Imagine being attacked by one of your own hands, which repeatedly tries to slap and punch you. Or you go into a shop and when you try to turn right, one of your legs decides it wants to go left, leaving you walking round in circles.
Alien hand syndrome is a rare neurological disorder in which one hand functions involuntarily, with the victim completely unable to control its action.
Less horrifying symptoms include involuntary reaching and grasping, touching the face or tearing. More extreme cases have involved involuntarily stuffing food in the mouth, preventing the normal hand from completing simple tasks and self-inflicted punching or choking.
People with alien hand syndrome may sense that the hand or limb is foreign or doesn’t belong to them. However, they don’t deny limb ownership, which can happen in other disorders.
Alien hand syndrome can be caused by several factors. Some people develop alien hand syndrome after a stroke, trauma, or tumour.
To understand what we should know about alien hand syndrome, we should take a brief look at the brain and how it works.
The frontal lobe is the section responsible for motor skills, like movement and speech, and cognitive functions, like planning and organization.
Let’s say you want to take a sip of your morning coffee. What seems like a simple task is really a complex sequence of brain functions, starting from the moment you think, “Mmmm, coffee,” until it hits your lips.
The frontal lobe tells the motor strip, “Hey, I need some coffee, do your thing,” and before you know it, you’re enjoying your nice morning roast. The key to making this happen is the successful sending of messages, thanks to the corpus callosum.
Think of the corpus callosum as the brain’s e-mail server, a bundle of message-sending nerves that connect and share information with the two hemispheres. Alien hand syndrome is a result of damage to these nerves.
When the callosum is damaged, it leaves the different sections of the brain disconnected and unable to speak to each other — its e-mail is permanently down. With Alien Hand Syndrome, one hand functions normally, carrying out purposeful tasks without signalling the other hand, resulting in a limb that can act on its own, sometimes in opposition to the functioning side.
There is not much evidence to support the most effective treatments for Alien Hand Syndrome, and no approved or recommended treatments currently exist.
