Spasmodic Dysphonia (SD)

Spasmodic Dysphonia (SD) is a voice disorder caused by the brain sending abnormal signals to the vocal folds. It affects roughly 50,000 people in North American and usually starts in people during their middle age, though it can present for the first time in children or the elderly. In addition, women are more commonly affected than men and the disease is more often diagnosed in people who talk a lot for work. The symptoms develop over one to two years and then stabilize and are non-progressive in nature. SD is not associated with other progressive neurological symptoms.

At the Grabscheid Voice and Swallowing Center of Mount Sinai, our experts have more than 25 years of experience treating patients with all forms of this disorder. Our specialists are known for their skill and expertise in the injection of Botox®, behavioral interventions, and surgical remediation of the symptoms. We will personal each patient’s treatment plan to meet their personal and professional vocal needs. We pride ourselves on providing reliable care to help you plan your life.

Symptoms and Types of Spasmodic Dysphonia

For reasons that are unknown to physicians, speech-language pathologist and researchers, in patients with SD, the brain sends abnormal signals to the muscle of the voice box (larynx) to causes the muscles to spasm. These spams cause the voice to break or crack or choke off. In the majority of patients (90 percent), the signals lead to spasms that cause the muscle of the vocal folds to close too tightly (adductor spasms or AddSD). In these patients the voice has a harsh or strangled quality. This often sounds like the person is about to cry. In about 10 percent of patients, the signals lead to spasms that cause the muscles of the vocal folds to open (abductor spasms or AbdSD). The voice sounds intermittently breathy or the patient whispers. Finally a small percentage of patients have a mix of both types of spasms (Mixed SD). The voice is has a combination of strain/strangle breaks and breathy breaks.

The voice breaks in patients’ with SD happen when people with the disease attempt to say certain sounds. The spams causing the voice breaks are limited to the muscles of the voice box. This is referred to as task specific spasms. For AddSD the task causing spasm is saying vowels sound. When the person attempts to say a word with a vowel, the muscles of the vocal folds spasm shut. For AbdSD the task is saying a consonant. During consonants production the vocal folds are apart or abducted. The vocal fold muscle to spasm open, all the air rushes out and the voice is breathy. These limited spasms that are triggered by a task (saying a vowel or saying a consonant) are the definition of a focal dystonia. SD is a “focal dystonia” because the area of the body affected is limited to one system (the voice box) and the spasm are triggered by the task of speaking.

Regardless of the type of SD, persons with the disorder complain of increased effort to speak. If they try to speak loudly the effort is worse. Persons with the disorder are also troubled because the spams are uncontrollable and they often spend effort searching for words that are less likely to trigger the stress. Imagine not only having to think about what you say but the words you choose to say it with. Patients with SD usually notice that their effort is less if they speak softly or whisper. Also, if they speak in a high pitched voice, the effort can be less as well. Finally people with SD judge the severity of their difficulty in what they feel. Their voice often feels worse than it may sound to others and others may, therefore, downplay the severity of their feelings.

Spasmodic Dysphonia and Vocal Tremor

SD can also be accompanied by vocal tremor. About 25 percent of patients with any form of SD will also have a tremor in their vocal apparatus when they attempt to speak. This tremor is different than the spasms as it is rhythmic and not caused by or related to certain sounds.

Diagnosis of Spasmodic Dysphonia

SD is a diagnosis of exclusion. There are no medical tests that can definitively diagnose patients with SD so all other illness need to be ruled out first. The diagnosis is made on the basis of finding no other medical problems that could cause the relatively typical changes in voice that are found with the disorder.
The diagnosis is made by a clinician who is experienced in listening to voices and can have the patient do tasks that may make the symptoms worse or better. If the person has the voice characteristics and all other possible causes are ruled out, then by exclusion, they have SD.

Treatment Options for Spasmodic Dysphonia

Several methods of treatment are available to patients with SD. At the Grabscheid Voice and Swallowing Center of Mount Sinai, our team of clinicians has experience with all of these modalities of treatment. We have piloted groundbreaking research in the use of novel medications to reduce the symptoms of laryngeal movement disorders. We use our experience to work with the patient to design treatment options that fit their needs. However, is should be stated that none of these treatments cure the disease; rather the treatments help the patient live with the disease. Treatment options include:

  • Speech and Voice Therapy

    By working with a clinician experienced in the behaviors needed to produce healthy voice, the person with SD may learn how to adapt to the spasms with less interruption in their speech. This can allow the patient to function with less effort. In addition, it may help the patient by decreasing the need for other treatments such as medications, Botox® injections or surgery. Patients can be taught to use great airflow, or a softer voice to lessen the spasm severity.

  • Oral Medications

    There are no specific medications approved by the FDA to treat symptoms in patients with SD. However, some medications that relax smooth muscles (Artane or Balcofen) have been used with limited benefit. In addition, many patients with SD report that alcohol will reduce the symptoms associated with SD as well. Therefore, some patients can find limited benefit from anxiolytic medications such as valium. However, most patients find all of these medications too sedating and do not continue taking them. Finally at Mount Sinai Hospital researchers have conducted trials with a medication called Xyrem. In some patients, particularly those who find their symptoms get better with a drink of alcohol, Xyrem, taken in small doses, helps relieve their symptoms.

  • Botulinum Toxin Type A Injections (Botox®)

    Probably accepted as the main form of therapy for patients with spasmodic dysphonia, Botox® is a chemical that relieves the muscle spasms in patients by stopping the abnormal nerve impulses from getting to the muscle. Botox®needs to be injected directly into the affected muscles. Clinicians at Mount Sinai, have been performing these injections into the larynx for over 25 years and recognized by directors of the National Spasmodic Dysphonia Association (NSDA) as leading experts in this technique. The injections, when done by an experienced clinician, are quick and relatively painless. They do not require simultaneous visualization and their success rate for patients with AddSD is 96 percent. Our clinicians use particularly small doses of medication. This helps avoid or reduce the breathy voice phase that occurs when larger doses are used. The main objection of Botox® as a form or treatment is that it needs to be injected every two to six months depending on your individual response. We work with the patient to find the dose and injection schedule that is right for their lifestyle and offer injection clinics twice each month so that patients can been treated when they need it. Each visit takes about 30 minutes, but the injection is only 2-3 minutes of that time.

  • Surgery

    Surgery, before the application of Botox® was the initial treatment for patients with the AddSD. The original form of surgery, developed in the early 1980’s. involved removing a portion of the nerve that controls vocal fold function, thus weakening the force of the laryngeal spasms. The surgery provides permanent relief in about 50 percent of patients. Some, however, have return of spasms and need to resume Botox®, while others find their voice too breathy after and need further surgery to address the breathy voice.

    Over the years, the original surgical techniques have been modified by other surgeons. Reported three year success rates range from 50 to 80 percent with these modifications. So surgery, while it can be an excellent form of treatment, is not for every patient. The physicians at Mount Sinai have 25 years of experience with all of these forms of surgery and can work with you to identify the particular procedure that is correct for you.

What to Expect at Your Appointment


Often patients are referred for a voice problem and the diagnosis of spasmodic dysphonia may not be secured. Therefore, when you call the Grabscheid Voice Center your initial visit will likely be scheduled with our team of voice clinicians. You will see a physician and a speech language pathologist on the same visit who will evaluate you voice production and laryngeal appearance. They will discuss with you their impressions as a team and your treatment options.


If you elect for treatment, we will likely suggest that you attempt either Botox®injections or voice therapy prior to jumping into surgery. If you have had these treatments at other centers and wish to proceed to surgery we will consider that option. Therapy or injection may be scheduled at a separate visit after approval can be obtained from your insurance carrier. Again, however, if you have been receiving treatment elsewhere and wish to switch your care to our center, we can attempt to get insurance carrier approval for treatment on your initial visit.

Neurologic Evaluation

If you have not had a recent evaluation by a neurologist or if you are interested in trying medical therapy such as Xyrem, for your illness we are able to refer you to our colleagues in neurology for evaluation and medical treatment.