It is often described as an attack of laryngitis that “just didn’t go away” or an unexplained break in the voice, especially when certain words are produced. This is spasmodic dysphonia, a poorly understood condition in which the muscles that control the voice box involuntarily tighten.
Spasmodic dysphonia appears to originate in the basal ganglia of the brain, according to Voice Doctor.com. Recent research indicates a problem with the feedback loop between the brain and the muscles that control the voice box. This results in over-control and therefore tightening of the muscles.
This condition is classified as a focal dystonia, or involuntary muscle contractions in a particular small area of the body. A common example of a focal dystonia is writer’s cramp, in which the muscles that control the hands involuntarily tense up. Spasmodic dysphonia is the same type of condition but it afflicts the muscles that control the voice box.
Medscape.com indicates that the usual age of onset of this condition is between 39 and 45 years of age, but it may appear as early as the 20’s or as late as the 90’s. No genetic link has been established, but about 12 percent of patients indicate they have a relative with spasmodic dysphonia. It also frequently occurs with tremor.
The cause of the condition is not clear. About half of patients with spasmodic dysphonia report that onset occurred after a respiratory infection or a stressful life event.
Two types of dysphonia affect the voice: adductor and abductor dystonia. Adductor dysphonia, the more common form, affects the muscles that close the vocal cords. The voice sounds strained or strangled.
Abductor dysphonia is associated with tension in the muscles behind the larynx which open the voice box for breathing. The voice is breathy or whispery, and unvoiced consonants are prolonged. The patient has difficulty producing vowel sounds after unvoiced consonants.
Early physicians believed spasmodic dysphonia to be a psychological disorder, but this has not been borne out by investigation. The treatment of choice today for this chronic condition is botox injections. The price of botox is about $10-15 per unit, and varying amounts are used depending on patient needs, symptoms and individual risk factors.
Botox injections for adductor problems are made in the muscles occurring at the front of the throat. To treat abductor dysphonia, the physician must inject botox into the muscles behind the voice box and in front of the pharynx.
Botox has a very limited shelf life and must be special-ordered. Once the injection is completed, an initial phase of voice weakness may be experienced. After this passes, the usual effect is an improved voice function for about 12 weeks. After this, the injection must be repeated.
A recent report by the National Institutes of Health indicates that a rare complication of botox treatment for adductor dysphonia may cause abductor dysphonia, with some difficulty in breathing on exertion. Adjustment or discontinuation of botox injections leads to resolution of this problem.
Botox treatments may improve the voice of a patient who has experienced difficulty with speaking for even a prolonged period of time. Each patient and physician must weigh the benefits and risks of treatment.