The 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. Early symptoms may include deterioration in handwriting, foot cramps, or a dragging foot after running or walking some distance. Other possible symptoms are tremor and voice or speech difficulties.
About half the cases of dystonia have no connection to disease or injury and are called primary or idiopathic dystonia. Of the primary dystonias, many cases appear to be inherited. Dystonias can also be symptoms of other diseases, some of which may be hereditary. Dystonia can occur at any age, but is often described as either early, or childhood, onset versus adult onset.
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 permanent physical deformities by causing tendons to shorten.
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 therapy, splinting, stress management, and biofeedback) aimed at reducing or eliminating muscle spasms and pain. Since response to drugs varies among individuals and even in the same person over time, the most effective therapy is often individualized.