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Acoustic neuroma

An acoustic neuroma is a benign non-cancerous growth, or tumour, in the brain. It's also known as a vestibular schwannoma.

An acoustic neuroma is a benign (non-cancerous) growth, or tumour, in the brain. It's also known as a vestibular schwannoma.

An acoustic neuroma grows on the vestibulocochlear nerve, which helps control hearing and balance. This nerve runs alongside the facial nerve, which carries information from the brain to the face muscles.

The symptoms of an acoustic neuroma tend to develop gradually and can vary in severity. This can make the condition difficult to diagnose (see below).

A small acoustic neuroma can lead to problems with:

  • hearing – causing hearing loss or tinnitus (a noise perceived inside the ear but with no outside source)
  • balance – causing vertigo (the sensation that you're spinning)

A large acoustic neuroma can cause a number of symptoms, including:

  • headaches with blurred vision
  • numbness or pain on one side of the face
  • problems with limb co-ordination on one side of the body

Occasionally, large neuromas can also result in muscle weakness on one side of the face. In rare cases, it may also cause changes to the voice or difficulty swallowing (dysphagia).

What causes an acoustic neuroma?

The cause of most acoustic neuromas is unknown, but a small number of cases (about 5%) are caused by a rare, inherited condition called neurofibromatosis type 2.

Acoustic neuromas grow from the cells that cover the vestibulocochlear nerve, called Schwann cells.

Read more about the causes of an acoustic neuroma.

Diagnosing an acoustic neuroma

If your GP thinks you have an acoustic neuroma, you'll be referred to hospital for tests.

The three types of test you may have are:

Read more about how an acoustic neuroma is diagnosed.

Treating an acoustic neuroma

Acoustic neuromas tend to grow slowly and don't spread to other parts of the brain.

They can be so small and grow so slowly that they may not cause any symptoms or problems. In such cases, the acoustic neuroma may just be monitored to avoid risks associated with surgery.

In rare cases, the tumour can grow large enough to press on the brain. However, most acoustic neuromas can be treated before they reach this stage, either with surgery to remove the tumour or radiotherapy to destroy it. 

Read more about treating an acoustic neuroma.

Complications of an acoustic neuroma

Acoustic neuromas aren't usually life-threatening but the symptoms can be disruptive. For example, the loss of hearing may affect your ability to communicate with others.

Speak to your GP or specialist if you feel the symptoms are having an impact on your day-to-day life. There may be ways of easing your symptoms, such as using a hearing aid or taking painkilling medication.

Read more about complications of an acoustic neuroma



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Acoustic neuroma

A small acoustic neuroma may not cause any symptoms, or your symptoms may develop gradually as acoustic neuromas tend to grow slowly.

A small acoustic neuroma may not cause any symptoms, or your symptoms may develop gradually as acoustic neuromas tend to grow slowly.

Acoustic neuromas may grow about 1-2mm every year. However, there could be long periods when the tumour doesn't grow at all.  

The possible symptoms of an acoustic neuroma are described below.

  • Hearing loss – is the most common symptom and usually develops gradually in one ear, although in some cases it can develop suddenly.
  • Tinnitus – the perception of noise in one or both ears that comes from inside the body rather than from an outside source. For example, you may hear ringing in one ear.
  • Vertigo – the sensation that you or the environment around you is moving or spinning. You may feel the sensation of movement even when you're standing completely still.
  • Facial numbness, tingling or pain are relatively rare symptoms which can occur if the tumour begins to press on the nerve that controls feeling and sensation in your face (known as the trigeminal nerve).
  • Headaches – also a relatively rare symptom, although it can happen if the tumour blocks the flow of cerebrospinal fluid surrounding your brain.
  • Temporary vision problems – this is rare and is also caused by a cerebrospinal fluid blockage.
  • Ataxia a loss of physical co-ordination that affects your ability to do activities, such as walking or writing. Ataxia caused by an acoustic neuroma usually only affects one side of the body (the same side as any hearing loss).

Hearing loss and tinnitus are the most common symptoms of acoustic neuroma. They usually only affect one ear. However, acoustic neuroma caused by neurofibromatosis type 2 (a rare inherited condition) can affect both ears.

The severity of hearing loss isn't necessarily linked to tumour size.

Read more about the causes of acoustic neuroma.



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Acoustic neuroma

An acoustic neuroma can be difficult to diagnose because the symptoms often develop gradually and can be difficult to spot.

An acoustic neuroma can be difficult to diagnose because the symptoms often develop gradually and can be hard to spot.

Symptoms, such as dizziness and hearing loss, can also be attributed to a number of other conditions, such as Ménière's disease (a rare disorder that affects the inner ear).

If your GP thinks that you may have an acoustic neuroma, you'll be referred to a hospital or clinic for further testing.

Neurological testing

You may need to have a series of tests to check whether your nervous system (brain, nerves and spinal cord) is being affected by an acoustic neuroma.

Hearing tests

Part of the neurological testing process involves checking your hearing.

You may have a number of hearing tests including a pure tone audiometry test and a speech recognition audiometry test.

During a pure tone audiometry test a machine called an audiometer is used to produce sounds at various volumes and frequencies. You listen through headphones and press a button when you hear a sound.

A speech recognition audiometry test tests your ability to recognise words spoken at different volumes.

Read more about how hearing tests are performed.

Magnetic resonance imaging (MRI) scan

magnetic resonance imaging (MRI) scan is one of the most accurate ways of diagnosing an acoustic neuroma. This type of scan allows your doctor to see the size and position of your tumour (growth).

An MRI scan uses a strong magnetic field and radio waves to produce a detailed picture of the inside of your head. It's a painless procedure that takes 15-60 minutes to complete. However, it can be noisy and you may feel slightly claustrophobic because you have to lie in a tunnel inside the scanner.

MRI scans don't use X-rays (high frequency radiation). However, if you're pregnant and in your first trimester (up to week 13 of the pregnancy) your MRI scan is likely to be delayed. After the first trimester, MRI scans can be used safely.

MRI scans are the most common way of looking for an acoustic neuroma.

Computerised tomography (CT) scan

Computerised tomography (CT) scans use X-rays and a computer to create detailed images of the structures inside the body, including internal organs, blood vessels, bones and tumours.

CT scans can't always locate small acoustic neuromas, but they're often useful in providing additional information, such as picking up a bone anomaly, which can help the doctor in charge of your care.

During a CT scan, you'll usually lie on your back on a flat bed. The CT scanner has an X-ray tube that rotates around your body. You'll usually be moved continuously through this rotating beam. The rays will be analysed by a detector on the opposite side of your body.

Unlike an MRI scan, where you're placed inside a tunnel, you shouldn't feel claustrophobic. The scan is painless and usually takes 10-30 minutes, depending on the part of your body being scanned.



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Acoustic neuroma

The symptoms of an acoustic neuroma can affect your day-to-life, but more serious complications are rare.

The symptoms of an acoustic neuroma can affect your day-to-day life, but more serious complications are rare.

Coping with your symptoms

Some symptoms of an acoustic neuroma can be difficult to live with and may affect your quality of life. For example, hearing impairment may have an impact on your job and communication may be more difficult. Severe dizziness and loss of balance may also affect your job and limit the activities you can do.

Speak to your GP or specialist if your acoustic neuroma is being monitored but you feel the symptoms are significantly affecting your daily life. There may be ways of easing your symptoms, such as using a hearing aid or painkilling medication, or you may need treatment to remove the tumour.

Read more about treating hearing loss and treating tinnitus.

Recurrence

Occasionally, acoustic neuromas return after being removed. The tumours reoccur in less than five in every 100 people who have surgery to remove them.

It's likely that you'll need to have magnetic resonance imaging (MRI) scans over a number of years, regardless of which treatment you have.

Hydrocephalus

One of the most serious complications of acoustic neuroma is a condition called hydrocephalus.

Hydrocephalus occurs when an acoustic neuroma is very large and presses on your brainstem (the lowest part of the brain that connects to the spinal cord).

This prevents the cerebrospinal fluid (CSF) from flowing between your brain and spinal cord. The blockage can cause pressure to build up inside your skull, which in turn puts pressure on the delicate tissues in your brain.

Hydrocephalus can be treated by draining away the excess CSF. It's important that it's treated quickly because in severe cases it can cause brain damage. In rare cases, hydrocephalus can be fatal.



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