Merck Manual

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Spasmodic Dysphonia

(Vocal Cord Spasms)


Clarence T. Sasaki

, MD, Yale University School of Medicine

Last full review/revision Jan 2020| Content last modified Jan 2020
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Spasmodic dysphonia is involuntary tightening of muscles in the voice box (larynx) that control the vocal cords, resulting in an abnormal voice.

In spasmodic dysphonia, people may not be able to speak or their voice may sound strained, quavery, hoarse, whispery, jerky, creaky, staccato, or garbled and be difficult to understand. Doctors do not know what causes spasmodic dysphonia, which is most common between ages 30 and 50 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.

There are two forms of spasmodic dysphonia:

  • Adductor spasmodic dysphonia

  • Abductor spasmodic dysphonia

In adductor spasmodic dysphonia, 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. Treatment is with surgery. Injections of botulinum toxin into the laryngeal muscles provide temporary improvement.

In abductor spasmodic dysphonia, 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 not helpful.

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