What Is Alien Hand Syndrome? - Brain And Life Magazine

Four months after experiencing flulike symptoms, Dona Kim Murphey, MD, PhD, a neurophysiologist in Pearland, TX, was still feeling less than 100 percent when something strange happened. While out walking one evening, she felt short of breath and sat down to rest. As she tried to send a text, she suddenly became obsessed with her left hand. “My brain was acutely attuned to my left hand—its position, orientation, and activity,” she recalls. “I was able to use both hands to send the text, but I was unnaturally and exquisitely aware of the left one.”

When the fixation persisted for a week, Murphey was reminded of a neurologic phenomenon she had learned about in medical training and witnessed in one of her patients: alien hand syndrome. She looked it up online and felt that the definition—feeling estranged from, or having a tenuous relationship with, a hand—described her sensations. She remembered that her patient had a far more pronounced experience. “Her left hand kept unhooking her bra and she couldn't control it,” says Murphey.

To understand the problem better and rule out a more serious condition, Murphey saw a neurologist, who ordered a brain MRI to see if a stroke might have caused the problem. Testing turned up nothing, but in the weeks that followed, Murphey would experience the strange sensation periodically, especially when she was sleep- deprived or overly stressed.

First described in 1908, alien hand syndrome can result from brain damage due to surgery, brain tumors, aneurysms, stroke, neurodegenerative disease, or trauma. Sometimes, as with Dr. Murphey, a specific cause is not identified. Variations of it involve different regions of the brain, but it generally stems from disruptions in brain networks involved in movement and control. It is also called alien limb syndrome because it can occur in the legs as well.

Strange Phenomenon

Film buffs may remember that the title character of the classic 1964 dark comedy Dr. Strangelove, or: How I Learned to Stop Worrying and Love the Bomb had what looked like alien hand syndrome. Dr. Strangelove's hand would perform what appeared to be purposeful acts but were in fact unintentional. This quirk was used for comic effect in the movie, but in real life the condition can be distressing—and can present in varying ways. One hand may swat at the other involuntarily, or an arm may inexplicably shoot into the air.

In a report documented in the medical literature, a man's alien hand started undoing the buttons on his shirt as his other hand buttoned them. In other case reports, patients have said they awoke from sleep to find their hands choking them.

In another case, a 56-year-old patient recovering from a stroke reported that his right hand was behaving of its own accord—flipping light switches, grabbing papers, and batting away his left hand. “He walked around with a rolled-up magazine in his right hand so it wouldn't get in the way of things,” says the patient's doctor, Anjan Chatterjee, MD, FAAN, professor of neurology at the University of Pennsylvania's Perelman School of Medicine.

The man would wake up because the hand was grabbing at his body. He pushed his bed against the wall to trap the hand and keep it still, says Dr. Chatterjee. At other times, the man's alien hand untucked his shirt from his pants and snatched a knife from his left hand as he cut food.

Brain imaging showed that the stroke had caused a lesion in the man's left medial frontal lobe that extended into the corpus callosum (a nerve tract connecting the brain's right and left hemispheres), which likely was the root of the problem, Dr. Chatterjee says. The patient's involuntary hand movements became less frequent and less severe over time.

In a 2014 case study, a 77-year- old woman was watching television when her left hand began stroking her face and hair of its own accord. She was terrified when she couldn't control the left hand with her right. The movements stopped after half an hour, but the woman's upper left arm was numb and slightly weak and her left hand dragged, according to the report. At the hospital, brain scans revealed that the woman had sustained a stroke, probably because she had stopped taking anticoagulants for atrial fibrillation in preparation for spine surgery. The report noted that 30 minutes was the shortest case of alien hand syndrome ever documented.

Another case study involved an 84-year-old woman who went to the emergency room because she had episodes during sleep in which her left arm moved as if it were groping around trying to grab at her body. The bizarre movements also happened while she ate, watched TV, and went to the bathroom. She found herself talking to her hand or yelling at it to get it to stop making embarrassing movements, and she even worried that she might be “possessed by the devil,” according to the report. A CT scan showed that the woman had sustained a stroke. By the time of her one-month checkup, the woman's alien hand had quieted down.

Some people refer to their alien hands in the third person, as if the limbs were distinct entities from their bodies; they may even scold them as if they were naughty children. “It's as if something else is controlling their hands,” Dr. Chatterjee says. “Part of your body is doing something you don't want it to do and getting in the way of doing something you do want to do.”

Different Manifestations

There are several variations of alien hand syndrome. The most common involves the brain's frontal lobe, which usually affects the right hand, and is characterized by impulsive groping, manipulation of objects, and difficulty releasing things after grasping them, says Anhar Hassan, MD, FAAN, associate professor of neurology at Mayo Clinic, who co-wrote a review on the disorder in Current Neurology and Neuroscience in 2016.

Another variation, callosal, is caused by an injury to the corpus callosum and results in conflicting movements between the two hands during two-handed tasks such as tying shoelaces, says Dr. Hassan.

The posterior version of the syndrome—involving the parietal lobe of the brain—usually produces less purposeful movements, such as the hand raising involuntarily. People with this variant may not recognize the limbs as their own, says Dr. Hassan.

A Cause for Study

Doctors diagnose based on patient history and a clinical exam. They may also order brain scans to look for lesions, says Dr. Hassan. While there is no direct treatment, supportive care, including occupational and physical therapy, can help patients develop strategies to minimize interference from the hand. Cases caused by stroke may improve weeks or months later as patients recover, says Dr. Hassan.

Researchers continue to study alien hand syndrome to determine the underlying pathophysiology and connections involved. As brain imaging technology evolves and reveals more about the organization and function of the brain, it may help us understand what causes the involuntary movements and may lead to better treatments, says Dr. Hassan.

While not painful, alien hand syndrome can be frustrating and embarrassing for patients and their families. “Our hands explore the space around us and provide information about the physical world and how we interact with it,” says Steven Frucht, MD, professor of neurology at NYU Langone Health. “It's bizarre to have a body part move around and do things you aren't asking it to do.”

Dr. Chatterjee says alien hand syndrome is intriguing both medically and psychologically because having a sense of agency and control over our actions is essential to interacting in the world. Alien hand syndrome challenges the notion of “what it means to feel ownership of your body,” he says.