Spasmodic dysphonia 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. While the cause of spasmodic dysphonia is unknown, most cases are believed to be neurogenic (having to do with the nervous system) in nature. Some cases occur along with movement disorders and some may be inherited. While anyone can be affected, spasmodic dysphonia more often affects women and begins in those between the ages of 30 and 50.
There are three different types of spasmodic dysphonia:
Adductor spasmodic dysphonia (causes the vocal cords to slam together and stiffen)
Abductor spasmodic dysphonia (causes the vocal cords to open)
Mixed spasmodic dysphonia (causes the vocal cords to open and close)
In some cases, spasmodic dysphonia may run in families and is thought to be inherited. Research has identified a possible gene on chromosome 9 (9q32-34) 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.
Last updated: 8/7/2010
How is spasmodic dysphonia diagnosed?
Because there is no definitive test for spasmodic dysphonia, the diagnosis rests on the presence of characteristic clinical symptoms and signs in the absence of other conditions that may mimic spasmodic dysphonia. It is important that an interdisciplinary team of professionals evaluate and provide accurate differential diagnosis. This team usually includes a speech-language pathologist who evaluates voice production and voice quality; a neurologist who carefully searches for other signs of dystonia or other neurological conditions; and an otolaryngologist who examines the vocal cords and their movements.
More details about the diagnosis of spasmodic dysphonia can be obtained by visiting the following link.