Nobody wants to hear the word “tumor” in a diagnosis. However, it is important to know that not all tumors are cancerous, and not all pose a deadly risk to your health. One of these kinds of tumor is an acoustic neuroma, a tumor inside the ear canal that is not malignant, but can cause severe symptoms if it is allowed to remain untreated.
What Is an Acoustic Neuroma?
An acoustic neuroma is a noncancerous growth that develops on the vestibulocochlear nerve. This nerve has two functions: transmitting sound from the inner ear to the brain and relaying balance information from the ear to the brain. The tumors are made of an overgrowth of Schwann cells, which form a sheath over the nerves to protect them. As a result, these tumors are sometimes called schwannomas (or neurilemomas).
The good news is that these tumors do not invade the cells of the brain. However, they will often press against the brain as they grow, causing numbness in facial nerves, partial deafness, or even death if they are allowed to impinge on the brain stem. These tumors usually grow slowly, but in some patients, they may grow rapidly and cause sudden symptoms.
The most common symptom of an acoustic neuroma is hearing disturbance, such as muffled hearing, a “plugged” sensation in the ear, or tinnitus. This is because the neuroma blocks the blood supply to the cochlear nerve and the inner ear, which can block or distort sound transmission. As the tumor grows, it may progress out of the auditory canal and into the brain cavity, causing the patient to experience balance problems, vertigo, headaches, difficulty swallowing, and loss of feeling in the face.
What Causes Acoustic Neuromas?
The development of acoustic neuromas has been linked to be a malfunctioning gene on chromosome 22. When this gene develops normally, it produces a protein that controls the growth of Schwann cells that cover the hearing and balance nerves. While the causes of this malfunction are not clear, the faulty gene is inherited in patients who suffer from neurofibromatosis type 2, a rare disorder that causes tumor growth on the balance nerves on both sides of the head. Patients who have received high doses of radiation to the head and neck are also at higher risk for acoustic neuroma than others.
How Is Acoustic Neuroma Diagnosed?
There are many tests used to diagnose acoustic neuroma. Tests may be used to determine the presence of a tumor, the size of the growth, and possible risk to the patient due to the placement of the neuroma, including:
- Audiological evaluation. Your hearing care professional should begin by taking a full medical history and physical examination before moving on to an audiological exam. Patients with acoustic neuroma may have different hearing responses due to the presence of a tumor.
- Auditory brainstem response (ABR). If your doctor suspects a tumor is present, she may order an ABR test. This uses a computerized audiometer to measure the electrical impulses in the acoustic nerves on both sides of your head. If there is an interruption in activity on one side, you may have a tumor.
- Radiological scans. A CT or MRI scan is generally used to confirm the presence of a suspected neuroma. These are sophisticated imaging tests that take pictures of the inside of your head, and can clearly show the location of a tumor.
- Electronystagmogram. This is an electronic test of the balance system. A hearing care professional will attach electrodes to your face to record involuntary rapid eye movements (nystagmus) and to determine how well your eyes and inner ears are communicating to preserve your balance.
What Is the Treatment for Acoustic Neuromas?
There are three forms of treatment for acoustic neuromas. The first is simply keeping a watchful eye on the tumor via MRI scans to make sure the patient is not at risk of developing severe symptoms. Some tumors may grow so slowly they do not need intervention. However, if the tumor becomes too large, a doctor may recommend surgical removal.
Surgery is the most common method for removing large or troublesome tumors. While preservation of a patient’s life is the most important objective in surgery, a doctor may be able to preserve the patient’s hearing if he is able to keep the vital structures of the ear intact. A doctor will often consult with a neurologist, otologist, or neurosurgeon to discuss which procedure is best for your condition. Facial nerve function is often monitored during surgery, and the cochlear nerve may also be monitored if the surgeon is attempting to preserve the patient’s hearing. Early treatment is key to full recovery, and patients who opt for surgery before the tumor gets too large experience fewer complications.
Radiation therapy may be used to shrink the size of some acoustic neuromas. Patients will receive extremely precise delivery of high doses of radiation to the tumor site, either in one sitting or in multiple sessions. Treatment varies from patient to patient depending on the size the tumor, the patient’s age, the health of the patient, and the patient’s hearing ability.
If a tumor removal surgery has resulted in a total loss of hearing on one side, patients may be able to restore hearing function with specialized hearing devices. A Contralateral Routing of Signals (CROS) hearing aid transfers sound from the ear with hearing loss to the patient’s other ear, allowing the patient a more normal hearing experience. To find out more about these devices, call us at 866-517-4415 or stop by one of our Florida locations today to meet with one of our hearing care specialists.