April 16 is World Voice Day. Joseph Spiegel, MD, an ear, nose and throat specialist and Co-Director of the Jefferson Voice and Swallowing Center, shares some information on Spasmodic dysphonia (SD), a vocal form of dystonia, is a neurological voice disorder that involves “spasms” of the vocal cords causing interruptions of speech and affecting voice quality. “SD can cause the voice to break up or to have a tight, strained or “strangled” quality,” says Dr. Spiegel. Here are five more facts about the disorder:
- Certain dystonias, including SD, are task-specific, meaning that the muscles spasm only when they are used for particular actions and not when they are at rest. When a person with SD attempts to speak, involuntary spasms in the tiny muscles of the larynx cause the voice to break up, or sound strained, tight, strangled, breathy, or whispered. The spasms often interrupt the sound, squeezing the voice to nothing in the middle of a sentence, or dropping it to a whisper. However, during other activities, such as breathing and swallowing, the larynx functions normally.
- SD is estimated to affect approximately 50,000 people in North America, but this number may be somewhat inaccurate due to ongoing misdiagnosis or undiagnosed cases of the disorder. Although it can start at any time during life, SD seems to begin more often when people are middle-aged. The disorder affects women more often than men. Onset is usually gradual with no obvious explanation. Symptoms usually occur in the absence of any structural abnormality of the larynx, such as nodules, polyps, carcinogens, or inflammation. People have described their symptoms as worsening over an approximate 18-month period and then remaining stable in severity from that point onward. Some people have reported brief periods of remission, however this is very rare and the symptoms usually return.
- SD is generally categorized into two primary forms: adductor spasmodic dysphonia (AdSD) and abductor spasmodic dysphonia (AbSD). Adductor SD, the most common form, affects approximately 80–90 percent of people with SD. In this type, spasms, usually in the thyroarytenoid muscle (TA), force the vocal folds together in adduction, or closing. AdSD may also affect the lateral cricoarytenoid muscle (LCA) or interarytenoid (IA). These spasms occur particularly on “voiced” speech sounds. AbSD, a less common form, occurs in approximately 10–20 percent of cases and results from spasms when the posterior cricoarytenoid muscles (PCA) abducts, or opens, the vocal folds. AbSD causes problems with the production of “voiceless” speech sounds, which normally sound “airy” or “breathy” when produced.
- Spasmodic dysphonia can be difficult to diagnose because the anatomy of the larynx is normal. SD has no objective pathology that is evident through x-rays or imaging studies like a CT or MRI scan, nor can a blood test reveal any particular fault. In addition, several other voice disorders may mimic or sound similar to it. Therefore, the best way to diagnose the problem is to find an experienced clinician with a good ear.
- Botox injections into the effected muscles in the larynx are utilized to diagnose SD and as primary treatment for most patients. These injections are performed as office procedures with local anesthesia.
If you or a loved one is suffering with voice or swallowing issues, call 1-800-JEFF-NOW to schedule an appointment with a Jefferson otolaryngologist.