Acoustic neuromas

An acoustic neuroma is a benign brain tumour of one of the nerves connecting the inner ear to the brain. Acoustic neuromas usually grow slowly and don’t spread to other parts of the brain. They can cause problems if they grow and press on important parts of the brain. The most common symptoms are loss of hearing in the affected ear, a buzzing or ringing noise (tinnitus), feeling dizzy and problems with balance. 

You’ll have some hearing tests and a MRI scan to diagnose the tumour. Your treatment will depend on the size of the tumour and how symptoms affect you. If they’re mild, you may not need treatment immediately. You’ll have regular scans to keep a check on the tumour. 

People are often treated with a type of targeted radiotherapy called stereotactic radiotherapy. Surgery is often done for bigger tumours. The operation may cause hearing loss and other side effects. Your doctors will discuss these with you and will explain how to cope with them.

Understanding acoustic neuromas

This information is about acoustic neuroma, its symptoms, diagnosis and treatments. It should be read with our general information about brain tumours which has more detailed information on tests, treatments and side effects.

An acoustic neuroma is a benign (non-cancerous) tumour that usually grows slowly. A benign tumour can cause problems as it grows by pressing on surrounding tissue. But, unlike a malignant tumour, it can’t spread from where it started to other parts of the brain.

Acoustic neuroma develops from the lining of the main nerve that connects the inner ear to your brain. This is called the acoustic or hearing nerve. It controls your hearing and balance. Alongside it runs the facial nerve.  Although acoustic neuromas are a type of brain tumour, they don’t spread into (invade) the brain. But if a tumour grows large enough it can interfere with important functions of the brain.

Acoustic neuromas start in schwann cells, which cover the nerve, so they are sometimes called a vestibular schwannoma. They are most likely to be found in people in their 40s to 60s.

Causes of acoustic neuromas

The cause is unknown. In a small number of people, acoustic neuroma is associated with an inherited (genetic) condition called neurofibromatosis type 2 (NF2). In this situation, there are usually tumours affecting both sides of the brain (bilateral tumours).

Low-dose radiation for benign head and neck conditions as a child may increase the risk of developing acoustic neuroma.

Symptoms of acoustic neuromas

Acoustic neuromas are usually slow-growing tumours and symptoms often develop gradually over several years. The most common symptoms are loss of hearing in the affected ear, a buzzing or ringing noise (tinnitus), feeling dizzy and problems with balance. If the tumour presses on the facial nerve, it can cause numbness or tingling of half of the face. Larger tumours may lead to increased pressure in the brain, causing headaches and changes to your eyesight.

Tests for acoustic neuromas

Your doctors need to find out as much as possible about the type, position and size of the tumour so they can plan your treatment. You may have a number of tests and investigations.

You will have a range of hearing tests (audiometry) and sometimes a test is done to check your sense of balance. The doctor will examine you thoroughly and also test your reflexes and the power and feeling in your arms and legs.

CT scan

A CT (computerised tomography) scan uses x-rays to build a three-dimensional picture of the inside of the body. You may be given either a drink or injection of dye. This is to make certain areas of the body show up more clearly. This scan takes around 30 minutes and is painless. We have more detailed information about having a CT scan.

MRI scan

The diagnosis of an acoustic neuroma is usually obvious from the MRI (magnetic resonance imaging) brain scan.

Treatment for acoustic neuromas

The treatment you have will depend on the size of the tumour, how the symptoms are affecting you and your general health. The main treatments are radiotherapy or surgery.

A team of specialists will plan your treatment. This will usually include a surgeon who specialises in operating on conditions of the nervous system (neurosurgeon), and a specialist ear, nose and throat (ENT) surgeon (called a neuro-otologist), a cancer doctor (oncologist) and a specialist nurse.

They will explain the aims of your treatment, the benefits and disadvantages, and possible risks. Deciding on the treatment that is right for you is a decision you make in partnership with your doctor. Make sure you have enough information and time to help you make any treatment decisions.

Monitoring (observation)

If the tumour is small and causing only mild symptoms, you may not need treatment straightaway. Acoustic neuromas tend to be very slow-growing and it may be a long time before you need treatment. You will have regular scans to make sure the tumour is not growing. This can be a good option when the effects of surgery or radiosurgery outweigh the risk of an acoustic neuroma affecting your health.

Stereotactic radiotherapy

Radiotherapy treatment uses high energy rays to destroy the tumour cells. Acoustic neuromas are treated with a targeted radiotherapy called stereotactic radiotherapy. You have this as a course of treatment over a number of daily sessions from Monday to Friday.

Several beams of radiation are given from different angles, overlapping at the tumour. This gives a high dose to the tumour and very low doses to surrounding healthy tissue so helps to reduce side effects.

These treatments reduce the risk of permanent effects such as hearing loss and facial nerve damage that you get with surgery. But some people may still have some hearing loss and occasionally some damage to the facial nerve.

Stereotactic radiosurgery

You have this type of stereotactic radiotherapy as a single session of high-dose focused treatment. This is often the treatment for smaller tumours, as there are likely to be fewer side effects than with surgery. It is sometimes called gamma knife treatment, named after the machine that’s used. It doesn’t involve any surgery.


Surgery is usually only used to remove larger tumours as an operation is likely to have more side effects than stereotactic radiotherapy or radiosurgery.

Your surgeon will explain what it involves and what the possible complications and risks are. The operation is done through the skull. Sometimes they leave a tiny part of the tumour to try to avoid damaging the facial nerve. Any tumour that is left behind can be treated with stereotactic radiosurgery.

Surgery will usually cause hearing loss in the affected ear. Your surgeon may talk to you about being fitted with a special type of hearing aid, which diverts sounds from the affected ear to your other ear. You will usually see a hearing specialist for expert help and advice.

Doctors may delay surgery, if possible, in people who have large tumours of both acoustic nerves because of the risk of total hearing loss. You will have MRI scans to monitor the tumours. Occasionally, they operate on one side first. If you can hear with this ear after surgery, you then have the other side operated on. If hearing is lost during the first operation it may be possible to delay surgery on the second tumour, or to use radiotherapy.

Sometimes surgery may damage the facial nerve. This can cause numbness or drooping (palsy) of one side of the face, which is sometimes permanent. It can affect actions like chewing and blinking. A physiotherapist will show you exercises and massage that you can do to help improve this. Some people also get a dry eye. Eye drops will help with this. If necessary, your doctor can refer you to an eye specialist. The British Acoustic Neuroma Association has more information.

Useful organisations

British Acoustic Neuroma Association

The British Acoustic Neuroma Association gives information and support for people with acoustic neuroma. It has a network of local branches throughout the UK.

The Neuro Foundation

The Neuro Foundation offers information and advice about neurofibromatosis.