Chorea is the occurrence of continuous rapid, jerky, involuntary movements that may involve the face and limb and result in an inability to maintain a posture. It is also known as St. Vitus Dance disease and is seen mostly in children.

When chorea is serious, slight movements will become thrashing motions, this form of severe chorea is referred to as "ballism." Walking may become peculiar, and include odd postures and leg movements. Unlike ataxia and dystonia, which affect the quality of voluntary movements or parkinsonism, which is a hinderance of voluntary movements, the movements of chorea and ballism occur on their own, without conscious effort.

Chorea may be caused by the dysfunction in the basal ganglia and include:

• Sydenham's chorea
• Huntington's chorea

The term chorea is derived from a Greek word khoreia (a kind of dance, see chorea), as the quick movements of the feet or hands are very comparable to dancing or piano playing.

See also: Vitus, movement disorder and choreoathetosis