Acoustic Neuroma: Symptoms, Causes, Risks, Complications, Diagnosis and Treatment

illustration of Acoustic Neuroma


The ears are important not only for hearing but also, for equilibrium and balance.
When the part of the ear responsible for balance is affected, it may take a toll on one’s life, particularly when it comes to daily activities.

A disease called acoustic neuroma may affect one’s balance. Acoustic neuroma is a benign tumor that can affect the nerves in the inner ear that’s connected to the brain. This is a non-cancerous or benign tumor in the brain that’s also called vestibular schwannoma.

The tumor is benign because it grows slowly over several years and it does not spread to the other parts of the body. However, the tumor affects hearing and balance, which can lead to certain problems of hearing and feeling unsteady.

Though the tumor is benign, it may still lead to serious complications especially if it grows very large. The tumor may affect people between the ages of 30 and 60 years old. Also, it could be caused by a genetic disease dubbed as neurofibromatosis type 2 (NF2).


The signs and symptoms of acoustic neuroma are mild and in most cases, it can take several years to develop. This means that most individuals affected by the disease do not experience any symptoms unless the disease will reach later stages.

Most symptoms of acoustic neuroma may come from the effects of the tumor on balance and hear nerves in the ear and brain. When these nerves are affected, the following signs and symptoms may arise:

Hearing loss – The first symptom of acoustic neuroma is problems with hearing.
This could be felt in one ear or can become more pronounced in one ear. Hearing loss may take a toll on one’s daily life, affecting both the performance in school and in work. Furthermore, in some cases, even after surgery or treatment, the hearing may not be fully restored.

Tinnitus – About 80 percent of people with acoustic neuroma will experience tinnitus, wherein they will feel a ringing in the ear.

Dizziness – Dizziness or vertigo can be experienced. Also, the patient may suffer from loss of balance.

Ear pain – In some cases of acoustic neuroma, there can be ear pain.

Headaches – In some cases, people with acoustic neuroma will feel headaches. Usually, this is seen in those with large tumors that increase the pressure inside the brain. Some patients may also have altered consciousness and vomiting.

Vision problemsAside from hearing loss, the vision may also be affected.

Sensation lossIf the tumor becomes big and puts pressure on the brainstem, the local cranial nerves may be affected. This may lead to sensation loss on one side of the face.

Large acoustic neuromas may cause:

  • Persistent headaches
  • Temporary double or blurred vision
  • Difficulty swallowing
  • Hoarse voice
  • Problems with limb-coordination on one side of the body (ataxia)


There are two types of acoustic neuromas – the sporadic form and the other type linked to a syndrome dubbed as neurofibromatosis type II (NF2).  The cause of acoustic neuromas appears to be a faulty gene on chromosome 22, which is responsible for the production of a tumor suppressor protein to help control Schwann cell growth.

The exact reason why the gene malfunction happens is still not clear. In fact, for most acoustic neuroma case, there is no identifiable cause. NF2 is an inherited disorder described as the condition where there is a growth of noncancerous tumors in the nervous system.

NF2 is a rare disorder and only accounts for about 5 percent of all cases. This means that many of the cases are categorized into the sporadic form. The exact cause of this form is also unclear but some factors may increase the risk of developing the disease like exposure to high doses of radiation, particularly in the neck and head.

4Risk Factors

Age – Most individuals who develop acoustic neuroma are 30 years old to 60 years old.

Radiation Exposure – For individuals who are exposed to radiation, there is a small chance that low-dose exposure on the neck and head area during childhood could increase the risk of acoustic neuroma.

The family history of neurofibromatosis type 2 – An estimated 5 percent of people with acoustic neuroma have neurofibromatosis type 2 (NF-2). However, the only confirmed risk is the presence of NF-2, a genetic disorder. The hallmark symptom is the emergence of noncancerous tumors on the nerves responsible for balance.


An acoustic neuroma may cause some permanent complications. These include:

Daily activities impact – Acoustic neuroma causes loss of balance and dizziness. These symptoms can make daily activities hard and difficult. Also, these may lead to negative impacts on school and work.

Hearing loss – Healing loss can take a toll on one’s quality of life. This could lead to problems with work and social life.

Facial palsy – Since acoustic neuroma can affect the facial nerve, the patient may have facial palsy. This could also happen as a complication of acoustic neuroma surgery.

Hydrocephalus – If the large tumor of acoustic neuroma develops against the brainstem, it could impede the flow of cerebrospinal fluid in the brain and spinal cord. As a result, the fluid may accumulate in the head leading to hydrocephalus.


Acoustic neuroma is often hard to detect and diagnose during its early phases. This is because the symptoms may be unnoticeable and often develop gradually. The doctor will often ask questions regarding the signs and symptoms, family history of the condition, and other important questions.

Aside from these, the doctor will also conduct a complete physical examination and other tests including:

Audiometry – Audiometry or hearing test is usually done by a hearing specialist or also called an audiologist. The specialist will direct sound to each ear with varying tones and volume. Aside from this, the doctor will help determine the hearing ability through the presentation of several words.

Imaging Tests – The doctor can also recommend various imaging tests such as a magnetic resonance imaging (MRI) and a computerized tomography (CT) scan to confirm the diagnosis of acoustic neuroma. These imaging tests can show images of the brain to determine the presence, severity, size, and location of a tumor.


There are various treatment options for acoustic neuroma. These depend on the location and size of the tumor, the severity of the condition and how fast the tumor is growing.
The common treatment options include:

Microsurgical removal – The procedure entails the removal of the tumor through a small incision in the skull. It is often done under general anesthesia and in the operating room. In approximately 95 percent of the cases of acoustic neuroma, surgery can already treat and control and tumor. However, if the tumor is so tiny that there is no damage to the surrounding tissues, hearing can be saved through surgery.

Stereotactic radiosurgery – In this procedure, the doctor will target the tumor by directing the radiation to it without having to make an incision or cut. Imaging scans will help locate the exact position of the tumor.

Radiation therapy – In this procedure, radiotherapy is used rather than the traditional surgery. This will help prevent further growth of the tumor and to reduce its size.

Radiosurgery – In this procedure, radiation is delivered to the tumor and a frame is attached to the scalp of the patient.

Monitoring – For small tumors that are not growing, imaging scans like MRI are used to monitor the tumor, making sure it’s not growing. The doctor usually prescribes imaging and hearing tests every six months or one year.

The doctors will also monitor the patients for possible complications associated with surgery like:

  • Leakage of cerebrospinal fluid through the wound
  • Facial weakness
  • Hearing loss
  • Numbness in the face
  • Tinnitus or ringing in the ear
  • Problems with balance or unsteadiness
  • A headache (can be persistent and severe)
  • Meningitis (infection of the meninges)
  • Brain bleed or stroke

The outlook of acoustic neuroma depends on the location and size of the tumor. Large tumors can be life-threatening because it can lead to the accumulation of fluid in the brain called hydrocephalus. However, this is very rare and since the tumor can progress slowly, the tumor can be treated even before they grow too big.

In some cases, even with treatment, the symptoms of tinnitus or ringing in the ear and tinnitus can continue. These symptoms may lead to the inability to perform properly in work and school. Also, hearing loss may become permanent if the nerves become damaged.

However, the prognosis is very good. Acoustic neuroma tumors often respond well to treatments and the complications are rare. Less than five in every 100 acoustic neuromas return even after being treated. It very possible that it returns, especially when the patient has the genetic condition called NF2.

After treatment, the tumors will need to be followed up regularly through scans to make sure they do not return or grow bigger. Also, the signs and symptoms of the condition will be checked as well. Acoustic neuroma is treated better if it is detected early and treatment is initiated right away.