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Alien hand syndrome is a rare condition associated with lesions of the corpus callosum and of the supplementary motor area, which can be caused by ruptured cerebral aneurysms. We present a novel case of a patient with a subarachnoid haemorrhage from an aneurysm of the anterior communicating artery who developed alien hand syndrome and intermanual conflict. In addition, we performed a systematic literature search and evaluated data on clinical presentation, treatment and radiological findings from relevant papers. To date, 17 cases of alien hand syndrome in aneurysmatic subarachnoid haemorrhage have been reported. Aneurysms of the anterior communicating artery were the most common origin of subarachnoid haemorrhage (10/17), followed by pericallosal artery aneurysms (7/10). The prognosis appears to be favourable; however, damage to the supplementary motor area during treatment should be avoided to keep symptoms minimal.

Alien hand syndrome (AHS) is a rare condition, which is defined as involuntary meaningful movements of a limb associated with loss of ownership over the limb. It affects mostly the left hand. Corticobasal degeneration, stroke and Creutzfeldt-Jakob disease are the three leading causes of AHS. AHS is classically divided into three subcategories: frontal, callosal and posterior. Loss of inhibitory tone and loss of bilateral hemisphere activation are the hypothesised pathophysiologic causes of AHS. This is a case report of a posterior AHS in a 47-year-old woman after stroke in the right parietal lobe.

Background Alien hand syndrome (AHS) is a disabling condition in which one hand behaves in a way that the person finds "alien". This feeling of alienation is related to the occurrence of movements of the respective hand performed without or against conscious intention. Most information on AHS stems from single case observations in patients with frontal, callosal, or parietal brain damage. Methods Retrospective analysis of distinctive clinical features of three out of 18 epilepsy patients who developed AHS with antagonistic movements of the left hand after corpus callosotomy (CC) (one anterior, two complete) for the control of epileptic seizures, particularly epileptic drop attacks (EDA). Results Remarkably, these three patients, two men and one woman, displayed atypical language dominance with a bilateral, left more than right hemisphere language representation in intracarotidal amobarbital testing before surgery. The overall additional distinctive feature of the target patients was genuine left-handedness, with writing retrained to right-handedness in two patients. After surgery the left hands became alien. The problem was permanent, despite strategies for compensation. Conclusion From this observation we suggest that under the conditions of dissociation of language and motor dominance, loss of both intentional control of contralateral action and physiological inhibition of antagonistic movements lead to post-callosotomy alien-hand-like motor phenomena. The dissociation pattern posing this risk seems rare but needs to be considered when evaluating candidates for callosotomy.

An alien limb is a debilitating disorder of volitional control. The core feature of alien limb is the performance of simple or complex semi-purposeful movements which the patient reports to be unintentional or unwanted, or occasionally in opposition to their intentions. Theories of the mechanism of alien limb phenomena have emphasised the role of disinhibition in the brain, and exaggerated action 'affordances'. However, despite advances in cognitive neuroscience research and a large public and media interest, there has been no unifying computational and anatomical account of the cause of alien limb movements. Here, we extend Bayesian brain principles to propose that alien limb is a disorder of 'predictive processing' in hierarchical sensorimotor brain networks. Specifically, we suggest that alien limb results from predictions about action outcomes that are afforded unduly high precision. The principal mechanism for this abnormally high precision is an impairment in the relay of input from medial regions, predominantly the supplementary motor area (SMA), which modulate the precision of lateral brain regions encoding the predicted action outcomes. We discuss potential implications of this model for future research and treatment of alien limb.

A previously independent 66-year-old right-handed male presented with right-sided weakness, preferring the lower-extremities with additional impaired gait and dysarthria for 1-day duration. Imaging found a large left hemispheric anterior cerebral artery ischemic infarction with multiple lacunar infarcts. He exhibited frontal, callosal, and posterior variants of Alien Hand Syndrome which impeded activities of daily living. Although limited in evidence, a trial of clonazepam was initiated based on previous case reports describing suspected efficacy. Botulinum toxin A was not used given the patient's immediate need and limited hospital length of stay. Right upper extremity constricting therapies improved intermanual conflict and spontaneous grasping and levitation (arm elevation in retroflexion) activity; however, concomitant left upper extremity motor apraxia complicated task-oriented activities. The combination of pharmaceutical and therapeutic interventions improved the patient's quality of life as assessed by clinical observation, functional independence measures from 41 to 57, and patient-reporting. This case report aims to increase awareness of a potential barrier to rehabilitation of a debilitating and rare condition and to discuss current assessment tools and treatment options supported by available evidence.

A 69-year-old woman presented with a cortical hand syndrome progressing over several weeks. MRI brain showed characteristic appearances of progressive multifocal leukoencephalopathy (PML), confirmed by detection of the JC virus in CSF, despite the absence of any evidence of immunosuppression. Treatment with mirtazapine, mefloquine and cidofovir did not affect the progression of the disease, which was fatal within 7 months of presentation. This report adds to the small case literature that suggests that PML can occur in immunocompetent people, albeit extremely rarely.

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.

OBJECTIVE 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. METHODS 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. RESULTS 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. INTERPRETATION 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.

Rationale: Alien Hand syndrome (AHS) is characterized in most patients by seemingly purposeful, involuntary movements of the extremities. It is not well known among physicians on account of its diverse clinical manifestations. Patient concerns: We present a 57-year-old Chinese man who could not stop or turn himself around as he involuntarily and uncontrollably walked forward, which had happened frequently in the month prior to treatment. He had been a heavy drinker for thirty years before the onset of the disease, with an alcohol intake of 600 to 800 ml/day. Diagnoses: History of alcohol intake and the brain magnetic resonance imaging findings indicated a diagnosis of Marchiafava–Bignami disease. The patient was additionally diagnosed with Alien Hand Syndrome according to his clinical symptoms. Interventions: The patient was treated with high doses of vitamin B for 1 month. Outcomes: The patient's abnormal behaviors never appeared during the treatment, and no instance of recurrence was observed during the 6 months of follow-up. Lessons: The clinical manifestation of AHS is non-specific. Only by considering its diverse manifestation can doctors better understand the disease and achieve early intervention.

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.

Alien limb syndrome following stroke within the territory of the posterior cerebral artery is exceedingly rare. A right-handed female experienced left homonymous hemianopia, visuospatial neglect, and proprioceptive loss of her left hemi-body. She experienced unintended, involuntary movements of her left arm and hand, which interfered with and disturbed motor actions of daily life performed with her right upper limb. There was no denial of ownership, but she interpreted movements of her left upper limb to be annoying, out of her will and unwanted. The alien limb phenomenon improved in parallel with improvement of proprioceptive loss over a 12-week of in-patient rehabilitation. A recently proposed theoretical concept of the alien limb phenomenon after posterior artery stroke is discussed.

An alien limb is a debilitating disorder of volitional control. The core feature of alien limb is the performance of simple or complex semi-purposeful movements which the patient reports to be unintentional or unwanted, or occasionally in opposition to their intentions. Theories of the mechanism of alien limb phenomena have emphasised the role of disinhibition in the brain, and exaggerated action 'affordances'. However, despite advances in cognitive neuroscience research and a large public and media interest, there has been no unifying computational and anatomical account of the cause of alien limb movements. Here, we extend Bayesian brain principles to propose that alien limb is a disorder of 'predictive processing' in hierarchical sensorimotor brain networks. Specifically, we suggest that alien limb results from predictions about action outcomes that are afforded unduly high precision. The principal mechanism for this abnormally high precision is an impairment in the relay of input from medial regions, predominantly the supplementary motor area (SMA), which modulate the precision of lateral brain regions encoding the predicted action outcomes. We discuss potential implications of this model for future research and treatment of alien limb.

Creutzfeldt-Jakob disease (CJD) is a rare, rapidly progressive, and fatal neurodegenerative disease with neuropsychological sequelae. This study highlighted a rare presentation of CJD (e.g. corticobasal syndrome [CBS]), reviewed updated diagnostic criteria and procedures for CJD (e.g. diffusion weighted imaging [DWI], real-time quaking-induced conversion [RT-QuIC]), and discussed differential diagnoses.Case report methodology focused on a 68-year-old, Hispanic, right-handed man with 11 years of education. He presented with a 1-2-month history of gait and motor difficulties (e.g. rigidity, myoclonus).After evaluation, a 'cortical ribboning' pattern on DWI and positive RT-QuIC was integrated with performance on neurobehavioral exam (i.e. alien limb phenomenon, unilateral ideomotor apraxia) and neuropsychological testing (i.e. frontal-parietal dysfunction pattern) to reach a diagnosis of sCJD-CBS. The patient expired 3 months after onset of symptoms.This literature review and case report highlighted the importance of staying abreast of developments in neurological literature and the added value of neuropsychology, when integrated with newer procedures, for confirming and excluding diagnostic considerations.

Background: Arm levitation is an involuntary elevation of the upper limb, a manifestation of the alien-limb phenomenon. It has rarely been reported in Creutzfeldt–Jakob disease (CJD), less so as an initial manifestation Case Report: We report a 56-year-old right-handed man with rapidly progressive gait ataxia and involuntary elevation of the left upper limb. During the next few weeks, the patient developed cognitive impairment, apraxia, visual hallucinations, and myoclonus. He met diagnostic criteria for CJD. We evaluated additional published cases of early-appearance of alien-limb phenomenon in the context of CJD; there were 22 such cases and alien-limb phenomenon was the first and exclusive manifestation in only five of them. Discussion: Arm levitation may be a distinct presentation of CJD, appearing earlier than other clinical features., Tremor and Other Hyperkinetic Movements, Tremor and Other Hyperkinetic Movements

A 94-year-old patient developed the alien hand syndrome in the left (nondominant) hand following an ischemic stroke of the right parietotemporal lobe (including postcentral gyrus, superior and inferior parietal lobule) due to an occlusion of the posterior division of the right middle cerebral artery.

We report the case of a 73-year-old right-handed female with a right parietal cerebral infarction and presented symptoms that were challenging to differentiate between alien hand sign (AHS) and sensory ataxia. She presented to our emergency department with chief complaints of abnormal involuntary movements and a feeling of foreignness on her left upper limb. The first neurological examination revealed left spatial neglect, left-side sensory impairment that included superficial and deep sensations, left limb-kinetic apraxia, and left limb ataxia. Furthermore, her symptoms and complaints had characteristics of AHS that includes a sensation that her left upper limb dose not belong to herself and an abnormal behavior of left hand that is contrary to her own intent. Brain MRI revealed an acute cerebral infarction confined to the right postcentral gyrus. This case highlights that sensory ataxia due to the disturbance of deep sensation might present symptoms similar to AHS. Previous studies suggested the involvement of the disturbance of somatosensory pathway in posterior-variant AHS. Therefore, a precise distinction between AHS and sensory ataxia, especially in posterior-variant AHS, is imperative to avoid confusion regarding the term "alien hand sign."

Background Alien Hand Syndrome (AHS) is an uncontrollable, involuntary, but in appearance, purposeful motor control disorder of the upper extremity. Case report A 42-year-old male patient was admitted to our clinic complaining of involuntary motor activity in his right hand. He had a previous history of migraine with visual aura. The uncontrollable motor control disorder was compatible with Alien Hand Syndrome, which was appearing immediately after the visual aura and before the beginning of headache. Conclusion Alien Hand Syndrome is usually observed with anterior cerebral artery infarction, midline tumors, trauma and several neurodegenerative diseases, but is rarely seen in paroxysmal conditions such as migraine with aura.

We report a 65-year-old man with a right cerebral infarction that occurred 15 years ago and a residual left hemiparesis that began with progressive contralateral hemiparesis. During the hospitalization, the patient developed a bilateral alien hand syndrome. Urgent CT, MR, CT angiography, and brain perfusion SPECT were performed that revealed an old right cerebral infarction and a new ischemic lesion in left parietal lobe and adjacent brain territories.

Corticobasal degeneration (CBD) may be expressed as an atypical parkinsonism with a mean disease survival of about 7 years,(1) the shortest reported survival being 24 months.(2) We report a patient with corticobasal syndrome (CBS) and pathology-confirmed CBD whose 10-month course was manifested as a frontal alien hand evolving into agrypnia excitata.

Any injury of a hand more or less disintegrates the injured hand. The rehabilitation of an alienated hand is prolonged. How can the alienation of the own but injured hand and the involuntary and unconscious inhibition of its perception and use be diagnosed, explained, avoided and designated? Medical observations and interviews with patients and therapists on the occasion of rehabilitation of hand injuries resulted in the development of a new concept of biopsychosocial integrating rehabilitation and a creative hand therapy with the objective of integrating injured and alienated hands.The inhibition of the gesture of thinking has been the most revealing sign for the diagnosis of a disintegration of an injured hand. Explanation: The involuntary inhibition to recognize and use an injured hand causes and implicates the alienation of the rested hand.Information by hand surgeons and hand therapists. Creative hand therapy guides the attention to complex and pleasing activities. In complex disintegrations after hand injuries the hand as well as the person need help. Designation: Hypotheses: Posttraumatic Proportionate Regional Disintegration while the tissues heal. Posttraumatic Complex Regional Disintegration, if the disintegration overruns the healing of tissues or if the person suffers. The Complex Regional Pain Syndrome is distinguished as a rare exception of a biopsychosocial disintegration. Posttraumatic regional disintegration seems to be proportionate while the tissues are healing. If the mentioned sensations of the patients and the visible signs of disintegration persist, the disorder spreads onto the biopsychosocial unit of the person. This disorder of hand and person may be designated as a complex disorder. The impact of a proportionate posttraumatic disintegration as well as the formation and exacerbation of a complex posttraumatic disintegration may be prevented by the facilitation of the integration of an injured hand. Scientific prove is needed for: the guiding impact of the healthy hand for physiotherapy; the impact of the gesture of thinking to diagnosis and treatment of disintegrations; the effectivity and the economic efficiency of a biowpsychosocial integrating rehabilitation and creative hand therapy.

Anarchic hand syndrome (AHS) is characterized by goal-directed movements performed without volitional control (agency). Different AHS subtypes have been identified; however, few studies have examined the posterior subtype. We report a case of AHS following right-hemisphere parietal damage, with left-sided somatosensory and proprioceptive impairment. Agency was examined for nonanarchic (volitional) movements performed using the anarchic hand. The patient experienced abnormal agency for movements whether motor intention and visual feedback were congruent or incongruent, but not when intention was absent (passive movement). Findings suggest a general disturbance of veridical motor awareness and agency in this case of parietal AHS.

Ischemic lesions within the territory of the anterior cerebral artery present with a variety of clinical signs and symptoms. Among these, frontal alien hand syndrome is rare and easily overlooked in the acute clinical setting, but significantly impacts on functional activities of daily life. Given its rareness, very little is known about its long-term outcome. To shade some more light onto this issue, clinical presentation, course of rehabilitation and outcome of two illustrative cases of frontal alien hand syndrome following anterior cerebral artery stroke are presented. Within seven and nine months from symptom onset, respectively, the clinical symptoms of frontal alien hand had resolved completely in both cases. We conclude that frontal alien hand syndrome has a favourable long-term outcome.

A 47-year-old man developed sudden-onset abulia and alien hand syndrome (AHS). MRI revealed bilateral ischemic injury within anterior cerebral artery territory (a complex bilateral corpus callosum infarction1) due to obstruction of a variant bihemispheric A2 branch by a thrombus (figures 1 and 2), also demonstrated on 3D volume-rendered CT angiography (figure 2). The finding of lower-limb deep venous thrombosis in a patient with right-to-left interatrial shunt accounted for the case, given workup was otherwise unremarkable.

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.

It has been shown that combinations of visual, tactile, and proprioceptive manipulations in healthy subjects may elicit illusory feelings of embodiment (the rubber hand illusion and the somatic rubber hand illusion). We report a case of alien hand syndrome in which the alien hand interacted with the somatic rubber hand illusion to provoke a very strong movement of the alien hand. This effect could be reliably replicated at every application of the experimental procedure. Thus, the illusion seemed to wake up the alien hand. The results demonstrate that the alien hand syndrome can be affected by experimentally induced bodily illusions, which are based on the manipulation of touch and proprioceptive information.

Anarchic hand syndrome (AHS) is a rare disorder characterized by unwilled, but seemingly purposeful movements of the affected upper limb which are perceived by the patients not to be under their control. It often interferes with goal-directed movements and bimanual tasks. At present there is no effective method of treatment of AHS. We report here a case of AHS following resection of a frontal lobe tumor and describe its effects on the patient's functional activities. The patient used avoidance behavior and mental concentration to overcome the disabling effect of AHS. These strategies appear to be useful in the management of AHS.

The alien hand syndrome (AHS) is a rare neuropsychological disorder characterized by involuntary, yet purposeful, hand movements. Patients with the AHS typically complain about a loss of agency associated with a feeling of estrangement for actions performed by the affected limb. The present study explores the integrity of the body representation in AHS, focusing on 2 main processes: multisensory integration and visual self-recognition of body parts. Three patients affected by AHS following a right-hemisphere stroke, with clinical symptoms akin to the posterior variant of AHS, were tested and their performance was compared with that of 18 age-matched healthy controls.AHS patients and controls underwent 2 experimental tasks: a same-different visual matching task for body postures, which assessed the ability of using your own body schema for encoding others' body postural changes (Experiment 1), and an explicit self-hand recognition task, which assessed the ability to visually recognize your own hands (Experiment 2).As compared to controls, all AHS patients were unable to access a reliable multisensory representation of their alien hand and use it for decoding others' postural changes; however, they could rely on an efficient multisensory representation of their intact (ipsilesional) hand. Two AHS patients also presented with a specific impairment in the visual self-recognition of their alien hand, but normal recognition of their intact hand.This evidence suggests that the AHS following a right-hemisphere stroke may involve a disruption of the multisensory representation of the alien limb; instead, self-hand recognition mechanisms may be spared. (PsycINFO Database Record

Alien hand syndrome (AHS) is a rare disorder of involuntary limb movement together with a sense of loss of limb ownership. It most commonly affects the hand, but can occur in the leg. The anterior (frontal, callosal) and posterior variants are recognized, with distinguishing clinical features and anatomical lesions. Initial descriptions were attributed to stroke and neurosurgical operations, but neurodegenerative causes are now recognized as most common. Structural and functional imaging and clinical studies have implicated the supplementary motor area, pre-supplementary motor area, and their network connections in the frontal variant of AHS, and the inferior parietal lobule and connections in the posterior variant. Several theories are proposed to explain the pathophysiology. Herein, we review the literature to update advances in the understanding of the classification, pathophysiology, etiology, and treatment of AHS.

A 58-year-old woman with a history of poorly controlled type 2 diabetes, hypertension and smoking presented with a left hemiparesis (grade 4/5). Admission glucose was 22.6 mmol/L. MRI of the brain demonstrated an area of restricted diffusion involving the corpus callosum of the left hemisphere (figures 1 and 2). Investigations into the cause of her stroke including vasculitic and thrombophilic causes, echocardiogram, telemetry and carotid Doppler, did not demonstrate any significant pathology. Rather alarmingly, the patient's glycated hemoglobin was elevated at 134 mmol/mol. Figure 1 Axial …

Background:Spontaneous pneumocephalus is a rare condition that has been reported infrequently. Alien limb syndrome is an uncommon phenomenon most often seen in patients with frontal and callosal lesions.Method:Case report of a patient with pneumocephalus presenting with alien limb syndrome. The patient underwent successful surgical management. A literature review and discussion of aspects of this presentation are also included.Conclusion:In this case, a spontaneous pneumocephalus has formed a frontal space-occupying lesion and presented with alien limb phenomena.

Alien hand syndrome is a term used to describe a variety of rare conditions in which uncontrolled behavior or feelings of strangeness are felt in one extremity, most commonly the left hand. Etiology usually involves infarct of the right anterior or posterior cerebral arteries or cortical-basal degeneration. The medical and neuropsychological data of an elderly female who suffered a left middle cerebral artery stroke with resulting right-sided alien hand sign is presented. Neuropsychological assessment revealed declines in visual- and perceptual-based abilities and right-sided motor and sensory abilities consistent with the affected areas indicated on neuroimaging. This case demonstrates the utility of neuropsychological assessment in patients with unusual sensory/motor presentations.

In patients with the callosal type of anarchic-hand syndrome, the left hand often does not act as intended and counteracts the right hand. Reports are scarce about the underlying neurophysiological mechanisms. We report the case G.H. who developed the syndrome after infarction of the left arteria pericallosa. It has been suggested that the syndrome arises out of lacking inhibition from the dominant left hemisphere on the right hemisphere. Yet, in tests of spatial intelligence G.H. performed much better with his "anarchic" left hand than with his dominant right hand, similar to observations commonly reported in split-brain patients. Left-right manual choice responses and event-related EEG potentials to laterally presented stimuli were measured. Asymmetries were evident in G.H.'s behavior and EEG potentials, different from age-matched healthy participants (n=11). His right-hand responses were fast and unaffected by incompatibility with stimulus location, whereas his left-hand responses were variable and accompanied by a large negative central-midline EEG potential, probably reflecting efforts in initiating the response. G.H.'s visual N1 component peaked earlier and was larger at the right than the left side of the scalp, and the P3 component was distinctly reduced at the right side. Both features occurred independent of side of stimulus presentation and side of responding hand. The effort indicated by the midline negativity and the asymmetrically reduced P3 might directly reflect G.H.'s lack of control on his right hemisphere's processing. The faster visual processing of the right hemisphere suggested by the N1 asymmetry might contribute to "anarchic" processing, making the right hemisphere process stimuli before control impulses exert their effect. These neurophysiological results tend to support the split-brain account which assumes that the syndrome arises by the lack of communication between hemispheres that act according to their respective competences.

Diagonistic dyspraxia (DD) is a behavioural disorder encountered in split-brain subjects in which the left arm acts against the subject’s will, deliberately counteracting what the right arm does. We report here an oculomotor and computational study of a patient with a long lasting form of DD. A first series of oculomotor paradigms revealed marked and unprecedented saccade impairments. We used a computational model in order to provide information about the impaired decision-making process: the analysis of saccade latencies revealed that variations of decision times were explained by adjustments of response criterion. This result and paradoxical impairments observed in additional oculomotor paradigms allowed to propose that this adjustment of the criterion level resulted from the co-existence of counteracting oculomotor programs, consistent with the existence of antagonist programs in homotopic cortical areas. In the intact brain, trans-hemispheric inhibition would allow suppression of these counter programs. Depending on the topography of the disconnected areas, various motor and/or behavioural impairments would arise in split-brain subjects. In motor systems, such conflict would result in increased criteria for desired movement execution (oculomotor system) or in simultaneous execution of counteracting movements (skeletal motor system). At higher cognitive levels, it may result in conflict of intentions.

Alien hand syndrome is a rare neurological disorder characterized by involuntary and uncontrollable motor behaviour, usually of an arm or hand. The patient perceives the affected limb as alien, and may personify it. The case of a 61-year-old right-handed woman who developed right posterior AHS after ischaemic stroke in the left posterior cerebral artery territory is reported. Neuroimaging studies disclosed no frontal or parietal involvement, while a posterior thalamic lesion was detected. A possible role of the thalamus in the genesis of AHS is discussed.

Alien hand syndrome (AHS) is a neurological disorder in which movements are performed against conscious will. It is rare but significant due to its disability impact on everyday life. This case highlights the clinical features, recovery course and response to rehabilitation of a patient with a dominant anterior cerebral artery territory infarct.Single case report.Clinical signs and symptoms included right hemiparesis, hemianesthesia, dysphagia, language and cognitive dysfunction, personification and autonomous movement of the affected limb; involuntary grasping of objects interfered with his activities of daily living (ADL). Education for diagnosis and compensatory strategies of AHS, including visualisation, distraction of affected limb and maintaining a slow/steady pace with activities decreased the frequency of his AHS movements from 10 times to twice a day. Over the course of 4 months the rehabilitation treatment targeted toward the specific needs of the patient, allowed improvement in his ADL. Commonly used upper extremity motor recovery outcome measures like the Chedoke McMaster Stroke Assessment cannot be considered as a sensitive tool for AHS. More sensitive outcome measures are needed to be determined for this condition.This case distinguishes the clinical findings and description to rehabilitation in a case of AHS.

Posterior alien hand syndrome is a new addition to a poorly understood group of movement disorders. Historically, anatomical lesions causing uncontrolled limb movement and a feeling of foreignness were found to be located in the corpus callosum or frontal lobe. Recent case reports, however, demonstrate the typical symptoms of alien hand syndrome with lesions located in the parietal/occipital lobes. Disturbance of normal function in these regions tends to produce less complex motor activity, such as hand levitation, along with a sensory component characterized by feeling of estrangement. We discuss a patient who presented with unusual symptoms following an outpatient procedure and was found to have posterior alien hand syndrome.

Patients with anarchic hand (AH) syndrome exhibit involuntary but seemingly purposeful controlesional upper limb movements. Here we report on the case of a patient (AC) presenting with a right AH following a left medial frontal lesion. Previous literature indicated that endogenous movements, particularly in the presence of distractors, are impaired in AH, whereas exogenous movements are spared. In this study we examined exogenous and endogenous (or sequential) movements using a new experimental procedure. Our main aim was to investigate whether the ability to perform sequential movements improves under verbal command as anecdotally observed in patients with AH. Results showed that the performance of AC's right AH was impaired in sequential tasks and that this impairment was improved by verbal command. The observed reduction in errors in sequential tasks under external verbal command was coupled with a compensatory increase in response times.