Spasmodic dysphonia

Spasmodic dysphonia is a condition where the muscles that control the voice go into spasm. As a result, a person's speech is interrupted and may become difficult or impossible to understand. It is a condition with a gradual onset, but once it appears it is usually chronic. It is very rare, occurring in about 2 out of every 100,000 people, although it is more common in women, and usual onset is between the ages of 30 and 50. It is difficult to diagnose as several other alternative diagnoses have to be eliminated. However, it is more common that the disease will be misdiagnosed.
The exact cause of the disorder is unknown, but it is believed it is a disorder of the central nervous system. Risk factors include family history, an infection of the upper respiratory tract, injury to the vocal cords, overuse of the voice and stress.
Treatment usually focuses on speech therapy. Botox may also provide relief of symptoms for a few months at a time. The use of surgery appears to be of limited benefit. 
Spasmodic dysphonia at Wikipedia
Category:Diseases