Why Spasmodic dysphonia is often mistaken for a functional disorder?


Spasmodic dysphonia, also called laryngeal dystonia, is a neurological disorder, responsible of a strangulated, strained voice and rarely of a whispering voice, which has a major negative influence at work and in personal life.

Patients with spasmodic dysphonia require to be distinguishing from patients with functional dysphonia and from patients with “muscle tension dysphonia” (MTD) which is also considered a functional disorder rather than a neurological disorder.

Many reasons can explain why spasmodic dysphonia , which is a dystonia of the larynx, is not well recognized by doctors.

1- Laryngeal dystonia is a rare condition (1/100 000), and like other focal dystonia, the diagnosis is clinical; if you have never heard somebody with spasmodic dysphonia speaking, it will be very difficult to recognize it.

2- It mainly occurs in women, who carry the stigma of being more vulnerable for functional disorders.

3- The onset can be sudden in 45% of the cases (Childs, 2011).  Sudden onset is also a characteristic of functional disorders.

4- When the onset is sudden, the majority of patients recognized triggering factors such as stress (42%), upper respiratory infection (33%), and pregnancy and parturition (10%).(Childs, 2011). Stress should be seen as a non-specific triggering factor making patients vulnerable to develop any medical conditions, and not specifically functional disorders.

5-A phobic component occurs very quickly after onset, as the patient avoid answering the phone, and speaking in public as it’s required such an effort to speak in these circumstances.

6-It’s a task specific condition as every focal dystonia,; spasmodic dysphonia occurs when speaking, and voice can be normal for singing or shouting. This task specific characteristic can be disconcerting for both the patient and the doctor.

At the difference, functional dysphonia is responsible of a permanent speech disturbance, with a whispering voice or a hoarse voice occurring when speaking, and impossibility of shouting or singing.

7- “Muscle tension dysphonia” (MDT) patients tend to exert too much effort on their vocal cords when speaking and can present with a strained voice, as spasmodic dysphonia.

But when examining the speech in details, three tasks: sustained vowel /a/, oral reading of a standard passage, and connected speech describing a standard picture have to be performed, as the spasmodic dysphonia could be more apparent in the connected speech situation, compared to MDT.


It’s very important to diagnose spasmodic dysphonia, as Botox injections into the vocal cords can alleviate the symptoms and restore confidence for effortless speaking.

At the London BTX centre, in Sloane Square, Dr. Marie-Helene Marion offers multidisciplinary clinics with voice specialists for the diagnosis and  treatment of spasmodic dysphonia with Botox injections.