Dystonias

Dystonia is a neurological movement disorder that can be associated with any part of the body that is characterized by sustained, involuntary muscle contractions of a single muscle, a group of muscles, or multiple groups of muscles. The abnormal movements are predictable and sustained for some period of time. Although dystonia can occasionally occur at rest ("rest dystonia"), more typically it occurs during voluntary movements ("action dystonia"). Action dystonia that occurs only in association with particular activities, such as writing, is referred to as a "task-specific dystonia". In some cases, dystonia progresses with overflow of the dystonic to previously unaffected body areas. Dystonic movements usually increase in intensity in association with stress or fatigue and decrease during rest or sleep. Dystonia does not affect cognitive abilities and is usually not fatal, although it can make an individual susceptible to a fatal illness.