What Is Spasmodic Dysphonia?
Spasmodic Dysphonia, also known as Laryngeal Dystonia, is a form of focal dystonia. Dystonia is the term used to describe an illness dominated by involuntary spasms and muscle contractions that induce abnormal movements and postures. Such dystonic spasms may affect one part of the body, such as the eyes, neck or a limb; a larger region, such as the neck and arms; or the whole body. Unfortunately, dystonia is frequently misdiagnosed. Over 300,000 persons in North America are estimated to be affected.
What Causes Spasmodic Dysphonia?
There is no known cause of dystonia, nor is there a definitive test for it. Spasmodic Dysphonia (SD) is thought to be due to abnormal functioning in an area of the brain called the basal ganglia. The basal ganglia help to coordinate movements of the muscles throughout the body. In SD, the normally smooth coordination of the vocal cords is disrupted, resulting in an abnormal voice pattern.
Who Gets Spasmodic Dysphonia?
Anyone can acquire Spasmodic Dysphonia and often the onset is so slow that initially it may feel as if one has an upper respiratory infection or is having an allergic reaction to something. Although SD can start at any time during life, it seems to begin frequently in the 40-to-50-year-old group, and is slightly more common in women than men. A genetic factor is suspected in some patients because other family members may have signs or symptoms of Spasmodic Dysphonia or dystonia involving some other part of the body.
There are a number of ways of classifying the different types of dystonia. Primary or idiopathic dystonia arises with no known organic lesion. In primary dystonia, there is no alteration of consciousness, sensation or intellectual function. Secondary dystonia generally arises from some insult to the basal ganglia of the central nervous system such as trauma, toxins, drugs, neoplasm, infarction or other organic causes. Another way of classifying the dystonias is based on the body region involved. These are further subdivided into generalized dystonia affecting the entire body (Generalized Dystonia or Idiopathic Torsion Dystonia) and focal dystonia affecting only a particular body part. The focal dystonias include spasmodic torticollis, blepharospasm, oromandibular dystonia, orofacial-buccal dystonia, spasmodic dysphonia (SD), and writer's cramp.
Spasmodic dysphonia (SD), sometimes also referred to as laryngeal dystonia or spastic dysphonia, is a neurological condition, a focal dystonia, affecting the vocal muscles of the larynx. Like other forms of dystonia it is characterized by abnormal involuntary muscle movements. The vocal cord muscles contract so that in the adductor type, speech is effortful and often strained and strangled. Symptoms may improve or disappear temporarily when yawning, laughing, singing or relaxing. Periods of spontaneous improvement or remission for no reason are also not uncommon. The disorder may be aggravated by specific situations, such as talking on the telephone or emotional stress or fatigue. Although the symptoms can be exacerbated by stress or fatigue, spasmodic dysphonia is not caused by stress and is not a psychological disorder.
There are basically two types of spasmodic dysphonia (SD). In the adductor type, speaking causes involuntary excessive contraction of the muscles that bring the vocal cords together. This causes a strained, strangled, choked voice quality, often with abrupt initiation and termination of voicing. The resulting speech pattern is broken, interrupted and often sounds extremely effortful. In the abductor type, there is an excessive action of the muscles that open up the vocal cords, resulting in a choppy and breathy, whispering voice pattern. In some patients, both adductor and abductor, these involuntary muscle contractions may also result in the addition of an irregular voice tremor.
How Is Spasmodic Dysphonia Diagnosed?
SD is a rare condition and is often mistaken for "vocal abuse" or "voice strain" or even some psychological disorder. Because there is no definitive test for the condition, the diagnosis rests on the presence of characteristic clinical symptoms and signs, in the absence of other conditions that may mimic SD. Most patients are evaluated by a team, including a neurologist who carefully searches for other signs of dystonia or other neurological conditions, an otolaryngologist who examines the vocal cords and their movements, and a speech language pathologist who evaluates voice production and vocal quality. Because other conditions often mimic some of the symptoms of Spasmodic Dysphonia, it is important that a team approach be used to evaluate patients with a suspected diagnosis of SD
How Has Spasmodic Dysphonia Been Treated?
How Has Spasmodic Dysphonia Been Treated? Since the underlying causes of SD are unknown, there is at present no known cure for the condition. Physical methods of therapy (speech therapy or relaxation therapy) moderate symptoms in SD but are not of long-term benefit to most persons. Speech therapy, however, may play an important role in alleviating some of the symptoms of SD. Drug therapy provides little relief. Surgical therapy by sectioning the recurrent laryngeal nerve has been tried, however, in one study, three years after surgery, 64% of patients were not improved and 48% were worse than before surgery. More recently, BOTOX has been used to treat SD. See link below for information on treatment:
Reference: National Spasmodic Dysphonia Association
What Is Botox and How Does It Work?
Local injections of botulinum toxin (Botox) into the vocal cord muscles have proven to be the most efficacious form of treatment for the condition. Botulinum toxin is a toxin produced by the Clostridium botulinum bacteria. It paralyzes the muscles by blocking the nerve impulse to the muscle. When diluted and injected into the vocal cord muscles in very small quantities, it can provide significant relief of SD and a marked improvement in voice quality. The effect of the toxin lasts on average of 3-4 months (in some individuals even longer), after which time reinjection is necessary. Side effects can include temporary softness and breathiness of speech or transient difficulty in swallowing. The toxin should be administered by a physician specially trained in the anatomy and physiology of the larynx and in the administration of the toxin, i.e. an otolaryngologist. Although dystonia has no cure, Botox injections successfully reduce the symptoms and restore patients to many daily living activities.