Spasmodic Dysphonia

Spasmodic Dysphonia is a neurologic voice disorder that involves the involuntary movements of one or more muscles of the larynx or voice box.   Typically, the voice will have a tight, strained, or strangled quality.  There are three types of spasmodic dysphonia: adductor spasmodic dysphonia, abductor spasmodic dysphonia, and mixed spasmodic dysphonia. (Watterson, 1992)

What are the features of each type of spasmodic dysphonia?

Adductor Spasmodic Dysphonia: The most common laryngeal distonia. Sudden involuntary muscle spasms or movements that lead to the slamming together or stiffening of the vocal folds.  Voice sounds strained or strangled, and speech may sound choppy or as if the individual is stuttering. (Watterson, 1992).

Abductor Spasmodic Dysphonia: Involuntary spasms or muscle movements that cause the vocal folds to open.  Vocal folds are unable to vibrate and allow air to escape. Voice sounds weak, quiet, and breathy. (Watterson, 1992)

Mixed Spasmodic Dysphonia: Has features of both adductor and abductor spasmodic dysphonia

Respiratory Dysphonia: Spasms of the vocal folds during speaking which results in noisy and difficulty taking a breath.

What causes SD? 

It is not yet known exactly what causes spasmodic

dysphonia, however most research shows that most

cases of spasmodic dysphonia are neurogenic and may occur with other movement disorders. Some research shows spasmodic dysphonia is a result of a problem in the feedback loop between the brain and the larynx.

As recently as the 1970’s, most people thought SD was

psycogenic in nature. However, research hasincreasingly

revealed that is false. Some believe spasmodic dysphonia may be hereditary, and research has identified a possible gene on chromosome 9 which is common to certain families that may cause spasmodic dysphonia.

How is SD diagnosed?

Diagnosis is typically made by a careful examination of the head and neck, and by identifying symptoms.  A team of professionals are used to rule out other pathologies and determine the presence of spasmodic dysphonia.  This team includes a Speech-Language pathologist, a Neurologist, and an Otolarynoglogist. 

What are the treatment options available?

Presently, there is no cure for spasmodic dysphonia, however there are treatments to help reduce the symptoms of the disorder.  An Otolaryngologist may perform surgery to cut the Recurrent Laryngeal Nerve of the vocal folds to cause a temporary improvement, or a speech-language pathologist may issue voice therapy to help reduce mild symptoms. 

The most common and promising treatment was developed in the late 1980’s that involves weakening the muscles of the larynx.  A very small amount of botulinum toxin (Botox) is injected into the affected area in order to weaken the muscle and in turn weaken the severity of the spasm of the vocal fold.