What is spasmodic dysphonia (laryngeal dystonia)?
Spasmodic dysphonia, also called as laryngeal dystonia, is a neurological disorder which causes improper movement of the muscles of the larynx (voice box). It changes the voice and lends it a strangled quality. There are three variants of this condition:
- Adductor spasmodic dysphonia, wherein the vocal cords close and stiffen, leading to a strained voice.
- Abductor spasmodic dysphonia, in which the vocal cords stay open, resulting in a weak and quiet voice.
- Mixed spasmodic dysphonia, where the vocal cords open and close inappropriately.
What are its main signs and symptoms?
Spasmodic dysphonia is a rare disorder which can affect anyone. Women are affected more than men. Generally, the condition develops gradually with mild symptoms.
- Adductor spasmodic dysphonia results in a voice that sounds full of effort or strangled due to the muscle spasms.
- On the other hand, the voice due to abductor spasmodic dysphonia sounds weak and breathy. Spasms are absent while laughing, crying or shouting.
What are the main causes?
The exact cause of the condition is unclear but it is often believed to be due to chemical alterations in a specific area of the brain – the basal ganglia. The basal ganglia contain several clusters of nerve cells deep inside the brain. They coordinate the movements of muscles throughout the body. Spasmodic dysphonia can be triggered by stress, injury to the voice box or illness as well. Genetic factors also increase the risk of being diagnosed with spasmodic dysphonia.
How is it diagnosed and treated?
Since the symptoms of spasmodic dysphonia are similar to those of other vocal cord disorders, its diagnosis is difficult. Hence, a team consisting of a speech pathologist, ENT specialist and a neurologist experienced in the management of spasmodic dysphonia is required for an accurate diagnosis.
The ENT specialist will perform a detailed laryngeal examination. The speech pathologist evaluates the quality of the voice and will provide information, encouragement and ideas to help manage the condition more effectively. Since stress is known to aggravate the symptoms, stress management or relaxation therapy may help to cope with the symptoms.
The neurologist evaluates the patient for other movement disorders and may try certain medicines where appropriate. Local injection of botulinum into the vocal cord muscles can provide temporary relief from the symptoms. Speech therapy also forms a part of the treatment plan. When conventional measures are ineffective, surgery may be suggested.