- An acoustic neuroma is a benign (noncancerous) tumor on the eighth cranial nerve (vestibulocochlear) leading from the brainstem to the ear.
- This nerve is involved in hearing and maintaining equilibrium.
- Acoustic neuromas grow relatively slowly.
Acoustic neuromas may occur sporadically, or in some cases occur as part of von Recklinghausen Neurofibromatosis, in which case the neuroma may take on one of two forms.
- In Neurofibromatosis type I, a schwannoma may sporadically involve the 8th nerve, usually in adult life, but may involve any other cranial nerve or the spinal root. Bilateral acoustic neuromas are rare in this type.
- In Neurofibromatosis type II, bilateral acoustic neuromas are the hallmark and typically present before the age of 21. These tumors tend to involve the entire extent of the nerve and show a strong autosomal dominant inheritance. Incidence is about 5 to 10%.
- The exact cause of an acoustic neuroma is unknown.
- Age: 30-60 (Average age of diagnosis is 50)
- History of the disease neurofibromatosis type 2 (for bilateral neuromas only, which are very rare)
The first symptoms of an acoustic neuroma include:
- Gradual hearing loss in one ear
- Decrease in sound discrimination, especially when talking on the telephone
- Ringing in the ears, called tinnitus
As the neuroma gradually enlarges, symptoms may include:
- Balance problems
- Facial numbness and tingling
- Weakness of the facial muscles
- Audiogram. A test that measures hearing in both ears.
- Auditory Brainstem Response Test (ABR, BAER, or BSER). A test that measures the rate of electric impulses traveling from the inner ear to the brainstem. A slowed or absent impulse may indicate the presence of an acoustic neuroma. This test is almost always abnormal in the presence of an acoustic neuroma.
- Electronystagmography. A test for balance. Cold and warm water or air is insterted in the ear canal, and the resulting dizziness and rapid eye movement (nystagmus) is recorded.
- MRI Scan. A test that uses magnetic waves to make pictures of the inside of the body.
- CT Scan. A type of x-ray that uses a computer to make pictures of the inside of the body.
- Risk for Falls related to loss of balance
- Disturbed Sensory Perception (auditory)
- Risk for Imbalanced Nutrition: Less Than Body Requirements RT weak facial muscles
- Observation. If the tumor is very small, the physician may just monitor its growth. This is common among people over age 70.
- Microsurgical Removal. As the tumor grows and/or hearing becomes impaired, removal of the tumor may be necessary. The surgical approach depends on the size and location of the tumor. Complications of surgery may include permanent hearing loss and/or paralysis of facial muscles on the affected side.
- Radiation Therapy (or Radiotherapy). The use of radiation to kill cells and shrink tumors. Radiation is expected to prevent further growth of the tumor. Radiation may be used when tumors are small and surgery is not possible. This method may preserve hearing.