Spasmodic Dysphonia (SD), also known as laryngeal dystonia, is a neurological voice disorder involving involuntary spasms of the vocal cords, which cause interruptions to speech and affects voice quality. In most cases it is limited to the vocal folds, but it can uncommonly involve other muscles in the head and neck region, or other parts of the body. It is rarely secondary to more generalised neurological conditions. Whilst the cause of Spasmodic Dysphonia is unknown, it is often triggered by stress or illness, affects more females than males and often presents around the age 40 – 50. People who suffer this condition find it emotionally draining and often find it hard to convey that it is a physical condition, not a nervous one!
Signs & Symptoms:
In most cases of spasmodic dysphonia there is an over contraction of the muscles that close the vocal cords, resulting in a tight, strained-strangled voice quality with intermittent breaks or stoppages (adductor form) with specific sounds or words. Often a great deal of effort is needed to speak and occasionally no sound is produced. In a smaller number of cases there is an over contraction of the muscles separating the vocal cords, resulting in a voice with breathy or whispery breaks (abductor type). Symptoms may improve or disappear when laughing, singing or whispering. They may also vary during the day, become aggravated by certain speaking tasks, or increase during stressful situations. SD may also be associated with a vocal tremour.
Diagnosing Spasmodic Dysphonia is difficult since the voice can vary significantly and the symptoms can present very similarly to other conditions such as Voice Tremor or Muscular Tension Dysphonia (a very common voice problem). This can lead to increased frustration and anxiety in the person with the condition and delays in accessing effective treatment. Specialist multidisciplinary Voice Clinics use high quality video-endoscopy of the larynx and vocal cords to aid in the differential diagnosis of this condition. If you have been seen initially at the Melbourne Voice Analysis Centre, you will be referred to a Neurologist for neurological examination and then, if appropriate, for treatment with Botox injections (see below). In many cases, a trial of voice therapy with a speech pathologist is also offered prior to Botox.
The treatment of choice, in most cases, is Botox® (Botulinum Toxin). This involves local injections of Botox into the affected vocal cord muscles, which can provide significant (although temporary) relief from symptoms and marked improvement in voice quality. Botox acts by weakening the overactive muscles for approximately two to six months, after which further injections are needed throughout the person’s life. Voice therapy in conjunction with Botox may prolong the improved voice quality. In some cases your treating ENT specialist may also discuss other medication or surgical options such as selective division and re-joining of nerves that supply the laryngeal muscles affected