage cells within the acoustic neuroma and stop it from growing. Not all acoustic neuromas are suitable for treatment by radiation. A number of techniques may be used and treatment is usually divided into small doses that are given over a period of days or weeks - a process called 'fractionation'.

Most people who decide to have radiotherapy receive the treatment as a hospital outpatient. Treatment involves lying on a couch on a radiotherapy machine. Treatments are painless and generally last a few minutes. You will be free to go about your normal daily activities before and after treatment.

Radiotherapy does not affect tumour cell growth immediately. Some tumour cells can take several months to die after radiation treatment. Some tumours will shrink in size, but the tumour does not disappear completely. Further MRI scans are needed from time to time to monitor the tumour.

Radiosurgery

Radiosurgery is a relatively new technique for treating acoustic neuromas and is available in the UK in only a few hospitals. It is a highly specialised form of radiotherapy that aims to stop the tumour growing by delivering a high dose of radiation to a precise location within the head. It is sometimes known as 'gamma knife' treatment because the radiotherapy consists of gamma rays and it is delivered very precisely like a surgeon's knife. The precise targeting means damage to surrounding nerves and tissues is limited. Radiosurgery can be done in just one visit and usually does not require an overnight stay.

The long-term effects of radiosurgery are not yet known. However, it has fewer immediate side effects than surgery or radiotherapy. Recovery is usually quick and in many cases it does not damage hearing. It is particularly useful for people who do not want or cannot have surgery but it is not suitable for large tumours. 

What can I expect after treatment?

Hearing loss

Surgery usually affects any remaining hearing you have in your affected ear and can result in partial or complete hearing loss in that ear. For small tumours it may be possible for the surgeon to preserve the hearing in the affected ear. For larger tumours the chances of preserving hearing are usually low.

The hearing in your good ear is not affected by surgery and most people are able to hear well in the majority of situations. However, it is usually more difficult to locate sounds and decide where they are coming from. It is also often more difficult to hear speech if there is a lot of background noise.

If your affected ear has a total hearing loss, a hearing aid will not be helpful. If the surgeon has been able to preserve some hearing in your affected side, it may be worth trying a hearing aid in that ear. If your good ear has any degree of hearing loss it is useful to try and correct this with a conventional hearing aid.

Your ENT surgeon or your GP may be able to refer you to a hearing therapist or support worker. They can give you many practical suggestions on coming to terms with hearing loss and getting the most out of hearing aids. They can also demonstrate equipment for deaf people and offer tips for communicating with other people.

For more information about hearing aids, see our factsheets and leaflets:

Tinnitus

Many people with tinnitus find that it improves or stays the same after surgery for acoustic neuroma. Some people find it gets worse. Occasionally, tinnitus can occur for the first time after surgery. If you have troublesome tinnitus, ask your GP to refer you for treatment.

You can also contact the RNID Tinnitus Helpline for a range of information about tinnitus

Balance

After surgery, some people have balance problems, which continue until the balance organ on the unaffected side, and the brain, compensate for losing the balance organ on the affected side. Sometimes this process of adaptation can be slow and it may be necessary to ask your GP for a referral to a specialist in balance disorders. For more information about balance disorders, see our factsheet "Dizziness and balance problems".

Facial paralysis

Surgery for acoustic neuroma can lead to facial paralysis because the facial nerve is very close to the hearing nerve (see What is an acoustic neuroma?). Even slight injury to the facial nerve can lead to temporary or permanent problems, causing the face to droop or sag. The facial nerve is carefully monitored during surgery but sometimes it is impossible to avoid injury.

In addition to weakness of the facial muscles, damage to the nerve can also:

If you cannot close your eyelids, it may be necessary to wear glasses or a plastic bubble over your eye to protect it from wind, smoke and other hazards. Occasionally, you may need a minor operation on the eyelids to correct this problem.

Where can I get further information?

British Acoustic Neuroma Association (BANA)

BANA provides support and information to people with acoustic neuromas.

BANA, Oak House, Ransom Wood Business Park, Southwell Road West, Mansfield NG21 0HJ
Freephone helpline: 0800 652 3143
Telephone: 01623 632143
Fax: 01623 635313
Email: admin@bana-uk.com
Website: Bana website (external link, opens new browser window)

Let's Face It Support Network for the Facially Disfigured

Let's Face It offers counselling, advice and support to people with facial disfigurement and their families. They have a self-help and sharing support network and can bring together people with similar problems.

Let's Face It, 72 Victoria Avenue, Westgate On Sea, Kent CT8 8BH
Telephone: 01843 833724
Fax: 01843 835695
Email: chrisletsfaceit@aol.com
Website: Let's Face It website (external link, opens new browser window)

Further information from RNID

Our Information Line offers a wide range of information on many aspects of deafness and hearing loss. Contact us for further copies of this factsheet and our full range of information factsheets and leaflets. You can also contact us if you would like information in Braille, on audiotape or large print.

RNID Information Line

The RNID Information Line offers a wide range of information on many aspects of deafness and hearing loss. You can contact us for printed copies of this factsheet and the full range of our information factsheets and leaflets.

RNID Information Line, 19-23 Featherstone Street, London EC1Y 8SL
Telephone: 0808 808 0123
Textphone: 0808 808 9000
Fax: 020 7296 8199
Email: informationline@rnid.org.uk

RNID Tinnitus Helpline

The RNID Tinnitus Helpline offers information and advice to people with tinnitus, their families and friends, and the professionals who work with them.

The RNID Tinnitus Helpline can also give you details of your nearest tinnitus support group. There are about 100 of these in the UK. They are set up and run by people with tinnitus, so they can give you more help with your tinnitus directly from other people who also have it. The type of support and help they are able to offer varies between groups.

RNID Tinnitus Helpline, 19-23 Featherstone Street, London EC1Y 8SL
Telephone: 0808 808 6666
Textphone: 0808 808 0007
Fax: 020 7296 8199
Email: tinnitushelpline@rnid.org.uk

This factsheet was produced with the help and advice of:
Don McFerran, Consultant ENT Surgeon, Essex County Hospital.