Dystonia

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Dystonias are movement disorders in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The movements, which are involuntary and sometimes painful, may affect a single muscle, a group of muscles (such as those in the arms, legs, or neck), or the entire body.

Contents

Other Names

Dystonia can be categorized by the area of the body affected:

  • 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.

Types

Torsion dystonia

This type of dystonia, also referred to as previously called dystonia musculorum deformans or DMD, is a rare, generalized dystonia that may be inherited, usually begins in childhood, and becomes progressively worse. It can leave individuals seriously disabled and confined to a wheelchair.

Cervical dystonia

This type, also called spasmodic torticollis, or torticollis, is the most common of the focal dystonias. The muscles in the neck that control the position of the head are affected, causing the head to twist and turn to one side. In addition, the head may be pulled forward or backward. Most individuals first experience symptoms in middle age. About 10 to 20 percent of those with torticollis experience a spontaneous remission, but unfortunately the remission may not be lasting.

Blepharospasm

Blepharospasm, the second most common focal dystonia is the involuntary, forcible closure of the eyelids. The first symptom may be uncontrollable blinking. Only one eye may be affected initially, but eventually both eyes are usually involved. The spasms may leave the eyelids completely closed causing functional blindness even though the eyes and vision are normal.

Cranial dystonia

This is term used to describe dystonia that affects the muscles of the head, face, and neck. Spasmodic torticollis can be classified as a type of cranial dystonia.

Oromandibular dystonia

Oromandibular dystonia affects the muscles of the jaw, lips, and tongue. The jaw may be pulled either open or shut, and speech and swallowing can be difficult.

Spasmodic dystonia

This type of dystonia involves the muscles of the throat that control speech. It is also called spastic dysphonia or laryngeal dystonia. It causes straining and difficulty in speaking and breathing, affecting speech.

Meige's syndrome

Meige's syndrome is the combination of blepharospasm and oromandibular dystonia and sometimes spasmodic dysphonia.

Writer's cramp

This is a dystonia 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.

Dopa-responsive dystonia (DRD)

DRD begins in childhood or adolescence with progressive difficulty in walking and, in some cases, spasticity (constant muscle tightness). In Segawa's dystonia (a variant of DRD), the symptoms fluctuate during the day from relative mobility in the morning to increasingly worse disability in the afternoon and evening as well as after exercise. The diagnosis of DRD may be missed since it mimics many of the symptoms of Cerebral Palsy.

Symptoms

Dystonia can affect many different parts of the body. Early symptoms may include:

  • A deterioration in handwriting after writing several lines.
  • Foot cramps, and/or a tendency of one foot to pull up or drag (this may occur spontaneously or after running/walking some distance).
  • Involuntary turning of the neck, especially when the patient is tired or stressed.
  • Rapidly and uncontrollably blinking of the eyes, rendering a person functionally blind.
  • Voice or speech difficulties.

The initial symptoms can be very mild and may be noticeable only after prolonged exertion, stress, or fatigue. Over a period of time, the symptoms may become more noticeable and widespread; however, sometimes there is little or no progression from mild to more severe symptoms.

In some individuals, symptoms of a dystonia appear in childhood, approximately between the ages of 5 and 16, usually in the foot or in the hand.

In generalized dystonia, the involuntary dystonic movements may progress quickly to involve all limbs and the torso, but the rate of progression usually slows noticeably after adolescence.

For some individuals, the symptoms emerge in late adolescence or early adulthood. In these cases, the dystonia often begins in upper body parts, with symptoms progressing slowly.

A dystonia that begins in adulthood is more likely to remain as a focal or segmental dystonia.

Dystonias often progress through various stages. Initially, dystonic movements are intermittent and appear only during voluntary movements or stress. Later, individuals may show dystonic postures and movements while walking and ultimately even while they are relaxed. Dystonic motions may lead to permanent physical deformities by causing tendons to shorten.

In secondary dystonias due to injury or stroke, people often have abnormal movements of just one side of the body, which may begin at the time of the brain injury or sometime afterward. Symptoms generally plateau and do not usually spread to other parts of the body.

Causes

Researchers believe that the dystonias result from an abnormality in an area of the brain called the basal ganglia where some of the messages that initiate muscle contractions are processed. Another theory is that dystonia may be caused by a defect in the body's ability to process a group of chemicals called neurotransmitters that help cells in the brain communicate with each other.

About half the cases of dystonia have no connection to disease or injury and are called primary or idiopathic dystonia. Genetic studies have revealed an underlying cause in many patients, a mutation in a gene named DYT1. It has been discovered that this gene is related not only to generalized dystonia, but also to some forms of focal dystonia.

The condition appears to be inherited in a dominant manner; i.e., only one carrier parent needs to contribute the defect in the dystonia gene for the disease to occur, thus each child has a 50% chance of being a carrier. However, a carrier may or may not develop a dystonia and the symptoms may vary widely even among members of the same family. In addition, some cases of primary dystonia may have different types of hereditary patterns. Knowing the pattern of inheritance can help families understand the risk of passing dystonia along to future generations.

Acquired dystonia, also called secondary dystonia results from environmental or disease-related damage to the basal ganglia, including:

  • Birth injury (particularly due to lack of oxygen)
  • Infections
  • Reactions to certain drugs
  • Heavy metal or carbon monoxide poisoning
  • Head Trauma
  • Stroke

Dystonias can also be symptoms of other diseases, some of which may be hereditary. An example is Wilson Disease, a neurological and liver disease caused by the accumulation of copper in the tissues.

Treatment

No one treatment has been found universally effective. Instead, physicians use a variety of therapies aimed at reducing or eliminating muscle spasms and pain:

Medications

Most of the medications used to treat dystonia work by affecting the neurotransmitter chemicals in the nervous system that send signals from the brain to affect muscle movement. Patients are typically started on the lowest dose of medication, and the dose is gradually increased until the benefit is fully realized and/or side effects require a lower dose.

The first drug administered belongs to a group that reduces the level of the neurotransmitter acetylcholine. Drugs in this group include:

Sometimes these medications can be sedating, especially at higher doses, and this can limit their usefulness. Other side effects include memory problems, hallucinations, dry mouth, blurred vision, urinary retention and constipation.

Drugs that regulate the neurotransmitter GABA may be used in combination with the acetylcholine-regulating drugs or, alone in patients with mild symptoms. GABA-regulating drugs include the muscle relaxants:

These drugs can cause sedation, depression and addiction. They should not be discontinued abruptly, as a withdrawl syndrome may result.

Drugs which increase the neurotransmitter dopamine include:

Side effects for these medicines include Side effects may include Parkinsonism (a syndrome resembling Parkinson disease, hypotension, and depression.

Ironically, patients have occasionally benefited from drugs that decrease dopamine. These include:

  • Reserpine
  • Tetrabenazine.

Anticonvulsants including carbamazepine (Tegretol), usually prescribed to control epilepsy, have occasionally helped individuals with dystonia.

Therapies

Botulinum toxin

Botulinum toxin (Botox) can be injected into affected muscles to provide temporary relief of focal dystonias. The toxin stops muscle spasms by blocking release of the excitatory neurotransmitter acetylcholine. The effect lasts for up to several months before the injections have to be repeated.

Surgery

Surgery may be recommended for some patients when medication is unsuccessful or the side effects are too severe. In selected cases, advanced generalized dystonias have been helped, at least temporarily, by surgical destruction of parts of the thalamus, a structure deep in the brain that helps control movement. Speech disturbance is a special risk accompanying this procedure, since the thalamus lies near brain structures that help control speech.

Surgically cutting or removing the nerves to the affected muscles has helped some focal dystonias, including blepharospasm, spasmodic dysphonia and torticollis.

The benefits of these operations, however, are also accompanied by the risks that surgery can lead to disfigurement, can be unpredictable, and is irreversible.

Other therapies

Some patients with spasmodic dysphonia may benefit from treatment by a speech-language pathologist.

Physical therapy, splinting, stress management, and biofeedback may also help individuals with certain forms of dystonia.

Holistic and alternative treatments

Complementary care may be an integral part of the treatment plan for dystonia. The following therapies may be helpful: [1]

  • Relaxation techniques
  • Body-mind techniques such as yoga, meditation, the Feldenkrais Method
  • Gentle and controlled physical exercise including Pilates and soft martial arts
  • Biofeedback
  • Acupuncture for pain relief

Living with Dystonia

Living with dystonia can be challenging. The condition can cause significant discomfort and the course can be unpredictable. Developing a modifiable treatment plan may be helpful, as may finding sources of information and support.

There are support groups for dystonia available. In addition, many of the organizations listed in the external links section have patient education materials available. Participating in a clinical trial may provide other treatment options.

Clinical Trials

A list of ongoing clinical trials is available from ClinicalTrials.gov: dystonia trials.

Research

Recent discoveries

  • In 1989, a team of researchers mapped a gene for early-onset torsion dystonia to chromosome 9; the gene was subsequently named DYT1 [2].
  • In 1997, researchers sequenced the DYT1 gene and found that it codes for a previously unknown protein now called "torsin A" [3]. The discovery of the DYT1 gene and the torsin A protein provides the opportunity for prenatal testing, allows doctors to make a specific diagnosis in some cases of dystonia, and permits the investigation of molecular and cellular mechanisms that lead to disease.
  • The gene for Segawa's dystonia has been found [4]. It codes for an enzyme important in the brain's manufacture of dopamine.
  • The use of deep brain stimulation to treat generalized dystonia was studied by the National Institute of Neurological Disorders and Stroke (NINDS). [5]
  • Using motor training to treat writer's cramp (focal hand dystonia) was studied. [6]
  • The use of transcranial magnetic stimulation (an insulated wire coil is placed on the subject's scalp and brief electrical currents are passed through the coil, creating magnetic pulses that pass into the brain. These pulses disrupt the function of the brain cells in the stimulated area) to examine how the brain controls muscle movement in focal and generalized dystonia. [7]

Future research

Ongoing studies include:

  • The use of botulinum toxin versus placebo in the treatment of cervical dystonia. [8]
  • A multicenter study of deep brain stimulation of the globus pallidus in the brain to treat cervical dystonia. [9]
  • Using transcranial magnetic stimulation and electrical stimulation of nerves to study dystonia. [10]

Expected Outcome

Approximately three to five years after symptoms begin, dystonia will often stabilize and not progress to other body areas. Symptoms may wax and wane over time, depending on such factors as stress, illness, and hormone levels.

As a general rule, the older a person is when dystonia develops, the less likely it will progress to multiple body areas. The younger a person is when dystonia develops, the more likely that it will progress to multiple body parts over time. In some dystonia patients, especially those with cervical dystonia, there may be a temporary remission that lasts months or years. [11]

Ultimately, the progress of dystonia is unpredictable. The treatment plan may be adjusted as the condition worsens and improves.

The good news is that dystonia is rarely, if ever, fatal. Serious complications are usually treatable.

Notable Experts

The Dystonia Medical Research Foundation has a list of providers that have experience and/or interest in treating people with dystonia. The list, covering Canada and the United States is available at: Find a Healthcare Professional.

References

  1. Dystonia Medical Research website. Complementary Therapy
  2. Valente E.M., Warner T.T., Jarman P.R. et al. The role of DYT1 in primary torsion dystonia in Europe. "Brain." 1998; 121: 2335-9. Abstract |Full Text
  3. Ozlius L.J., Hewett J.W., Page C.E. et al. The early-onset torsion dystonia gene (DYT1) encodes an ATP-binding protein. "Nat. Genet." 1997; 17(1): 17-9. Abstract
  4. Gordon, N. Segawa's disease: dopa-responsive dystonia. "Int. J. Clin. Pract." 2007; 62(6): 943-6. Abstract
  5. ClinicalTrials.gov. Deep Brain Stimulation for Cervical Dystonia
  6. ClinicalTrials.gov. Motor Training to Treat Hand Dystonia
  7. ClinicalTrials.gov. Transcranial Magnetic Stimulation (TMS) Studies of Dystonia
  8. ClinicalTrials.gov. NT 201 Versus Placebo in the Treatment of Cervical Dystonia
  9. ClinicalTrials.gov. A Multicenter Pilot Study of Pallidal Deep Brain Stimulation for Cervical Dystonia
  10. ClinicalTrials.gov. Transcranial Magnetic Stimulation and Electrical Stimulation of Nerves to Study Focal Dystonia
  11. Dystonia Medical Research Foundation web site. Prognosis

External Links

Dystonia Medical Research Foundation

National Spasmodic Torticollis Association

WE MOVE (Worldwide Education & Awareness for Movement Disorders)

Benign Essential Blepharospasm Research Foundation

Bachmann-Strauss Dystonia & Parkinson Foundation

Spasmodic Torticollis Dystonia/ST Dystonia

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