Vestibular schwannomas start in the vestibular branch of the vestibulocochlear nerve (8th cranial nerve Overview of the Cranial Nerves Twelve pairs of nerves—the cranial nerves—lead directly from the brain to various parts of the head, neck, and trunk. Some of the cranial nerves are involved in the special senses (such as seeing... read more ), 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 Overview of the Inner Ear The fluid-filled inner ear (labyrinth) is a complex structure consisting of two major parts: The organ of hearing (cochlea) The organ of balance (vestibular system) The cochlea and the vestibular... read more .)
Symptoms of Vestibular Schwannoma
Early symptoms of vestibular schwannoma include
Slowly progressive hearing loss in one ear
A feeling of pressure or fullness in the ear
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
Magnetic resonance imaging (MRI)
To diagnoses vestibular schwannoma doctors usually do an audiogram(a hearing test Testing Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss. More than 15% of people in the United States have some degree of hearing loss that affects their... read more ) first. If hearing is lost in only one ear, MRI, preferably gadolinium-enhanced MRI Magnetic Resonance Imaging (MRI) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more , is then done.
Other hearing tests that may be done include tympanometry Testing Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss. More than 15% of people in the United States have some degree of hearing loss that affects their... read more (tests how well sound can pass through the eardrum and middle ear) and auditory brain stem response testing Testing Worldwide, about half a billion people (almost 8% of the world's population) have hearing loss. More than 15% of people in the United States have some degree of hearing loss that affects their... read more (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 Radiation Therapy for Cancer Radiation is a form of intense energy generated by a radioactive substance, such as cobalt, or by specialized equipment, such as an atomic particle (linear) accelerator. Radiation preferentially... read more . 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.