Alien hand syndrome represents one of the most striking dissociations between voluntary agency and motor execution known to clinical neurology. Individuals experiencing this rare neuropsychiatric phenomenon find one of their limbs performing purposeful, complex, and goal-directed actions entirely outside their conscious volition, presenting profound challenges to classical models of motor control and subjective selfhood. By severing the connection between intentionality and physical action, this condition illuminates the delicate neurological architecture that produces the unified human experience of free will.
Alien Hand Syndrome
1. Concise Definition
Alien hand syndrome (AHS), historically described as the anarchic hand or the syndrome of the foreign limb, is a neurological condition characterized by involuntary, purposeful, and coordinated motor activity of an upper limb, typically accompanied by a subjective sense of estrangement or external control over the extremity. The patient retains intact primary somatosensory perception yet experiences a profound loss of voluntary agency, often feeling as though the limb is directed by an external agent or possesses a distinct will of its own.
From a neurobiological standpoint, alien hand syndrome emerges from disruptions within the neural circuits that mediate motor planning, sensorimotor integration, and interhemispheric communication. Lesions localized to the supplementary motor area (SMA), anterior cingulate cortex, corpus callosum, or posterior parietal cortex disrupt the balance between internal motor intentions and sensory-driven affordances. Consequently, environmental stimuli can trigger autonomous, complex motor behaviors in the affected limb without the patient’s endorsement or conscious awareness.
2. Etymology & Linguistic Origin
The earliest detailed clinical description of the phenomenon is credited to the German neuropsychiatrist Kurt Goldstein in 1908. Goldstein documented a female patient who suffered an apoplectic stroke that impaired her left upper limb; she subsequently reported that her left arm acted against her conscious intentions, at times even grasping her own neck in an apparent attempt at strangulation. Goldstein conceptualized this clinical presentation as a manifestation of motor apraxia resulting from central cerebral disconnections.
The specific designation alien hand entered modern medical nomenclature through the French neuropsychiatrists Serge Brion and Christine-Paule Jedynak in 1972. In their foundational study published in Revue Neurologique, they introduced the French phrase “le signe de la main étrangère” (the sign of the foreign hand) to describe the behavioral and phenomenological observations of patients with tumors involving the corpus callosum. The term stems from the Latin alienus, meaning “belonging to another, foreign, or strange,” combined with the Old English hand. In contemporary neurology, scholars distinguish between the “anarchic hand”—a limb that acts autonomously while the patient still recognizes it as their own—and the “alien hand,” in which the patient genuinely disowns the physical extremity.
3. Pronunciation & Grammatical Form
Alien Hand Syndrome is pronounced phonetically as /ˈeɪ.li.ən hænd ˈsɪn.droʊm/ in General American English and /ˈeɪ.li.ən hænd ˈsɪn.drəʊm/ in British English. Grammatically, the term functions as a compound noun phrase.
In clinical and scientific literature, the condition can be pluralized as alien hand syndromes when addressing the distinct anatomical subtypes (e.g., frontal, callosal, and posterior variants). The term is also employed adjectivally in expressions such as alien-hand phenomenon, alien-limb sign, or alien-hand behavior. Neurologists frequently use the related terminology anarchic hand syndrome interchangeably in broader contexts, although clinical neuropsychology maintains precise semantic boundaries between the two constructs.
4. Detailed Conceptual Explanation
At the center of alien hand syndrome lies a profound disruption of the sense of agency (SoA)—the subjective awareness of initiating, executing, and controlling one’s volitional motor actions. Under healthy physiological conditions, voluntary action is accompanied by an efference copy: an internal duplicate of the motor command routed to sensory prediction centers. This efference copy predicts the sensory feedback of the upcoming movement, muting the sensory impact and confirming to the conscious self that the action was internally generated. In alien hand syndrome, this internal forward model fails or is uncoupled from conscious awareness, leaving the executed movement stripped of its subjective signature of self-authorship.
Crucially, the involuntary movements observed in alien hand syndrome differ fundamentally from hyperkinetic movement disorders such as chorea, athetosis, hemiballismus, or myoclonus. Rather than producing erratic, non-purposeful twitches or flings, the affected limb in AHS performs intricate, goal-directed sequences. An alien hand might unbutton a shirt that the normal hand has just buttoned, grasp a glass of water, pick up a telephone receiver, or manipulate eating utensils. Because these actions are contextually meaningful and interact directly with objects in the immediate environment, they mirror volitional human action in every outward physical metric, even though the internal cognitive endorsement is absent.
Patients experiencing AHS frequently exhibit intermanual conflict (also known as diagonistic dyspraxia). In this presentation, the two hands appear to compete with one another in direct opposition. If the patient uses their intact hand to pull up their trousers, the alien hand immediately pulls them down. If the dominant hand attempts to turn a page of a book, the contralateral alien hand slams the book shut. This direct behavioral antagonism highlights a profound fracture in bilateral motor coordination, demonstrating how uninhibited primary and premotor networks can default to competing motor repertoires in the absence of transcallosal or medial frontal suppression.
Another defining conceptual element is utilization behavior and environmental dependency. Without top-down inhibition from medial frontal regions such as the supplementary motor area, the premotor cortex responds automatically to sensory “affordances”—the functional possibilities presented by physical items. When a door handle, cup, or pen enters the visual and tactile field of the alien hand, the extremity reflexively reaches out, grasps, and operates the object. The patient often feels compelled to verbally scold the hand, sit on it, or physically restrain it with the unaffected limb to prevent embarrassing, inconvenient, or dangerous behaviors.
5. Historical Development
The conceptual framework of alien hand syndrome developed over more than a century of neurological observation, evolving through distinct phases marked by expanding anatomical knowledge, advances in neurosurgery, and neuroimaging:
Following Kurt Goldstein’s 1908 description, the condition was initially cataloged alongside apraxias and agnosias. During the 1930s and 1940s, neurosurgeons like William P. van Wagenen began performing therapeutic corpus callosotomies to alleviate intractable epilepsy. In 1944, Andrew J. Akelaitis documented behavioral abnormalities in these post-surgical patients, observing transient or persistent motor dissociations between the hemispheres. However, Akelaitis noted that complete callosotomy did not always lead to severe disorganization, sparking debate over whether callosal lesions alone could account for involuntary limb actions.
A critical shift occurred during the 1960s with the landmark split-brain research of Roger Wolcott Sperry and Michael Gazzaniga. Their empirical investigations proved that surgical transection of the neocortical commissures isolated two conscious processing streams within the same cranium, each capable of independent cognition and motor intent. This research laid the neurocognitive groundwork for Brion and Jedynak’s 1972 clinical formulation of the “alien hand sign,” which established the syndrome as a recognizable clinical entity linked to medial frontal and callosal pathology.
In the 1980s and 1990s, the anatomical taxonomy of AHS was systematically organized. Joseph Bogen (1979) and Gary Goldberg (1981) articulated the neuroanatomical distinctions between callosal and medial frontal subtypes. Goldberg emphasized that damage to the supplementary motor area allows the lateral premotor cortex to dominate motor output, driving responses exclusively through visual and somatosensory inputs. Later in the 1990s, Sergio Della Sala and colleagues introduced a rigorous neurocognitive distinction between the anarchic hand (intact sense of ownership with lost motor control) and the alien hand (loss of both agency and limb ownership), cementing modern clinical terminology.
6. Theoretical Foundations
Contemporary cognitive neuroscience explains alien hand syndrome using integrative computational and neuroarchitectural models of motor control:
The foremost theoretical model is the Comparator Model of voluntary agency, articulated by Chris Frith and Daniel Wolpert. According to this framework, the central nervous system issues a motor command while simultaneously generating an internal copy—the efference copy. This copy passes into a forward model that predicts the sensory consequences of the motor act. Under normal conditions, a neural “comparator” matches the predicted sensory state with the actual incoming somatosensory and visual inputs. When an action matches its prediction, the sense of self-agency is confirmed. In alien hand syndrome, structural lesions to the supplementary motor area, medial prefrontal cortex, or parietal regions decouple the efference copy from conscious monitoring. As a result, the comparator registers a profound prediction error: the limb moves purposefully, but the conscious self receives no forewarning of the action, attributing its agency to an outside source.
A complementary framework is the Dual-Premotor System Hypothesis proposed by Gary Goldberg. This model posits two balanced motor control networks: an internal (medial) motor system consisting of the supplementary motor area and anterior cingulate cortex, and an external (lateral) motor system composed of the lateral premotor cortex and posterior parietal regions. The internal system coordinates actions based on internal drives, goals, and voluntary intentions, exerting inhibitory control over the lateral system. Conversely, the lateral system is driven by environmental stimuli and sensory cues. When medial frontal structures or callosal inhibitory fibers are damaged, the lateral premotor cortex is freed from internal regulation. The affected hand defaults to an environmentally reactive state, grasping and manipulating objects purely in response to their physical presence.
Finally, hemispheric disconnection theories account for the intermanual conflict seen in callosal variants. In a healthy brain, each cerebral hemisphere communicates continuously across the corpus callosum to inhibit conflicting motor schemas and orchestrate unified bimanual action. When this commissural connection is interrupted, each hemisphere maintains independent goal-directed processing. If the left hemisphere initiates an intentional motor sequence (e.g., buttoning a jacket), the right hemisphere—lacking access to the left hemisphere’s motor plan—may interpret the closed jacket as an undesirable state or respond to a different impulse, commanding the contralateral hand to unbutton it.
7. Key Components, Types & Dimensions
Alien hand syndrome is not a uniform clinical entity; it is categorized into distinct anatomical and behavioral variants based on lesion localization and clinical signs:
- Frontal Alien Hand Syndrome: Arising from lesions in the supplementary motor area, anterior cingulate cortex, or medial prefrontal cortex of the dominant hemisphere. It typically affects the patient’s dominant hand and is characterized by compulsive grasping, instinctive tactile exploration, and prominent utilization behavior. Patients exhibit reflex-like grasping when an object touches the palm and struggle to release the item voluntarily.
- Callosal Alien Hand Syndrome: Caused by isolated lesions to the corpus callosum, often the anterior rostrum, genu, or trunk. The hallmark of this variant is intermanual conflict without significant involuntary grasping. The non-dominant (typically left) hand acts in direct opposition to the deliberate actions of the dominant hand, reflecting a competition between the decoupled cerebral hemispheres.
- Frontocallosal Alien Hand Syndrome: Resulting from extensive infarctions (such as anterior cerebral artery strokes) that compromise both the corpus callosum and the medial frontal cortex. Patients display a mixed clinical picture featuring severe intermanual conflict, compulsive grasping, and prominent motor antagonism.
- Posterior (Sensory/Parietal) Alien Hand Syndrome: Stemming from infarctions or atrophy within the posterior parietal cortex, thalamus, or occipitoparietal junction. This form is characterized by marked somatosensory deficits, ataxia, levitation of the arm (where the limb drifts unpredictably into space), and a true loss of limb ownership (somatoparaphrenia or asomatognosia). Patients often perceive the limb as physical debris, an artificial object, or a foreign body attached to their torso.
- Diagonistic Dyspraxia: A specialized behavioral manifestation of callosal disruption wherein complex, multi-step actions initiated by the dominant hand are systematically undone or interrupted by the non-dominant hand, illustrating an uncoordinated conflict of motor plans.
8. Examples & Illustrative Cases
Documented clinical cases illustrate the severe daily disruptions experienced by individuals living with alien hand syndrome:
In a classic case documented by Sergio Della Sala and colleagues, a 60-year-old stroke patient was observed eating soup. When her right hand carefully lifted a spoon toward her mouth, her left (alien) hand reached out, grasped the bowl, and dumped the contents across the table. When questioned, the patient expressed exasperation, stating that she was fully aware of what the left hand was doing but was powerless to stop it. She often addressed her left hand in the third person, chastising it as if it were a disobedient child.
Another illustrative case describes a 42-year-old woman who underwent anterior callosotomy to treat intractable epilepsy. Several weeks post-surgery, she experienced severe intermanual conflict while dressing. Her right hand would select a blouse from the closet and slip her arm through the sleeve, only for her left hand to yank the garment off and throw it on the floor. When she attempted to dial a telephone with her right index finger, the left hand repeatedly slammed the receiver down on the cradle. The patient managed these episodes by physically sitting on her left hand or holding it behind her back with her right hand while walking in public.
Posterior alien hand presentations showcase distinct phenomenology. A 73-year-old man who sustained a right parieto-occipital stroke woke to find a hand resting on his chest. In distress, he attempted to push the limb out of his bed, believing that the hospital staff had left an anatomical model or a cadaveric arm next to him. When clinicians demonstrated that the hand was anatomically continuous with his own shoulder, the patient remained unconvinced, acknowledging the visual connection while insisting the limb felt fundamentally foreign and was not his own.
9. Measurement & Assessment
Assessing alien hand syndrome requires comprehensive neurological, neuropsychological, and neuroimaging evaluations, as no single laboratory test confirms the diagnosis:
Clinical Neurological Examination: The primary diagnostic step involves systematic bed-side behavioral observation to distinguish AHS from involuntary hyperkinetic movements (chorea, dystonia, hemiballismus), psychogenic motor disorders, and basic apraxias. Neurologists evaluate the patient for:
- Grasp reflex and groping behavior: Stroking the patient’s palm with a pencil or tongue depressor to assess whether the fingers close reflexively and cannot be disengaged upon verbal command.
- Utilization behavior: Placing everyday objects (e.g., eyeglasses, a cup, a hairbrush) directly within reach to observe whether the affected limb automatically interacts with the items without prompt.
- Intermanual conflict tests: Asking the patient to perform coordinated bimanual tasks, such as opening a jar, tying shoelaces, or stacking blocks, and observing for antagonistic motor interference.
- Proprioception and cortical sensory testing: Evaluating two-point discrimination, graphesthesia, stereognosis, and joint-position sense to distinguish medial frontal variants from posterior parietal subtypes.
Neuroimaging Modalities: Structural magnetic resonance imaging (MRI) is the diagnostic gold standard, providing high-resolution anatomical views of infarctions, hemorrhages, demyelinating plaques, or tumors. T1-weighted, T2-weighted, and fluid-attenuated inversion recovery (FLAIR) sequences can pinpoint damage to the corpus callosum, supplementary motor area, anterior cingulate cortex, or posterior parietal lobe. Diffusion Tensor Imaging (DTI) and tractography are increasingly used to assess microstructural disruptions in callosal white-matter pathways connecting the premotor regions of both hemispheres.
Functional and Neurophysiological Tools: Functional MRI (fMRI) and positron emission tomography (PET) can map the neural correlates of alien hand movements. Functional imaging typically reveals that when an alien hand moves involuntarily, the primary motor cortex (M1) and lateral premotor areas activate without the normal upstream activation of the pre-SMA, SMA, or anterior cingulate. Electroencephalography (EEG) studies examining the Bereitschaftspotential (readiness potential) have documented absent or aberrant slow negative cortical shifts over the midline frontal regions prior to an alien movement, confirming that the limb acts without the motor preparation typical of conscious volition.
10. Applications & Practical Significance
Beyond its clinical rarity, alien hand syndrome carries meaningful implications across clinical rehabilitation, legal jurisprudence, and the philosophy of mind:
Neurorehabilitation and Compensatory Strategies: Therapeutic interventions for AHS focus primarily on behavioral adaptations and environmental modifications. Occupational therapists train patients to use sensory substitution and distraction techniques to quiet the hyperactive limb. For example, giving the alien hand an object to hold—such as a stress ball, cane, or tactile ring—can occupy the limb’s grasping reflex and prevent it from reaching for environmental affordances. Clinicians also use “spatial restraint” strategies, such as having patients tuck the alien hand into a pocket, use an oven mitt to dampen tactile triggers, or wear a wrist splint to limit fine-motor manipulation.
Legal Jurisprudence and Forensic Psychiatry: In criminal law, establishing guilt requires both an intentional mental state (mens rea) and a voluntary physical act (actus reus). Alien hand syndrome presents a real-world separation between bodily movement and conscious intent. If an individual with AHS commits a harmful act (e.g., striking a person, damaging property, or driving recklessly due to an involuntary grasp on the steering wheel), the legal system must determine whether the actus reus was voluntary. Forensic evaluations rely on clinical neuroimaging and verified neurological histories to confirm whether the individual lacked the physical ability to inhibit the motor command.
Philosophy of Mind and Free Will: AHS remains a focal point in discussions on consciousness and the philosophy of action. The syndrome challenges Cartesian notions of an indivisible, unified self that exercises top-down control over the body. Instead, it supports a modular view of cognition, in which conscious agency is a retrospective cognitive attribution rather than an essential driver of complex motor output. Studying AHS helps cognitive neuroscientists map how our subjective sense of free will is assembled from distributed neural networks.
11. Research & Empirical Evidence
Empirical research into alien hand syndrome has advanced through rigorous case series and experimental paradigms designed to isolate its neural mechanisms:
A foundational study by Chris Frith and colleagues (2000) evaluated the sense of agency and motor control in neurological patients using positron emission tomography. Their research demonstrated that alien hand movements bypass the medial prefrontal systems that typically govern voluntary action, relying instead on direct sensorimotor loops between the parietal cortex and the lateral premotor regions. These findings provided empirical validation for Goldberg’s dual-premotor hypothesis, showing that purposeful action can be sustained through sensory-driven pathways even when conscious intentionality is absent.
In a controlled study by Sergio Della Sala and colleagues (1994), researchers tested a patient with an anarchic left hand using a series of modified choice-reaction time tasks. They exposed the patient to congruent and incongruent visual cues, discovering that the anarchic hand was uniquely vulnerable to visual distractors within its hemifield. While the patient’s normal hand successfully suppressed responses to irrelevant stimuli, the anarchic hand triggered immediate, erroneous motor outputs toward the distractors. This demonstrated that the fundamental deficit in frontal AHS is a failure of motor inhibition rather than a failure of motor execution.
More recently, functional neuroimaging investigations using event-related fMRI have captured brain activation during spontaneous alien movements. Research led by Assal and colleagues (2007) tracked an acute stroke patient experiencing alien movements of the right hand. The data revealed that during involuntary movements, the primary motor cortex showed robust activation without the typical preparatory engagement of the supplementary motor area or frontoparietal control networks. This confirmed that complex, coordinated motor sequences can unfold along the corticospinal tract in the complete absence of upstream volitional planning.
12. Cultural & Cross-Cultural Considerations
The interpretation and subjective experience of alien hand syndrome vary considerably across cultural settings, particularly regarding how patients and their communities make sense of involuntary, goal-directed behavior:
In Western medical contexts, AHS is viewed primarily through a biomedical framework of neurovascular injury, demyelination, or neurodegeneration. Patients receive explanations grounded in structural lesions, disconnections, and neurotransmitter pathways, which can alleviate their distress by framing the limb’s actions as a neurological symptom rather than a psychological or spiritual failing. Even so, Western patients frequently personify the affected limb, assigning it an independent persona, a humorous name, or a malevolent identity to make sense of its apparent willfulness.
In cultural contexts where physical health is intertwined with spiritual beliefs, the purposeful, sometimes aggressive movements of an alien hand can be interpreted as supernatural agency. Anthropological and neuropsychiatric field reports note that patients exhibiting alien hand behaviors have been viewed as experiencing demonic possession, ancestral retribution, or witchcraft, especially when the hand grabs at family members or makes culturally taboo gestures. In these settings, families may seek traditional healing, exorcisms, or ritual cleansings alongside or in place of neurological care. These dynamics highlight why clinicians must navigate cultural explanatory models with care when diagnosing and treating neurological disorders that alter conscious agency.
13. Criticisms, Debates & Limitations
Despite clinical recognition, alien hand syndrome remains an area of ongoing debate within behavioral neurology and neuropsychiatry:
A major point of contention is the inconsistent terminology used across clinical literature. Some researchers use “alien hand syndrome” as an umbrella term for any involuntary, goal-directed movement of a limb accompanied by feelings of estrangement. Others argue that this conflation blurs vital distinctions between the anarchic hand and the alien hand proper. In the anarchic hand, the patient experiences intact somatosensation and acknowledges the limb as their own (“I know this is my arm, but it will not do what I tell it”). In contrast, true alien hand syndrome (typically of posterior parietal origin) involves an explicit denial of limb ownership (asomatognosia or somatoparaphrenia). Critics argue that combining these two distinct phenomenological and anatomical presentations under one diagnostic label hinders clear research and clinical communication.
Another debate centers on whether the posterior parietal variant belongs in the AHS classification at all. Critics maintain that posterior AHS is primarily an extreme sensory neglect or body-schema disruption accompanied by sensory ataxia, rather than a true disorder of motor control. In posterior presentations, the limb often drifts aimlessly into space without the goal-directed, purposeful manipulation of objects seen in classical frontal and callosal variants. Consequently, some neuroscientists suggest restricting the diagnosis of AHS to frontal and callosal forms driven by executive and commissural disconnections.
Finally, research into AHS is limited by the rarity of the condition. Most published studies are single-case reports or small case series, which limits the ability to conduct large-scale, randomized controlled trials of rehabilitation techniques or pharmacological therapies. The reliance on retrospective stroke registries and post-callosotomy patients also makes it challenging to generalize findings across broader clinical populations.
14. Related Terms & Distinctions
To ensure diagnostic clarity, alien hand syndrome must be differentiated from several related neurological, psychiatric, and behavioral conditions:
- Anarchic Hand: Often used interchangeably with AHS, but specifically denotes purposeful, autonomous movements where the patient retains a sense of ownership over the limb, recognizing it as their own while lamenting the loss of voluntary motor control.
- Utilization Behavior: A neurobehavioral condition resulting from frontal lobe damage where a patient automatically uses objects in their environment according to their conventional purpose. Unlike AHS, utilization behavior is typically bilateral, and the patient usually does not express distress or a sense of conflict regarding the actions.
- Diagonistic Dyspraxia: A specific manifestation seen after callosal lesions where the non-dominant hand directly opposes the actions of the dominant hand during bimanual tasks (e.g., one hand unbuttoning what the other buttons).
- Somatoparaphrenia: A neuropsychiatric delusion in which a patient denies ownership of an entire limb or side of their body, often claiming that the limb belongs to a clinician, a relative, or an inanimate object. While somatoparaphrenia can accompany posterior AHS, it does not typically feature the goal-directed, complex motor actions characteristic of frontal AHS.
- Functional Neurological Disorder (Conversion Disorder): Psychogenic motor deficits or involuntary movements that lack structural neuroanatomical lesions. Unlike AHS, these movements generally do not exhibit environmental utilization behavior or intermanual conflict, and they often fluctuate significantly with cognitive distraction.
- Apraxia: The inability to execute learned, purposeful motor acts despite intact motor strength, sensation, and coordination. Unlike alien hand syndrome, where the limb acts autonomously without conscious initiation, patients with apraxia struggle to perform actions upon command.
15. Summary / Key Takeaways
- Alien hand syndrome (AHS) is a rare neurological disorder characterized by involuntary, purposeful, goal-directed motor activity of an upper limb, paired with a subjective loss of voluntary agency.
- The condition results from neuroanatomical disruptions to the corpus callosum, supplementary motor area (SMA), anterior cingulate cortex, or posterior parietal cortex, which disconnect internal motor planning from external motor execution.
- AHS is categorized into distinct variants: frontal (compulsive grasping, utilization behavior), callosal (intermanual conflict, diagonistic dyspraxia), frontocallosal (mixed presentation), and posterior (loss of limb ownership, levitation, sensory ataxia).
- The primary cognitive mechanism involves a failure of the internal comparator model of motor agency: without an efference copy to anticipate the sensory outcome of a movement, the brain does not register the action as self-generated.
- Assessment relies on neurological exams, structural MRI (to identify lesions), and specialized neurocognitive evaluations to rule out hyperkinetic movement disorders, apraxias, and functional disorders.
- Management strategies center on neurorehabilitation, sensory substitution, and environmental adaptations (such as holding a stress ball or tucking the hand away) to keep the limb occupied and minimize functional interference.
Alien hand syndrome illustrates the complex neural architecture that underpins the human sense of agency and physical autonomy. By decoupling purposeful action from conscious will, the condition reveals that the sense of self-authorship is an actively generated neural construct rather than an inevitable feature of motor performance. As neuroimaging and cognitive neuroscience advance, studying this rare syndrome will continue to illuminate how the brain unifies mind and body into a cohesive conscious self.
References
- Assal, F., Schwartz, S., & Vuilleumier, P. (2007). Moving with or without will: Functional neural correlates of alien hand syndrome. Annals of Neurology, 62(3), 301–306. https://doi.org/10.1002/ana.21173
- Brion, S., & Jedynak, C. P. (1972). Troubles du transfert interhémisphérique (callosal disconnection): À propos de 3 observations de tumeurs du corps calleux. Le signe de la main étrangère. Revue Neurologique, 126(4), 257–266.
- Della Sala, S., Marchetti, C., & Spinnler, H. (1991). Right-sided anarchic (alien) hand: A longitudinal study. Neuropsychologia, 29(11), 1113–1127. https://doi.org/10.1016/0028-3932(91)90081-4
- Frith, C. D., Blakemore, S. J., & Wolpert, D. M. (2000). Abnormalities in the awareness and control of action. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 355(1404), 1771–1788. https://doi.org/10.1098/rstb.2000.0734
- Goldberg, G., Mayer, N. H., & Toglia, J. U. (1981). Medial frontal cortex infarction and the alien hand sign. Archives of Neurology, 38(11), 683–686. https://doi.org/10.1001/archneur.1981.00510110043004