Alien hand syndrome (AHS) is a rare medical condition that was first described in 1908. People with this syndrome lose control of one of their hands.
Their minds can no longer give the "alien hand" directions, but it continues to move and perform activities — seemingly with a will of its own. These motions are often completely unnecessary or inappropriate at the time and can be terrifying to experience.
Versions of Alien Hand Syndrome
Alien hand syndrome is essentially the same thing as alien limb syndrome. The broader name reflects the fact that a similar condition can happen to your legs too. So far, people have only had one limb affected at a time.
There are three main categories of alien hand syndrome based on the part of your brain that’s causing the condition. They are the:
- Frontal lobe version. This is the only version reported that affects your right hand.
- Callosal version. This involves the corpus callosum area of your brain.
- Posterior version. This involves your parietal lobe.
Alien Hand Syndrome Causes
There isn’t one universal cause for alien hand syndrome. But it’s always caused by some kind of damage to your brain in a way that disrupts your movement and control.
Usually, when someone chooses to start moving their arm, they activate multiple extensive neural networks within their brain. In people with AHS, the areas of activation are more isolated.
More research is currently needed on the syndrome — and the brain itself — in order to fully explain this condition on a neurological level.
On a broader level, causes of brain damage that can lead to AHS include:
- Brain tumors
- Brain damage from an injury
- As a side effect of brain surgery
- Parry–Romberg Syndrome
- Creutzfeldt–Jakob Disease
- Atypical Parkinson’s variants, like corticobasal syndrome
- Various other neurodegenerative diseases
Keep in mind that this is a very rare side effect of most of these conditions. For example, it’s highly unlikely that you’ll develop AHS if you have a stroke.
But for some specific conditions, the rate can be surprisingly high. Data indicates that it appears in 30% of people with the Parkinson’s variant — corticobasal syndrome. It also occurs in 4% of people with Creutzfeldt–Jakob disease.
In some cases, the condition is idiopathic — meaning that the exact cause remains unknown.
Who Gets Alien Hand Syndrome?
Anyone can get this syndrome. All it requires is a certain brain injury.
This means that the more at risk that you are for certain brain injuries — like a stroke — the more likely it is that you’ll develop AHS. Many of the cases are in people over 60 years old, but one case has even been reported in a 13-year-old girl.
How Is Alien Hand Syndrome Diagnosed?
Because of its rarity — there are only a few handfuls of reported cases in the scientific literature — some doctors may not be familiar with this condition.
When you see a doctor, try to remember the exact actions that your hand has been doing and how it’s made you feel. These details will help rule out motor-based dysfunction. Your doctor will also need to know your full health history, including all of your medications and the doses you’ve taken lately.
The next step is to look at your brain to try to figure out the underlying cause. Your doctor may order any combination of the following imaging procedures:
Alien Hand Syndrome Symptoms
AHS has both physical and psychological effects. In some cases, people have completely dissociated from their hand and no longer recognize it as their own — which can be incredibly disturbing.
The exact symptoms of your AHS will depend on which version you’ve developed. But keep in mind that there can be substantial overlap between the versions. Interestingly, no one has ever reported any pain from the condition.
The symptoms generally attributed to the frontal lobe version include:
- Involuntary groping — mostly of other parts of your body and your clothes
- Involuntary grasping — this can be of any object
- Difficulty releasing objects
The symptoms that are common in the posterior version include:
- Levitation — where your arm starts rising into the air for no reason
- Less purposeful movement — like simply waving about
- Psychological struggles — this is the version that most commonly causes people to stop recognizing their hand as their own
The callosal variety is characterized by one main symptom — conflict during two-handed tasks. For example, you may be intentionally buttoning your shirt with your right hand as your alien left immediately undoes your work.
Once the condition begins, it can last anywhere from 30 minutes — the shortest reported case — to the rest of your life.
Alien Hand Syndrome Treatment
There is no treatment for alien hand syndrome. All techniques to manage it are mostly anecdotal.
The techniques that people have tried have attempted to address both the physical and psychological complications caused by AHS. These include:
- Cognitive behavioral therapy. This can help people come to terms with the emotional realities of their condition. It helps them to think about their alien hand in new ways.
- Distracting the hand. Some people have found it helpful to occupy the alien hand with simple and non-embarrassing tasks to keep it distracted. This can be as easy as having your out-of-control hand hold a magazine as you go about your day.
- Visuospatial coaching techniques. This strategy attempts to help with your perception of the alien limb in relation to the rest of your body — hopefully well enough for you to regain some control.
- Clonazepam. There’s one reported case where a 13-year-old girl, whose right arm was affected by AHS, took clonazepam in an attempt to treat her symptoms. It led to a 70% reduction in her symptoms after 2 days. Unfortunately, the drug did not agree with her, so they had to try another technique.
- Botulinum toxin injections. The same 13-year-old girl was injected with botulinum toxin in a few areas up and down her affected arm. This showed an 80% reduction in her symptoms.
This syndrome is so rare that people are still trying to figure out the best ways to handle it. If you have this condition, your input is crucial to helping your medical team figure out strategies for your specific symptoms.
It doesn’t hurt to be creative. In one case, a man was distressed because his hand kept grabbing his body while he slept. He was able to sleep soundly again simply by wearing an oven mitt to bed.
Other people feel most comfortable sitting on their alien hand whenever they’re in public. This way, they don’t need to constantly monitor it for inappropriate activities.
Your doctor will also need to treat any of the underlying causes they’ve found. The exact treatment will depend on the cause. A brain tumor, for example, could require surgery.
When to See a Doctor
Because this condition is so bizarre — even terrifying — to experience, you’ll likely want to seek medical attention as soon as it starts. This is exactly what you should do.
In all likelihood, your AHS is caused by a much more serious underlying medical condition. Not all people with AHS can be helped with immediate medical attention. But in some cases, this step could save your life.