Anatomy of the Condition
Dystonia is a neurological disorder which causes involuntary muscle movements. Spasmodic dysphonia is a form of dystonia. It produces involuntary spasms of the vocal folds, causing disordered speech.
There are two typical forms of spasmodic dysphonia:
- Adductor type is the most common form of spasmodic dysphonia. Abrupt, involuntary contraction of the muscles that bring the vocal folds together cause this type. It causes closure of the vocal folds. This causes broken, strained speech and a tight quality to the voice.
- Abductor type is the less common form of spasmodic dysphonia. It happens when involuntary contractions in the muscles that open the vocal folds let air escape suddenly. This causes breathy, whispery voice breaks.
There are other, less common, forms of spasmodic dysphonia. These include a combination of the two types.