An acoustic neuroma
is a benign (noncancerous), usually slow-growing tumor that develops from the nerves associated with balance and hearing that supply the inner ear. It comes from an overproduction of Schwann cells -- the cells that normally wrap around nerve fibers like the skin of an onion to help support and insulate the nerves.
Other names for an acoustic neuroma include:
Unilateral Versus Bilateral
An acoustic neuroma can affect one or both ears. When one ear is affected, it's known as unilateral acoustic neuroma. When both ears are affected, it's known as bilateral acoustic neuroma.
Unilateral Acoustic Neuroma
Unilateral acoustic neuroma affects only one ear. This type accounts for approximately 8 percent of all tumors inside the skull. One out of every 100,000 individuals per year develops an acoustic neuroma. Symptoms may develop at any age, but usually appear between the ages of 30 and 60. This is not a hereditary condition.