I’ve just found a video of someone with alien hand syndrome – a condition which usually occurs after brain injury or stroke where the affected person loses conscious control over the hand and where it seems to move with a will of its own.
In this case, the video was uploaded by YouTube user frankenerin, who asked someone to video her when she was in intensive care after suffering a stroke and having brain surgery while her ‘alien hand’ was still present.
There’s a couple of things to notice in the video. The first is that the clinician asks the patient to do the actions for using scissors and brushing teeth. This is to check the problem is not a form of general ideomotor apraxia, where common action patterns are damaged.
She can do the actions with one hand but not the other, suggesting her strange movements are not due to global action planning problems.
The clinician then asks whether the patient recognises the arm as hers.
This may seem an odd question, but he’s checking for somatoparaphrenia, where patients can deny ownership of a paralysed or action-impaired limb, sometimes saying that it belongs to someone else.
As it turns out, the patient says she generally knows it is hers, but when it is draped across her body in a certain position and making involuntary movements she can think it is someone else’s limb. In other words, she seems to have fleeting somatoparaphrenia.
The video then shows the hand moving of its own accord and the patient having to use the other hand to keep it out of trouble.
Despite looking like she’s in pretty bad shape, frankenerin later posted a wonderful follow-up video where she is back on her feet and feeling fine, although discusses how she’s had to adjust her career aspirations owing to the longer-term effects of the brain injury.
Unfortunately, the Wikipedia page on alien hand syndrome, also known as anarchic hand syndrome, is dreadful, but there’s an excellent 2005 article from The Psychologist by neuropsychologist Sergio Della Sala that covers the neuropsychology of the condition and what it tells us about free will. You can read it online as a pdf.
Link to alien hand syndrome video.
pdf of The Psychologist on alien / anarchic hand.
Mind Hacks 
Hi, First of all I just wanted to say I love your blog. As a young psychology student and aspiring scientist I enjoy all of your writing. I think this post is particularly salient and interesting because I just saw an episode of the show House that used such a case in their plot. One of the characters was particularly bothered by the fact that the patient in the show was seemingly two people, and was irked by the idea of not being a single individual agent in ones own body. You’re right about the implications that conditions like this have on the concept of free will and the self. I would love to hear more of your thoughts on this. Thanks again, and I look forward to future posts.
The lady I know with Alien Hand Syndrome calls it her “naughty hand”. She has real trouble with her left hand as it will occasionally do things like throwing drinks over people, slap people, and even once slammed her good hand in a door.
She also has trouble coordinating her eyes, with the left eye wandering a bit, kind of like a lazy eye.
The thing that I managed to do to convince the staff she was working with that it was genuine Alien hand was to see if she could coordinate her opposite eye and hand to do something, by using a blindfold. She could easily pick something up with her right hand and right eye, or even with her left (naughty) hand and left eye. But she found it impossible to coordinate her left hand and right eye, or right hand and left eye, even though in both cases she could see the object. Curiously she couldn’t name objects viewed with her left eye either, although her left hand could mime what they were used for.
Does it seem to anyone else, that her left hand/arm seem to gesture in a manner appropriate to her speech?