All about laryngeal dystonia
Laryngeal dystonia, also known as spasmodic dysphonia, is a neurological voice disorder that affects the muscles of the larynx, or voice box. It causes involuntary muscle spasms during speech, resulting in interruptions to normal voice production.
This condition can make the voice sound strained, breathy, tight, or unstable. Laryngeal dystonia is a chronic condition, but effective treatments are available to improve voice quality and communication.
What is laryngeal dystonia and what causes it?
Laryngeal dystonia is a type of focal dystonia, meaning it affects a specific group of muscles. In this case, the muscles that control the vocal cords contract involuntarily when a person speaks. These spasms interfere with the smooth opening and closing of the vocal cords, which is necessary for normal voice production.
The exact cause is not fully understood, but it is linked to abnormal signalling in the brain areas responsible for movement control. It is considered a neurological condition rather than a structural problem with the throat.
Several factors may contribute to its development, including:
- Genetic predisposition in some cases
- Previous upper respiratory infections
- Voice strain or excessive voice use
- Neurological sensitivity affecting muscle control
Laryngeal dystonia is not caused by anxiety or psychological factors, although stress can worsen symptoms.
What are the symptoms of laryngeal dystonia?
The main symptom is difficulty producing a steady and clear voice. Symptoms can vary depending on the type of dystonia.
Common features include:
- Strained, tight, or strangled voice quality
- Sudden voice breaks during speech
- Effortful speaking with increased vocal effort
- Breathy or weak voice in some cases
- Voice fatigue when speaking for prolonged periods
Symptoms typically occur during speaking but may not affect breathing, whispering, or laughing. The condition usually develops gradually and may worsen over time without treatment.
How is laryngeal dystonia diagnosed?
Diagnosis requires specialist assessment by an ear, nose and throat specialist with expertise in voice disorders. Evaluation includes a detailed history and examination of voice function.
A key investigation is flexible nasendoscopy, which involves passing a thin camera through the nose to visualise the vocal cords during speech. This allows the specialist to observe abnormal muscle movements and confirm the diagnosis.
Other tests may be performed to exclude conditions such as vocal cord nodules, vocal cord paralysis, or neurological diseases.
Early and accurate diagnosis is important to ensure appropriate treatment.
What treatments are available?
The most effective treatment for laryngeal dystonia is botulinum toxin injection into the affected laryngeal muscles. This treatment temporarily relaxes the muscles and reduces spasms, improving voice quality.
Treatment options may include:
- Botulinum toxin injections performed in a specialist clinic
- Voice therapy with a speech and language therapist
- Supportive strategies to optimise vocal function
- Ongoing specialist follow-up to adjust treatment as needed
Botulinum toxin injections are considered the standard treatment and typically provide improvement for several months. Repeat injections are usually required to maintain results.
What can patients expect after treatment?
Most patients notice improvement in voice quality within days to weeks after treatment. The voice may initially sound slightly weak or breathy, but this usually improves as the muscles stabilise.
Treatment does not cure the underlying neurological condition, but it effectively manages symptoms and improves communication and quality of life.
With appropriate specialist care, patients with laryngeal dystonia can achieve significant improvement in voice control and daily functioning.