A vestibular schwannoma (also called an acoustic neuroma) is a noncancerous (benign) tumor that originates in the cells that wrap around the vestibular nerve (Schwann cells).
Vestibular schwannomas start in the vestibular branch of the vestibulocochlear nerve (8th cranial nerve), which helps maintain balance. The other branch, the cochlear (auditory) branch of the vestibulocochlear nerve, carries sound signals to the brain. The tumor grows and presses on the auditory nerve, causing hearing loss in one ear that usually progresses slowly.
(See also Overview of the Inner Ear.)
Symptoms of Vestibular Schwannoma
Early symptoms of vestibular schwannoma include
Slowly progressive hearing loss in one ear
Noise or ringing in the ear (tinnitus)
Headache
A feeling of pressure or fullness in the ear
Ear pain
Imbalance or unsteadiness when the person turns quickly
Sometimes hearing loss occurs abruptly. Hearing loss varies in severity.
If the tumor grows larger and compresses other parts of the brain, such as the facial nerve (7th cranial nerve) or the trigeminal nerve (5th cranial nerve), weakness (facial droop) or pain and numbness of the face may result.
Diagnosis of Vestibular Schwannoma
Hearing tests
Magnetic resonance imaging (MRI)
To diagnoses vestibular schwannoma doctors usually do an audiogram(a hearing test) first. If hearing is lost in only one ear, MRI, preferably gadolinium-enhanced MRI, is then done.
Other hearing tests that may be done include tympanometry (tests how well sound can pass through the eardrum and middle ear) and auditory brain stem response testing (measures nerve impulses in the brain stem resulting from sound signals in the ears).
Treatment of Vestibular Schwannoma
Sometimes surgery or radiation therapy
Tumors that are small and not growing or causing symptoms do not require treatment. Tumors that begin growing or cause symptoms are removed with surgery or controlled using radiation therapy. Surgery may be done using a microscope (microsurgery) to avoid damaging the facial nerve, and hearing can sometimes be saved. Radiation therapy may be done using a very precise technique (called stereotactic radiation therapy) so that only the tumor is affected. Whether surgery or stereotactic radiation therapy is done depends on a number of factors including the person's age, health, amount of hearing loss, and size of the tumor.
