Alien Hand Research Articles

From embodying tool to embodying alien limb: sensory-motor modulation of personal and extrapersonal space

Years ago, it was demonstrated (e.g., Rizzolatti et al. in Handbook of neuropsychology, Elsevier Science, Amsterdam, 2000) that the brain does not encode the space around us in a homogeneous way, but through neural circuits that map the space relative to the distance that objects of interest have from the body. In monkeys, relatively discrete neural systems, characterized by neurons with specific neurophysiological responses, seem to be dedicated either to represent the space that can be reached by the hand (near/peripersonal space) or to the distant space (far/extrapersonal space). It was also shown that the encoding of spaces has dynamic aspects because they can be remapped by the use of tools that trigger different actions (e.g., Iriki et al. 1998). In this latter case, the effect of the tool depends on the modulation of personal space, that is the space of our body. In this paper, I will review and discuss selected research, which demonstrated that also in humans: 1 spaces are encoded in a dynamic way; 2 encoding can be modulated by the use of tool that the system comes to consider as parts of the own body; 3 body representations are not fixed, but they are fragile and subject to change to the point that we can incorporate not only the tools necessary for action, but even limbs belonging to other people. What embodiment of tools and of alien limb tell us about body representations is then briefly discussed.

A Neural Circuit for Spirituality and Religiosity Derived From Patients With Brain Lesions

BackgroundOver 80% of the global population consider themselves religious, with even more identifying as spiritual, but the neural substrates of spirituality and religiosity remain unresolved. MethodsIn two independent brain lesion datasets (N1 = 88; N2 = 105), we applied lesion network mapping to test whether lesion locations associated with spiritual and religious belief map to a specific human brain circuit. ResultsWe found that brain lesions associated with self-reported spirituality map to a brain circuit centered on the periaqueductal gray. Intersection of lesion locations with this same circuit aligned with self-reported religiosity in an independent dataset and previous reports of lesions associated with hyper-religiosity. Lesion locations causing delusions and alien limb syndrome also intersected this circuit. ConclusionsThese findings suggest that spirituality and religiosity map to a common brain circuit centered on the periaqueductal gray, a brainstem region previously implicated in fear conditioning, pain modulation, and altruistic behavior.

REVIEWING RARE SYNDROMES

This article is an examination of the Rare Syndromes The scientific development and subsequent “syndromes” continues to influence the researchers all over the globe today. This article examines the research done and published by researchers and scientists. Consideration of current trends and data in scientific queries and demonstrates further aspects of auto brewery syndrome, alien hand syndrome, Alice in wonderland syndrome. Additionally, this article explores options for syndrome listed with some significance.
 Keywords: Rare Syndromes, Autobrewery Syndrome, Alien Hand Syndrome, Alice In Wonderland Syndrome.

Three cases of paroxysmal alien limb phenomena due to epileptic seizures and review of literatures

BackgroundThe alien hand phenomenon (AHP) is a rare disorder of involuntary limb movement together with a loss of sense of limb ownership. AHP occurs as a consequence of frontal, callosal, or posterior cerebral lesions. To characterize the phenomenon of AHP, three patients with paroxysmal AHP were described and proved to be focal seizures by using video-EEG monitoring.MethodClinical history of 3 epileptic patients with AHP was collected. EEG and MRI were performed in each patient. One patient completed EEG monitoring and postoperative pathological examination. We also review the recent literatures and summarize the characteristics, types and hypothetic mechanisms of epileptic AHP.ResultsCase 1 had AHP of the left arm followed by the left arm convulsion or AHP only. MRI imaging showed a lesion in the posterior parietal lobe. After complete resection of the lesion, he remained seizure free for 1.5 years. Cases 2 and 3 had AHP and convulsion. The three cases did not have auto-motor signs, so they were identified to be the posterior type of APH.ConclusionsThe mechanism underlying AHP remains poorly .understood. Currently, little is known for the epileptic paroxysmal AHP, a quite rare form of AHP. AHP can be represented before or immediately after convulsion, or be represented by the paroxysmal symptom only.

Alien hand and complex regional pain syndromes during rehabilitation program

Introduction: Alien hand syndrome (AHS) belongs to the group of asymmetrical movement symptoms that are a characteristic picture of neurodegenerative diseases such as corticobasal degeneration syndrome (CBS). Changes in the musculoskeletal system such as dystonia, bradykinesia and myoclonus may also occur in the subacute stage of complex regional pain syndrome (CRPS) type I. Aim: To learn about difficulties related to diagnosis and rehabilitation of a patient with AHS and CRPS type I complicated by an upper limb fracture. Case study: A case of a patient admitted to the rehabilitation department with compulsive unilateral involuntary groping and grasping movements of the left hand for about half a year is presented. The woman has been suspected of CBS. A few months after the diagnosis, the patient was admitted to the rehabilitation ward, where she suffered an elbow fracture during exercise. Two months after fracture, type I CRPS was diagnosed. Results and discussion: AHS in CBS and CRPS type I may have a similar clinical picture, which makes differentiation difficult. It is very rare that both diseases coexist with each other. They can also lead to a number of unwanted symptoms such as limb fractures. Conclusions: CRPS may increase the symptoms of dystonia due to other causes. Patients with AHS and dystonia are more likely to break because of rapid movements alone or because of immobilization and osteoporotic changes. As a result, treatment and rehabilitation cannot be based on a questionable diagnosis of a neurological syndrome.

Corticobasal syndrome in a 23‐year‐old female

AbstractBackgroundThe Corticobasal Syndrome (CBS) is characterized by unilateral parkinsonism and higher cortical dysfunction including apraxia, cortical sensory loss, agnosia, and alien limb phenomena. The underlying neurodegenerative causes of CBS include tauopathies (Corticobasal degeneration [CBD], progressive supranuclear palsy), Alzheimer disease, Lewy body disease, and prion disease, with CBD being most common (CBS‐CBD). Disease onset is typically in the fifth to sixth decade of life. Here we present a case of a woman with sporadic CBS due to underlying tauopathy with first signs and symptoms of disease noted at the age 23 yearsMethodThe patient is a participant of the University of California, San Francisco (UCSF) Memory and Aging Center (MAC) observational, longitudinal research program. The patient underwent structured neurological history and examination, neuropsychological testing, brain MRI, and neurodegenerative disease biomarker studiesResultThe patient is 28‐year‐old, right‐handed, bilingual (Spanish and English) woman with 12 years education. She presented with a 5 year history of slowly progressive left upper and lower extremity sensorimotor deficits, involuntary movements of the left upper extremity, and imbalance. There was no family history of progressive neurological or psychiatric illness. Her neurological examination was notable for left upper and lower extremity rigidity, myoclonic jerks, and dystonic posturing of the left hand. She demonstrated ideomotor apraxia, agraphesthesia, astereognosis, and finger agnosia of the left hand. Neuropsychological examination revealed mild deficits in frontal‐executive functions. Serological and cerebrospinal fluid analyses were unrevealing. Brain MRI with and without gadolinium enhancement showed severe right‐sided peri‐rolandic atrophy. Tau PET imaging showed asymmetric moderate tracer uptake over the dorsal fronto‐parietal cortices. Genetic testing was negative for MAPT, C9orf72, GRN, TARDBP, FUS, PSEN1, PSEN2, and APP mutations/expansions.ConclusionCBS is rare before the age of 50 years. We present a case of a 28‐year‐old woman who meets research criteria for CBS, with brain MRI and tau PET imaging findings suggestive of underlying tauopathy, most likely CBD (CBS – CBD). To our knowledge, this is the youngest case of CBS – CBD ever reported.

Network Localization of Alien Limb in Patients with Corticobasal Syndrome.

Perirolandic atrophy occurs in corticobasal syndrome (CBS) but is not specific versus progressive supranuclear palsy (PSP). There is heterogeneity in the locations of atrophy outside the perirolandic cortex and it remains unknown why atrophy in different locations would cause the same CBS-specific symptoms. In prior work, we used a wiring diagram of the brain called the human connectome to localize lesion-induced disorders to symptom-specific brain networks. Here, we use a similar technique termed "atrophy network mapping" to localize single-subject atrophy maps to symptom-specific brain networks. Single-subject atrophy maps were generated by comparing cortical thickness in patients with CBS versus controls. Next, we performed seed-based functional connectivity using a large normative connectome to determine brain regions functionally connected to each patient's atrophied locations. Patients with CBS had perirolandic atrophy versus controls at the group level, but locations of atrophy in CBS were heterogeneous outside of the perirolandic cortex at the single-subject level (mean spatial correlation = 0.04). In contrast, atrophy occurred in locations functionally connected to the perirolandic cortex in all patients with CBS (spatial correlation = 0.66). Compared with PSP, patients with CBS had atrophy connected to a network of higher-order sensorimotor regions beyond perirolandic cortex, matching a CBS atrophy network from a recent meta-analysis. Finally, atrophy network mapping identified a symptom-specific network for alien limb, matching a lesion-induced alien limb network and a network associated with agency in healthy subjects. We identified a syndrome-specific network for CBS and symptom-specific network for alien limb using single-subject atrophy maps and the human connectome. ANN NEUROL 2020;88:1118-1131.

The debate on apraxia and the supplementary motor area in the twentieth century.

Hand function and apraxia are equally relevant to neurosurgeons: as a symptom, as well as through the functional anatomy of "praxis" which underlies the dexterity needed for neurosurgical practice. The supplementary motor area is crucial for its understanding. Historically, Hugo Liepmann dominated the apraxia debate at the beginning of the twentieth century, a debate that has remained influential until today. Kurt Goldstein, a contemporary of Liepmann, is regularly mentioned as the first to have described the alien hand syndrome in 1909. Wilder Penfield was a key figure in exploring the role of the fronto-mesial cortex in human motor control and coined the term "supplementary motor area". It was Goldstein who not only contributed substantially to the apraxia debate more than 100years ago; he also established the link between the dysfunction of the fronto-mesial cortex and abnormal higher motor control in humans.

Progressive aphasia, apraxia of speech and agraphia in corticobasal degeneration: A 12-case series clinical and neuropsychological descriptive study.

Despite initial underreporting of language dysfunctions in corticobasal syndrome (CBS), aphasia is now recognized as a frequent feature of this disease. Aphasia in CBS seems clinically overlying to a non-fluent/agrammatic primary progressive aphasia (nfaPPA), which is also a clinical phenotype associated with corticobasal degeneration (CBD) pathology. However, the clinical features of aphasia in CBS still remain poorly delineated, resulting in misjudgements in the differential diagnosis from a PPA presentation of the disease. To investigate the language disorders of this syndrome, also through a systematic examination of recoding skills (reading, written spelling and repetition) and articulatory disturbances, which have been rarely examined in previous studies. We present a clinical and neuropsychological descriptive study of the language impairments in a case series of 12 aphasic patients with a clinical diagnosis of CBS. Language assessment was conducted by means of the Esame NeuroPsicologico dell'Afasia, a comprehensive Italian battery for language functions, the Token Test, and the Apraxia of Speech Rating Scale. The language profile of the patients showed a severe expressive language disorder, characterized by non-fluent speech, apraxia of speech (AoS) with predominant stuttering-like dysfluencies, spatial/apraxic agraphia, lack of word-finding and defective sentence repetition. Severe limb apraxia, visual-spatial deficit and alien hand syndrome were also present. Neuroimaging showed bilateral left asymmetric atrophies and hypometabolism in the frontal premotor, parietal posterior and temporal areas. These findings suggest that aphasia in CBS might present as a 'mixed PPA', instead of an nfaPPA as previously stated, showing a combination of features of the nfa and logopenic variants of the PPA, associated with AoS, stuttering and agraphia, which might be additional important cognitive markers for the clinical diagnosis of CBS and discriminating features of an nfaPPA presentation of a CBD. These results might also suggest specific intervention areas in the rehabilitation of patients with CBS. What this paper adds What is already known on the subject Language disorders in CBS patients usually present clinically overlying to an nfaPPA, which is also a clinical phenotype associated with CBD pathology, according to recent diagnostic criteria. However, the clinical features of aphasia in CBS still remain poorly delineated, and this raises difficulties and misjudgements for clinicians in the differential diagnosis from a PPA presentation of the disease. What this paper adds to existing knowledge This study shows that the language profile of our CBS patients was characterized by severe expressive language disorders, with non-fluent speech, apraxia of speech (AoS) with predominant stuttering-like dysfluencies, spatial/apraxic agraphia, lack of word-finding, and defective sentence repetition. These findings suggest that aphasia in CBS might present as a 'mixed PPA', rather than an nfaPPA as previously stated, showing a combination of features of the nfa and logopenic variants of the PPA associated with AoS, stuttering and agraphia. What are the potential or actual clinical implications of this work? These results suggest that AoS, stuttering and agraphia might be important additional cognitive markers for the clinical diagnosis of CBS, and discriminating features of an nfaPPA presentation of a CBD. The language disorders exhibited in the present study might also support speech and language therapists in targeting specific intervention areas in the rehabilitation of patients with CBS.

Social Preservation of Traditional Administration of Indigenous Peoples — The Ho Tribe in India

Indigenous peoples have distinguished cultural traditions and linguistic identity. Across the world, Indigenous peoples have always asked the State to recognise their social structure and opportunities to preserve their traditional lifestyles. The issues at stake are their rights over habitat and natural resources and the need to curtail private and public sector exploitation through alien hands. Due to the need to survive, helplessness and systematically forced assimilation, the traditional fabric of their culture are being distorted and defaced. This study deals with the concerns and issues relating to the protection of identity, tradition and customs of Ho tribe that inhabits the West Singhbhum in the State of Jharkhand in India.

The specifics of manipulative influence in contemporary social interactions and communications

In the presented article socio-psychological mechanisms and basic principles of communicative intersubjective mutual influence in a context of contemporary social reality are regarded, and also possible ways of overcoming the arising manipulations are designated. The main goal of the work can be considered to identify the conceptual foundations for the implementation of intersubjective manipulative influence, study the basic principles and methods of applied socio-psychological impact on the interpersonal and personal-group levels of communications and interactions, and define possible methods of effectively countering unwanted and harmful manipulations. As a result of the undertaken analysis, it was found that the methodology of intersubjective influence in modern society consists of 7 key principles based on the paradigm of standardized and stereotypical behavioural responses of members of society, which include the principles (and the corresponding methods of applied manipulative influence) of contrasting perception, mutual exchange, consistent commitment, social affirmation, determinate emotional disposition, and authority reference. The author’s interpretation and generalization of relevant areas and examples of domestic and foreign everyday social practice allowed forming a holistic vision of the issues under consideration. As a result, the presented article not only contains analytical conclusions about the nature and mechanisms of modern social interactions and communications, but also offers specific practical recommendations to avoid unwanted and dangerous intersubjective manipulative influences through the development of internal self-control in a person and the formation of a rationalized and differentiated critical perception surrounding people, the proposals and claims put forward by them, and following resulting social events. Thanks to this approach, modern citizens, voters, and consumers have the opportunity to stop being “passive puppets” in the skilful alien hands and turn into full-fledged actors, making independent decisions and forming their own behaviour models.

Alien limb in the corticobasal syndrome: phenomenological characteristics and relationship to apraxia

Alien limb refers to movements that seem purposeful but are independent of patients’ reported intentions. Alien limb often co-occurs with apraxia in the corticobasal syndrome, and anatomical and phenomenological comparisons have led to the suggestion that alien limb and apraxia may be causally related as failures of goal-directed movements. Here, we characterised the nature of alien limb symptoms in patients with the corticobasal syndrome (n = 30) and their relationship to limb apraxia. Twenty-five patients with progressive supranuclear palsy Richardson syndrome served as a disease control group. Structured examinations of praxis, motor function, cognition and alien limb were undertaken in patients attending a regional specialist clinic. Twenty-eight patients with corticobasal syndrome (93%) demonstrated significant apraxia and this was often asymmetrical, with the left hand preferentially affected in 23/30 (77%) patients. Moreover, 25/30 (83%) patients reported one or more symptoms consistent with alien limb. The range of these phenomena was broad, including changes in the sense of ownership and control as well as unwanted movements. Regression analyses showed no significant association between the severity of limb apraxia and either the occurrence of an alien limb or the number of alien limb phenomena reported. Bayesian estimation showed a low probability for a positive association between alien limb and apraxia, suggesting that alien limb phenomena are not likely to be related to severity apraxia. Our results shed light on the phenomenology of these disabling and as yet untreatable clinical features, with relevance to theoretical models of voluntary action.

Acquired Hemicerebral Atrophy Secondary to Chronic Internal Carotid Steno-Occlusive Disease: A Case Series.

Cerebral atrophy is a common finding in elderly patients; however, cerebrovascular disease causing progressive focal cerebral atrophy and dysfunction is unusual. In this report, we present 3 cases of hemicerebral atrophy due to ipsilateral internal carotid artery (ICA) stenosis or occlusion mimicking neurodegenerative conditions. Patient 1 had a frontal dysexecutive syndrome potentially consistent with a diagnosis of behavioral variant frontotemporal dementia; however, neuroimaging revealed a chronically occluded left ICA and a pattern of atrophy restricted to the left middle cerebral artery territory, suggestive of a vascular etiology. Patient 2 presented with progressively worsening seizures and right-sided weakness consistent with left hemispheric dysfunction, with radiographic evidence of left hemicerebral atrophy. Angiography revealed a chronic dissection of the left ICA leading to left cerebral hypoperfusion. Patient 3 had asymmetric parkinsonism, alien limb, and cognitive impairment consistent with a diagnosis of corticobasal syndrome. His imaging, however, revealed atrophy and encephalomalacia within the anterior circulation watershed territories with chronic, severe stenosis of the left ICA suggestive of a chronic hypoperfused state. In this case series, we report 3 examples of hemicerebral atrophy secondary to chronic ipsilateral ICA vascular disease with diverse progressive clinical symptoms mimicking primary neurodegenerative conditions. This case series highlights the importance of considering chronic hypoperfusion and large-vessel severe stenosis or occlusion in patients with cognitive impairment and evidence of asymmetric brain atrophy. In addition to symptomatic treatment, the management of vascular risk factors including treatment with antiplatelet agents, statins, and revascularization procedures can be considered.

Defective Embodiment of Alien Hand Uncovers Altered Sensorimotor Integration in Schizophrenia.

The observation that people with schizophrenia misattribute the source of their own actions has led to the hypothesis that they suffer from altered sensorimotor processes underlying sense of agency. Furthermore, rubber hand studies suggest an abnormal experience of embodiment in schizophrenia. However, this latter finding is based on a procedure that elicits ownership sensations for a fake hand by visuo-tactile stimulation, leaving the agency subcomponent of embodiment relatively untouched. By using a visuo-motor version of the embodiment illusion able to actively elicit also sense of agency for an alien hand, we tested whether the putative sensorimotor deficits are also involved in altering embodiment sensations in schizophrenia. Subjective (questionnaire) and perceptual (forearm bisection performance) indexes of the embodiment illusion were collected. Differently from controls, both the explicit agency component and the implicit body metrics update were not modulated by the extent of visuo-motor congruency in participants with schizophrenia. We conclude that motor prediction and/or temporal binding window impairments may alter the feeling of embodiment and body representation in schizophrenia.

Editors' note: Alien hand syndrome

In the Video NeuroImage, “Alien hand syndrome,” Drs. Debray and Demeestere presented a striking video of a 94-year-old patient who developed alien hand syndrome in her left hand following a right parieto-temporal ischemic stroke, with this hand often counteracting purposeful movements of the right hand. In response, Dr. Mark highlights the distinction between the callosal alien hand variant, exemplified by the video, and the frontal alien hand variant, which involves compulsive grasping and grabbing but without such intermanual conflict. In the Video NeuroImage, “Alien hand syndrome,” Drs. Debray and Demeestere presented a striking video of a 94-year-old patient who developed alien hand syndrome in her left hand following a right parieto-temporal ischemic stroke, with this hand often counteracting purposeful movements of the right hand. In response, Dr. Mark highlights the distinction between the callosal alien hand variant, exemplified by the video, and the frontal alien hand variant, which involves compulsive grasping and grabbing but without such intermanual conflict.

Reader response: Alien hand syndrome.

The Video NeuroImage by Debray and Demeestere1 is a good demonstration of the callosal alien hand variant, typified by intermanual conflict. This is in contrast to the frontal alien hand variant, where there is compulsive grasping and grabbing, but without fighting over control of an object.

Unraveling corticobasal syndrome and alien limb syndrome with structural brain imaging

Alien limb phenomenon is a rare syndrome associated with a feeling of non-belonging and disowning toward one's limb. In contrast, anarchic limb phenomenon leads to involuntary but goal-directed movements. Alien/anarchic limb phenomena are frequent in corticobasal syndrome (CBS), an atypical parkinsonian syndrome characterized by rigidity, akinesia, dystonia, cortical sensory deficit, and apraxia.The structure–function relationship of alien/anarchic limb was investigated in multi-centric structural magnetic resonance imaging (MRI) data. Whole-group and single-subject comparisons were made in 25 CBS and eight CBS-alien/anarchic limb patients versus controls. Support vector machine was used to see if CBS with and without alien/anarchic limb could be distinguished by structural MRI patterns.Whole-group comparison of CBS versus controls revealed asymmetric frontotemporal atrophy. CBS with alien/anarchic limb syndrome versus controls showed frontoparietal atrophy including the supplementary motor area contralateral to the side of the affected limb. Exploratory analysis identified frontotemporal regions encompassing the pre-/and postcentral gyrus as compromised in CBS with alien limb syndrome. Classification of CBS patients yielded accuracies of 79%. CBS-alien/anarchic limb syndrome was differentiated from CBS patients with an accuracy of 81%. Predictive differences were found in the cingulate gyrus spreading to frontomedian cortex, postcentral gyrus, and temporoparietoocipital regions.We present the first MRI-based group analysis on CBS-alien/anarchic limb. Results pave the way for individual clinical syndrome prediction and allow understanding the underlying neurocognitive architecture.

The significant characteristics of corticobasal syndrome

Corticobasal syndrome (CBS) is a rare neurodegenerative disorder. Mutation in the microtubule associated protein tau (MAPT) has been presented in patients with CBS. Also, a mutation in the gene that encodes progranulin (PGRN) is frequently observed in CBS patients. Patients with this syndrome present predominantly dementia findings. This syndrome is associated with various clinical and laboratory characteristics which give the opportunity to differentiate among the other dementia syndromes. The aim of this study was to described symptoms and signs of the CBS and its confirmation with mutation analysis of the related genes. Patients with CBS commonly present Parkinsonism like syndrome/ Parkinson disease findings such as akinesia, rigidity and dystonia. Myoclonus, limb apraxia and alien limb phenomena are also included in the clinical presentation of the disease. Most patients also complained because of agraphia, difficulties in spontaneous speech and both single-word and sentence repetition inability. Magnetic resonance imaging (MRI) present damage to the primary motor cortex, inferior parietal, left supplementary motor area and basal ganglia. Levodopa, benzodiazepines and anticholinergic agents are commonly used for the therapeutic process of the syndrome. Even though a tiny amelioration of patient’s symptoms is usually observed, the outcome is very poor. CBS is a rare dementia disorder which is associated with symptoms commonly found in Parkinsonism like syndrome/ Parkinson disease plus dementia. The response of the therapeutic treatment is very disappointing.

'See Me, Feel Me': Prismatic Adaptation of an Alien Limb Ameliorates Spatial Neglect in a Patient Affected by Pathological Embodiment.

Pathological embodiment (E+) is a specific contralesional delusion of body ownership, observed following brain damage, in which patients embody someone else’s arm and its movements within their own body schema whenever the contralesional ‘alien’ arm is presented in a body-congruent position (i.e., 1st person perspective and aligned with the patient’s shoulder). This disorder is often associated with spatial neglect, a neurological syndrome in which patients are unaware of stimuli presented in the contralesional (often the left) space. Capitalizing on previous evidence demonstrating that prismatic adaptation of the ipsilesional arm to right-deviating prisms is effective in ameliorating neglect symptoms, here we investigated whether such amelioration also occurs in E+ patients with neglect when prismatic training is performed by the ‘alien’ embodied arm. Four left neglect patients (one with and three without pathological embodiment) underwent visuomotor prismatic training performed by an ‘alien’ arm. Specifically, while patients were wearing prismatic goggles shifting the visual field rightward, a co-experimenter’s left arm presented in a body-congruent perspective was repeatedly moved toward visual targets by another examiner. In a control condition, the co-experimenter’s arm was moved toward the targets from a body-incongruent position (i.e., 3rd person perspective). Neglect symptoms were assessed before and after training through paper-and-pencil tasks. In the E+ patient, neglect improved significantly more in 1st than in 3rd person perspective training, suggesting that prismatic adaptation of the ‘alien’ embodied arm is effective in modulating spatial representation. Conversely, for control E- patients (not embodying the ‘alien’ arm), we observed more limited improvements following training. These findings indicate that the ‘alien’ embodied arm is so deeply embedded in the patient body and motor schema that adaptation to prismatic lenses can affect multiple processing stages, from low level sensory-motor correspondences, to higher level body, motor and spatial maps, similarly as it occurs in normal subjects and neglect patients without pathological embodiment.

Rehabilitation of two patients presenting with alien hand sign

Rehabilitation of two patients presenting with alien hand sign