What is Alien Hand Syndrome?

Alien hand syndrome or Dr. Strangelove syndrome is an unusual medical condition, most often caused by damage to the connection between right and left brain hemispheres. This may occur through surgery. In rare cases, splitting the brain can be proposed to treat epilepsy that does not respond to more traditional drug therapy. Alternately, stroke, infection, brain degenerative disorders, or traumatic injury to the brain separates or injures the connection between the hemispheres.

In alien hand syndrome, the affected person feels that one hand has “a mind of its own,” and that the hand appears to be outside of voluntary control. It may do things in opposition to the other hand’s actions, grasp for things, need to be kept occupied, or keep itself occupied without willful thought on the part of the person. Though this condition is often the fodder for horror films, it is unlikely that the affected hand would willfully commit violence or start writing disturbing messages. Rather, its actions are relatively benign and simply out of the person’s control. Treatment for this condition generally involves giving the alien hand something to grasp or some activity to do to keep it from performing any unwanted actions.

Where injury or damage to the brain occurs determines which hand will be affected, and how it will exhibit alien hand syndrome. A right-handed person, who has specific injury or damage to the corpus collusum, the part of the brain that connects to the two hemispheres, can cause alien hand syndrome in the left hand. Injury in the front of the brain may cause alien hand syndrome to occur in the dominant right hand.

A hand that acts purposefully and perhaps aggressively outside the patient’s control — aggressive could be defined as unbuttoning buttons, grasping things, and sometimes tearing clothing — usually suggests significant injury to several parts of the brain via degenerative disease, stroke, or a brain tumor. Again, it is important to understand that aggressive seldom means violent. However, even without violent acts, it is very challenging for the person with alien hand syndrome to be attached to a limb that he or she cannot control.

In most cases, the person still can perceive what the hand is doing, and can feel sensations with the hand. This can be distracting and frustrating. Whatever the person tries to do with the hand under their control can be thwarted or simply difficult to perform with the other hand acting on its own and sending all kinds of nerve signals to the brain. Depending upon where and how brain injury occurs, some people are able to regain some conscious control over the affected hand. Others must merely adapt to alien hand syndrome, a frustrating and irritating hurdle.