Dystonia is a movement disorder that involves unintended (involuntary) muscle contractions that can cause twisting and repetitive movements or abnormal postures. The movements are sometimes painful. There are several different forms of dystonia that may affect a single muscle; a group of muscles such as those in the arms, legs, or neck; or the entire body. Dystonia can occur at any age.
Symptoms may include:
- a worsening in handwriting
- foot cramps
- a dragging foot after running or walking some distance
- tremor, and
- voice or speech difficulties.
The dystonias can be divided into three groups:
- idiopathic dystonia, which does not have a clear cause
- genetic, which may involve one or more gene mutations, and
- acquired, which results from environmental or other damage to the brain, or from exposure to certain types of medications.
Different forms of dystonia include:
- generalized dystonia, which affects most or all of the body
- focal dystonia, which is localized to a specific part of the body, such as the muscles in the neck or the muscles controlling eye blink, and
- task-specific dystonia, which tends to occur only when peforming a particular repetitive activity, such as writer's cramp.
No one treatment has been found to be universally effective. Instead, doctors use a variety of therapies (medications, surgery, and other treatments such as physical and other therapies). Treatments may include: botulinum toxin, the most effective treatment for the focal dystonias, involves small amounts of the chemical being injected into affected muscles to prevent muscle contractions medications aimed at blocking the activity of certain naturally occurring chemicals, and surgery, including deep brain stimulation that involves implanting small electrodes that are connected to a pacemaker-like device (that sends periodic coltrolled amounts of electricity) into specific brain regions that control movement.
The initial symptoms can be very mild and may be noticeable only after prolonged exertion, stress, or fatigue. 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 fixed postures and shortening of tendons.
Investigators believe that the dystonias result from an abnormality in an area of the brain called the basal ganglia or other brain regions that control movement. There may be abnormalities in the brain's ability to process certain chemicals or in the way the brain processes information and generates commands to move. The National Institute of Neurological Disorders and Stroke (NINDS) conducts research related to dystonia in its laboratories at the National Institutes of Health (NIH) and also supports additional dystonia research through grants to major research institutions across the country. Scientists at other NIH Institutes (National institute on Deafness and Other Communications Disorders, National Eye Institute, and Eunice Kennnedy Shriver National Institute on Child Health and Human Development) also support research that may benefit individuals with dystonia. Scientists at NINDS laboratories and clinics have conducted detailed investigations of the pattern of muscle activity, imaging studies of brain activity, and physiological studies of the brain in people with dystonia. The search for genes responsible for some forms of dystonic continues. Treatment studies--using medications or surgery--are being conducted in many centers. The Dystonia Coalition is a clincal research network for dystonia created with support from NINDS and the NIH Office of Rare Diseases as part of the Rare Disease Clinical Research Network. For more information on the clinical studies and patient registry established by the Coalition, see rarediseasesnetwork.org/cms/dystonia.