athetosis

n. disease which causes unintentional movement of the fingers and limbs

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, and can also be caused by a lesion of the motor thalamus.
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Athetosis /ath·e·to·sis/ repetitive involuntary, slow, sinuous, writhing movements, especially severe in the hands. ath·e·to·sis n. [more]Athetosis - Community and Resources

Noun
1. a continuous succession of slow writing involuntary movements of the hands and feet and other body parts
(hypernym) nervous disorder, neurological disorder, neurological disease

(n.)
A variety of chorea, marked by peculiar tremors of the fingers and toes.