The National Institute of Neurological Disorders and Stroke defines dystonia as a disorder of involuntary muscle contractions that cause slow, repetitive movements and abnormal postures. There are many types of dystonia, and the exact cause of the disorder is unknown.
NINDS notes that dystonia effects people of any age, but it typically arises in childhood. Researchers divide dystonia into three general categories: idiopathic, genetic and acquired. Idiopathic dystonias have no clear origin. Genetic dystonias are inherited. Acquired dystonias occur after a brain injury. Each of these types are further classified based on how they effect the body. Current treatments for dystonia are botulism toxin injections, medications, deep brain stimulation, physical therapy and surgery.