Laryngeal dystonia (previously called spasmodic dysphonia) is involuntary tightening of muscles in the voice box (larynx) that control the vocal cords, resulting in an abnormal voice.
In laryngeal dystonia, people may not be able to speak, or their voice may sound strained, quavery, hoarse, whispery, jerky, creaky, staccato, or garbled and difficult to understand. Doctors do not know what causes laryngeal dystonia, which has an average age of onset of 51 years and is more common in women. Doctors think it may be a form of dystonia, a type of movement disorder involving involuntary contraction of various muscles in the body. A family history of such movement disorders, a recent viral illness, and heavy use of the voice are all considered risk factors.
There are 3 forms of laryngeal dystonia:
Adductor laryngeal dystonia
Abductor laryngeal dystonia
Mixed laryngeal dystonia
In adductor laryngeal dystonia, the laryngeal muscles spasm and the vocal cords close together, usually when vowel sounds are being formed at the beginning of words, making a squeezed or strained sound. Injections of botulinum toxin into the laryngeal muscles provide improvement lasting up to 3 months in most people. Because the effect of the injections is temporary, injections must be repeated to maintain the improvement. Surgery is also a treatment option in some cases.
In abductor laryngeal dystonia, spasms cause the vocal cords to open too far, making the voice sound weak and breathy. Injections of botulinum toxin into specific laryngeal muscles provide temporary improvement. Surgery is also a treatment option in some cases.
In mixed laryngeal dystonia, people may have symptoms of both adductor and abductor laryngeal dystonia to varying degrees and at different times.
