In this video-clip from Stanley Kubrick’s film, “Dr. Strangelove”, we see the character from whom the movie derives its name, struggle to keep his right arm in check, as it repeatedly tries to give the Nazi salute. It literally seems as if Dr. Strangelove’s right arm has a mind of its own.
I remember watching this movie some years back (or decades maybe), finding Dr. Strangelove’s ordeal extremely funny, never suspecting that this remarkable affliction could exist in the real world.
Dr. Strangelove’s syndrome
Dr. Strangelove bizarre behavior might be explained by a rare, neurological condition called alien-hand syndrome (and sometimes referred to as Dr. Strangelove’s syndrome, capricious hand or anarchic hand). People with this affliction typically experience one of their hands as alien, and acting independently of their conscious will or even moving in opposition to conscious intention. To stop the alien hand from doing what it is doing, the person must use the other hand, like Dr. Strangelove does in the video (in addition to his mouth). The patient describes a feeling as if an external agent is controlling the hand. This condition was first described in 1908 by Goldstein, whose patient was a woman who believed her left hand had a will of its own and experienced unintentional movements, such as grabbing and self-choking. Autopsy revealed a damage in the right hemisphere of the brain and the corpus callosum. This actually makes a lot of sense, as the corpus callosum is the cable that connect the left and right cerebral hemispheres and transfers information between them.
When the corpus callosum is damaged, the left hemisphere (that controls the right hand) doesn’t get information from and cannot get information to the right hemisphere (that controls the left hand), i.e. each hemisphere controls different behaviors and different hands and when there is a lack of communication, things get confused. Matters are of course never this simple, as evidence has shown that alien-hand syndrome can also occur with damage to the right parietal lobe (possibly because of a disconnection between the part of the motor cortex that moves the left hand and the parietal cortex that perceives the left hand movement as its own). Damage to the frontal and occipital lobes has also been associated with alien hand syndrome.
The case reports of these patient can be funny to read because of the bizarreness of the behavior involved, although this is obviously a very debilitating condition. As you can imagine, there has to be a whole lot of negotiation involved for things to run smoothly, when the two hands are not under unitary control. One patient for example was buttoning her shirt with her right hand but the left hand came along just behind the right one, undoing the buttons as fast as the right one could fasten them. Another patient´s hands struggled with each other as they competed to answer the telephone. A woman could not eat her dinner in peace, as her left hand suddenly began to interfere with the process. Each time she brought food to her mouth, her left hand reached up and struggled with her right hand, groped about her face, and even struck her in the cheek. Another patient had to abandon the book he was reading, because each time he used his right hand to turn a page, the left one tried to close the book. The same patient used his right hand to shave while his left hand was busy unzipping his jacket. A woman would even sleep with her left hand tied, to prevent it from grasping at her throat in her sleep and another slept with a pillow on her chest to prevent injuries from the beating of her left hand.
Alien-hand syndrome, conscious awareness and free will
The gestures and movements of the alien hand are not haphazard flailings, but seemingly purposeful movements. The action of the (usually) left hand that does not seem to be under the patient’s conscious, intentional control, therefore seems to be under the (intentional but unconscious) control of the right hemisphere: Here is yet another example of a purposeful behavior in the absence of conscious awareness (like here in a post about blindsight).
-Assal, F., Schwartz, S. and Vuilleumier, P. (2007). Moving with or without will: functional neural correlates of alien hand syndrome. Annals of Neurology, 62(3), 301-306.
-Spector, A. R., Freeman, W. D. og Cheshire, W. P. (2009). The Stroke that Struck Back: An Unusual Alien Hand Presentation. Journal of Stroke and Cerebrovascular Diseases, 18(1), 72-73.