Vanderbilt Bill Wilkerson Center

Spasmodic Dysphonia

What is it?

Spasmodic dysphonia (SD) is a voice disorder that is a ‘dystonia’. Dystonias are characterized by excessive normal movement. Some examples are blepharospasm (uncontrolled eye blinking), torticollis (uncontrolled head turning), and writer’s cramp (uncontrolled contraction of fingers and thumb). In the case of spasmodic dysphonia, the vocal folds close too much or open too much during the production of voice.


The cause of spasmodic dysphonia is unknown. We know that it’s a neurological disorder and that disruption probably occurs in the basal ganglia area of the brain – this area controls and modifies movement. This disorder can emerge gradually or have a sudden onset. It is considered to be a rare disorder. More women than men have SD; some estimate that 60-80% of people with SD are women. The typical age of onset of the disorder is approximately 40 years. Some people go through a long process of trying to obtain a definitive diagnosis and may be told that they have chronic laryngitis, a stroke, gastroesophageal reflux, or a psychological problem. In rare cases, there appears to be a genetic, inherited component to the disorder.


The voice symptoms that people experience depend on which type of spasmodic dysphonia is present. For individuals with ‘adductor’ spasmodic dysphonia, the voice sounds tight, ‘squeezed’, with breaks in speech that correspond with spasms of the vocal folds. In this type of SD, the vocal folds are closing for longer periods than normal on specific sounds like “m”, “b”, “d”, or ‘g” (for example), and the voice sounds strained.

For people with ‘abductor’ spasmodic dysphonia, there are prolonged voiceless breaks for words with sounds such as ‘s’, ‘p’, ‘t’, ‘k’. Individuals with abductor spasmodic dysphonia will have air escape on each of these specific sounds, making the voice sound weak and breathy.

A voice tremor can also be present for individuals with abductor or adductor SD. Often, this is most apparent when saying a prolonged ‘ah’ sound, and often described as a consistent ‘shake’ in the voice.

A third, but more rare, type of spasmodic dysphonia is a combination of the two variations of SD above. Typically, this ‘mixed’ category of SD has symptoms of adductor and abductor spasmodic dysphonia and the voice can sound both strained and breathy.

How Stress Can Affect You

While spasmodic dysphonia is not caused by stress, people will report that their symptoms worsen in the presence of stress, tension, emotional duress, fatigue or pressure. The severity of the spasms will vary throughout the day, and some individuals will report that they experience ‘normal’ voicing for short periods of time. Some people are able to have a better voice if they raise their pitch. For some, the spasms occur less frequently and are smaller when they sing. This variability in the severity of the symptoms of spasmodic dysphonia is precisely what makes it a challenge to diagnose, and often family and friends don’t understand the problem, creating feelings of isolation and further frustration for the individual with this voice problem.

It can be particularly difficult for people who depend on their voices for their professions because without treatment, some people are unable to work in their chosen occupations.


There is no definitive laboratory test for spasmodic dysphonia. Diagnosis is made by listening to the voice and observing the vocal folds during speech. While the voice of someone with SD is fairly characteristic, in the early stages of the disorder the voice can sound like someone with “muscle tension dysphonia”. Muscle tension dysphonia is a voice disorder that is caused by using too much muscle effort when producing voice, making the voice sound strained.

Management and Treatment

Currently, the most common treatment for spasmodic dysphonia is the injection of botulinum toxin (BoTox) into the muscles that control vocal fold opening or closing. The BoTox temporarily interrupts the connection between the muscle fibers and the nerves that control them. Very small amounts are used and the effects usually last about 3 months. BoTox does not ‘cure’ spasmodic dysphonia, but is a way to eliminate or reduce the symptoms for a time. Patients generally have a breathy voice initially and may have some small effects on swallowing, but these side effects usually go away after a short period of time

In the early stages of SD, voice therapy may be of some help. Some patients undergo voice therapy between injections of BoTox to help them maximize and sustain the benefits of the medication.


Find Us On: