Alien hand syndrome (also known as anarchic hand or Dr. Strangelove syndrome) is a neurological disorder in which one of the hands of people who have it appears to take on a mind of its own. Alien hand syndrome is best documented in cases where a person has had the two hemispheres of their brain surgically separated, a procedure sometimes used to relieve the symptoms of extreme cases of epilepsy. It also occurs in some cases after other brain surgery, strokes, or infections.
Symptoms
A person with alien hand syndrome can feel normal sensation in the hand and leg, but believes that the hand, while still being a part of their body, behaves in a manner that is totally distinct from the sufferer’s normal behavior. They lose the ‘sense of agency’ associated with the purposeful movement of the limb while retaining a sense of ‘ownership’ of the limb. They feel that they have no control over the movements of the ‘alien’ hand, but that, instead, the hand has the capability of acting autonomously — i.e., independent of their voluntary control. The hand effectively has ‘a will of its own.’ “Alien behavior” can be distinguished from reflexive behavior in that the former is flexibly purposive while the latter is obligatory. Sometimes the sufferer will not be aware of what the alien hand is doing until it is brought to his or her attention, or until the hand does something that draws their attention to its behavior.
A related syndrome described by the French neurologist François Lhermitte involves the release through disinhibition of a tendency to compulsively utilize objects that present themselves in the surrounding environment around the patient (Lhermitte 1983; Lhermitte et al. 1986). The behavior of the patient is, in a sense, obligatorily linked to the “affordances”(using terminology introduced by the American ecological psychologist, James J. Gibson) presented by objects that are located within the immediate peri-personal environment. This condition, termed “utilization behavior”, is most often associated with extensive bilateral frontal lobe damage and might actually be thought of as “bilateral” alien hand syndrome in which the patient is compulsively directed by external environmental contingencies (e.g., the presence of a hairbrush on the table in front of them elicits the act of brushing the hair) and has no capacity to “hold back” and inhibit pre-potent motor programs that are obligatorily linked to the presence of specific external objects in the peri-personal space of the patient. When the frontal lobe damage is bilateral and generally more extensive, the patient completely loses the ability to act in a self-directed manner and becomes totally dependent upon the surrounding environmental indicators to guide his behavior in a general social context, a condition also identified by Lhermitte (1986), and referred to as “Environmental Dependency Syndrome”.
Sufferers of alien hand will often personify the rogue limb, for example believing it to be “possessed” by some intelligent or alien spirit or an entity that they may name or identify. There is a clear distinction between the behaviors of the two hands in which the affected hand is viewed as “wayward” and sometimes “disobedient” and generally out of the realm of their own voluntary control, while the unaffected hand is under normal volitional control. At times, particularly in patients who have sustained damage to the corpus callosum that connects the two cerebral hemispheres (see also split-brain), the hands appear to be acting in opposition to each other. For example, one patient was observed putting a cigarette into her mouth with her intact, ‘controlled’ hand (her right, dominant hand), following which her alien, non-dominant, left hand came up to grasp the cigarette, pull the cigarette out of her mouth, and toss it away before it could be lit by the controlled, dominant, right hand. The patient then surmised that “I guess ‘he’ doesn’t want me to smoke that cigarette.” This type of problem has been termed “intermanual conflict” or “diagonistic Ideomotor apraxia.”
