Your Left Hand, In Darkness: Dr. Strangelove Syndrome

May 12, 2009

On this week's House finale, the title character's actions and memories -- at odds with reality even more than usual -- were contrasted with the episode's central patient: a man suffering from Alien Hand Syndrome. The doctors on the show were unrestrainedly specific about the causes and specifics of the disorder for this particular patient, which usually lends itself to two possibilities: either the team is wrong and the person doesn't have the disorder, or, much less frequently, they're talking about something so interesting that they don't have to really do much else to make the disease they're diagnosing both dramatic and horrifying. And if you've seen the episode, you know just how effective the juxtaposition turned out to be.

You Are Your Territory, my grandmother always taught me. But if the reverse isn't true -- if you're not in control of something that should rightfully be yours, like for example your hand -- that touches everything: it's got to be terrifying. Your identity, your kinesthetic sense, your relationship with the unconscious and nonverbal parts of your own mind. Patients have done everything from assuming God's in charge of their hands to giving it a name of its own; often the alien hand busies itself by undoing everything the controlled hand tries to accomplish. One real-life case study showed a woman whose right hand would put a cigarette in her mouth, only to have it removed by the left before she could light it. That's one way to make a good decision, I suppose.

The symptoms as related on the show -- in which the patient's angry left hand spent a lot of the time smacking his girlfriend around, just for starters -- are pretty consistent with actual case studies, as well as the cause. Due to a misdiagnosis of epilepsy years prior, the character's corpus callosum -- the part of the brain that connects the left and right hemispheres -- had been surgically severed. This can cause a well-known break called "split-brain," in which the nonverbal part of the brain can't use the dominant side of the brain to find words, for example, for things they only see with their non-dominant eyes. They can draw pictures or point to the object, but can't name it. (I'm left-handed, so I always get thrown off by all the right brain/left brain talk, because it's switched for me, but we'll stick with the usual terms.)

Damage to another part of the brain, the frontal lobe, can trigger purposeful movements in the contralateral hand, and often results in situations like the necessity of using the right hand to physically pull the fingers of the left hand off an object. A third form, associated with damage to posterior parts of the brain, like the parietal or occipital lobe, cause the hand to pull away from objects, rather than reaching toward them. There is a specific set of movements associated with this third form in which the palm "levitates" away from the object. The type of corpus callosum damage in the show gives rise to purposeful action in the non-dominant hand, and can result in the "intermanual conflict" above, where the right hand not only doesn't know what the left hand is doing, but finds it doing things in direct conflict to its own purposeful action.

The most interesting theory, for my money, is that you're looking at two different aspects of movement control. There are regions which command bodily movement, but can't generate a conscious feeling of self-control over those movements. In this scenario, it's about the dissociation between these two processes -- execution and the feeling of conscious control -- which causes an internal sensation that the movements are being controlled somehow by an outside force.

So yes, the show as usual proceeds with flying colors. But in researching this, I learned about two even weirder related issues. The first is a woman who reported last month that, after her stroke at 64, she'd developed a "pale, milky-white and translucent third arm" that she uses to scratch itchy parts of her body, and cannot penetrate solid objects. It's the first recorded case of a person being able to feel, see and deliberately move a limb that doesn't exist. But get this: when they put her in an MRI and asked her to move her translucent arm, her brain responded in terms of both motor and visual activity: in terms of her conscious brain activity, she really is moving it, and can even look down and see it. I don't really have a point to make about that, but it's sort of awesome.

The second thing I learned about this week is more closely related to AHS than it might seem: a syndrome resulting from frontal lobe damage called "Utilization Behavior," in which your hands can't help but put things to use. If there's a hairbrush on the table, the patient can't help picking it up and brushing their hair with it. (I think I might have this with shopping at Amazon and Etsy, but that might also be due to my alcoholism and love of handmade crafts.)

Even worse, when the frontal lobe damage is bilateral and more extensive, the patient completely loses their ability to self-direct movement, and becomes totally dependent on surrounding indicators to guide their basic behavior, which is called Environmental Dependency Syndrome. That's even scarier than your basic Alien Hand Syndrome, because it's like Alien Everything Syndrome: no choices at all. You become entirely a tool of your environment. When we talk about brain damage, we have ideas about what that means, but until today I didn't know just how many bizarre things your body might decide to do.

Questions, issues, comments? You know where to go. And if you've got questions or suggestions for upcoming entries on this blog, take them to the Nitpickers' Bazaar.

Jacob Clifton is a culture critic and staff writer for Television Without Pity.