What is Dystonia?

Dystonia is a neurological muscle disorder characterized by involuntary muscle spasms. Patients experience uncontrollable twisting, repetitive movements or abnormal postures and positions. This little-known movement disorder can affect any part of the body including the arms, legs, trunk, eyelids and even the vocal cords. Depending on the part of the body that is affected, dystonia can be a very disabling problem. For example, if the neck muscles are affected, a patient may have difficulty even chewing and swallowing.

Dystonia results from abnormal functioning of the parts of the brain that control coordination of movement, namely, the basal ganglia. These deep regions of the brain control the speed and fluidity of movement and prevent unwanted movements.

Dystonia is thought to be six times more prevalent than other better-known muscular disorders such as Huntington's chorea, ALS or Muscular Dystrophy. About 300,000 people in North America suffer from dystonia, but as few as 5 percent of them are estimated to have a correct diagnosis. Dystonia can affect any ethnic group or gender.

Dystonia, though not life threatening, can severely impact a person's ability to function in society. The involuntary nature of the disorder is embarrassing for most patients and affects their self-image. Many patients suffer from depression and have trouble holding a job.

Few people have ever heard of dystonia. Unfortunately, even the medical community itself is not well acquainted with the disorder. Consequently, some people with dystonia do not know they have it. Sufferers are often told their problem is psychological, which adds to the frustration and distress these patients feel.

Symptoms

How do you know if you may have dystonia? Doctors often misdiagnose it as stress, a stiff neck or as a psychosomatic problem. Diagnosis of dystonia is difficult because its symptoms are similar to those of other conditions.

Dystonia initially arises after specific movements or tasks, but in advanced stages it can occur at rest. It usually affects the same group of muscles, thus causing a repetitive pattern of movements over time.

Dystonia generally develops gradually. Localized symptoms suggest the onset of the disorder. Eye irritation, excessive sensitivity to bright light and increased blinking precede dystonia in the eyelids. Subtle facial spasms, difficulty chewing or changes in speech cadence may indicate face, jaw or voice dystonia. Cramping of the hand during writing or fatigue during walking or other manual activities suggests possible limb dystonia.

Dystonia has a changeable nature. Dystonia of the foot may happen when walking straight ahead but disappear when turning to the left or right. The disorder may also flare up while writing but not with any other activity involving the hand. The intermittent character of the disorder leads medical practitioners to wrongly conclude that a psychological disorder is to blame.

Dystonia is also variable in its progression. For some patients, the disease steadily worsens; for others, it plateaus. The advanced stage is marked by rapid and involuntary rhythmic movements, twisting postures, contortions of the torso, abnormal gait and, ultimately, fixed postural deformities.

For some patients, dystonia stabilizes at a relatively minor stage and progresses no further. As a general rule, the older a patient is when dystonia develops, the more likely that the disease will remain less severe.

Dystonia causes physical pain in only a minority cases (though the uncontrollable movements certainly can result in emotional distress, anxiety and depression). Neck dystonia can be particularly painful due to degeneration of the spine, irritation of nerve roots or frequent headaches. Dystonia in the limbs may not cause pain initially but it can lead to pain. The uncontrolled muscle movements cause the joints to deteriorate, and painful arthritis eventually develops.

Different Types of Dystonia

Dystonia is classified in three different, overlapping ways, and classified by cause, age at onset and body region affected (distribution).

Classification by Cause

Most instances of primary (also known as idiopathic) dystonia are believed to be caused by an inherited gene. The culprit is the DYT-1 gene. Scientists are not sure why this gene can cause dystonia, but they do know that about 30 percent of the people who inherit the gene will develop dystonia. Symptoms usually begin in childhood and start in a limb before spreading to other limbs, the trunk, neck and possibly the facial muscles.

Secondary or symptomatic dystonia is caused by a separate neurological disease such as stroke, multiple sclerosis, or trauma. Secondary dystonia also can result as a side effect from drugs. Tardive dyskinesia (a form of dystonia) is often caused by antipsychotic medication used to treat schizophrenia and psychosis.

Classification by Age at Onset

Early-onset dystonia begins in childhood to late adolescence. Adult-onset dystonia typically begins after the age of 26. As a general rule, the younger the age of onset, the more likely that the disorder will become severe and spread to other parts of the body. The older the age of onset, the more likely dystonia will remain in one part of the body.

Classification by Distribution

Focal dystonia involves only a single area of the body. Frequently seen types of focal dystonia are commonly described as writer’s cramp, occupational cramp, spastic dysphonia and oromandibular dystonia. Segmental dystonia affects adjacent body regions such as the neck and the arm. Multifocal dystonia involves two or more regions of the body that are not contiguous. Generalized dystonia affects many regions of the body.

Treatment

There is no cure for dystonia. But treatment can reduce pain and alleviate the symptoms. To reduce the pain, over-the-counter pain medications such as ibuprofen and acetaminophen should be tried first. Muscle relaxants may also be helpful.

The most common treatment for dystonia is botulinum toxin (Botox), injected directly into the affected muscle. Botox blocks the communication between the nerve and the muscle and lessens abnormal movements and postures.

Botox is a purified, diluted form of the toxin from the bacteria that causes botulism. The substance is poisonous if taken by mouth. But when injected directly into the muscle it inhibits muscle contractions and provides relief.

Botulinum toxin type A was developed in the 1980s. In 2001, the U.S. Food and Drug Administration approved botulinum toxin type B for treatment of cervical dystonia. Researchers created the new drug after some patients began developing resistance to the type A form. The type B drug has mild to moderate side effects such as dry mouth, dysphagia (difficulty in swallowing) and indigestion.

A new and promising surgical treatment is now partially approved by the FDA.  PNNI is one of only 20 sites in the country currently performing deep brain stimulation for dystonia. Patients with severe, generalized dystonia for whom drugs are no longer effective may opt for surgical treatment performed by a neurosurgeon. This procedure inserts a small electrode into the movement center of the brain, and is thought to disrupt the abnormal signals being sent to the muscles.  Our early experience has shown very promising results.

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