Focal Task-Specific Dystonia

Focal task-specific dystonia (FTSD) is a movement disorder that is localized to a specific part of the body. The dystonias are a group of movement problems characterized by involuntary, sustained muscle contractions, tremors, and other uncontrolled movements. FTSD interferes with the performance of particular tasks, such as writing, playing a musical instrument, or participating in a sport. Additionally, FTSD has been reported in tailors, shoemakers, hair stylists, and people who frequently type or use a computer mouse. While the abnormal movements associated with focal dystonia are usually painless, they can cause high levels of anxiety. The causes of focal dystonia are unknown, although the disorder likely results from a combination of genetic and environmental factors. It is possible that the different forms of FTSD have different underlying causes. Researchers have found that at least some cases are related to malfunction of the basal ganglia, which are structures deep within the brain that help start and control movement. Most cases of focal dystonia are sporadic, which means they occur in people with no history of the condition in their family. However, at least 10 percent of affected individuals have a family history which seems to follow an autosomal dominant pattern of inheritance.