Athetosis
Athetosis is a continuous stream of slow, sinuous, writhing movements, typically of the hands and feet. Movements typical to athetosis are sometimes called athetoid movements. It is said to be caused by damage to the corpus striatum of the brain.
Athetosis is to be distinguished from pseudoathetosis, which is abnormal writhing movement, usually of the fingers, occurring when the eyes are closed, caused by a failure of joint position sense (proprioception), for example in peripheral neuropathy.