The alien limb phenomenon

When the diagnosis is in the patient's hand and in the neurologist's eye

The objective of this study was to encompass current knowledge about pathophysiological mechanisms of those specific hand postures or deformities caused by central nervous system disorders. In the era of high-resolution neuroimaging and molecular biology, clinicians are progressively losing confidence with neurological examination. Careful hand observation is of key importance in order to differentiate neurological from non-neurological conditions, central from peripheral aetiologies, and organic from functional disorders. Localizing the potential anatomical site is essential to properly conduct subsequent exams. We provided a practical guide for clinicians to recognize hand patterns caused by central nervous system disorders, avoiding mimicking conditions, thus optimizing and prompting the diagnostic pathway.

Clinical Reasoning: A 38-Year-Old Woman Presenting With Acute Hyperkinetic Movements of Her Right Arm

We present a case report of a 38-year-old woman who presented to the hospital with acute onset high amplitude, non-rhythmic, hyperkinetic movements of the right upper extremity, abnormal sensation of the right upper extremity from the elbow to the hand, and the inability to recognize her hand without visual input. This case discusses the differential diagnoses of acute hyperkinetic movement disorders and concurrent alien-limb in a patient presenting within the time window for vascular intervention. Readers are led through the reasoning behind acute interventional decision-making in a patient with a rare presentation. Workup reveals the eventual diagnosis.

Progression to corticobasal syndrome: a longitudinal study of patients with nonfluent primary progressive aphasia and primary progressive apraxia of speech

BACKGROUND AND OBJECTIVES

Nonfluent variant primary progressive aphasia (nfvPPA) and primary progressive apraxia of speech (PPAOS) can be precursors to corticobasal syndrome (CBS). Details on their progression remain unclear. We aimed to examine the clinical and neuroimaging evolution of nfvPPA and PPAOS into CBS.

METHODS

We conducted a retrospective longitudinal study in 140 nfvPPA or PPAOS patients and applied the consensus criteria for possible and probable CBS for every visit, evaluating limb rigidity, akinesia, limb dystonia, myoclonus, ideomotor apraxia, alien limb phenomenon, and nonverbal oral apraxia (NVOA). Given the association of NVOA with AOS, we also modified the CBS criteria by excluding NVOA and assigned every patient to either a progressors or non-progressors group. We evaluated the frequency of every CBS feature by year from disease onset, and assessed gray and white matter volume loss using SPM12.

RESULTS

Asymmetric akinesia, NVOA, and limb apraxia were the most common CBS features that developed; while limb dystonia, myoclonus, and alien limb were rare. Eighty-two patients progressed to possible CBS; only four to probable CBS. nfvPPA and PPAOS had a similar proportion of progressors, although nfvPPA progressed to CBS earlier (p-value = 0.046), driven by an early appearance of limb apraxia (p-value = 0.0041). The non-progressors and progressors both showed premotor/motor cortex involvement at baseline, with spread into prefrontal cortex over time.

DISCUSSION

An important proportion of patients with nfvPPA and PPAOS progress to possible CBS, while they rarely develop features of probable CBS even after long follow-up.

Alien Hand Syndrome Unveiled in a Patient With Right Middle Cerebral Artery Stroke

Alien hand syndrome (AHS) is a rare but significant disorder, characterized by involuntary and often complex movements of one's hand. These movements seem to occur independently and unconsciously, separate from a person's intended actions.  We report a case of a 70-year-old male who presented to the emergency department with left sided hemiplegia following a stroke in the right middle cerebral artery (MCA) that affected the right temporal, parietal and internal capsule region. Upon additional inquiry, the patient reported experiencing involuntary, abrupt movements in his left upper and lower limbs particularly while attempting voluntary movements. As per the patient, these symptoms occurred prior to the onset of limb weakness. The diagnosis of AHS was made after excluding other differentials based on the clinical, metabolic and radiological picture.  Our patient exhibited unique symptoms and had a different presentation from that mentioned in the literature, as the onset of symptoms preceded the development of limb weakness typically associated with stroke. Involvement of the upper and lower limb and onset of symptoms prior to limb weakness make this case exceptionally rare. Moreover, acknowledging alien hand/limb syndrome as a distinct condition, separate from the broad category of post-stroke movement disorder, carries significant implications for both the management and prognosis of affected individuals.

Alien hand syndrome, a rare presentation of corpus callosum and cingulate infarction

Alien hand syndrome (AHS) is a rare apraxia syndrome, characterized by involuntary and uncontrollable movements of one upper limb, often accompanied by intermanual conflict. Damage to the corpus callosum, acute infarction and neurodegenerative disease may result in AHS. Based on the presentation and impairment region, AHS has three variants: frontal, callosal and posterior. Each type may have a different clinical presentation. A total of 157 patients admitted to hospital with corpus callosum infarction between 2012 and 2022 were included for this study, of whom a number of 5 presented with AHS. 4 of them had significant symptoms of intermanual conflict and 1 had strong grip symptoms in the affected upper limb. Moreover, new infarcts involving the corpus callosum and cingulate gyrus were found on MRI in all five patients. We simultaneously performed a retrospective study on all reported AHS cases caused by infarction of the corpus callosum. Case reports and literature reviews were conducted in order to provide clinicians with a better understanding of AHS, its etiology, clinical presentation, diagnosis, and treatment.

Frontal lobe motor syndromes

The motor phenomena accompanying frontal lobe disease are diverse, reflecting the various roles the frontal lobes play in the organization of motor control. The principal frontal motor areas, the primary motor cortex, the premotor cortex, and the supplementary motor area, have different but interrelated functions in motor control. The principal efferent pathway of the primary motor cortex is the corticospinal tract which conducts fine motor control. Damage to the primary motor cortex and the corticospinal tract results in paralysis and loss of skilled, particularly distal, motor function. Lesions of the premotor cortex interfere with the preparation for the execution of movements and coordinating sequences of limb movement. Mediated through cortico-reticulospinal pathways, the premotor cortex adjusts axial and limb muscle activities. The fine motor skills of the corticospinal tract are superimposed upon these stabilizing movements. Supplementary motor area lesions interrupt self-initiated movements, release alien limb behaviors, and result in grasping. Paralysis, primitive reflexes, and frontal gait disorders are readily observed on examination, but difficulties initiating and sequencing movements are more subtle signs of perturbed higher motor control and require special examination procedures. Prefrontal motor syndromes include motor behaviors that only become apparent when the subject performs spontaneous or self-directed activities, unconstrained by instructions from the examiner. Clinical observation also reveals a slowness to respond to instruction with long delays before initiating action (inertia), but once underway they may be unable to stop (perseveration). Patients sit motionless without spontaneous movement or interest in their surrounds (apathy), yet exhibit distractibility, diverting attention to an incidental peripheral stimulus or an object with which they may then fiddle (environmental dependency and utilization behavior). Little spontaneous speech is initiated (abulia) but echolalia may be stimulated by the examiner's conversation. Restlessness, distractibility, perseveration, and environmentally dependent utilization behaviors coexist with apathy, inertia, and abulia. Mutism and akinesia may alternate with stereotypies and agitation in catatonia. These paradoxical combinations are of considerable diagnostic significance in recognizing frontal lobe motor syndromes.

Alien-hand syndrome with mirror movements in hereditary diffuse leukoencephalopathy with spheroids

Hereditary diffuse leukoencephalopathy with spheroids is a rare genetic disorder caused by mutations of the colony-stimulating factor 1 receptor gene. It is an adult-onset leukodystrophy, with a wide spectrum of neurological and psychiatric manifestations that includes Parkinsonism, dementia, seizures, limb weakness, spasticity and abnormal motor behaviour. Alien-hand syndrome and mirror movements are rare manifestations of this and other neurodegenerative disorders. We describe a woman with progressive limb and trunk rigidity, Parkinsonism and dementia, who also had involuntary left arm levitation (part of the posterior variant of alien-hand syndrome) and left-hand mirror movements. We discuss the different types of alien-hand syndrome, and the likely mechanisms of arm levitation and mirror movements.

The Alien Limb Phenomenon in Creutzfeldt-Jakob Disease: A Systematic Review of Case Reports

Alien limb phenomenon (ALP) is a clinical finding seen in numerous neurological disorders, including Creutzfeldt-Jakob disease (CJD). We aimed to conduct a systematic review to update advances in understanding the classification and pathophysiology of ALP in CJD. We used PubMed advanced-strategy searches and only included full-text observational studies and case reports conducted on humans and written in English. We used the PRISMA protocol for this systematic review and the Methodological Quality of Case Reports tool to assess the bias encountered in each study. After applying the inclusion/exclusion criteria, 10 case reports were reviewed. Two independent reviewers analyzed data and confirmed the phenotype of each case of the alien limb in CJD separately. Overall, the most prevalent ALP phenotype presenting in patients with CJD was the posterior phenotype, usually in the early stages of the disease. Our findings corroborate previous research in demonstrating the pathophysiology behind ALP in CJD. We suggest physicians suspect CJD whenever patients present with ALP as the initial symptom.

Writing errors in primary progressive aphasia

Peripheral errors in writing, that is errors produced download the spelling, have been occasionally described in primary progressive aphasia (PPA), but the possibility that these errors might be a marker of parkinsonism associated to some subtypes of PPA has not been explored. We investigated whether errors of peripheral nature characterize the writing disorder in PPA when associated with parkinsonian signs (PSs). Subgroups of PPA without PSs and with PSs were studied. The proportion of the central and peripheral errors in writing words and pseudowords was calculated in each group. In writing words, central errors significantly exceeded peripheral errors in subgroups without PSs. The higher the number of peripheral errors, the higher the probability of presenting PSs. No relation emerged between any error and the Unified Parkinson's Disease Rating Scale, but both types of errors correlated with measures of cognitive ability. Peripheral errors emerge when PSs are associated with PPA and may be linked to a decay of the cognitive control on movement, possibly involving the right hemisphere. Peripheral errors have clinical relevance in PPA, to the extent that they may assume the significance of a marker of specific subtypes and can help to outline the specific clinical picture of individual patients.

Alien Limb Phenomenon After Diffuse Corpus Callosum Ischemic Stroke

The alien limb is a phenomenon characterized by a cluster of clinical features wherein the limb behaves autonomously and as separated from a person's identity. We herein report a 36-year-old Indian female with multiple comorbidities who presented with recurrent episodes of limb-shaking transient ischemic attacks for 1 year, followed by left-sided hemiplegia. During recovering, the patient noticed a feeling that as if her left hand did not belong to herself and acted autonomously (alien limb phenomenon) along with visuospatial deficits. Magnetic resonance imaging of the brain revealed ischemic stroke diffusely involving corpus callosum. Magnetic resonance angiography was suggestive of compromised right-sided anterior circulation. This was corroborated by digital subtraction angiography that revealed reduced flow in right internal carotid artery. Diffuse infarction of the corpus callosum requires involvement of both the anterior and the posterior circulation. Due to the lack of clinical features suggestive of chronic internal carotid artery dissection, occlusive atherosclerotic disease of the anterior cerebral circulation associated with possible steal phenomenon from the posterior circulation was the most probable underlying mechanism for the callosal stroke. Steal phenomenon has been proposed as a compensatory mechanism in hemodynamically compromised ischemic parenchyma and it can explain the co-existence of anterior and posterior circulation strokes. This case also highlights how both anterior and posterior types of the alien limb phenomenon can co-exist in a background of vascular insult, resulting from intra-cranial atherosclerotic disease.

What neurologists wish palliative care physicians knew

As the incidence of neurologic (particularly neurodegenerative) diseases continues to rise, so too will the palliative needs in this patient population. To appropriately care for these patients and families, neurologists and palliative care providers will need to strengthen collaboration. Palliative care providers not formally trained in neurology may feel ill-equipped to manage some of the distinct neuropalliative care needs of these patients. Here, we provide insights into the unique characteristics of patients with neurologic disease and emphasize the relevance of the palliative care skillset in this population to aid the collaboration between palliative care providers and neurologists.

A Critical Review of Alien Limb-Related Phenomena and Implications for Functional Magnetic Resonance Imaging Studies

Consensus criteria on corticobasal degeneration (CBD) include alien limb (AL) phenomena. However, the gist of the behavioral features of AL is still “a matter of debate.” CBD-related AL has so far included the description of involuntary movements, frontal release phenomena (frontal AL), or asomatognosia (posterior or “real” AL). In this context, the most frequent symptoms are language and praxis deficits and cortical sensory misperception. However, asomatognosia requires, by definition, intact perception and cognition. Thus, to make a proper diagnosis of AL in the context of CBD, cognitive and language dysfunctions must be carefully verified and objectively assessed. We reviewed the current literature on AL in CBD and now propose that the generic use of the term AL should be avoided. This catchall AL term should instead be deconstructed. We propose that the term AL is appropriate to describe clinical features associated with specific brain lesions. More discrete sets of regionally bound clinical signs that depend on dysfunctions of specific brain areas need to be assessed and presented when posing the diagnosis. Thus, in our opinion, the AL term should be employed in association with precise descriptions of the accompanying involuntary movements, sensory misperceptions, agnosia-asomatognosia contents, and the presence of utilization behavior. The review also offers an overview of functional magnetic resonance imaging-based studies evaluating AL-related phenomena. In addition, we provide a complementary set of video clips depicting CBD-related involuntary movements that should not mistakenly be interpreted as signs of AL.

Case Report: Good Prognosis of Mixed Alien Hand Syndrome by Verbal-Cue Rehabilitation Exercise

Mixed alien hand syndrome is a rare disease reported in the literature. The mixed callosal–frontal variant of alien hand syndrome is associated with uncoordinated hand movements, and patients may present with an involuntary grasp reflex and intermanual conflict. There are few videos in the existing literature on the comparison of patients' condition before and after recovery of the symptoms of mixed alien hand syndrome. We presented the prognosis of mixed alien hand syndrome in the form of a video. In addition, we have included some videos on the comparison of the condition of patients before and after recovery of the symptoms of mixed alien hand syndrome. A 57-year-old woman presented with left-handed intermanual conflict and right-handed involuntary grasp reflex due to infarction of the frontal lobe and corpus callosum. She was diagnosed with a mixed callosal–frontal variant of alien hand syndrome. Her left hand counteracted the purposeful movements of the right hand. However, the intermanual conflict disappeared after 3 months of therapy, including drug treatment and verbal-cue rehabilitation, and she regained normal coordination of her hand movements. Her prognosis was good despite the large corpus callosum lesions. The uncoordinated hand movements of the patient affected her daily life and caused psychological problems. Initiating rehabilitation early was important and necessary for her to regain coordination. It is possible that the verbal-cue training method played an important role in the recovery of the patient. Therefore, this method of rehabilitation deserves consideration and can be adopted in larger cohort studies as we presented only a single case. The possible mechanisms behind the verbal-cue exercise require further studies, and this patient had a good prognosis despite severe corpus callosum injury, which may merit further investigation.

Corticobasal syndrome: a practical guide

Corticobasal syndrome is a disorder of movement, cognition and behaviour with several possible underlying pathologies, including corticobasal degeneration. It presents insidiously and is slowly progressive. Clinicians should consider the diagnosis in people presenting with any combination of extrapyramidal features (with poor response to levodopa), apraxia or other parietal signs, aphasia and alien-limb phenomena. Neuroimaging showing asymmetrical perirolandic cortical changes supports the diagnosis, while advanced neuroimaging may give insight into the underlying pathology. Identifying corticobasal syndrome carries some management implications (especially if protein-based treatments arise in the future) and prognostic significance. Its treatment is largely symptomatic and is best undertaken within a multidisciplinary setting, including a neurologist, physiotherapist, occupational therapist, speech language therapist, psychiatrist and, ultimately, a palliative care clinician. Corticobasal syndrome can be a confusing entity for neurologists, not least because it has over time evolved from being considered predominantly as a movement disorder to a condition spanning a wide range of cognitive and motor manifestations. In this practical review, we attempt to disentangle this syndrome and provide clarity around diagnosis, its underlying pathological substrates, key clinical features and potential treatments.

Beliefs: A challenge in neuropsychological disorders

INTRODUCTION

Beliefs have recently been defined as the neural product of perception of objects and events in the external world and of an affirmative internal affective state reflecting personal meaning. It is, however, undetermined in which way diseases of the brain affect these integrative processes.

METHODS

Here, the formation and updating of abnormal beliefs in cerebral disorders are described.

RESULTS

It will be shown that well-defined neuropsychological syndromes resulting from brain lesions also interfere with the neural processes that enable the formation, up-dating and communication of beliefs. Similarly, in neuropsychiatric disorders abnormal and delusional beliefs appear to be caused by altered perception and/or misattribution of aversive meaning.

CONCLUSION

Given the importance of beliefs for ordinary social behaviour, abnormal beliefs are a challenge in neuropsychological disorders.

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

Background

The 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.

Method

Clinical 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.

Results

Case 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.

Conclusions

The 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.

Rehabilitation of a Patient with Alien Hand Syndrome: a Case Report of a 61-Year Old Man

Objective

Alien hand syndrome is a rare neurological disorder in which the patient makes seemingly purposeful movements of one hand, which are dissociated from any conscious intent. These abnormal movements are very annoying, and can be disabling, for the patient. There is no established effective treatment for alien hand syndrome.

Methods

Report of a case of a 61-year old man with frontal variant of alien hand syndrome following ischaemic stroke.

Results

During therapy, the patient unwittingly grabbed objects with his right hand and could not voluntarily release his grip. Multidisciplinary rehabilitation was started, with learning of compensation strategies and a focus on bimanual tasks. Follow-up after 5 months showed a major improvement in the Functional Index Measure (FIM) score, an improvement from 36 to 79 on 126 scored items.

CONCLUSION

It is important to recognize this rare syndrome because of its disabling character. Evidence about the best treatment for alien hand syndrome is scarce. There is an important role for specific exercises and patient education. During rehabilitation of the patient, most improvement occurred with bimanual tasks and different colours (black, white and other bright colours) to navigate the subject’s attention more to one side. Another exercise strategy was letting the alien hand catch a cube, after which the patient was able to perform more exercises with the other hand during one – handed training. In the current case, the alien hand syndrome resolved following specific and multidisciplinary rehabilitation.

Diagnostic Challenges in Outpatient Stroke: Stroke Chameleons and Atypical Stroke Syndromes

Failure to diagnose transient ischemic attack (TIA) or stroke in a timely fashion is associated with significant patient morbidity and mortality. In the outpatient or clinic setting, we suspect that patients with minor, transient, and atypical manifestations of cerebrovascular disease are most prone to missed or delayed diagnosis. We therefore detail common stroke chameleon symptoms as well as atypical stroke presentations, broadly review new developments in the study of diagnostic error in the outpatient setting, suggest practical clinical strategies for diagnostic error reduction, and emphasize the need for rapid consultation of stroke specialists when appropriate. We also address the role of psychiatric disease and vascular risk factors in the diagnostic evaluation and treatment of suspected stroke/TIA patients. We advocate incorporating diagnostic time-outs into clinical practice to assure that the diagnosis of TIA or stroke is considered in all relevant patient encounters after a detailed history and examination are conducted in the outpatient setting.

Network Localization of Alien Limb in Patients with Corticobasal Syndrome

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.

Breakdown of the affective-cognitive network in functional dystonia

Previous studies suggested that brain regions subtending affective‐cognitive processes can be implicated in the pathophysiology of functional dystonia (FD). In this study, the role of the affective‐cognitive network was explored in two phenotypes of FD: fixed (FixFD) and mobile dystonia (MobFD). We hypothesized that each of these phenotypes would show peculiar functional connectivity (FC) alterations in line with their divergent disease clinical expressions. Resting state fMRI (RS‐fMRI) was obtained in 40 FD patients (12 FixFD; 28 MobFD) and 43 controls (14 young FixFD‐age‐matched [yHC]; 29 old MobFD‐age‐matched [oHC]). FC of brain regions of interest, known to be involved in affective‐cognitive processes, and independent component analysis of RS‐fMRI data to explore brain networks were employed. Compared to HC, all FD patients showed reduced FC between the majority of affective‐cognitive seeds of interest and the fronto‐subcortical and limbic circuits; enhanced FC between the right affective‐cognitive part of the cerebellum and the bilateral associative parietal cortex; enhanced FC of the bilateral amygdala with the subcortical and posterior cortical brain regions; and altered FC between the left medial dorsal nucleus and the sensorimotor and associative brain regions (enhanced in MobFD and reduced in FixFD). Compared with yHC and MobFD patients, FixFD patients had an extensive pattern of reduced FC within the cerebellar network, and between the majority of affective‐cognitive seeds of interest and the sensorimotor and high‐order function (“cognitive”) areas with a unique involvement of dorsal anterior cingulate cortex connectivity. Brain FC within the affective‐cognitive network is altered in FD and presented specific features associated with each FD phenotype, suggesting an interaction between brain connectivity and clinical expression of the disease.

Alien limb syndrome: A Bayesian account of unwanted actions

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.

Posterior Variant of Alien Limb Syndrome with Sudden Clinical Onset as Self-Hitting Associated with Thalamic Stroke

We present a case of sudden postischaemic onset of alien limb syndrome, with unintentional self-injury. Alien limb syndrome is an uncommon neurological disorder featured by uncontrolled and involuntary movements of a limb. Three variants of alien limb syndrome have been described: the anterior, featured by grasping of surrounding objects, the callosal, presenting with intermanual conflict, and the posterior, associated with involuntary levitation of the limb. Our patient suffered from an acute presentation of the posterior variant of the alien limb syndrome, resulting from an isolated thalamic stroke which was documented using 24-h computed tomography brain scan. Only one previous case of alien limb syndrome after thalamic infarct has been reported. Our case enhances the possibility that pure thalamic injury may represent a trigger for this condition.

Corticobasal degeneration

Corticobasal degeneration (CBD) is a rare neurodegenerative disease characterized by the predominance of pathological 4 repeat tau deposition in various cell types and anatomical regions. Corticobasal syndrome (CBS) is one of the clinical phenotypes associated with CBD pathology, manifesting as a progressive asymmetric akinetic-rigid, poorly levodopa-responsive parkinsonism, with cerebral cortical dysfunction. CBD can manifest as several clinical phenotypes, and similarly, CBS can also have a pathologic diagnosis other than CBD. This chapter discusses the clinical manifestations of pathologically confirmed CBD cases, the current diagnostic criteria, as well as the pathologic and neuroimaging findings of CBD/CBS. At present, therapeutic options for CBD remain symptomatic. Further research is needed to improve the clinical diagnosis of CBD, as well as studies on disease-modifying therapies for this relentlessly progressive neurodegenerative disorder.

Neural correlates of altered insight in frontotemporal dementia: a systematic review

Altered insight into disease or specific symptoms is a prominent clinical feature of frontotemporal dementia (FTD). Understanding the neural bases of insight is crucial to help improve FTD diagnosis, classification and management. A systematic review to explore the neural correlates of altered insight in FTD and associated syndromes was conducted. Insight was fractionated to examine whether altered insight into different neuropsychological/behavioural objects is underpinned by different or compatible neural correlates. 6 databases (Medline, Embase, PsycINFO, Web of Science, BIOSIS and ProQuest Dissertations & Theses Global) were interrogated between 1980 and August 2019. 15 relevant papers were found out of 660 titles screened. The studies included suggest that different objects of altered insight are associated with distinctive brain areas in FTD. For example, disease unawareness appears to predominantly correlate with right frontal involvement. In contrast, altered insight into social cognition potentially involves, in addition to frontal areas, the temporal gyrus, insula, parahippocampus and amygdala. Impaired insight into memory problems appears to be related to the frontal lobes, postcentral gyrus, parietal cortex and posterior cingulate. These results reflect to a certain extent those observed in other neurodegenerative conditions like Alzheimer's disease (AD) and also other brain disorders. Nevertheless, they should be cautiously interpreted due to variability in the methodological aspects used to reach those conclusions. Future work should triangulate different insight assessment approaches and brain imaging techniques to increase the understanding of this highly relevant clinical phenomenon in dementia.

Alien limb phenomenon following posterior cerebral artery stroke: a distinct clinical entity

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.

Depersonalization- and derealization-like phenomena of epileptic origin

Objective

Depersonalization refers to the sensation of being detached from one’s body, often associated with feelings of loss of control over one’s own body, actions, or thoughts. Derealization refers to the altered perception of one’s surroundings that is experienced as unreal. Although usually reported by psychiatric patients suffering from depression or anxiety, single case reports and small case series have described depersonalization‐ and derealization‐like symptoms in the context of epilepsy.

Methods

We investigated the brain mechanisms of ictal depersonalization– and derealization like symptoms by analyzing clinical and neuropsychological data as well as the epileptogenic zone based on a multimodal approach in a group of patients reporting depersonalization‐ (n = 9) and derealization‐like symptoms (n = 7), from a single presurgical epilepsy center with focal epilepsy. We compared them with a group of control patients with experiential phenomena due to temporal lobe epilepsy (n = 28).

Results

We show that all patients with ictal depersonalization‐like symptoms report altered self‐identification with their body and mostly suffer from frontal lobe epilepsy with the epileptogenic zone in the dorsal premotor cortex, while patients with derealization‐like symptoms suffer from temporal lobe epilepsy. This finding is supported by post‐ictal neuropsychological deficits, showing that depersonalization‐like symptoms were significantly more often associated with frontal lobe dysfunction as compared to the control patients and patients with derealization‐like symptoms.

Conclusion

We argue that depersonalization of epileptic origin constitutes a distinct disorder due to frontal lobe epilepsy. We discuss these findings with respect to earlier accounts of depersonalization and the recent concept of bodily self‐consciousness.

Intermittent alien hand syndrome caused by Marchiafava-Bignami disease: A case report

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.

Signs and symptoms method in neuropsychology: A preliminary investigation of a standardized clinical interview for assessment of cognitive decline in dementia

Psychologists usually perform a preliminary assessment of the person's cognitive status through a brief interview conducted before the formal testing. However, this exam has not yet been standardized with ad hoc recommendations in psychology literature. In this work, a standard observational NeuroPsychological Examination (NPE) designed for psychologists was proposed, and its clinical effectiveness evaluated. The NPE was administered to patients referred to a neuropsychological service in a memory clinic over a 2-year period. The NPEs of the patients with Alzheimer dementia (AD), vascular dementia (VaD), and healthy controls (HC) were retrospectively retrieved. Comparisons among the three groups were conducted. Abnormalities/signs identified during the NPE in the AD and VaD groups are more numerous compared to those reported in the HC group. About 80% of HCs show none or only one abnormal sign. Vice versa, 87.5% of both AD and VaD patients show three or more abnormalities. Accordingly, the NPE has 0.88 (95%CI = 0.81-0.95) sensitivity and 0.95 (95%CI = 0.88-1.02) specificity for detecting cognitive decline when a cut-point of three or more signs is applied. Some significant differences also emerge on the number of pathological signs between AD and VaD patients. NPE is a promising tool with demonstrated diagnostic utility in dementia patients.

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.

Arm Levitation as Initial Manifestation of Creutzfeldt-Jakob Disease: Case Report and Review of the Literature

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.

Pseudodystonia: A new perspective on an old phenomenon

Pseudodystonia represents a wide range of conditions that mimic dystonia, including disorders of the peripheral nervous system, spinal cord, brainstem, thalamus, cortex and non-neurological conditions such as musculoskeletal diseases. Here, we propose a definition of pseudodystonia and suggest a classification based on underlying pathophysiological mechanisms. We describe phenomenology of different forms of pseudodystonia and point to distinctions between dystonia and pseudodystonia as well as challenging issues that may arise in clinical practice. The term pseudodystonia can be used to describe abnormal postures, repetitive movements or both, in which results of clinical, imaging, laboratory or electrophysiological investigations provide definite explanation of symptoms which is not compatible with dystonia. Pseudodystonia can be classified into non-neurological disorders of the musculoskeletal system, disorders of sensory pathways, disorders of motor pathways and compensatory postures in other neurological diseases. Presence of associated neurological findings in the affected body part is the key towards diagnosis of pseudodystonia. Additional supporting features are the presence of fixed postures, the absence of sensory trick, acute mode of onset and severe pain. Worsening on eye closure, traditionally considered typical for pseudodystonia, is not always present and can also appear in dystonia. It is challenging to separate dystonia and pseudodystonia in patients with thalamic lesions or corticobasal syndrome, where abnormal postures coexist with sensory loss. Many cases of pseudodystonia are treatable. Therefore, it is essential to consider pseudodystonia in a differential diagnosis of abnormal postures until a detailed neurological examination rules it out.

Lesion network localization of free will

Our perception of free will is composed of a desire to act (volition) and a sense of responsibility for our actions (agency). Brain damage can disrupt these processes, but which regions are most important for free will perception remains unclear. Here, we study focal brain lesions that disrupt volition, causing akinetic mutism (n = 28), or disrupt agency, causing alien limb syndrome (n = 50), to better localize these processes in the human brain. Lesion locations causing either syndrome were highly heterogeneous, occurring in a variety of different brain locations. We next used a recently validated technique termed lesion network mapping to determine whether these heterogeneous lesion locations localized to specific brain networks. Lesion locations causing akinetic mutism all fell within one network, defined by connectivity to the anterior cingulate cortex. Lesion locations causing alien limb fell within a separate network, defined by connectivity to the precuneus. Both findings were specific for these syndromes compared with brain lesions causing similar physical impairments but without disordered free will. Finally, our lesion-based localization matched network localization for brain stimulation locations that disrupt free will and neuroimaging abnormalities in patients with psychiatric disorders of free will without overt brain lesions. Collectively, our results demonstrate that lesions in different locations causing disordered volition and agency localize to unique brain networks, lending insight into the neuroanatomical substrate of free will perception.

Bringing order to higher order motor disorders

Majority of movements in everyday situations are complex and involve volition, planning of the movement and selection of the motor programme, all occurring before movement execution. Higher order motor disorders may be defined as abnormal motor behaviours resulting from disruption of any of the cortical processes that precede execution of the motor act. They are common in patients with neurodegenerative disorders, psychiatric diseases and structural brain lesions. These abnormal behaviours may be overlooked in the clinic, unless specifically evoked by the examiner. We discuss clinical and pathophysiological aspects of higher order motor disorders including: (1) disorders of disinhibition, such as grasp reflex and grasping behaviour, utilisation and imitation behaviour, motor preservations and paratonia; (2) disorders of motor intention such as motor neglect and motor impersistence; (3) alien limb syndrome; and (4) motor overflow phenomena, such as mirror movements and synkinesias. A video illustration of each phenomenon is provided. We place the findings from recent neurophysiological studies within the framework of theories of motor control to provide better insight into pathophysiology of different disorders.

Alien Hand Syndrome

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.

Violations of Expectations As Matter for the Believing Process

For the purpose of this communication it is postulated that violation of expectation means a disturbing event or conflict interfering with a previously established mental state that affords a firm belief or confident feeling. According to this hypothesis a violation of an expectation contradicts predictions and intentions that have been attained on stored experiences, valuations, and actual mood. We will argue that the notion of belief as static or stable which is usually described by expressions such as "my belief" or "our general belief" has to be extended to accommodate the process of belief formation. The credition model emphasizes the procedural aspect of belief by which the "process of believing" becomes similar to other psychological processes. We will describe that the "violation of expectation" can be decoded from the credition perspective and has brain functional correlates.

When Playing Is a Problem: An Atypical Case of Alien Hand Syndrome in a Professional Pianist

Alien hand syndrome (AHS) is a neurological illness characterized by limb movements which are carried out without being aware of it. Many patients describe these movements as aggressive and some perceive a strong feeling of estrangement and go so far as to deny ownership. The sense of body ownership is the perception that parts of one’s body pertain to oneself, despite it is moving or not and if movement is intentional or unintentional. These anomalous self-experiences may arise in patients with focal brain lesions and provide unique opportunities to disclose the neural components underlying self-body perception. The feeling of foreignness described in AHS is often observed in post-central cortical lesions in the non-dominant hemisphere and is typical of the “posterior alien hand variant”. We used Diffusion-Tensor magnetic resonance imaging (DT-MRI) in an unusual case of posterior AHS of the dominant hand in a professional pianist with corticobasal syndrome (CBS). The patient showed uncontrolled levitation with the right arm while playing the piano and perceived as if her hand had a “mind of its own” which prevented her from playing. MRI-scans show asymmetric brain atrophy, mainly involving left post-central regions and SPECT-Tc99m-ECD patterns of hypometabolism over the left parietal-occipital cortices. DT-MRI revealed extensive damage which comprised left fronto-temporal cortex and extends into the ipsilateral parietal cortex causing a disruption of corpus callosum (CC) projections from the rostrum to the splenium. Our case illustrates that posterior AHS may occur in the dominant hemisphere due to widespread damage, which exceed parietal cortex. The parietal lobe has been recognized as a multimodal association region that gets input from several networks and organizes motor output. We suggest that the disturbance to this pathway could result in disruption of motor output and associate an abnormal motor control and anomalous self-body perception.

A Wolf in Sheep's Clothing: An "Alien Leg" in Corticobasal Syndrome

Background

Alien limb phenomenon occurs in 50–60% of patients with corticobasal syndrome (CBS) and usually presents with an “alien hand” phenomenon. The “alien foot” presentation is rarer and may be misdiagnosed, as foot involvement can lead to erroneous localization of the clinical problem to the knee, hip, or back. Subsequently misdiagnoses such as myelopathy, radiculopathy, functional disorder, stiff leg syndrome, neuromyotonia, and painful leg moving toes syndrome may occur.

Case report

We describe two patients with alien foot symptoms that resulted in multiple opinions from different specialists, multiple diagnostic and therapeutic procedures, and delayed diagnosis. Eventually a diagnosis of CBS was made in both. Alien foot symptoms may be more common than initially thought and can result in a delayed diagnosis of CBS.

Conclusion

The inclusion of this clinical finding in recently proposed diagnostic criteria highlights the need for increased clinical awareness.

The Desire for Amputation or Paralyzation: Evidence for Structural Brain Anomalies in Body Integrity Identity Disorder (BIID)

Background

Body Integrity Identity Disorder (BIID) is a condition in which individuals perceive a mismatch between their internal body scheme and physical body shape, resulting in an absolute desire to be either amputated or paralyzed. The condition is hypothesized to be of congenital nature, but evidence for a neuro-anatomical basis is sparse.

Methods

We collected T1-weighted structural magnetic resonance imaging scans on a 3T scanner in eight individuals with BIID and 24 matched healthy controls, and analyzed the data using voxel-based morphometry.

Results

The results showed reduced grey matter volume in the left dorsal and ventral premotor cortices and larger grey matter volume in the cerebellum (lobule VIIa) in individuals with BIID compared to controls.

Conclusion

The premotor cortex and cerebellum are thought to be crucial for the experience of body-ownership and the integration of multisensory information. Our results suggest that BIID is associated with structural brain anomalies and might result from a dysfunction in the integration of multisensory information, leading to the feeling of disunity between the mental and physical body shape.

Alien hand syndrome following corpus callosum infarction: A case report and review of the literature

Alien hand syndrome (AHS) is characterized by involuntary and autonomous activity of the affected limbs, and consists of the frontal, callosal and posterior AHS variants. The callosal subtype, resulting from damage to the corpus callosum, frequently features intermanual conflict. However, infarction of the corpus callosum is rare due to abundant blood supply. The present study reported a case of AHS (callosal subtype, in the right hand) caused by callosal infarction. Infarction of the left corpus callosum was confirmed with magnetic resonance imaging. In addition, magnetic resonance angiography and digital subtraction angiography examinations revealed multiple lesions in the feeding arteries. Subsequent to antiplatelet therapy for 2 weeks following admission, the patient gradually recovered. Furthermore, the current study reviewed 31 previously reported cases of AHS following callosal infarction in the literature.

Cortical Activation During Levitation and Tentacular Movements of Corticobasal Syndrome

Levitation and tentacular movements (LTM) are considered specific, yet rare (30%), features of Corticobasal Syndrome (CBS), and are erroneously classified as alien hand. Our study focuses on these typical involuntary movements and aims to highlight possible neural correlates.LTM were recognizable during functional magnetic resonance imaging (fMRI) in 4 of 19 CBS patients. FMRI activity was evaluated with an activation recognition program for movements, during LTM, consisting of levitaton and finger writhing, and compared with the absence of movement (rest) and voluntary movements (VM), similar to LTM, of affected and unaffected arm-hand. FMRI acquisition blocks were balanced in order to match LTM blocks with rest and VM conditions. In 1 of the 4 patients, fMRI was acquired only during LTM and with a different equipment.Despite variable intensity and range of involuntary movements, evidenced by videos, fMRI showed, during LTM, a significant (P<0.05-0.001) activation only of the contralateral primary motor cortex (M1). Voluntary movements of the affected and unaffected arm elicited the known network including frontal, supplementary, sensory-motor cortex, and cerebellum. Willed movements of the LTM-affected arm induced higher and wider activation of contralateral M1 compared with the unaffected arm.The isolated activation of M1 suggests that LTM is a cortical disinhibition symptom, not involving a network. Higher activation of M1 during VM confirms that M1 excitability changes occur in CBS. Our study calls, finally, attention to the necessity to separate LTM from other alien hand phenomena.