Science fiction or real diagnosis? What to do when your patient has alien hand syndrome
Key Takeaways
Alien hand syndrome (AHS) is a rare neurological disorder in which a patient’s limb moves intermittently and involuntarily against their will.
AHS may be evidence of a stroke or development of neurodegenerative disease. Brain lesions on the supplementary motor area, corpus callosum, medial frontal lobe, posterior parietal, and thalamus may also cause AHS.
There is currently no evidence of a gold-standard treatment for AHS; however, patients who live with it have shown progress by undergoing physical exercises, multidisciplinary rehabilitation, and verbal cue training.
If you see a patient losing control of one of their hands—as if the limb is foreign or that it has a will of its own—it may be the manifestation of a rare neurological disease.
Alien hand syndrome (AHS), also referred to as "Dr. Strangelove syndrome," is a phenomenon associated with many underlying disabling neurological disorders, and therefore should warrant immediate medical attention.
For example, stroke is the major pre-existing condition for AHS and other diseases such as multiple sclerosis, Creutzfeldt-Jakob Disease (CJD), corticobasal syndrome (CBS), migraines, and hypertension are also risk factors for AHS. Although evidence-based treatment for AHS is limited, physicians can help their patients manage it with multidisciplinary rehabilitation.
Origins of 'alien hand'
At its most basic, AHS is a rare neurological phenomenon characterized by the patient’s inability to control the movements of their hand and arm.
According to a 2020 article published by the Journal of Community Hospital Internal Medicine Perspectives, AHS was initially chronicled by German doctor Hugo Liepmann in 1908 upon seeing a patient’s involuntary grasp reflex be triggered after a stroke.[] That same year, Dr. Kurt Goldstein was the first physician to describe this phenomenon as “alien.”
Drs. Brion and Jedynak expanded on this in 1972, stating that three patients with callosal tumors were experiencing “alien hand.” Thus, alien hand syndrome was coined.
AHS can occur depending on which part of the brain is affected. For example, when the frontal region of the brain is affected, patients may start grasping involuntarily. They know that the limb is theirs, but lack the physical ability to control the hand’s movements.
When the callosal region is affected, patients can develop agnostic dyspraxia. This occurs when one hand refuses to obey a command, so the other hand performs the task in its place. When the posterior region of the brain is affected, the patient experiences impaired motor control and may lose the ability to recognize the limb as their own.
AHS can be caused by a number of underlying illnesses including stroke, neurodegenerative disease, midline tumor, aneurysm, or corpus callosum damage.
Although research on optimal treatments for AHS is lacking, it is important to recognize early on so patients can pursue available treatments that may reduce unwanted long-term outcomes.
Diagnostics & treatment
If you have a patient who exhibits signs of AHS, take note of their symptoms, as some may share features with other diseases.
For example, while involuntary grasping is a hallmark of AHS, that is also associated with focal cerebral injuries such as a traumatic brain injury and degenerative cerebral disorders such as Parkinson’s, Alzheimer’s dementia and Huntington’s disease, according to a 2022 article published by Cureus.[]
To accurately diagnose AHS, doctors must assess the frequency and intensity of the patient’s physical movements. For instance, patients who move suddenly in a disconnected fashion, or attempt to steal someone’s wallet without any intention of doing so, may very likely have AHS.
There is no current go-to treatment for AHS.
Further research is necessary to devise a reliable treatment plan. However, some patients have been able to manage their condition with different forms of therapy and rehabilitation.
A 2021 case report published by Frontiers in Neurology recounted how a 57-year old woman with a mixed callosal-frontal variant of AHS was able to dissolve intermanual conflict (hand is autonomous from the brain and body) after 3 months of antiplatelet therapy and verbal-cue rehabilitation, which she pursued soon after being diagnosed.[] She also regained coordination and was able to comb her hair without the alien hand acting out of turn.
A 61-year-old man who developed AHS after enduring an ischaemic stroke found multidisciplinary rehabilitation to be effective, according to a Journal of Rehabilitation Medicine case report.[]
He learned compensation strategies and practiced completing bimanual tasks. One physical exercise that helped him regain coordination was letting the alien hand catch a cube and then returning attention to the other hand.
Other forms of treatment for AHS may include mirror box therapy, visuospatial coaching techniques, distracting the alien hand, goal-oriented training, and additional cognitive and physical therapies.
You may also use botulinum toxin injection or clonazepam treatments on patients with AHS.
What this means for you
Patients with AHS experience intermittent, involuntary movement of one hand and arm. This rare disease may signal underlying conditions such as neurodegenerative diseases, strokes, or corpus callosum damage. Evidence shows that AHS may be caused by several lesions on the supplementary motor area, corpus callosum, medial frontal lobe, posterior parietal, and thalamus. Patients who have this condition may be disabled as a result. Help patients manage AHS with physical therapy, verbal-cue training, and other forms of therapy.