Medical Edge Newspaper Column

Treatment for Spasmodic Dysphonia Can Offer Help

August 21, 2009
Dear Mayo Clinic:
My 79-year-old mother has suffered from spasmodic dysphonia for many years. Has any progress been made for a treatment or cure?

Answer:
Although there is no current cure for spasmodic dysphonia — a disorder that affects the vocal folds and muscles in the voice box (larynx) — treatment can offer help. And researchers are working to identify causes and new treatment options for the disorder.

The vocal folds are two flexible bands of muscle tissue that sit at the entrance to the windpipe (trachea). When you speak, the vocal folds come together and vibrate to make sound. The rest of the time, they are relaxed in an open position, so you can breathe. In people who have spasmodic dysphonia, the vocal folds and other muscles in the larynx spasm involuntarily interfering with speech.

Spasmodic dysphonia is categorized into three types. The most common is adductor spasmodic dysphonia, typically characterized by a strained or strangled sound caused by spasms that close the vocal folds. A less common type is abductor spasmodic dysphonia, typically characterized by a breathy-sounding voice caused by spasms that open the vocal folds. A rare third type is mixed spasmodic dysphonia that occurs when both adductor and abductor spasms occur.

Spasmodic dysphonia can make talking extremely effortful. Some people with spasmodic dysphonia change their voice to make it easier and clearer by speaking in a higher pitch, slowing or speeding up their speaking rate, or by talking with an accent such as an actor might use. The effects of these changes are usually temporary. Whispering, singing, laughing or crying often sound completely normal and spasm-free. The variability of the sound of the person's voice can be very frustrating for those who have spasmodic dysphonia. It can also make obtaining a correct diagnosis challenging.

Once accurately diagnosed, treatment for spasmodic dysphonia is targeted at reducing the spasms. The most common treatment involves injections of botulinum toxin type A (Botox). Botox is injected into muscles of the larynx, weakening them. This can quite effectively reduce the symptoms of spasmodic dysphonia. Unfortunately, the effects are temporary and repeated treatments at intervals of three months or more are needed to help voice symptoms.

Finding the right dose of Botox to improve the sound of the voice can take time. For some people, as many as three or four injections are necessary before an individual's best dose is determined. Researchers are studying ways to determine a reliable method of predicting the most effective dose of Botox for each person's needs.

In addition to Botox, other treatments are available for spasmodic dysphonia. They include surgical procedures such as a midline type II thyroplasty. In this procedure, the larynx is split down the front and spread apart a few millimeters. Another operation involves cutting and reattaching certain nerves to the larynx. The purpose of surgery is to prevent the vocal folds from squeezing together so tightly, but it is not a cure. The long-term results of the surgeries mentioned are still under investigation.

Spasmodic dysphonia is quite rare, can be very frustrating, and is sometimes misdiagnosed. If your mother is interested in pursuing treatment options that are currently available, I encourage her to seek care from an ear, nose and throat specialist who specializes in the larynx (laryngologist). A speech pathologist who is experienced in working with voice problems may also be helpful.

— Diana Orbelo, Ph.D., Otorhinolaryngology, Mayo Clinic, Rochester, Minn.