Dystonia

Dystonia is a movement disorder consisting of involuntary muscle contractions, which force certain parts of the body into abnormal, sometimes painful, movements or postures. This can affect any part of the body including the arms, legs, trunk, neck, eyelids, face, or vocal cords. This movement is not controlled by the patient and can be painful. Dystonia can be present in patients with cerebral palsy, Parkinson's disease, or other neurological problems. If dystonia causes any type of impairment, it is because muscle contractions interfere with normal body function. Features such as cognition, strength, and the special senses are usually normal. Dystonia is not fatal; however, it is a chronic disorder and prognosis is difficult to predict due to the different body systems involved. It is the third most common movement disorder after Parkinson's disease and tremor that affect more than 300,000 people in North America. Dystonia does not discriminate and it effects all races and ethnic groups the same way. In the developing world, diagnosis and treatment of dystonia can be elusive and complex as symptoms vary and neurological diagnostics are often nonexistent. The German neurologist, Dr. Hermann Oppenheim, of Berlin was interested in the variation in muscle tone seen in neurologic pathologies that he encountered in several young patients. In his papers, he used the term dystonia to indicate that muscle tone was hypotonic at one occasion and tonic spasm at another. Hypotonic means having less-than-normal tension in the muscle and tonic is continuous tension or nonstop contraction of muscles.

As the term dystonia has been widely accepted and has been used by neurologists and other physicians alike; other terms such as repetitive movement disorder and muscle twitch have also been used. These terms and concepts are directly related to muscle tone. This is the level of muscle contraction present during resting state. With increased tone, there is stiffness and rigidity, while with decreased tone, there is looseness of the limbs and trunk.

However, the definition of dystonia has grown with the levels of diagnosis and categories expanding. The major issue most diagnosticians have with these additions to dystonia is that by using only sustained postures for their definition, this allows many types of abnormal postures to be called dystonia, such as fixed postures that could develop from a stroke. Furthermore, these [Page 572]definitions do not take into account other types of abnormal neurological movements. In the early 1980s, a committee consisting of members of the Scientific Advisory Board of the Dystonia Medical Research Foundation developed the following definition: “Dystonia is a syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements, or abnormal postures.” This committee also proposed a classification schedule for dystonia. This scheme recommends three classifications: age at onset, parts of body affected, and etiology or the cause and origin of disease.