Understanding Acoustic Neuromas

It’s rare, but if you’ve been experiencing hearing loss in one ear, it may be caused by a small brain tumor.

Acoustic neuromas are slow growing, benign tumors that develop on the eighth cranial nerve which connects the ear to the brain. Most of them remain small and go unnoticed; however, if the tumor grows too large, it may produce symptoms such as headaches, problems with vision or understanding speech, pain or numbness in the face or ear and fatigue. Affected individuals may also experience vertigo, tinnitus and problems with balance.

If you experience any symptoms of acoustic neuromas, make an appointment to see your family physician. Acoustic neuromas are often difficult to diagnose because they develop gradually and their symptoms are also indications of other inner or middle ear conditions. If your physician suspects you have an acoustic neuroma, he may refer you to an ear, nose and throat (ENT) specialist or neurologist and order a variety of tests including:

• 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.

Hearing health professionals say acoustic neuromas develop as the result of a malfunctioning gene on chromosome 22. The majority of these tumors appear spontaneously, without any previous health condition or genetic predisposition although having a parent with the genetic disorder neurofibromatosis type 2 increases the risk by as much as 50 percent.

This condition is rare, occurring in approximately two of every 100,000 people, and is most often diagnosed in persons between the ages of 30 and 60. Other possible causes may be exposure to loud noise, childhood exposure to low-dose radiation of the head and neck and a history of benign tumors in the parathyroid glands in the neck.

Once diagnosed, your physician may want to monitor the acoustic neuroma’s growth with frequent MRIs and hearing tests. While small tumors are usually unnoticeable with few or no symptoms, larger ones can press against the brainstem, creating other medical problems which require treatment. Options to remove the tumor may include:

• Stereotactic radiosurgery, which delivers radiation precisely to the tumor without making an incision, or
• Surgically removing the tumor. While many tumors can be completely removed, your physician may opt to remove only a portion in order to prevent damage to the facial nerve.