This topic provides information about Acoustic Neuroma.
What is Acoustic Neuroma?
An acoustic neuroma, also called a vestibular schwannoma is a slow-growing benign tumor located on the vestibulocochlear nerve, or 8th cranial nerve, running from the inner ear to the brain.
The vestibulocochlear nerve is responsible for sending and receiving hearing and balance information between the inner ear and brain.
Tumors can be classified as small, medium, or large. Most patients diagnosed with acoustic neuromas are between the ages of 30 and 60 years old.
What Causes Acoustic Neuroma?
There is no known cause for acoustic neuromas. Tumors on the 8th cranial nerve are thought to be a malfunctioning gene on chromosome 22. It is unlcear what causes this malfunction. In a small 5% of cases there is an inheritable condition called Neurofibromatosis Type 2 (NF2) which can lead to the formation of an acoustic neuroma on both sides of the head.
What are the symptoms?
- Loss of hearing in one ear
- Loss of balance
- Dizziness or vertigo
- Fullness in one ear
- Facial numbness or weakness
In rare cases when an acoustic neuroma grows large enough, it can compress the brainstem and be life-threatening.
How is Acoustic Neuroma diagnosed?
An acoustic neuroma can be diagnosed by an Otolaryngologist (ENT) or Neurologist. Tests used to diagnose an acoustic neuroma include:
- Case History
- Audiologic Evaluation
How is it treated?
Observation (watch and wait): When the tumor is small, under 1.5 to 2.0 cm, observation of the tumor is an option. Observation may be recommended when the patient is older and/or the symptoms are minimal. Regular MRIs and audiological evaluations should be performed to monitor the size of the tumor and the progression of the symptoms.
Radiation: An option when the tumor is small to medium, the patient is older, and the tumor is not pressing on the brainstem. Delivers precise doses of radiation to the tumor to delay growth of the tumor. The progress of the radiation will be monitored with imaging (MRI) and audiologic evaluations.
Microsurgery: An option when the tumor is large, greater than 2.5 cm, preservation of hearing is possible, and the patient is young and healthy. The goal of surgery is to remove the tumor while preserving hearing and facial nerve function.
Symptoms of an acoustic neuroma, such as hearing loss, tinnitus, and loss of balance can be managed using several methods, including:
Hearing technology: Specialized hearing devices that can be used for people with acoustic neuromas, or any person with significantly poor hearing in one ear. This type of hearing loss is classified as single-sided deafness. The hearing technology available to manage single-sided deafness includes bone conduction hearing devices and CROS hearing aids.
Sound generators/music-based therapy: Devices used for management of tinnitus. Utilizes low levels of white noise and/or “music therapy noises” delivered to the ears to desensitize the person to their tinnitus. These types of devices are prescribed by an Audiologist who specializes in tinnitus management.
Vestibular rehabiliation therapy (VRT): Exercise-based therapy used for people with loss of balance due to loss of vestibular function. Helps to improve postural control and balance functions. VRT is usually performed by a qualified physical therapist or occupational therapist.
Does Acoustic Neuroma cause lasting problems?
Depending on the size of the tumor, acoustic neuromas can cause permanent hearing loss, tinnitus, loss of balance, dizziness, and or facial paralysis/weakness. In cases where the tumor is large enough to press against the brainstem, acoutic neuromas can be life-threatening.