Alien Hand Syndrome has been most widely documented in cases where sufferers of epilepsy and seizures have had the two hemispheres of their brains separated to relieve the problems they suffer.
As a by-product of such a separation, many patients find that, quite literally, their left hand does not know what their right hand is doing.

Whilst a patient has complete control over one hand; they report, and it can be shown, that they have no control over the action of their other hand.

In at least one case it has been reported that a patient was happily driving home when the Alien Hand seized the wheel of the vehicle nearly causing an accident whilst in other cases, simply trying to write one's own name is thwarted by the other hand pushing the controlled hand away from the paper being written upon.

Despite various theories around a single consciousness interfering with itself on a subconscious level; it has been fairly widely accepted that the behaviour exhibited can be demonstrated to show that there is a separate personality that exists within each hemispshere of the brain that has seized control over each hand.

Alien hand syndrome: The feeling that one's hand is possessed by a force outside of ones control. The syndrome typically arises after trauma to the brain, after brain surgery or after a stroke or an infection of the brain. A person with the alien hand syndrome can feel sensation in the affected hand but thinks that the hand is not part of their body and that they have no control over its movement, that it belongs to an alien.

Different types of brain injuries cause different subtypes alien hand syndrome. For example, take an injury to the corpus callosum (the area of the brain which connects the two cerebral hemispheres, the two halves of the brain). Such an injury in a right-handed person can give rise to purposeful movements of the left hand, while injury to the brain's frontal lobe of the brain can trigger grasping and other purposeful movements in the dominant right hand. More complex hand movements such as unbuttoning or tearing of clothes are usually associated with brain tumors, aneurysms or strokes.

There is currently no treatment for alien hand. All a patient can do to control the problem is to keep the hand busy by having it hold an object.

Alien Hand Syndrome is an unusual mental disorder A mental illness is a psychiatric disorder that results in a disruption in a person's thinking, feeling, moods, and ability to relate to others. Psychiatrists generally attribute mental illness to organic/neurochemical causes that can be treated with psychiatric medication, psychotherapy, lifestyle adjustments and other supportive measures. Compare rational-emotive therapy.
Mental illness is distinct from the legal concept of insanity.
. in which one of the sufferer's hands seems to take on a life of its own. AHS is best documented in cases where a person has had the two hemispheres of their brain

For other articles about other subjects named brain see brain (disambiguation).

In the anatomy of animals, the brain, or encephalon, is the supervisory center of the nervous system. Although the brain is usually cited as the supervisory center of vertebrate nervous systems, the same term can also be used for the invertebrate central nervous system.
. surgically separated, a procedure sometimes used to relieve the symptoms of extreme cases of epilepsy Epilepsy is a chronic neurological condition characterized by recurrent unprovoked seizures. The condition is named from the Greek epilepsia ("a taking hold of or seizing"), and has in the past been associated with religious experiences and even demonic possession. Many neurologists prefer the less stigmatized term seizure disorder as a description of the condition.

Historically epilepsy was called the Sacred Disease because people thought the seizures experienced by people living with epilepsy were a form of attack by demons.
. It also occurs in some cases after other brain surgery, strokes The article is about stroke as medical term. For other uses of stroke, see stroke (disambiguation).

A stroke or cerebrovascular accident (CVA) occurs when the blood supply to a part of the brain is suddenly interrupted by occlusion (an ischemic stroke) or by hemorrhage (a hemorrhagic stroke). The latter occur when a blood vessel in the brain bursts, spilling blood into the spaces surrounding the brain cells or when a cerebral aneurysm ruptures.
, or infections An infection is the detrimental colonization of a host organism by a foreign species. The colonizing organism interferes with the normal functioning and perhaps the survival of the host. The infecting organism is referred to as a pathogen.

All multicellular organisms are colonized to some degree by extrinsic organisms, and the vast majority of these exist in either a symbiotic, commensal, or parasitic relationship with the host. An example of the former would be the anaerobic bacteria species which colonize the mammalian colon, an example of the latter would be the various species of staphylococcus which exist on human skin. Neither of these colonizations would be considered infections.


An Alien Hand sufferer can feel normal sensation in the hand, but believe that it is not part of their body and that they have no control over its movements. Alien hands can perform complex acts such as undoing buttons or removing clothing. Sometimes the sufferer will not be aware of what the hand is doing until it is brought to his or her attention. Sufferers of Alien Hand will often personify the rogue limb, for example believing it "possessed" by some intelligent spirit, and may fight or punish it in an attempt to control it.

There are several distinct subtypes of Alien Hand that appear to be associated with specific types of triggering brain injury. Damage to the corpus callosum

The corpus callosum is the largest white matter structure in the mammalian brain. It consists of mostly of contralateral axon projections. It appears as a wide, flat region just ventral (below) the cortex. It is missing in monotremes.

The corpus callosum connects the left and right cerebral hemispheres. Most (but certainly not all) communication between regions in different halves of the brain are carried over the corpus callosum.


Anatomy
In the human brain, the central sulcus separates the frontal lobe from the parietal lobe along the top of each cerebral cortex. The lateral sulcus separates the inferior frontal gyrus of lower frontal lobes from the temporal lobes.

COUNTRY OF PUBLICATION: ENGLAND

ABSTRACT: An 81 year old right handed woman developed a left alien hand syndrome characterised by involuntary movements of choking and hitting the face, neck, and shoulder. The patient showed multiple disorders of primary sensation, sensory processing, hemispatial attention, and visual association, as well as a combination of sensory, optic, and cerebellar ataxia (triple ataxia) of the left arm in the absence of motor neglect or hemiparesis. Imaging studies disclosed subacute infarction in the right thalamus, hippocampus, inferior temporal lobes, splenium of corpus callosum, and occipital lobe due to right posterior cerebral artery occlusion. This rare syndrome should be considered as a "sensory" or "posterior" form of the alien hand syndrome, to be distinguished from the "motor" or "anterior" form described more commonly.

MINOR MESH HEADINGS: Aged-; Aged,-80-and-over; Brain-Mapping; Cerebral-Infarction-physiopathology; Dominance,-Cerebral-physiology; Hemiplegia-physiopathology; Magnetic-Resonance-Imaging; Neurologic-Examination; Sensation-Disorders-diagnosis; Sensation-Disorders-physiopathology; Tomography,-Emission-Computed

MAJOR MeSH HEADINGS: *Attention-physiology; *Awareness-physiology; *Cerebral-Infarction-diagnosis; *Hand-innervation; *Hemiplegia-diagnosis; *Laterality-physiology; *Motor-Activity-physiology