What is Alien Hand Syndrome?
By Richa Nakrani
Highlights
Involves one hand being out of control of the mind
Can occur after stroke, trauma, or tumor
Sometimes related to cancer, neurodegenerative diseases, and brain aneurysms
Introduction
Alien hand syndrome is a rare neurological condition in which one hand is out of the control of the mind and moves on its own free will. This was first reported around 1908 and 1909, and there are several different causes of this. It is almost always caused by some damage to your brain which leads to a disturbance in your movement and control. This condition can come about after having trauma, neurosurgery, tumors, and rarely strokes and can also be associated with cancer, neurodegenerative diseases, and brain aneurysms. Surgeries that involve an incision along the corpus callosum, the structure that divides the two brain hemispheres, in order to separate the two hemispheres can sometimes lead to this. Those with the condition also show lesions in the anterior cingulate cortex, posterior parietal cortex, and supplementary motor cortex areas of the brain.
Symptoms & Behaviors
This syndrome involves the hand acting independently and is classified into three main categories based on the part of your brain that is affected and is contributing to the condition. The first category is frontal lobe version, the only version reported that affects the right hand. Some behaviors and symptoms associated with this category are involuntary groping of other parts of the body and clothes, involuntary grasping of any object, and difficulty releasing objects. The second category is the callosal version, which concerns the corpus callosum part of your brain. shThis involves one main symptom which is difficulty during two-handed tasks where the alien hand might undo the work done by your other hand. The last category is the posterior version, which concerns the parietal lobe. This involves levitation, in which the arm starts lifting up into the air with no meaning, other less purposeful movements, and psychological struggles.
Treatments
Unfortunately, there is no direct cure for alien hand syndrome. There is still ongoing research and attempts to find treatments to decrease symptoms. Recovery can happen on its own for those who had the syndrome after a brain illness or stroke, but is less likely for those with neurodegenerative diseases. Cognitive behavioral therapy can help people accept the emotional realities of their condition and think about their alien hand through a different perspective. Muscle control therapies like botulinum toxin (Botox) as well as neuromuscular blocking agents can help reduce symptoms. Clonazepam is a medication that can assist in reducing symptoms, and visuospatial coaching techniques can help regain some control. Distracting the hand is another technique to prevent consequences of the syndrome. Examples include holding the alien hand between legs or sitting on it, holding a magazine, and doing other small tasks.
References
https://www.webmd.com/brain/what-is-alien-hand-syndrome