U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES ∙ National Institutes of Health 

NIDCD Fact Sheet | Voice, Speech, and Language 

Spasmodic Dysphonia 

What is spasmodic dysphonia? 

Spasmodic dysphonia, or laryngeal dystonia, is a disorder 

affecting the voice muscles in the larynx, also called the 

voice box. When you speak, air from your lungs is pushed 

between two elastic structures—called vocal folds—causing 

them to vibrate and produce your voice. In spasmodic 

dysphonia, the muscles inside the vocal folds spasm (make 

sudden, involuntary movements), interfering with vocal 

fold vibrations. Spasmodic dysphonia may occur along with 

other forms of dystonia that cause repeated spasms in other 

parts of the body, including the eyes, face, jaw, lips, tongue, 

neck, arms, or legs. 

Spasmodic dysphonia causes voice breaks during speaking 

and can make the voice sound tight, strained, or breathy. In 

some people, the breaks occur once every few sentences. 

In more severe cases, spasms may occur on every word, 

making a person’s speech very diffcult to understand. Some 

people with spasmodic dysphonia may also have vocal 

tremor—a shaking of the larynx and vocal folds that causes 

the voice to tremble. 

Spasmodic dysphonia is a chronic condition that continues 

throughout a person’s life. Spasmodic dysphonia may 

develop suddenly, with severe voice symptoms present from 

the start of the disorder, or it may start with mild symptoms 

and occur only occasionally before worsening and becoming 

more frequent over time. 

Spasmodic dysphonia is a rare disorder. It can affect anyone, 

but the frst signs occur most often in people between the 

ages of 30 and 50. It affects more women than men. 

Parts of the throat involved 

in spasmodic dysphonia 

Source: NIH/NIDCD 

What are the types of spasmodic 

dysphonia? 

} Adductor spasmodic dysphonia is the most 

common form of spasmodic dysphonia. In this 

disorder, spasms cause the vocal folds to slam 

together and stiffen. These spasms make it difficult 

for the vocal folds to vibrate and produce sounds. The 

voice of someone with adductor spasmodic dysphonia 

NIDCD...Improving the lives of people with communication disorders 
may sound strained and strangled. The person’s 

speech may be choppy, with words cut off or difficult 

to start because of muscle spasms. The spasms are 

usually absent—and the voice sounds normal—while 

laughing, crying, or whispering. Stress often makes 

the muscle spasms more severe. 

} Abductor spasmodic dysphonia is less common. In 

this disorder, spasms cause the vocal folds to remain 

open. The vocal folds cannot vibrate when they are 

open too far. The open position also allows air to 

escape from the lungs during speech. As a result, 

the voice often sounds weak and breathy. As with 

adductor spasmodic dysphonia, the spasms are often 

absent during activities such as laughing, crying, or 

whispering. 

} Mixed spasmodic dysphonia, a combination of the 

above two types, is very rare. Because the muscles 

that open and the muscles that close the vocal folds 

are not working properly, it has features of both 

adductor and abductor spasmodic dysphonia. 

What causes spasmodic dysphonia? 

Spasmodic dysphonia is thought to be caused by 

abnormal functioning in an area of the brain called the 

basal ganglia. The basal ganglia help coordinate the 

movements of muscles throughout the body. Recent 

research has found abnormalities in other regions 

of the brain associated with spasmodic dysphonia, 

including areas of the cerebral cortex that control 

commands to muscles and coordinate these commands 

with incoming sensory information. 

In some cases, spasmodic dysphonia may run in 

families. Although a specific gene for spasmodic 

dysphonia has not yet been identified, a mutation in a 

gene that causes other forms of dystonia has also been 

associated with spasmodic dysphonia. 

How is spasmodic dysphonia 

diagnosed? 

Diagnosis of spasmodic dysphonia can be difficult 

because the symptoms are often similar to those 

of other voice disorders. Diagnosis usually follows 

examination by a team, including: 

} An otolaryngologist, a doctor who specializes in 

diseases of the ear, nose, throat, head, and neck. 

The otolaryngologist will pass a small lighted tube 

through the nose and into the back of the throat—a 

procedure called fiberoptic nasolaryngoscopy—to 

evaluate vocal fold anatomy and movements during 

speech and other activities of the larynx. 

} A speech-language pathologist, a health professional 

trained to evaluate and treat voice, speech, and 

language disorders. The speech-language pathologist 

will assess voice symptoms. 

} A neurologist, a doctor who specializes in nervous 

system disorders. The neurologist will evaluate for 

signs in the brain of dystonia and other movement 

disorders. 

There is currently no cure 

for spasmodic dysphonia, 

but treatment can help 

reduce its symptoms. 

What treatment is available for 

spasmodic dysphonia? 

There is currently no cure for spasmodic dysphonia, 

but treatment can help reduce its symptoms. The 

most common treatment is the injection of very small 

amounts of botulinum toxin directly into the affected 

muscles of the larynx. Botulinum toxin is produced 

by Clostridium botulinum, the same bacterium found 

in improperly canned foods and honey. The toxin 

weakens muscles by blocking the nerve impulse to 

the muscle. Botulinum toxin injections generally 

improve the voice for three to four months, after 

which voice symptoms slowly return. Reinjections are 

2 
Augmentative and 

assistive devices can 

help some people with 

spasmodic dysphonia to 

communicate more easily. 

needed to maintain a good speaking voice. Initial side 

effects include a temporarily weak, breathy voice and 

occasional swallowing problems, but these usually 

improve after a few days to a few weeks. Botulinum 

toxin injections are more effective with adductor 

spasmodic dysphonia than with abductor spasmodic 

dysphonia. They do not help in every case. 

Behavioral therapy (voice therapy) may reduce 

symptoms in mild cases. Voice therapy may work along 

with botulinum toxin injections to reduce voice strain. 

Some people may also benefit from psychological 

counseling to help them accept and live with their 

voice problems. 

Augmentative and assistive devices can help some 

people with spasmodic dysphonia to communicate 

more easily. Some devices can help amplify a person’s 

voice, whether in person or over the phone. Computer 

software and tablet or smartphone apps can be used 

to translate text into synthetic speech. 

When more conventional measures have failed, surgery 

may be performed on the larynx. Several surgical 

approaches are used to treat spasmodic dysphonia. 

Some surgical treatments show overall positive 

outcomes, but the results are not the same for all 

individuals. To date, there are no comparative studies 

pointing to a single, best treatment. 

A physician can explain the potential outcomes, risks, 

and benefits of surgical treatment and can help to 

manage expectations. 

What research does the NIDCD 

support on spasmodic dysphonia? 

The National Institute on Deafness and Other 

Communication Disorders (NIDCD) currently funds 

research to better understand spasmodic dysphonia, 

determine its causes, and develop new diagnostics and 

better treatment options. NIDCD-supported scientists 

are conducting research to identify brain abnormalities 

and genes that cause spasmodic dysphonia. Through 

this research program, the NIDCD is directly addressing 

the need for more accurate detection, prediction, 

and diagnosis. NIDCD-funded scientists are also 

pursuing several new areas for future therapies and 

surgical interventions, including locating specific 

brain areas involved in regulating abnormal laryngeal 

muscle activity and looking for new oral medications 

that affect the abnormal brain activity underlying 

spasmodic dysphonia. Researchers are also working to 

determine if deficits in auditory and sensory feedback 

processing contribute to spasmodic dysphonia 

symptoms. 

Visit the NIH Clinical Research Trials and You website 

(https://www.nih.gov/health-information/nih-clinicalresearch-trials-you) to read about these and other 

clinical trials that are recruiting volunteers. 

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Where can I fnd more information 

on spasmodic dysphonia? 

The NIDCD maintains a directory of organizations 

that provide information on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language. Visit the NIDCD website at 

https://www.nidcd.nih.gov/directory to search the directory. 

More NIDCD fact sheets on Voice, Speech, and 

Language: 

} Assistive Devices for People with Hearing, Voice, Speech, 

or Language Disorders 

} What Is Voice? What Is Speech? What Is Language? 

Visit the NIDCD website at https://www.nidcd.nih.gov to 

read, print, or download fact sheets. 

For more information, contact us at: 

NIDCD Information Clearinghouse 

1 Communication Avenue 

Bethesda, MD 20892-3456 

Toll-free voice: (800) 241-1044 

Toll-free TTY: (800) 241-1055 

Email: nidcdinfo@nidcd.nih.gov 

https://www.nidcd.nih.gov

 Follow the NIDCD on Twitter at @NIDCD 

The NIDCD supports and conducts research and 

research training on the normal and disordered 

processes of hearing, balance, taste, smell, voice, 

speech, and language and provides health information, 

based upon scientifc discovery, to the public. 

Spasmodic Dysphonia 

NIH Publication No. 10-4214 

March 2020 

NIH...Turning Discovery Into Health®