Spasmodic Dysphonia

Spasmodic Dysphonia

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.

Causes or Contributing Factors

Spasmodic dysphonia (SD) has no known cause. Many physicians believe a neurological disorder causes SD. Abnormal functioning of the basal ganglia structure in the brain would be to blame. Onset occurs without warning or explanation. Spasmodic dysphonia is more prevalent in women and among people between ages 40 and 50.

Causes or Contributing Factors

A halting, interrupted voice pattern is the key symptom for the adductor variety of SD. With the abductor type of SD, the voice has breathy voice breaks. When patients with SD try to control spasms, we often hear a tight or constricted sounding voice. Symptoms may improve or worsen, depending on the time of day.


The condition is hard to diagnose and is frequently misdiagnosed. The disease often mimics other conditions or speech patterns. Appropriate diagnosis requires a thorough examination by an experienced team of voice specialists.

There is not a definitive test for the condition. Diagnosis depends on a combination of symptoms and evaluation by the clinical voice team.

Non-Operative Treatments

Botox offers one of the most effective treatments for spasmodic dysphonia. The drug softens and weakens vocal muscles, diminishing spasms. This treatment also reduces voice wispiness from the abductor form of the disease.

The results of Botox may vary, but the drug normally takes effect 24-48 hours after the injections. First, the voice becomes soft and breathy for a period of several days to two weeks. Then the voice should get stronger and stronger, with fewer spasms. The duration of the effect varies. Most patients see relief for three to four months before needing the next injection.

Because Botox weakens vocal muscles, an initial side effect may be difficulty swallowing. Our speech pathologists can usually train the patient in alternative swallowing techniques.

Voice relaxation techniques and other speech therapies may help reduce symptoms.

Operative Treatments

In some instances, we may recommend surgery. Selective laryngeal adductor denervation reinnervation is a new surgical option. Our surgeon divides the nerves to the muscles, which brings the vocal folds together. Alternate neural tissue is then used to lessen the symptoms of spasmodic dysphonia.


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