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What is it?
Spasmodic dysphonia, a focal form of dystonia, involves involuntary “spasms” of the vocal cords, causing interruptions of speech and affecting the voice quality.
Doctors recognise two types of spasmodic dysphonia. In the more common adductor type, speaking causes abnormal, involuntary, excessive contractions of the muscles that bring the vocal cords together. This causes a tight voice quality, often with abrupt initiation and termination of voicing, resulting in a broken speech pattern and short breaks in speech.
In the abductor type, there is an overcontraction of the muscles that separate the vocal cords, resulting in a breathy, whispering voice pattern.
Three other sub-types of SD have been identified by clinicians. One is a combination of adductor and abductor symptoms in which an individual may demonstrate both types of spasms as he/she speaks. In a second subtype, SD symptoms are accompanied by a voice tremor. A third subtype involves a primary voice tremor that is so severe the patient experiences adductor voice stoppages during the tremor.
Symptoms may improve or disappear when whispering, laughing, or singing. Many of the symptoms vary during the day, become aggravated by certain speaking, especially talking on the phone, or increase during stressful situations.
Although it can start any time during a life, spasmodic dysphonia seems to begin frequently in the 40 to 50 year-old group.
SD may also be referred to as Laryngeal Dystonia.
If spasmodic dysphonia causes any type of impairment, it is because muscle contractions interfere with normal function. Features such as cognition, strength, and the senses, including vision and hearing, are normal.
In most cases the cause of spasmodic dysphonia is unknown. The general medical consensus is that SD is a central nervous system disorder and is a focal form of dystonia.
Dystonia disorders are thought to be due to abnormal functioning in the area of the brain called the basal ganglia. The basal ganglia are structures situated deep in the brain.
Onset is usually gradual with no obvious explanation. Researchers are investigating possible mechanisms involved in the triggering of SD including familial factors, inflammation, and/or injury that may lead to central nervous system changes in laryngeal motor control.
SD may co-occur with other dystonias such as blepharospasm, oromandibular dystonia, or cervical dystonia.
Spasmodic dysphonia is reported to be one of the most frequently misdiagnosed conditions in Speech-Language Pathology. Because there is no definitive test for the SD, the diagnosis rests on the presence of characteristic clinical symptoms and signs in the absence of other conditions that may mimic spasmodic dysphonia.
It is important that an interdisciplinary team of professionals evaluate and provide accurate differential diagnosis. This team usually includes a speech therapist who evaluates voice production and voice quality; a neurologist who carefully searches for other signs of dystonia or other neurological conditions; and an otolaryngologist who examines the vocal cords and their movements.
The excessive strain and misuse of muscle tension dysphonia, the harsh strained voice of certain neurological conditions, the weak voice symptoms of Parkinson’s disease, certain psychogenic voice problems, and voice tremors are often confused with spasmodic dysphonia.
Treatment for spasmodic dysphonia is designed to help lessen the symptoms of the vocal spasms and improve the quality of the person’s voice. Working with your doctor, an individualized strategy for treatment can be developed.
Oral medications provide little relief in the symptoms of spasmodic dysphonia.
Botulinum Toxin Injections
Local injections of botulinum toxin into the vocal cord muscles have proven to be the most effective treatment for spasmodic dysphonia. Botulinum toxin is a therapeutic muscle-relaxing agent that helps weaken the vocal muscles so that spasms are diminished and speech is improved. The treatment can also reduce the breathiness and help decrease the effort required to speak. It acts to weaken muscle activity sufficiently to reduce spasms but not enough to cause paralysis.
People with the more common adductor form of spasmodic dysphonia typically respond better to botulinum toxin injections than those persons with the abductor form of spasmodic dysphonia. One reason for this is that the muscles affected in abductor are located behind the larynx, making injections more difficult.
The benefits of botulinum toxin injections vary for each individual depending on injection technique, sub optimal dosing, and patient biology, but results can last anywhere from six weeks to six months
The two most common side effects are dysphagia, difficulty in swallowing, and an increase breathiness of voice. Both usually only last from 6 to 12 days after the injection. Adjusting the dose by using the lowest possible effective dose should prevent breathy after-effects of botulinum toxin injections.
Surgery for spasmodic dysphonia has recently been re-examined as a form of treatment for people for whom botulinum toxin injections are no longer providing relief of symptoms. Selective Laryngeal Adductor Denervation-Reinnervation surgery involves cutting the nerve to the affected vocal cord and re-innervating the muscle with another muscle to prevent muscle atrophy.
General voice relaxation techniques and speech therapy may play an adjunct role in the treatment of spasmodic dysphonia. These include reducing one’s vocal effort, loudness, intonation, and rate of utterance while increasing pause time between phrases. These techniques can only be reinforced and
adapted if they do not intrude on the vocal naturalness.
Some people with spasmodic dysphonia suggest the use of a voice amplifier for the phone or that of a self-contained microphone used in conjunction with any FM radio.
Dystonia and its emotional offshoots affect every aspect of a person’s life - how we think, the way we act, and how we cope. By educating yourself with information, you have taken the first step in dealing with dystonia.
Stress is an inevitable part of life, and although it clearly does not cause dystonia, it can aggravate dystonia symptoms. Stress-reduction programmes such as relaxation techniques, meditation, and journal writing may be beneficial.
Sometimes depression can be a byproduct of dystonia. It, too, can aggravate symptoms and make them worse, but, often, treating depression can result in an improvement of dystonia. It is important to remember that depression is a disorder; it is treatable and not a reflection of one’s self.
Many people are experiencing similar symptoms. Reassurance from family, friends, and others who have dystonia is beneficial. Dystonia Ireland has a support group in Dublin and it is our intention eventually to set up similar groups throughout Ireland. Sharing experiences at support group eetings offers encouragement, camaraderie, and the latest information about new treatments and medical advances.
With written permission, this information is reproduced from materials published and copyrighted by the Dystonia Medical Research Foundation, Chicago, IL, USA www.dystonia-foundation.org