What is spasmodic dysphonia?

What is spasmodic dysphonia?

Spasmodic dysphonia is a neurological voice disorder affecting the voice muscles in the larynx, or voice box. The speech sounds strangled or very breathy depending on the form of SD. It is also called laryngeal dystonia.

Spasmodic dyshonia makes it very difficult to talk and to express oneself. Most of the time people who are affected  can still sing, cry, shout and whisper.

Spasmodic dysphonia causes voice breaks and can give the voice a tight, strained quality. People with spasmodic dysphonia may have occasional breaks in their voice that occur once every few sentences. Usually, however, the disorder is more severe and spasms may occur on every other word, making a person’s speech very difficult for others to understand. At first, symptoms may be mild and occur only occasionally, but they may worsen and become more frequent over time. Spasmodic dysphonia is a chronic condition that continues throughout a person’s life.

Spasmodic dysphonia can affect anyone. It is a rare disorder, occurring in roughly one to four people per 100,000 people. The first signs are found most often in people between 30 and 50 years of age. It affects women more than men.

Muscle Tension Dysphonia

What is Muscle Tension Dysphonia?

Muscle Tension Dysphonia (MTD) is a voice disorder characterised by strained, effortful voice that can usually tire your voice and in some cases cause damage to the vocal folds if used extensively.

Causes of Muscle Tension Dysphonia?

The cause of MTD is not very well understood.
It may be caused by irritants such as:

  • upper respiratory infection
  • passive smoking
  • acid reflux (heartburn)
  • excessive demand placed on your voice or stressful life events.
  • Often, it is likely that more than one of these factors contribute to MTD.

two types of MTD:

Primary MTD – in this type the muscles in your neck are tense when using your voice but there is no abnormality in the Larynx (“voice box”).
Secondary MDT – in this type there is an abnormality in the voice box causing you to over-use other muscles to help produce voice.

What are the symptoms of Muscle Tension Dysphonia?

Changes to your voice:

  • Your voice may sound husky, hoarse, breathy and/or rough.
  • The loudness of your voice may decrease.
  • You may find it difficult or effortful to make yourself heard in a noisy environment.
  • Your voice may become deeper.
  • The sound of your voice may deteriorate with prolonged voice use.

Adductor spasmodic dysphonia

This is the the type of spasmodic dysphonia I have; adductor spasmodic dysphonia,
or in short ADSD.

With this type, your voice sounds strangled and it requires a lot of effort
to push your voice out.

Workings of adductor spasmodic dysphonia

This is the most common form of spasmodic dysphonia. It is characterized by spasms that cause the vocal folds to slam together and stiffen. These spasms make it difficult for the vocal folds to vibrate and produce sounds. Words are often cut off or are difficult to start because of muscle spasms. Therefore, speech may be choppy. The voice of someone with adductor spasmodic dysphonia is commonly described as strained or strangled and full of effort. The spasms are usually absent—and the voice sounds normal—while laughing, crying, or shouting. Stress often makes the muscle spasms more severe.


Treatment of adductor spasmodic dysphonia

This SD type has the greatest chance of improvement with Botox.
When your doctor is skilled it will be a piece of cake to have the Botox injections
throught he front of your neck. You don’t need any anaestetic, because you will
only feel a small needle prick.

Diagnosis of spasmodic dysphonia

It usually takes a long time, sometimes many years, before the right diagnosis is made.
People notice that their voice is off and sounds different. You first think that it is because
you are fatigued. Then you think you have a laryngitis, maybe caught a cold. It doesn’t
go away and you go to see the doctor.

The doctor

The doctor sees no strange things and sends you to a ENT.
The ENT thinks that it is maybe psychological and sends you to a therapist or
psychologist. You start to doubt your sanity and you become depressed.
Hopefully soon in this process you encounter somebody who knows what is going on.
When you end up with some doctor or speech therapist who can recognize spasmodic
dysphonia you are in luck. They will send you to a specialized ENT who can make the
correct diagnosis.

Medical history

They take your medical history, and then they have a look at your vocal chords while
you have to make certain sounds. There are two ways of doing this.

Flexible endoscope

The doctor will stick the flexible piece through your nose and let is glide down to look at
your vocal chords from above. He looks through the eye-piece on the left to evaluate the
closing and opening of the chords.

Rigid endoscope

This is a straight rod which is inserted through the mouth and can provide better image
quality and video recording of the movement of the vocal chords.

Below you see a video where the flexible and the rigid endoscope are demonstrated.

What you need for voice production

For the production of voice we need 4 things:

1. Air pressure produced by the lungs to vibrate the vocal chords
2. Vocal chords that open and close creating vibrations in the air-flow
3. Resonance of the air vibrations in the vocal tract
4. Openings in the body like the mouth and the nose to let the produced sound out
If there is a problem with one or more of these requirements the voice quality will suffer.

When the vocal chords close more, there is more surface to vibrate or to produce sound. So
when they are closer together, the sound becomes louder, with a lower pitch, with more vibration.
After each vibration, the vocal chords close very fast, for a short moment. Air under the vocal
chords builds up pressure and when they re-open the vibrating air comes out, producing the

Male and female voice

The frequency of the male voice is around 120 Hz and of the average woman lies around 210
Hz. This means that the vocal chords will close 120 times and 210 times a second for the male
and female voice. If you have a job where speaking is important, they will close 30.000 times an hour.

What is spasmodic dysphonia?

When you suffer from spasmodic dysphonia there is a problem with the learned skill of speaking. The
cells in the brain where the learned controls of the vocal chords muscles situate, are damaged.
The muscles that open or close the vocal chords in a smooth and controlled way, are receiving
scrambled signals. The signals that are being sent to the voice muscles normally do not operate like an on or off
switch. The activation of the muscles that close or open the vocal chords goes normally in a very
smooth and controlled way.

The brake is busted

All the muscles in your body receive two signals at the same time. You can compare it to your
car’s gas pedal and the brake. They receive an activation signal accompanied by an slow down
signal. If the activation signal is stronger then the slow down signal, the muscle contracts. The
more slow down signal there is, the less the muscle contracts.

On or off

When you suffer from spasmodic dysphonia there is a problem with the brain cells that produce
the slow-down signal. The muscles do not operate in a smooth way anymore, but they contract
like an on-off switch. It is like pressing the gas pedal fully down fast with your foot, while your
brake is not functioning anymore. And then releasing it in an instant. Your car will move in a very
jerky way. It is all or nothing.

All or nothing

This is exactly the problem with the muscles that move your vocal chords.
They go all the way open or all the way shut.


Spasmodic dysphonia diagnosis

Diagnosis of spasmodic dysphonia is often delayed due to lack of recognition of its symptoms by screening physicians. Most patients who are correctly diagnosed are evaluated by a team that usually includes an otolaryngologist, a speech-language pathologist and a neurologist.

The otolaryngologist examines the vocal folds to look for other possible causes for the voice disorder. Fiberoptic laryngoscopy, a method whereby a small lighted flexible tube is passed through the nose and into the throat, is a helpful tool that allows the otolaryngologist to evaluate vocal cord movement during speech.

Additional diagnostic testing may include stroboscopy, which allows the physician to view the vibrations of the vocal cords in slow motion. The speech-language pathologist evaluates the patient’s voice and voice quality.

The neurologist evaluates the patient for signs of other movement disorders.


Spasmodic Dysphonia types

The three types of spasmodic dysphonia (SD) are adductor spasmodic dysphonia, abductor spasmodic dysphonia and mixed spasmodic dysphonia.

Adductor spasmodic dysphonia

In adductor spasmodic dysphonia (ADSD), sudden involuntary muscle movements or spasms cause the vocal folds (or vocal cords) to slam together and stiffen.These spasms make it difficult for the vocal folds to vibrate and produce voice. Words are often cut off or difficult to start because of the muscle spasms. Therefore, speech may be choppy but differs from stuttering. The voice of an individual with adductor spasmodic dysphonia is commonly described as strained or strangled and full of effort. Surprisingly, the spasms are usually absent while laughing, speaking at a high pitch, or speaking while singing, but singers can experience a loss of range or the inability to produce certain notes of a scale or with projection. Stress, however, often makes the muscle spasms more severe.

Abductor spasmodic dysphonia

In abductor spasmodic dysphonia, sudden involuntary muscle movements or spasms cause the vocal folds to open. The vocal folds cannot vibrate when they are open. The open position of the vocal folds also allows air to escape from the lungs during speech. As a result, the voices of these individuals often sound weak, quiet and breathy or whispery. As with adductor spasmodic dysphonia, the spasms are often absent during activities such as laughing or singing, but singers can experience a loss of range or the inability to produce certain notes of a scale or with projection.

Mixed spasmodic dysphonia

Mixed spasmodic dysphonia involves both muscles that open the vocal folds and those that close them and therefore has features of both adductor and abductor spasmodic dysphonia