Spasmodic dysphonia (SD) (occasionally called spastic dysphonia) is a disorder that causes abnormal speech. Although relatively rare, it may affect anyone, and is a chronic condition. Because most physicians have little experience with this disorder, many patients are not properly diagnosed for years. These patients suffer from an inability to communicate on a daily basis, and are often self-conscious about their voice. With proper treatment, however, these patients can return to a relatively normal lifestyle.
How do I know if I have SD?
Characteristically, SD patients have a “jerky” or “tremulous” quality to their voice. They often sound strained. The quality of the voice may vary, and is typically worse when on the telephone or speaking in front of a crowd.
SD can be diagnosed by a physician who is familiar with the condition. Although the diagnosis is fairly straightforward in most cases, it may be complicated if the patient’s symptoms are not typical. In such cases, your doctor may ask you to undergo special testing to help confirm the diagnosis. Such testing may include voice analysis or laryngeal electromyography.
What causes SD?
While there has been a lot of research into the causes of SD, the medical community has no answers to this question. We do know that SD a part of a family of disorders known as dystonias. This family includes such disorders as blepharospasm (uncontrollable eye blinking) and “Writer’s Cramp.” A dystonia is a neurological disorder in which there is uncontrolled and abnormal muscle contraction. It is currently believed that most dystonias are caused by an abnormality in the body’s ability to coordinate movement.
SD is a focal laryngeal dystonia, which means the abnormal muscle contraction is limited to the muscles of the larynx (or “voice box”). Most patients with SD never develop dystonias in other parts of their bodies, though their voice may become worse with time.
Are there different types of SD?
Yes, SD comes in many different forms. The most common form is called adductor SD, in which there is abnormal closure of the vocal cords. Abductor SD is the result of abnormal opening of the vocal cords. SD may also have a component of tremor associated with it, making the voice sound more “shaky.” There are other forms, but these are much less common.
How is SD treated?
While we know little about the origin of the disorder, we do have a better handle on the treatment. The most common and reliable therapy involves the use of a substance called botulinum toxin. This is actually a poison produced by bacteria, and in large doses, can lead to botulism. The doses used in treating SD, however, are incredibly small. Botulinum toxin (also called BoTox) is injected into the vocal cords to partially weaken them. By doing this, abnormal contraction can be effectively prevented. BoTox typically lasts several months, but when it runs out, the voice will return to its previous condition. Therefore, patients typically require injections for the rest of their lives. The frequency of injections, as well as the dose given each time varies for each patient. Since each patient is unique, the treatment is designed around the individual.
What should I expect with the treatments?
The injections are typically done using a machine called an electromyography (EMG) machine. This device helps in locating the proper muscles that need to be injected. The machine makes “popping” noises when the muscle is entered. A small, flexible needle is attached to the machine, and is used to inject the BoTox. The procedure begins with the patient lying down. The needles are inserted into the voice box through the neck skin. Once the muscle is located, the BoTox is injected. The entire procedure takes a couple of minutes. Afterwards, you may experience a sense of a “lump” in the throat, and rarely, you may cough up a tiny bit of blood. Your neck may be sore for a day or two.
The effects of the BoTox begin to appear in 12-72 hours after the injection. You may experience a period of “breathiness,” during which you loose your voice completely. This may last from a few days to a few weeks. During this period, if you are particularly susceptible, you may notice trouble with swallowing. Once the breathiness period passes, your voice will return, and the shakiness in your voice will likely have disappeared. Gradually, you will notice a return of the SD over the next few months. This is because the body grows new muscle to replace the ones damaged by the BoTox. At that point, you may be ready for another injection. As mentioned, each individual is different in their response to the drug. Additionally, the result will vary depending on the dose used, the “quality” of the injection, and the severity of the dystonia.
Where can I get more information on SD?
Contact the National Spasmodic Dysphonia Association, www.dystonia-foundation.org/NSDA.
