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Spasmodic
Dysphonia
What is spasmodic dysphonia?
Spasmodic dysphonia (or laryngeal dystonia) is a voice disorder caused
by involuntary movements of one or more muscles of the larynx or voice
box. Individuals who have spasmodic dysphonia may have occasional difficulty
saying a word or two or they may experience sufficient difficulty to interfere
with communication. Spasmodic dysphonia causes the voice to break or to
have a tight, strained or strangled quality. There are three different
types of spasmodic dysphonia.
What
are the types of spasmodic dysphonia?
The three types of spasmodic dysphonia are adductor spasmodic dysphonia,
abductor spasmodic dysphonia and mixed spasmodic dysphonia.
What are the features of spasmodic dysphonia?
In adductor spasmodic
dysphonia, sudden involuntary muscle movements or spasms cause the vocal
folds (or vocal cords) to slam together and stiffen. These spasms make
it difficult for the vocal folds to vibrate and produce voice. Words
are often cut off or difficult to start because of the muscle spasms.
Therefore, speech may be choppy and sound similar to stuttering. The
voice of an individual with adductor spasmodic dysphonia is commonly
described as strained or strangled and full of effort. Surprisingly,
the spasms are usually absent while whispering, laughing, singing, speaking
at a high pitch or speaking while breathing in. Stress, however, often
makes the muscle spasms more severe.
In abductor spasmodic dysphonia,
sudden involuntary muscle movements or spasms cause the vocal folds
to open. The vocal folds can not vibrate when they are open. The open
position of the vocal folds also allows air to escape from the lungs
during speech. As a result, the voices of these individuals often sound
weak, quiet and breathy or whispery. As with adductor spasmodic dysphonia,
the spasms are often absent during activities such as laughing or singing.
Mixed spasmodic dysphonia
involves muscles that open the vocal folds as well as muscles that close
the vocal folds and therefore has features of both adductor and abductor
spasmodic dysphonia.
Who
is affected by spasmodic dysphonia?
Spasmodic dysphonia can affect anyone. The first signs of this disorder
are found most often in individuals between 30 and 50 years of age.
More women appear to be affected by spasmodic dysphonia than are men.
What causes spasmodic dysphonia?
The cause of spasmodic
dysphonia is unknown. Because the voice can sound normal or near normal
at times, spasmodic dysphonia was once thought to be psychogenic, that
is, originating in the affected personšs mind rather than from a physical
cause. While psychogenic forms of spasmodic dysphonia exist, research
has revealed increasing evidence that most cases of spasmodic dysphonia
are in fact neurogenic or having to do with the nervous system (brain
and nerves). Spasmodic dysphonia may co-occur with other movement disorders
such as blepharospasm (excessive eye blinking and involuntary forced
eye closure), tardive dyskinesia (involuntary and repetitious movement
of muscles of the face, body, arms and legs), oromandibular dystonia
(involuntary movements of the jaw muscles, lips and tongue), torticollis
(involuntary movements of the neck muscles), or tremor (rhythmic, quivering
muscle movements).
In some cases, spasmodic
dysphonia may run in families and is thought to be inherited. Research
has identified a possible gene on chromosome 9 that may contribute to
the spasmodic dysphonia that is common to certain families. In some
individuals the voice symptoms begin following an upper respiratory
infection, injury to the larynx, a long period of voice use, or stress.
How is spasmodic dysphonia diagnosed?
The diagnosis of spasmodic dysphonia is usually made based on identifying
the way the symptoms developed as well as by careful examination of
the individual. Most people are evaluated by a team that usually includes
an otolaryngologist (a physician who specializes in ear, nose and throat
disorders), a speech-language pathologist (a professional trained to
diagnose and treat speech, language and voice disorders) and a neurologist
(a physician who specializes in nervous system disorders). The otolaryngologist
examines the vocal folds to look for other possible causes for the voice
disorder. Fiberoptic nasolaryngoscopy, a method whereby a small lighted
tube is passed through the nose and into the throat, is a helpful tool
that allows the otolaryngologist to evaluate vocal cord movement during
speech. The speech-language pathologist evaluates the patient's voice
and voice quality. The neurologist evaluates the patient for signs of
other muscle movement disorders.
What treatment is available for spasmodic dysphonia?
There is presently
no cure for spasmodic dysphonia. Current treatments only help reduce
the symptoms of this voice disorder. Voice therapy may reduce some symptoms,
especially in mild cases. An operation that cuts one of the nerves of
the vocal folds (the recurrent laryngeal nerve) has improved the voice
of many for several months to several years but the improvement is often
temporary. Others may benefit from psychological counseling to help
them to accept and live with their voice problem. Still others may benefit
from job counseling that will help them select a line of work more compatible
with their speaking limitations.
Currently the most promising
treatment for reducing the symptoms of spasmodic dysphonia is injections
of very small amounts of botulinum toxin (botox) directly into the affected
muscles of the larynx. Botulinum toxin is produced by the Clostridium
botulinum bacteria. This is the bacterium that occurs in improperly
canned foods and honey. The toxin weakens muscles by blocking the nerve
impulse to the muscle. The botox injections generally improve the voice
for a period of three to four months after which the voice symptoms
gradually return. Reinjections are necessary to maintain a good speaking
voice. Initial side effects that usually subside after a few days to
a few weeks may include a temporary weak, breathy voice or occasional
swallowing difficulties. Botox may relieve the symptoms of both adductor
and abductor spasmodic dysphonia.
Where
can I get additional information?
American Academy
of Neurology
1080 Montreal Avenue
St. Paul, MN 55116
Voice: (612) 695-1940
Fax: (612) 695-2791
Internet: www.aan.com
American Academy of
Otolaryngology-Head and Neck Surgery
One Prince Street
Alexandria, VA 22314
Voice: (703) 519-1589
Voice/TTY: (703) 519-1585
Fax: (703) 299-1125
E-mail: entinfo@aol.com
Internet: www.entnet.org
American Speech-Language-Hearing
Association
10801 Rockville Pike
Rockville, MD 20852
Voice/TTY: (301) 897-5700
Voice: (800) 638-8255
Fax: (301) 571-0457
Internet: www.asha.org
Dystonia Medical Research
Foundation
One East Wacker Drive, Suite 2430
Chicago, IL 60601-1905
Voice: (312) 755-0198
Voice: (800) 377-3978
Fax: (312) 803-0138
E-mail: dystonia@dystonia-foundation.org
Internet: www.dystonia-foundation.org
National Spasmodic
Dysphonia Association
One East Wacker Drive, Suite 2430
Chicago, IL 60601-1905
Voice: (800) 795-6732
Fax: (312) 803-0138
E-mail: nsda@aol.com
Updated September 1999
For more information, contact
the health.htm#contact">NIDCD Information Clearinghouse.
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