How to distinguish Athetosis from Chorea ?

Sometimes is difficult to distinguish athetosis from chorea (hence the term choreoathetosis). Typically, however, athetoid movements are slower than choreiform movements.

Athetosis is an extrapyramidal sign characterized by slow, continuous, twisting, involuntary movements. Typically, these movements involve the face, neck, and distal extremities, such as the forearm, wrist and hand.
Facial grimaces, jaw and tongue movements, and occasional phonation are associated with neck movements. Athetosis worsens during stress and voluntary activity, may subside during relaxation, and disappears during sleep. It is commonly a lifelong affliction.

A: With athetosis, movements are typically slow, twisting, and writhing. They're associated with spasticity and most commonly involve the face, neck, and distal extremities. 

B: With chorea, movements are brief, rapid, jerky, and unpredictable. They can occur at rest or during normal movement. Typically, they involve the hands, lower arm, face, and head.

Positions of fingers in movements of athetosis.

Athetosis usually begins during childhood, resulting from hypoxia at birth, kernicterus, or a genetic disorder. In adults, athetosis usually results from a vascular or neoplastic lesion, a degenerative disease, drug toxicity, or hypoxia.