Spasmodic Dysphonia (SD) is a localized muscle disorder (dystonia) of the voice box or larynx. Another term that has been used in the past that is not used much now is Spastic Dysphonia. It is not clear what causes SD but it generally begins in 3rd to 4th decade and progresses from a mild problem to more significant effect on voice over time. Although there may be an inciting event such as a viral illness or trauma, this is usually not the case. There are rare cases that would appear to be genetic with a strong family history. The voice characteristics are classic with interruptions in voice with either a strained spastic quality or a breathy quality.
There are 2 types of SD. One is when there is forceful closure or spasm with speech called Adductor SD. The other is when the focal fold spasm open with speech and there is s very breathy voice with the patient losing there air quickly which is called Abductor SD. There is a much less common situation where a person has both spasm with closing and opening during speech which is called mixed spasmodic dysphonia. Adductor SD is much more common than abductor SD, accounting for about 80% of cases. Spasmodic dysphonia typically occurs as a solitary muscle disorder, confined to the voice box, although a number of patients have other dystonias, such as blepherospasm (spasm of the eye), hemifacial spasm (spasm of face), spasmodic torticollis (spasm of the neck muscle), and others.
Listen to examples:
- Adductor Spasmodic Dysphonia (ADD)
- Abductor Spasmodic Dysphonia (ABD)
The diagnosis if SD may be difficult in the early stages since many people will just have a strained or breathy voice. In some cases, they may be told that there is no problem or it is just due to tension. As the problem worsens, which it typically will, the individual usually gets in to see an Otolaryngologist (ENT) or a Speech-Language Pathologist, where the diagnosis is made by the characteristics of voice and confirmed by looking at the larynx (voice box) with a small scope that can be used comfortably in the office.
There are many treatments that have been used for SD. Voice therapy may be valuable in the early treatment or combined with other treatments. Over the past couple of decades, the treatment of choice for most patients has been botulinum toxin (BOTOX) injections into the muscles of the larynx. This temporarily weakens or paralyzes these muscles which reduces or eliminates the spasms. The procedure is simple, easily accomplished in the office setting and has had predictably good results, with most patients experiencing a return to normal voice. BOTOX injections are temporary, so patients that are treated with these will usually need repeat injections 2-4 times a year. Using a scale of 0 (no voice or full disability) to 100 (normal voice) to assess the responses to treatment of BOTOX for SD, it has been shown that on average a score of 90 was attained following injection.
There are other, less common procedures that have been used to treat SD. Cutting one of the nerves that supplies the larynx (recurrent laryngeal nerve section) was performed before BOTOX was routinely used, but is rarely performed at this time. There are newer procedures such as cutting one of the small branches of the nerve to the larynx or adjusting the cartilage framework of the larynx, but these are generally reserved for the rare patient that does not due well with BOTOX injections.
Since SD is not uncommon there are support groups available in most communities. These can be reached through the National Spasmodic Dysphonia Association or through the National Dystonia Association.