What is SD? 

Spasmodic dysphonia (SD), a focal form of dystonia, is a neurological voice disorder that involves involuntary "spasms" of the vocal cords causing interruptions of speech and affecting the voice quality. SD can cause the voice to break up or to have a tight, strained, or strangled quality. 

There are two main types of Spasmodic Dysphonia, ADductor SD and ABductor SD.  

In ADductor SD, the most commonly occurring type of SD, the muscles affected are those which close the vocal cords.  These muscles spasm uncontrollably and force the vocal cords together.  A person with ADductor SD sounds like they are being strangled when they talk. Approximately 85-95% of all people with this disorder have the ADductor type of Spasmodic Dysphonia.

in ABductor SD, the muscles affected are those which open the vocal cords.  These muscles spasm and force the vocal cords open resulting in a very breathy sounding voice.  This type of SD is more rare with only approxiamately 5 - 15% of all people with the disorder having ABductor SD.

Currently, there is no known cure for Spasmodic Dysphonia.  Injection of Botox into the spasming muscles is the "gold standard" for treating SD with better results for ADductor SD than for ABductor SD.

There is a National Spasmodic Dysphonia Association which acts as a clearing house for information about the disorder and its treatment.  They also sponsor research projects in the hopes of discovering better treatments and, possibly, a cure.  The NSDA also provides information about doctors who work with SD patients and helpful information about dealing with insurance companies during the treatments. A moderated bulletin board is hosted by the association to give people with SD an outlet to interact with others who have the same disorder.

If you would like more information about Spasmodic Dysphonia, please go to the NSDA's website:  http://dysphonia.org

A link to the NSDA is available in our links page.