Alien Hand Syndrome

Alien Hand Syndrome (AHS) is a rare neurological disorder, but the symptoms are bizarre. This disorder is usually caused by some kind of brain injury or by surgery that results in separation of the two brain hemispheres. Patients with AHS experience reduced awareness of their actions, more specifically, they lose voluntary control over one hand. The results are both comical and bizarrely unsettling. The patient is completely unaware of what one hand is doing until they "see" it or someone points it out. Alien hands can perform complex acts such as undoing buttons, removing clothing, and yes, alien hands can masturbate :-). In an often-cited example, a lady with the condition was given a cup of tea and immediately commented that it was too hot to drink, so she would let it cool first. As soon as she stated that intention, however, her alien hand grabbed the cup of tea in an effort to drink it, and she had to restrain it with her other hand (possibly spilling the tea).



AHS (or some form of it) is widely referenced in pop culture, the most famous one being Dr. Stranglove. We have the spooky image of the ex-Nazi Dr. Strangelove trying to strangle himself (or give the Hitler salute), while his other hand tries to stop the Alien Hand from doing its thing.

Patients of AHS can fool themselves into believing that their actions are intentional. There is a weird disconnect between the intention and the actual actions. Alien Hand Syndrome raises fascinating questions about the nature of free will and separation of intention from actions.

More on Alien Hand Syndrome at wikipedia