Vocal Cord Paralysis
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Vocal cord paralysis is a voice disorder that occurs when one or both of the
vocal cords (or vocal folds) do not open or close properly. Vocal cord paralysis
is a common disorder, and symptoms can range from mild to life threatening.
The vocal cords are two elastic bands of muscle tissue located in the larynx (voice
box) directly above the trachea (windpipe). The vocal cords produce voice when
air held in the lungs is released and passed through the closed vocal cords,
causing them to vibrate. When a person is not speaking, the vocal cords remain
apart to allow the person to breathe.
Someone who has vocal cord paralysis often has difficulty swallowing and coughing
because food or liquids slip into the trachea and lungs. This happens because
the paralyzed cord or cords remain open, leaving the airway passage and the
lungs unprotected.
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Vocal cord paralysis may be caused by head trauma, a neurologic insult such
as a stroke, a neck injury, lung or thyroid cancer, a tumor pressing on a nerve,
or a viral infection. In older people, vocal cord paralysis is a common problem
affecting voice production. People with certain neurologic conditions, such
as multiple sclerosis or Parkinson's disease, or people who have had a stroke
may experience vocal cord paralysis. In many cases, however, the cause is unknown.
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People who have vocal cord paralysis experience abnormal voice changes, changes
in voice quality, and discomfort from vocal straining. For example, if only
one vocal cord is damaged, the voice is usually hoarse or breathy. Changes
in voice quality, such as loss of volume or pitch, may also be noticeable.
Damage to both vocal cords, although rare, usually causes people to have difficulty
breathing because the air passage to the trachea is blocked.
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Vocal cord paralysis is usually diagnosed by an otolaryngologist-a doctor
who specializes in ear, nose, and throat disorders. Noting the symptoms the
patient has experienced, the otolaryngologist will ask how and when the voice
problems started in order to help determine their cause. Next, the otolaryngologist
listens carefully to the patient's voice to identify breathiness or harshness.
Then, using an endoscope--a tube with a light at the end--the otolaryngologist
looks directly into the throat at the vocal cords. A speech-language pathologist may
also use an acoustic spectrograph, an instrument that measures voice frequency
and clarity, to study the patient's voice and document its strengths and weaknesses.
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There are several methods for treating vocal cord paralysis, among them surgery
and voice therapy. In some cases, the voice returns without treatment during
the first year after damage. For that reason, doctors often delay corrective
surgery for at least a year to be sure the voice does not recover spontaneously.
During this time, the suggested treatment is usually voice therapy, which may
involve exercises to strengthen the vocal cords or improve breath control during
speech. Sometimes, a speech-language pathologist must teach patients to talk
in different ways. For instance, the therapist might suggest that the patient
speak more slowly or consciously open the mouth wider when speaking.
Surgery involves adding bulk to the paralyzed vocal cord or changing its position.
To add bulk, an otolaryngologist injects a substance, commonly Teflon, into
the paralyzed cord. Other substances currently used are collagen, a structural
protein; silicone, a synthetic material; and body fat. The added bulk reduces
the space between the vocal cords so the nonparalyzed cord can make closer
contact with the paralyzed cord and thus improve the voice.
Sometimes an operation that permanently shifts a paralyzed cord closer to
the center of the airway may improve the voice. Again, this operation allows
the nonparalyzed cord to make better contact with the paralyzed cord. Adding
bulk to the vocal cord or shifting its position can improve both voice and
swallowing. After these operations, patients may also undergo voice therapy,
which often helps to fine-tune the voice.
Treating people who have two paralyzed vocal cords may involve performing
a surgical procedure called a tracheotomy to help breathing. In a tracheotomy,
an incision is made in the front of the patient's neck and a breathing tube
(tracheotomy tube) is inserted through a hole, called a stoma, into the trachea.
Rather than breathing through the nose and mouth, the patient now breathes
through the tube. Following surgery, the patient may need therapy with a speech-language
pathologist to learn how to care for the breathing tube properly and how to
reuse the voice.
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The National Institute on Deafness and Other Communication Disorders (NIDCD)
supports research studies that may help provide new clinical measurements to
diagnose vocal cord paralysis. For instance, computer software is being developed
that can describe important aspects of the health of a person's larynx by analyzing
the sounds it produces. By measuring instabilities in the motion of the vocal
cords, the software may allow scientists and treatment clinics to relate these
measurements to the study of the misuse of the voice and help diagnose disorders
such as muscle paralysis and tissue loss.
Currently, the treatment for patients with damage to both vocal cords involves
a tracheotomy, which may, however, cause voice production problems and decrease
protection of the lungs in an effort to improve the airway. Recent studies
show that another feasible approach to laryngeal rehabilitation may be using
an electrical stimulation device to activate the reflexes of the paralyzed
muscles that open the airway during breathing.
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If you notice any unexplained voice changes or discomfort, you should consult
an otolaryngologist or a speech-language pathologist for evaluation and possible
treatment.
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American Academy of Otolaryngology-
Head and Neck Surgery (AAO-HNS)
American Speech-Language-Hearing
Association (ASHA)
National Center for Voice and Speech
(NCVS)
Voice Foundation
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