object using the opposite controlled hand to enable the release of the grasped object (also referred to as tonic grasping or the "instinctive grasp reaction"). some (for example, the neurologist derek denny-brown) have referred to this behavior as "magnetic apraxia" goldberg and bloom described a woman with a large cerebral infarction of the medial surface of the left frontal lobe in the territory of the left anterior cerebral artery which left her with the frontal variant of the alien hand involving the right hand. there were no signs of callosal disconnection nor was there evidence of any callosal damage. the patient displayed frequent grasp reflexes; her right hand would reach out and grab objects without releasing them. in regards to tonic grasping, the more the patient tried to let go of the object, the more the grip of the object tightened. with focused effort the patient was able to let go of the object, but if distracted, the behaviour would re-commence. the patient could also forcibly release the grasped object by peeling her fingers away from contact with the object using the intact left hand. additionally, the hand would scratch at the patient's leg to the extent that an orthotic device was required to prevent injury. another patient reported not only tonic grasping towards objects nearby, but the alien hand would take hold of the patient's penis and engage in public masturbation. parietal and occipital lobes a distinct "posterior variant" form of alien hand syndrome is associated with damage to the posterolateral parietal lobe and/or occipital lobe of the brain. the movements in this situation tend to be more likely to withdraw the palmar surface of the hand away from sustained environmental contact rather than reaching out to grasp onto objects to produce palmar tactile stimulation, as is most often seen in the frontal form of the condition. in the frontal variant, tactile contact on the ventral surface of the palm and fingers facilitates finger flexion and grasp of the object through a positive feedback loop (i.e. the stimulus generates movement that reinforces, strengthens and sustains the triggering stimulation). in contrast, in the posterior variant, tactile contact on the ventral surface of the palm and fingers is actively avoided through facilitation of extension of the fingers and withdrawal of the palm in a negative feedback loop (i.e. the stimulus, and even anticipation of stimulation of the palmar surface of the hand, generates movement of the palm and fingers that reduces and effectively counteracts and eliminates the triggering stimulation, or, in the case of anticipated palmar contact, decreases the likelihood of such contact). alien movements in the posterior variant of the syndrome also tend to be less coordinated and show a coarse ataxic motion during active movement that is generally not observed in the frontal form of the condition. this is generally thought to be due to an optic form of ataxia since it is facilitated by the visual presence of an object with visual attention directed toward the object. the apparent instability could be due to an unstable interaction between the tactile avoidance tendency biasing toward withdrawal from the object, and the visually based acquisition bias tendency pushing toward an approach to the object. the alien limb in the posterior variant of the syndrome may be seen to "levitate" upward into the air withdrawing away from contact surfaces through the activation of anti-gravity musculature. alien hand movement in the posterior variant may show a typical posture, sometimes referred to as a "parietal hand" or the "instinctive avoidance reaction" (a term introduced by neurologist derek denny-brown as an inverse form of the "magnetic apraxia" seen in the frontal variant, as noted above), in which the digits move into a highly extended position with active extension of the interphalangeal joints of the digits and hyper-extension of the metacarpophalangeal joints, and the palmar surface of the hand is actively pulled back away from approaching objects or up and away from supporting surfaces. the "alien" movements, however, remain purposeful and goal-directed, a point which clearly differentiates these movements from other disorganized non-purposeful forms of involuntary limb movement (e.g. athetosis, chorea, or myoclonus). similarities between frontal and posterior variants in both the frontal and the posterior variants of the alien hand syndrome, the patient's reactions to the limb's apparent capability to perform goal-directed actions independent of conscious volition is similar. in both of these variants of alien hand syndrome, the alien hand emerges in the hand contralateral to the damaged hemisphere. treatment there is no cure for the alien hand syndrome. however, the symptoms can be reduced and managed to some degree by keeping the alien hand occupied and involved in a task, for example by giving it an object to hold in its grasp. specific learned tasks can restore voluntary control of the hand to a significant degree. one patient with the "frontal" form of alien hand who would reach out to grasp onto different objects (e.g., door handles) as he was walking was given a cane to hold in the alien hand while walking, even though he really did not need a cane for its usual purpose. with the cane firmly in the grasp of the alien hand, it would generally not release the grasp and drop the cane in order to reach out to grasp onto a different object. other techniques proven to be effective include; wedging the hand between the legs or slapping it; warm water application and visual or tactile contact. additionally, wu et al. found that an irritating alarm activated by biofeedback reduced the time the alien hand held an object. in the presence of unilateral damage to a single cerebral hemisphere, there is generally a gradual reduction in the frequency of alien behaviors observed over time and a gradual restoration of voluntary control over the affected hand. actually, when ahs originates from focal injury of acute onset, recovery usually occurs within a year. one theory is that neuroplasticity in the bihemispheric and subcortical brain systems involved in voluntary movement production can serve to re-establish the connection between the executive production process and the internal self-generation and registration process. exactly how this may occur is not well understood, but a process of gradual recovery from alien hand syndrome when the damage is confined to a single cerebral hemisphere has been reported. in some instances, patients may resort to constraining the wayward, undesirable and sometimes embarrassing actions of the impaired hand by voluntarily grasping onto the forearm of the impaired hand using the intact hand. this observed behavior has been termed "self-restriction" or "self-grasping". in another approach, the patient is trained to perform a specific task, such as moving the alien hand to contact a specific object or a highly salient environmental target, which is a movement that the patient can learn to generate voluntarily through focused training in order to effectively override the alien behavior. it is possible that some of this training produces a re-organization of premotor systems within the damaged hemisphere, or, alternatively, that ipsilateral control of the limb from the intact hemisphere may be expanded. another method involves simultaneously "muffling" the action of the alien hand and limiting the sensory feedback coming back to the hand from environmental contact by placing it in a restrictive "cloak" such as a specialized soft foam hand orthosis or, alternatively, an everyday oven mitt. other patients have reported using an orthotic device to restrict perseverative grasping or restraining the alien hand by securing it to the bed pole. of course, this can limit the degree to which the hand can participate in addressing functional goals for the patient and may be considered to be an unjustifiable restraint. theoretically, this approach could slow down the process through which voluntary control of the hand is restored if the neuroplasticity that underlies recovery involves the recurrent exercise of voluntary will to control the actions of the hand in a functional context and the associated experiential reinforcement through successful willful suppression of the alien behavior. history the first known case described in the medical literature appeared in a detailed case report published in german in 1908 by the preeminent german neuro-psychiatrist, kurt goldstein. in this paper, goldstein described a right-handed woman who had had a stroke affecting her left side from which she had partially recovered by the time she was seen. however, her left arm seemed as though it belonged to another person and performed actions that appeared to occur independent of her will. the patient complained of a feeling of "strangeness" in relationship to the goal-directed movements of the left hand and insisted that "someone else" was moving the left hand, and that she was not moving it herself. when the left hand grasped an object, she could not voluntarily release it. the senses of touch and proprioception of the left side were impaired. the left hand would make spontaneous movements, such as wiping the face or rubbing the eyes, but these were relatively infrequent. with significant effort, she was able to move her left arm in response to spoken command, but conscious movements were slower or less precise than similar involuntary motions. goldstein developed a "doctrine of motor apraxia" in which he discussed the generation of voluntary action and proposed a brain structure for temporal and spatial cognition, will and other higher cognitive processes. goldstein maintained that a structure conceptually organizing both the body and external space was necessary for object perception as well as for voluntary action on external objects. in his classic papers reviewing the wide variety of disconnection syndromes associated with focal brain pathology, norman geschwind commented that kurt goldstein "was perhaps the first to stress the non-unity of the personality in patients with callosal section, and its possible psychiatric effects". in popular culture in stanley kubrick's 1964 film dr. strangelove, the eponymous character, played by peter sellers, apparently has alien hand syndrome, as he can't stop himself from doing the nazi salute. "dr. strangelove syndrome" was suggested as the official name for ahs. this was not approved, though it is sometimes used as an alternative name. in the 1999 movie idle hands the main character of the movie has his left hand possessed by the devil and cannot control it, though the title is a reference to "idle hands are the devil's playground," the fact that the hand literally has a mind of its own is highly similar. in the medical drama tv series house episode "both sides now", a patient has alien hand syndrome. an episode of dark matters: twisted but true – a documentary tv series on discovery science – described alien hand syndrome and traced its history. the 2017 indian tamil dark comedy film peechankai is about a person with ahs. in season 2 of the tv series scream queens, dr. brock holt appears to have alien hand syndrome.