Disorders of the facial nerve, including paralysis, develop from a variety of causes. Most are idiopathic, which means that the cause remains unknown. Twitching, weakness, and paralysis of the face are symptoms of a disorder involving the facial nerve, and not a disease in itself. Abnormal movement or paralysis of the face can result from infection, injury, or tumors, and an evaluation by your physician is needed to determine the cause. The neurotologists at Columbia Presbyterian Medical Center have advanced training and long experience in managing the full range of facial nerve disorders.
The facial nerve resembles a telephone cable and contains about ten thousand individual nerve fibers. Each fiber carries electrical impulses to a specific facial muscle. Information passing along the fibers of this nerve allows us to laugh, cry, smile, or frown, hence the name, "the nerve of facial expression."
When there is nerve damage, facial weakness occurs. If these nerve fibers are irritated, then movements of the facial muscles appear as spasms or twitching. The facial nerve not only carries nerve impulses to the muscles of the face, but also to the tear glands, to the saliva glands, and to the muscle of the stirrup bone in the middle ear (the stapes). It also transmits taste from the front of the tongue. Since the function of the facial nerve is so complex, many symptoms may occur when the fibers of the facial nerve are disrupted. A disorder of the facial nerve may result in twitching, weakness, or paralysis of the face, in dryness of the eye or the mouth, or in disturbance of taste.
The anatomy of the facial nerve is very complex. The facial nerve passes through the base of the skull in transit from the brain to the muscles of facial expression. After leaving the brain, the facial nerve enters the bone of the ear (temporal bone) through a small bony tube (the internal auditory canal) in very close association with the hearing and balance nerves. Along its inch-and-a-half course through a small canal within the temporal bone, the facial nerve winds around the three middle ear bones, in back of the eardrum, and then through the mastoid (the bony area behind the part of the ear that is visible). After the facial nerve leaves the mastoid, it passes through the salivary gland in the face (parotid gland) and divides into many branches, which supply the various facial muscles. The facial nerve gives off many branches as it courses through the temporal bone: to the tear gland, to the stapes muscle, to the tongue (for taste sensation), and to the saliva glands.
The most common cause of facial weakness which develops suddenly is referred to as "Bell's palsy." The etiology of this disorder is unknown, but is probably due to the body's response to a virus: in reaction to the virus the facial nerve within the ear (temporal) bone swells, and this pressure on the nerve in the bony canal damages it.
In order to determine the cause of the facial weakness, a special set of questions will be asked. After an examination of the head, neck, and ears, a series of tests may be performed. The most common tests include:
Hearing Tests: Determine if the cause of damage to the nerve has involved the hearing nerve or inner ear.
Imaging: CT (computerized tomography) or MRI (magnetic resonance imaging) may determine if there is infection, tumor, bone fracture, or other abnormality in the area of the facial nerve. MRI is the gold standard for diagnosis of facial nerve disorders; CT scans are used in cases of mass lesions or trauma.
Electrical Tests: By stimulating the facial nerve, electrical tests can be used to assess how badly the nerve is damaged. They includeNerve Excitability test to determine the extent of nerve fiber damage in the case of total paralysis. If the test is normal despite paralysis, this may suggest a higher chance of recovering function.
Electroneurography uses electrodes placed on the face and a small current to stimulate the facial nerve. During stimulation, a computer measures the muscular response.
Electromyography is an electrical test that measures the muscles during rest, during voluntary movements, and during electrical stimulation. It is used to determine if the nerve and muscles are recovering.
These tests may be repeated at frequent intervals to see if the disease is progressing.
The standard of care for facial paralysis is to treat the cause. We work with our patients to accurately determine the cause of the disorder and prescribe the best treatment for the condition. For Bell's palsy, the usual regimen includes steroids and antiviral medications. Surgical decompression and rehabilitative procedures including gold weights and reanimation surgery may also be appropriate.
When the facial nerve is paralyzed, considerable attention must be given to maintaining a healthy eye, which requires a constant flow of tears. These tears are spread out over the eye by blinking, but blinking is diminished or eliminated in facial nerve paralysis. Diminished blinking and the absence of tearing together can reduce or eliminate the flow of tears across the eyeball, resulting in drying, erosion, and ulcer formation on the cornea and possible loss of the eye.
The eye is kept moist initially with artificial tears during the day and ointment at night. It may also be taped shut.
Patients with permanent facial paralysis may be rehabilitated through a variety of surgical procedures including gold eyelid weights or springs, muscle transfers and nerve substitutions. Implantation of gold weights is done by the plastic surgeons at Columbia Presbyterian. Other medical treatments for complications of facial paralysis including excessive motion of the face or muscle spasm may involve surgical division of overactive muscles or weakening them by chemical injection.
At Columbia Presbyterian, we are concerned about patients’ complete well being. While we offer the most advanced medical therapies to speed physical recovery, we also recognize the significant emotional and psychological issues that often accompany disease and healing, for both the patient and family members. To address patients’ quality of life in recovering from facial nerve disorders, we provide a complete range of services, including educational services and counseling.
Read about Research on Facial Nerve Regeneration currently underway in the Department of Otolaryngology.
Information on this page was provided in part by the American Academy of Otolaryngology – Head and Neck Surgery.