Understanding acoustic neuromas

Acoustic neuromas are rare, benign brain tumors that develop on the eighth cranial nerve, known as the vestibulocochlear nerve. This nerve leads from your inner ear to the brain and is responsible for hearing and balance.

According to the National Organization of Rare Diseases (NORD), these slow-growing tumors occur in one of every 100,000 people who are between the ages of 30 and 60. They affect more women than men. Approximately 2,500 new cases are diagnosed each year. 

Acoustic neuroma causes

Medical professionals aren’t certain what causes acoustic neuromas. Most of these tumors appear spontaneously, without any previous health condition or genetic predisposition. However, in some cases people inherit a genetic disorder known as neurofibromatosis 2, which causes tumors to grow on nerves. Other risk factors include loud noise exposure, childhood exposure to low-dose radiation of the head and neck, and a history of benign tumors in the parathyroid glands in the neck.

Acoustic neuroma symptoms

When they grow and press against neighboring cranial nerves or brain structures, acoustic neuromas can cause a variety of physical problems. Symptoms may include:

• Hearing loss in the affected ear
• Tinnitus (ringing in the ears)
• Dizziness and problems with balance
• Facial numbness or paralysis
• Difficulty swallowing
• Headaches
• Problems with coordination
• Mental confusion
• In rare cases, diplacusis, or "double hearing"

Diagnosis of acoustic neuroma

If you experience any of these symptoms, make an appointment to see your family physician. Because the majority of these tumors appear spontaneously without any previous health conditions, they are often difficult to diagnose. If your doctor suspects you have an acoustic neuroma, she may refer you to an otolaryngologist (an ear, nose, throat doctor) or neurologist to have the following tests:

• Hearing test to determine if you have any hearing loss.
• Brainstem auditory evoked response (BAER) to check your hearing and neurological functions.
• Electronystagmography (ENG) to test your balance
• MRIs or CT scans which will provide images of your brain to confirm the presence of the acoustic neuroma.

Acoustic neuroma treatments

The treatment for an acoustic neuroma depends upon its size, location, and your physical and hearing health. Options include:

• Observation. If you aren’t experiencing any life-threatening or physical difficulties, your physician may suggest a “wait and watch” approach using frequent MRIs and hearing tests to monitor the situation. Due to the slow growing nature of these tumors, yours may never require treatment.
• Microsurgery. If your tumor is causing health problems, your physician may recommend removing all or part of the tumor. Partial removal may be required to minimize surgical complications, such as facial paralysis or additional hearing loss. 
• Radiation. If your tumor is growing in an area which makes surgery difficult or risky, your medical team may opt for this noninvasive treatment. Results can take several years to see. 
• Drug treatment. Although there are no drug therapies for acoustic neuromas on the market today, research is ongoing and mifepristone may be an off-label option. Information on current clinical trials can be found at www.clinicaltrials.gov.

More aggressive treatment is usually recommended for people with neuromas that are near or pressing on the brain stem, which regulates basic functions like breathing. These tumors can be life threatening. 

Coping with acoustic neuromas

If you’re diagnosed with an acoustic neuroma, it's normal to feel upset and scared. In most cases, acoustic neuromas are bothersome but not life-threatening. Your medical team will help you decide whether or not surgery is an option and how to cope with any uncomfortable symptoms—such as headaches, dizziness or tinnitus—caused by the tumor. The most important thing to remember is to follow the recommended plan of treatment and see your healthcare professionals regularly to keep an eye on things. Also, the Acoustic Neuroma Association provides support groups and resources, and may be helpful to you as you navigate the healthcare system.