Spasmodic dysphonia (SD) is a voice problem resulting from neurologic causes. SD is usually slow in onset and progression, and usually does not impact other parts of the body.

The most common type of SD is the adductor type, in which the vocal cords have spasms that bring them together too strongly. People with this type of SD often have a strained or strangled quality to their voice and increased effort to speak. Typically, these patients have problems with sounds like “p”, “t”, or “sh” sounds (as in Peter,” “Tom,” and “shell”).

Abductor SD is much less common. The vocal cords spasm away from each other, resulting in a loss of the volume of the voice and an episodic breathiness that makes it difficult for them to speak. Typically, these patients have trouble with the “ga” or “ra” sounds (as in “garage”).

Most patients with SD typically have better voices while singing, and their voices are made worse by stressful situations. SD usually does not respond to voice therapy alone (by speech pathologists) and requires an integrated approach of medical treatment with voice therapy.

Treatments

Treatment of SD is aimed at restoring the “balance” of the muscles. In some cases, weakening of specific muscles in the voice box can improve the voice.

In the last 15-20 years, Botulinum Toxin A (Botox) has been used to temporarily weaken or paralyze specific muscles. In SD, either the vocalis muscles or the posterior cricoarytenoid muscles are weakened by Botox, improving the voice. The type of SD that a patient has determines which muscle needs to be injected.

Botox is injected through a small needle using signal guidance provided by a neurologist. We use the guidance technique because these muscles are tiny, and the method ensures a more precise injection.

Botox is not a cure for SD but provides temporary improvement in voice symptoms. Patients typically need to have the treatment repeated every four to six months to maintain good voice quality. Duke University Medical Center has staff with specialized training in the use of Botox for the treatment of SD and other dystonias of the head and neck.

Voice therapy can also be beneficial in helping patients maximize the benefit of the Botox injection and use the voice in the most efficient way possible. Therapy can also help to eliminate any compensatory vocal strain and incoordinated breathing, which often occur when people have tried to adapt to the SD condition.