What Is Acoustic Neuroma? (Vestibular Schwannoma)

Acoustic neuroma, also known as vestibular schwannoma, are non-cancerous tumors that form along the structures of the ear that impact hearing and balance. These specific nerves connect from your inner ear to your brain. Schwannoma (tumors that develop from Schwann cells) can occur in nerves throughout the body, but when they are found in the head, it usually develops along the vestibular nerve. The vestibular nerve is what affects balance.

Typically, these tumors are slow growing (sometimes over many years) and are more common in adults than children, although it can occur in people of all ages. It is most common in older adults and occur in one ear only. People with a genetic disorder called neurofibromatosis type 2 (NF2), may be affected in both ears.

Although acoustic neuromas are non-cancerous, these tumors still have potential to cause significant problems in addition to hearing and balance issues. Sometimes the tumors can impact nerves that are involved in facial movements. Additionally, if the tumors grow large enough and are in a location that presses against the brainstem, which allows the spinal fluid to flow out of the brain, it can be life-threatening.

Treatments for acoustic neuroma include monitoring, surgery, and radiation.

Signs and Symptoms

There are several symptoms of acoustic neuroma. The most common symptom is hearing loss in one ear (unilateral). This symptom occurs in 90% of the people who have acoustic neuroma. Other symptoms include:

• Balance issues
• Tinnitus (ringing in the ear)
• Vertigo
• Ear fullness or pressure in the ear
• Vision issues (blurry or double vision)
• Facial movement issues (numbness, weakness, spasms, pain, or paralysis)
• Headache
• Taste changes
• Change in tear production
• Nausea or vomiting
• Difficulty with swallowing

Symptoms of acoustic neuroma have some overlap with other conditions, sometimes making it challenging to diagnose. Consult with your healthcare provider so they can determine the cause of symptoms and begin treatment.

Causes

95% of all acoustic neuroma cases have no known cause and develop spontaneously. The other 5% of cases belong to people who have neurofibromatosis type 2 (NF2). People with NF2 are more likely to develop acoustic neuroma, and it typically develops in both ears.

Risk Factors

The only known risk factor for developing acoustic neuroma is having neurofibromatosis type 2 (NF2). 5% of acoustic neuroma cases are people who have NF2.

Diagnosis

Acoustic neuroma often resembles other ear conditions, which sometimes make diagnosing difficult. To begin, your doctor will take a thorough medical history and ask questions about symptom frequency, duration, and severity. Typically, there will be a series of tests run to assess for any hearing damage and balance issues. Tests may include:

• Audiogram. This test measures a person’s hearing ability.
• Electronystagmography. This test measures balance and records eye movement to assess how your eye and ear nerves are functioning.
• Auditory brainstem response. This test assesses brain stem functioning and measures how nerves respond to sound.
• MRI and CT scans. This provides an image of the tumor and allows doctors to see the exact size and location of the tumor(s).

Treatment

Treatment will depend on symptoms and symptom severity, age, and overall health. Usually treatment options consist of monitoring, surgery, or radiation/radiosurgery. The main forms of treatment include:

• Monitoring. A watch and wait approach may be recommended if the tumors are small and not causing any symptoms. A doctor may also recommend monitoring if the patient is older or has other health conditions that make treatment riskier. A doctor would have you periodically get imaging tests to assess the size of the tumor to determine if surgery is necessary.
• Surgery. This is often a successful treatment option. Although surgery cannot repair damage that has already been done to hearing, it may be able to preserve the hearing that remains. Additionally, it can help alleviate other symptoms such as balance issues and facial numbness. The most common procedures are the suboccipital, translabyrinthine and middle fossa craniotomy.
• Radiation/stereotactic radiation surgery. This type of surgery can deliver targeted radiation to a specific area, thereby protecting healthy surrounding tissue from the radiation. Radiation does not make the tumor go away, it simply stops or slows down the growth of the tumor. Typically, radiation is not recommended for younger patients or for large tumors.

You and your doctor will discuss what treatment options are best for you. The primary goals of treatment are to preserve facial function, prevent further hearing damage, stabilize balance issues, and enhance your quality of life.

Prevention

There is no way to prevent acoustic neuromas from developing. It is important to consult with your doctor if you start noticing symptoms of hearing loss and balance issues. The earlier you start treatment the better the treatment outcomes and less risk of complications.

Complications

There are several potential complications that can arise from having acoustic neuroma or from having surgery to remove or slow the growth of the tumors.

Complications include:

• Hearing loss
• Facial numbness or weakness
• Balance problems (dizziness)
• Tinnitus (ringing in the ear)
• Eye issues (dry eyes, difficulty closing eyelid, blurred or double vision)
• Taste issues (dry mouth or trouble swallowing)
• Persistent headache
• Cerebrospinal fluid leaks (CFS)
• Hydrocephalus (fluid buildup in the head that increases pressure inside the skull)
• Infection at the surgery site
• In rare occasions, an infection of the cerebrospinal fluid (meningitis) can occur
• In rare occasions, a stroke or brain bleed can occur