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What is an Acoustic Neuroma?

An acoustic neuroma [uh-KOO-stik noo-ROW-muh], also known as a vestibular schwannoma [veh-STIH-byoo-LUHR shwa-NO-muh] is a slow-growing, noncancerous tumor that can grow on the nerves in your ear. When it grows, it can press on the nerves in your ear that help you hear and keep your balance. Sometimes, you might not notice any symptoms, but as the tumor grows, new symptoms can start, or your symptoms can get worse.

What Is a Tumor?

A tumor is a growth in your body that is not normal. Normally, the cells in your body grow at a certain speed and die in time for new cells to replace them. With a tumor, old cells don’t die, so the area grows without stopping. Sometimes, the tumor grows quickly, but other times it grows so slow that it can take months or years to cause symptoms. There are two main types of tumor:

  • Benign [bih-NINE]. A benign tumor will grow only in one part of your body. It doesn’t spread to other parts of your body, and it is not cancer. Acoustic neuromas are benign tumors.
  • Malignant [ma-LIG-nant]. A malignant tumor is also a growth that starts in one part of your body, but it can spread to other parts like your organs, skin, blood, and bones. This kind of tumor is cancer.

Types of Acoustic Neuroma

There are two main types of acoustic neuromas:

  • Unilateral (YOU-nih-LAT-uh-ruhl] means you have a tumor on only one side of your head. This is the most common type of acoustic neuroma, and makes up 95% of cases.
  • Bilateral [BYE-lat-uh-ruhl] means you have acoustic neuromas on both sides of your head. This is related to a genetic condition that children can inherit from their parents.


Sometimes, you might have an acoustic neuroma and not have any symptoms at all. Because this is a slow-growing tumor, symptoms can take a long time to appear. The larger the tumor is, the more likely you are to have symptoms. Some of these can include:

  • Tinnitus [tin-EYE-tis]. This is a ringing, roaring, or buzzing sound that you hear in your ears even when nothing is making sounds where you are.
  • Hearing Loss. You might not be able to hear as much in the ear on the side where the acoustic neuroma is. Sometimes, it might be harder to hear, or you will hear only some sounds, other times you may not be able to hear anything, but this is rare.
  • Dizziness or imbalance. Because the nerves attached to your ears help you keep your balance, you can have feelings of dizziness or feel like it’s hard to keep your balance when you’re walking or standing.
  • Face tingling. If your tumor is larger, it can push on a nerve that helps to control your face and cause numbness and tingling. This is known as the facial nerve and it runs alongside the hearing and balance nerve. Sometimes this symptom comes and goes. • Neurological symptoms. Larger tumors can push on the nerves and other structures in your brain and head, causing headaches, clumsiness, and confusion.
  • Neurological symptoms. Larger tumors can push on the nerves and other structures in your brain and head, causing headaches, clumsiness, and confusion.

When to See a Doctor

You should talk to your doctor if you have any of the above symptoms. Hearing loss and tinnitus are common symptoms that can be caused by many variables other than the presence of an acoustic neuroma. If you notice either of these symptoms in only one ear you should seek medical attention understanding that there could be many other causes. Face tingling and neurological symptoms can be a sign that your tumor has grown large, and can be life-threatening. You should get emergency medical help or talk to your doctor right away if you notice these symptoms, especially if your doctor has already diagnosed you with a small acoustic neuroma.


The basic cause of an acoustic neuroma is a problem with the cells in your body. Sometimes, these cells can stop growing normally, and can grow too fast or live longer than they are supposed to. This can cause a growth, called a tumor, in a part of your body.

Doctors don’t always know what causes an acoustic neuroma to grow but radiation therapy to the head might be a factor in some cases. Also, in 5% cases, doctors have found that there is a genetic disorder called neurofibromatosis [NOO-row-FYE-broh-muh-TOW-sis] type 2 that can cause these tumors.

Diagnosis and Tests

If you have symptoms that suggest a possible acoustic neuroma, your doctor will likely perform a physical exam and then will likely order various diagnostic tests.

Sometimes, the physical exam can give your doctor enough information to diagnose you with a different condition that has the same symptoms as an acoustic neuroma. If not, your doctor might order some diagnostic tests:

  • Hearing test. Your doctor might order a hearing test to see what sounds you can hear, and how good your hearing is.
  • Brainstem auditory evoked response (BAER). This is a specialized test that gives information about the inner ear (cochlea) and the nerve pathways for hearing.
  • Imaging. If your doctor does some tests and thinks you might have an acoustic neuroma, they might order a test that will take pictures of your head. The most common test is an MRI (magnetic resonance imaging), a test that uses strong magnets to take pictures of your brain and head.


Sometimes, your acoustic neuroma will be small and won’t cause any symptoms. If this is true for you, your doctor might want to keep an eye on the tumor and make sure it doesn’t grow. If your neuroma is causing symptoms like vertigo or hearing loss, your doctor might recommend additional treatment such as:

  • Surgery. Your doctor might refer you to a surgeon. The surgeon will discuss with you whether the best treatment would be to remove the tumor with surgery. It’s important to understand the many complication risks associated with this type of surgery. 
  • Radiation therapy. High-energy beams of radiation can kill the cells in the tumor, shrinking it or removing it all the way. This radiation can sometimes hurt other cells, but doctors take every precaution to limit damage to surrounding cells, reducing side effects and risks.


Because doctors don’t know all the causes of acoustic neuroma, they don’t know how to prevent them. There is a link between high-dose radiation therapy and acoustic neuromas, so you should talk to your doctor about the risk of procedures that use this level of radiation. About 5% of acoustic neuromas have a genetic cause and can’t be prevented.

An acoustic neuroma is a noncancerous tumor that grows on the nerves attached to your inner ear and can get larger over time, causing symptoms that can range from minor to life-threatening. Common treatments for acoustic neuroma include surgery and radiation therapy.