Spastic dysphonia (also known as spasmodic dysphonia) is a form of laryngeal dystonia in which vocal cord spasms interfere with phonation and speaking. The major subtypes of spastic dysphonia are adductor and abductor dysphonia. Adductor spastic dysphonia is the most common form and is characterized by an intermittently strained or strangled-sounding voice. Abductor spastic dysphonia is characterized by breathy voice breaks. Spastic dysphonias are task-specific; they typically occur while speaking and are absent or reduced with other types of vocal communication (such as laughing, coughing, crying, shouting, and singing).

There are multiple potential etiologies. Onset of spastic dysphonia has been associated with a history of childhood mumps or rubella infection, recent upper respiratory infection, laryngeal damage, extensive voice use, or a family history of neurologic disease. Periods of high stress may also precede symptom onset. Although a clear link between isolated spastic dysphonia and specific genetic mutations has not been identified, genetic factors likely contribute in some cases of spastic dysphonia. In some forms of genetic generalized dystonia, spastic dysphonia is a prominent symptom.

Spastic dysphonia is a rare disorder, affecting approximately 1 per 100 000 individuals. It is more common in women, and the average age at onset is 45 years.