Spasmodic Dysphonia,
Essential Tremor, and Botox Therapy
Ryan M. Hendricker, MD, FACS
Midwest ENT Office: (309) 691-6616
OSF Voice and Swallowing Disorders Center: (309) 683-5080
Spasmodic Dysphonia
This information sheet is designed to guide you through the basics regarding spasmodic dysphonia, essential
tremor, and Botox therapy. It is not intended to be comprehensive. If you have any questions, please ask
your physician.
What is spasmodic dysphonia?
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Spasmodic dysphonia (SD) is a long-term voice disorder involving abnormal movements or spasms of
the vocal folds and surrounding muscles in the larynx. Movements of the vocal folds are forceful
leading to jerky, shaky, hoarse, or a tense voice quality.
There are three basic types of SD: adductor SD, abductor SD, and mixed SD.
Spasms, periods of no sound, and periods of normal voice may occur. Symptoms may be mild and
occasional at first and gradually increase in frequency and severity.
The vocal folds appear normal at rest. During phonation, the abnormal movements occur.
The disorder most commonly presents in people ages 30-50, but may occur at anytime.
The exact etiology of SD is unknown. The general consensus is that SD represents a focal laryngeal
dystonia. A dystonia is the general neurological term for a variety of problems characterized by
excessive contraction of muscles associated with various abnormal movements or postures.
Types of spasmodic dysphonia
TYPE
1. Adductor SD (80-95% of cases)
2. Abductor SD
3. Mixed SD
WHAT HAPPENS
Vocal folds come together (close)
tightly at the wrong time during
speech, making it difficult to
produce voice
Vocal folds move apart (open) at
the wrong time during speech,
causing air leaks
Combination of adductor and
abductor SD
HOW THE VOICE SOUNDS
Strained, strangled breaks while
speaking
Breathy or soundless breaks while
speaking
Sometimes strained, strangled
breaks; sometimes breathy or
soundless breaks
What is the treatment for SD?
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There is no cure for spasmodic dysphonia presently. There are various treatment options.
Oral medications have been found to be ineffective.
The most widely accepted form of treatment involves repeated Botox injections into one or both vocal
folds. Botox is a neuromuscular blocking agent that weakens the muscles leading to a smoother, less
strained voice. Patients must undergo repeated injections for ongoing benefit. This is done on average
every 3 months. Possible side effects include loss of voice and swallowing problems. This procedure is
pre-certified and covered by insurance.
There are other treatments described including surgery. The results are not as reliable as Botox
injections and have additional side effects. Additional adjunctive treatments have also been described.
The National Spasmodic Dysphonia Foundation has an excellent website at www.dysphonia.org for
additional details.
What is essential tremor?
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Essential tremor causes shakiness to the voice that can also commonly affect the head and the hands.
Shaking in the head and hands can be treated with a pill, but this does not work for the voice.
Often, essential tremor, is passed through families.
Treatment often involves Botox therapy to stabilize the voice shakiness.
How is Botox given?
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Botox is given by an injection into the muscle. The amount of medicine used for this treatment is very
small. After a Botox injection, there is little change for the first 24 hours. The medicine usually starts
to work in 7-10 days and works best in 2-4 weeks after the injection. It can last 3-4 months on average.
Since the medication wears off over time, repeated injections are required.
All patients are different and the treatment will be planned to treat your problem. You can eat before
and after the injection. It should not interact with any of your medications.
Side effects of Botox
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Generally, this is a very safe treatment.
Mild cold-like symptoms.
A change in your voice may occur if you are sensitive to the medication. The voice may become weak
and breathy. This usually lasts 1-2 weeks but can last up to 1 month.
Difficulty swallowing occurs in about 10% of patients. Most of the time this is very mild and does not
require you to change the food you eat. This usually lasts around 1 week.
Some patients simply do not respond to treatment with Botox.