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Spasmodic dystonia is a neurological disorder. Although the exact cause of this condition is not yet known, there is an adequate treatment for this condition.


Dysphonia causes the larynx muscles to contract uncontrollably. The complaints depend on the type of muscles that contract. If the muscles that close the vocal cords are affected, we speak of "adductor" spasmodic dystonia. The voice then sounds 'cascaded'. If the muscles that open the vocal cords open (as in the case of inhalation) are affected, we speak of "abductor" spasmodic dystonia. The voice is interrupted by whispering sounds.


The most frequent voice complaints of this condition are:

  • I have had a cold / respiratory infection and the complaints have not gone as usual.

  • my voice is very variable

  • I have to make an effort to express my words

  • I can sing more easily than speak

  • when I speak with a high voice the spasms go away

  • I hate talking on the phone

  • I have good weeks and bad weeks

  • I must stop teaching, working (if speaking profession)


Spasmodic dysphonia is a neurologic disorder. Medical science does not yet know the cause or exactly how the disorder works. There seems to be some emerging research that points to a problem in the feedback loop between the brain and the organ with the dystonia – in this case the voice box. Due to a problem with this feedback loop, there is over-control with resultant spasms or overly tight muscle contractions. Research with PET scans has shown a decrease in activation of the brain once treatment has decreased the effortfulness of using the associated muscle. Despite this lack of knowledge of the etiology, there is a good treatment for the symptoms of the disorder.



The voice organ and its function are examined by an ENT doctor and a speech therapist. The voice has 3 functions: breathing, protecting the airway while swallowing and speaking. Every person is dependent on these 3 functions every moment of the day.

In addition to a thorough survey and a clinical examination of the neck, an inspection of the vocal cords (laryngoscopy) takes place at rest and during vocalization. This is supplemented by a stroboscopy, research in which through short flashes of light, the vibration pattern of the vocal cords is delayed and thus displayed in more detail.

Then, the voice and voice capacity is listened to. One can often hear the nature of the voice problem while speaking. Sliding, softer or louder voices, soft singing can help to find the right cause of the weak or painful voice.

In addition, a voice examination usually takes place, including aerodynamic parameters (the maximum phonation time), acoustically perceptual parameters (e.g. habitual speech pitch, voice quality in function of the change intensity and pitch) and the vocal range (intensity and frequency dynamics).



The treatment of dystonia consists of weakening the uncontrolled contractile muscles. This is done by locally injecting a Botox product (a toned botulinum toxin). This gives a temporary effect (on average a few months) and has to be re-injected after elaboration. This procedure is performed on the basis of an electromyographic signal (EMG) to treat the most affected muscles and for that reason is carried out together with a colleague physician of physical medicine.

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