Did You Know!
A Neurological Disorder Can Make Your Own Hand Seem to Have a Mind of Its Own
One of the strangest documented neurological conditions is appropriately called alien hand syndrome.
A person with this rare condition can experience movements of a hand or arm that occur without their conscious intention. Even more unusually, those movements can sometimes appear purposeful.
For example, someone may intentionally button a shirt with one hand while the other hand unexpectedly begins unbuttoning it. A hand might reach toward an object, grab something, or interfere with what the person’s other hand is trying to accomplish.
The individual is generally aware that the limb physically belongs to them. The disturbing part is the feeling that they aren’t fully controlling what it is doing.
Alien hand syndrome has been associated with damage to or disruption of brain regions involved in movement, planning, awareness, and communication between different areas of the brain. It has been reported following strokes, certain types of brain surgery, and some neurodegenerative diseases.
The condition provides scientists with an extraordinary window into how the brain produces something most of us rarely think about: the feeling that “I decided to make this movement.”
Normally, intention and physical movement are so closely connected that they seem like one process. Alien hand syndrome demonstrates that the brain systems responsible for voluntary action and our conscious sense of controlling that action can, under unusual circumstances, become separated.
