Spasmodic dysphonia (or laryngeal dystonia) is a voice disorder characterized by involuntary movements of one or more muscles of the larynx (vocal folds or voice box) during speech. Individuals who have spasmodic dysphonia may have occasional difficulty saying a word or two or they may experience sufficient difficulty to interfere with communication. Spasmodic dysphonia causes the voice to break or to have a tight, strained or strangled quality. more...
Spasmodic dysphonia can affect anyone. The first signs of this disorder are found most often in individuals between 30 and 50 years of age. More women appear to be affected by spasmodic dysphonia than are men.
Types of spasmodic dysphonia
The three types of spasmodic dysphonia are adductor spasmodic dysphonia, abductor spasmodic dysphonia and mixed spasmodic dysphonia.
Adductor spasmodic dysphonia
In adductor spasmodic dysphonia, sudden involuntary muscle movements or spasms cause the vocal folds (or vocal cords) to slam together and stiffen. These spasms make it difficult for the vocal folds to vibrate and produce voice. Words are often cut off or difficult to start because of the muscle spasms. Therefore, speech may be choppy and sound similar to stuttering. The voice of an individual with adductor spasmodic dysphonia is commonly described as strained or strangled and full of effort. Surprisingly, the spasms are usually absent while whispering, laughing, singing, speaking at a high pitch or speaking while breathing in. Stress, however, often makes the muscle spasms more severe.
Abductor spasmodic dysphonia
In abductor spasmodic dysphonia, sudden involuntary muscle movements or spasms cause the vocal folds to open. The vocal folds can not vibrate when they are open. The open position of the vocal folds also allows air to escape from the lungs during speech. As a result, the voices of these individuals often sound weak, quiet and breathy or whispery. As with adductor spasmodic dysphonia, the spasms are often absent during activities such as laughing or singing.
Mixed spasmodic dysphonia
Mixed spasmodic dysphonia involves muscles that open the vocal folds as well as muscles that close the vocal folds and therefore has features of both adductor and abductor spasmodic dysphonia.
The cause of spasmodic dysphonia is unknown. Because the voice can sound normal or near normal at times, spasmodic dysphonia was once thought to be psychogenic, that is, originating in the affected person¹s mind rather than from a physical cause. While psychogenic forms of spasmodic dysphonia exist, research has revealed increasing evidence that most cases of spasmodic dysphonia are in fact neurogenic or having to do with the nervous system (brain and nerves). Spasmodic dysphonia may co-occur with other movement disorders such as blepharospasm (excessive eye blinking and involuntary forced eye closure), tardive dyskinesia (involuntary and repetitious movement of muscles of the face, body, arms and legs), oromandibular dystonia (involuntary movements of the jaw muscles, lips and tongue), torticollis (involuntary movements of the neck muscles), or tremor (rhythmic, quivering muscle movements).
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