An acoustic neuroma is a benign, usually slow-growing tumor that develops from certain nerves in the inner ear. No one knows exactly what causes acoustic neuroma. As an acoustic neuroma develops, it presses against the nerves related to balance and hearing, causing early symptoms such as: one-sided or high-tone hearing loss, ringing in the ear, dizziness, and problems with balance. Once a diagnosis of acustic neuroma is made, the doctor can describe the available treatment options.