Spasmodic dysphonia, also known as SD or laryngeal dystonia, is a condition of the larynx (voice box) that causes excessive tension and spasms in the vocal cords when speaking.
There are two main types of spasmodic dysphonia (SD). In adductor spasmodic dysphonia (ADSD), the vocal cords squeeze too tightly when talking, resulting in a strained, harsh voice.
In abductor spasmodic dysphonia (ABSD), the vocal cords open excessively when talking, resulting in a breathy voice.
Example of ADSD
Audio sourced from https://laryngopedia.com/classic-variant-spasmodic-dysphonia/
Example of ABSD
Audio sourced from https://youtu.be/kJ86-FwZYYI
SD is known as a “task-specific” dystonia. This means that the voice effects tend to be worse with speaking, as opposed to singing, laughing, or crying. Many people with SD also notice that their voice is worse when speaking on the phone or when speaking in high pressure situations (such as presentations).
SD is caused by abnormal signaling between the brain and the nerves that control movement of the vocal cords. The underlying trigger of SD is unknown in most people. In rare cases, there may be a genetic cause.
Voice therapy is generally not considered effective for SD, although certain voice techniques may help to reduce the symptoms in specific situations. The most common treatment for SD is Botox injections into the affected muscles in the vocal cords. Surgical procedures may be effective in certain people, but these are not commonly performed.