What is dystonia?
Dystonia is a neurological movement disorder characterized by involuntary (unintended) muscle contractions that cause slow repetitive movements or abnormal postures that can sometimes be painful. There are several different forms of dystonia that may affect only one muscle, groups of muscles, or muscles throughout the body. The affected areas and severity of symptoms varies from person to person.
Dystonia can occur on its own or be the result of another condition, some of which may be hereditary. Some forms of dystonia are genetic. The disorder typically is not associated with problems thinking or understanding. Dystonia is not fatal, but problems related to conditions that may result from dystonia may be life-threatening.
The initial symptoms can be very mild and may be noticeable only after prolonged exertion, stress, or fatigue. Over time, the symptoms may become more noticeable or widespread; sometimes, however, there is little or no progression. Symptoms may include:
- A foot cramp or a tendency for one foot to turn or drag—either occurring occasionally or in irregular patterns or after running or walking some distance
- A worsening in handwriting after writing several lines
- An involuntary turning of the neck, especially when the person is tired or under stress
- Rapid and uncontrollable blinking of both eyes; other times, spasms will cause the eyes to close
- Difficulty speaking
Dystonia often progresses through various stages. Initially, the movements may be intermittent and appear only during voluntary movements or stress. Later, the dystonic postures and movements can be seen while walking and ultimately even when the person is relaxed. Dystonia can be associated with fixed postures and shortening of tendons.
In some cases, dystonia can affect only one specific action, while allowing others to occur without any problems. For example, a musician may have dystonia when using a hand to play an instrument, but not when using the same hand to type.
Dystonia can occur at any age, but some forms are often divided as either early (childhood) or adult onset.
- Early onset dystonia often begins with symptoms in the arms and legs and may progress to involve other regions of the body. Some symptoms tend to occur after periods of exertion and/or fluctuate over the course of the day.
- Adult-onset dystonia usually is located in one or adjacent parts of the body, most often involving the neck and/or facial muscles. Some dystonias can affect other regions of the body.
Dystonia is classified along two distinct axes.
- Axis I is based on clinical features which include age at onset, body region affected, specific features, and whether there are associated clinical problems.
- Axis II is based on the cause of the dystonia. This classification includes dystonia that doesn't have a known cause as well as dystonia caused by genetics or abnormalities in the brain.
There are many different forms of dystonia. Within Axis I, some are grouped by the regions of the body which they affect:
- Generalized dystonia affects most or all of the body.
- Focal dystonia is localized to a specific part of the body.
- Multifocal dystonia involves two or more unrelated body parts.
- Segmental dystonia affects two or more adjacent parts of the body.
- Hemidystonia involves the arm and leg on the same side of the body.
Some of the more common forms that involve a specific part of the body are:
Cervical dystonia, also called spasmodic torticollis or torticollis, is the most common of the focal dystonias. It affects the muscles in the neck that control the position of the head, causing the head to turn to one side or to be pulled forward or backward. Sometimes the shoulder is pulled up. Cervical dystonia can occur at any age, although for most individuals it first occurs in midlife. It often begins slowly and usually reaches a plateau over a few months or years. About 10 percent of those with torticollis may experience a spontaneous remission, but it may not be lasting.
Blepharospasm, the second most common focal dystonia, is the involuntary, forcible contraction of the muscles controlling eye blinks. The first symptoms may be increased blinking, and usually both eyes are affected. Spasms may cause the eyelids to close completely, resulting in “functional blindness” even though the eyes are healthy and vision is normal.
Cranial dystonia affects the muscles of the head, face, and neck. The term Meige syndrome is sometimes applied to cranial dystonia accompanied by blepharospasm.
Oromandibular dystonia affects the muscles of the jaw, lips, and tongue. It may cause difficulties with opening and closing the jaw, and speech and swallowing can be affected.
Spasmodic dysphonia, also called laryngeal dystonia, involves the muscles that control the vocal cords, resulting in strained or breathy speech.
Task-specific dystonias tend to occur only when undertaking a particular repetitive activity. Examples include writer's cramp that affects the muscles of the hand and sometimes the forearm, and only occurs during handwriting. Similar focal dystonias have also been called typist's cramp, pianist's cramp, and musician's cramp. Musician's dystonia is a term used to classify focal dystonias affecting musicians, specifically their ability to play an instrument or to perform. It can involve the hand in keyboard or string players, the mouth and lips in wind players, or the voice in singers.
Who is more likely to get dystonia?
Researchers believe that dystonia results from an abnormality in or damage to the basal ganglia or other brain regions that control movement. There may be abnormalities in the brain's ability to process a group of chemicals called neurotransmitters that help cells in the brain communicate with each other. There also may be abnormalities in the way the brain processes information and generates commands to move. In most cases, no abnormalities are visible using magnetic resonance imaging or other diagnostic imaging.
The dystonias can be divided into three groups: idiopathic, genetic, and acquired.
Idiopathic dystonia refers to dystonia that does not have a clear cause. Many instances of dystonia are idiopathic.
Genetic dystonia is caused by inheriting an abnormal gene. Symptoms may vary widely in type and severity even among members of the same family. In some instances, a person who inherits the defective gene may not develop dystonia. Dystonia can be a symptom of other diseases, some of which may be hereditary. Known genetic forms of dystonia include:
- DYT1 dystonia is a rare form of dystonia that typically begins in childhood, affects the limbs first, and continues to worsen, often causing significant disability.
- Dopa-responsive dystonia (DRD), also known as Segawa's disease, typically begins during childhood and may cause progressive difficulty with walking. Symptoms characteristically fluctuate and are worse late in the day and after exercise. Some forms of DRD are due to mutations in the DYT5 gene. People living with this disorder have dramatic improvements in symptoms after treatment with levodopa, a medication commonly used to treat Parkinson's disease.
Other genes that are known to cause dystonia include:
- DYT3, which causes dystonia associated with parkinsonism (has Parkinson-like symptoms such as tremor, muscle stiffness, and slow movement)
- DYT6, which affects muscles in the head, neck, and arm (and sometimes a leg)
- DYT11, which causes dystonia associated with myoclonus (brief contractions of muscles)
- DYT12, which causes rapid onset dystonia associated with parkinsonism, and
- DYT28, which is associated with childhood onset dystonia.
Acquired dystonia, also called secondary dystonia, results from environmental or other damage to the brain, or from exposure to certain types of medications. Some causes of acquired dystonia include birth injury (including hypoxia, a lack of oxygen to the brain, and neonatal brain hemorrhage), certain infections, reactions to certain drugs, heavy metal or carbon monoxide poisoning, trauma, or stroke. Acquired dystonia often plateaus and does not spread to other parts of the body. Dystonia that occurs as a result of medications often ceases if the medications are stopped quickly.
How is dystonia diagnosed and treated?
Diagnosis is based on a physical and neurological exam, the individual's personal and family history of disease, laboratory tests, diagnostic imaging, measuring electrical activity produced by muscles, and other tests to rule out any conditions that may be causing symptoms similar to dystonia. Genetic testing can confirm a known mutation for some forms of dystonia.
Currently, there are no medications to prevent dystonia or slow its progression. There are, however, several treatment options that can ease some of the symptoms of dystonia, so physicians can select a therapeutic approach based on each individual's symptoms.
Botulinum toxin. Botulinum injections often are the most effective treatment for the focal dystonias. Injections of small amounts of this chemical into affected muscles prevent muscle contractions and can provide temporary improvement. The toxin decreases muscle spasms by blocking release of the neurotransmitter acetylcholine, which normally causes muscles to contract. The effect typically is seen a few days after the injections and can last for several months before the injections must be repeated.
Several classes of drugs that affect different neurotransmitters may be effective in treating muscle spasms for various forms of dystonia. These medications are used “off-label,” meaning they are approved by the U.S. Food and Drug Administration (FDA) to treat different disorders or conditions but have not been specifically approved to treat dystonia. The response to drugs varies among individuals and even in the same person over time. These drugs include:
- Anticholinergic agents block the effects of the neurotransmitter acetylcholine. Drugs in this group include trihexyphenidyl and benztropine. Sometimes these medications can be sedating or cause side effects such as dry mouth, constipation, and difficulty with memory.
- GABAergic agents are drugs that regulate the neurotransmitter GABA. These medications include the benzodiazepines such as diazepam, lorazepam, clonazepam, and baclofen. Drowsiness is their common side effect.
- Dopaminergic agents act on the dopamine system and the neurotransmitter dopamine, which helps control muscle movement. Some individuals may benefit from drugs that block the effects of dopamine, such as tetrabenazine. Side effects (such as weight gain, depression, and involuntary and repetitive muscle movements) can restrict the use of these medications. Dopa-responsive dystonia is a specific form of dystonia that most commonly affects children, and often can be well managed with levodopa.
- Deep brain stimulation (DBS) may be recommended for some individuals with dystonia, especially when medications do not sufficiently ease symptoms or if the side effects are too severe. DBS involves surgically implanting small electrodes that are connected to a pulse generator into specific brain regions that control movement. Controlled amounts of electricity are sent into the exact region of the brain that generates the dystonic symptoms and interfere with and block the electrical signals that cause the symptoms.
- Other surgeries aim to interrupt the pathways responsible for the abnormal movements at various levels of the nervous system. Some operations purposely damage small regions of the thalamus (thalamotomy), globus pallidus (pallidotomy), or other deep centers in the brain. Other surgeries include cutting nerves leading to the nerve roots deep in the neck close to the spinal cord (anterior cervical rhizotomy) or removing the nerves at the point they enter the contracting muscles (selective peripheral denervation). Some individuals report significant symptom reduction after surgery.
Physical, speech, and occupational therapies can help many people with dystonia. Speech therapy and/or voice therapy can be helpful for some affected by spasmodic dysphonia. Physical therapy, the use of splints, stress management, and biofeedback also may help individuals with certain forms of dystonia. Occupational therapy involves learning new ways of performing everyday activities such as eating and getting dressed.
What are the latest updates on dystonia?
The ultimate goals of research are to find the cause(s) of the dystonias so that they can be prevented, and to find ways to cure or more effectively treat people who are affected. The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), is the Federal agency with primary responsibility for brain and neuromuscular research. NINDS sponsors research on dystonia both in its facilities at the NIH and through grants to medical centers and institutions throughout the country. Other NIH institutes also sponsor research on dystonia. For more information about NIH research on dysphonia and other disorders, see NIH RePORTER, a database of NIH-funded research projects. For research articles and summaries on dystonia, search PubMed, which contains citations from medical journals and other sites.
Scientists at NINDS laboratories and clinics have conducted detailed investigations of the patterns of muscle activity, imaging studies of brain activity, and physiological studies of the brain in persons with dystonia. Scientists continue to search for genes responsible for some forms of dystonia.
Treatment studies, using surgery or medication, are being conducted in many centers, including the NIH. To learn more about clinical studies on dystonia, visit ClinicalTrials.gov.
How can I or my loved one help improve care for people with dystonia?
Consider participating in a clinical trial so clinicians and scientists can learn more about dystonia and related conditions. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.
All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.
For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with dystonia at Clinicaltrials.gov, a database of past and current clinical trials.
Where can I find more information about dystonia?
Information on dystonia and related movement disorders is available from the following organizations:
National Spasmodic Torticollis Association
Phone: 714-378-9837 or 800-487-8385
Benign Essential Blepharospasm Research Foundation