Anosognosia For Hemiplegia Research Articles

Evaluation of upper limb perception after stroke with the new Affected Limb Perception Questionnaire (ALPQ): a study protocol

BackgroundFollowing a stroke, patients may suffer from alterations in the perception of their own body due to an acquired deficit in body representations. While such changes may impact their quality of life as well as recovery, they are not systematically assessed in clinical practice. This study aims at providing a better understanding of the rate, evolution, and impact on recovery of upper limb (UL) body perceptions (BPs) alterations following stroke. In addition, we will investigate associations among BPs alterations items, their associations with the sensorimotor functions, UL activity, damages in brain structure and connectivity.MethodsWe developed a new tool named ALPQ (for Affected Limb Perception Questionnaire) to address the present study objectives. It assesses subjective alterations in the perception of the affected UL following stroke, by measuring several dimensions, namely: anosognosia for hemiplegia, anosodiaphoria for hemiplegia, hemiasomatognosia, somatoparaphrenia, personification of the affected limb, illusion of modification of physical characteristics (temperature, weight, length), illusory movements, super- or undernumerary limb, UL disconnection, misoplegia, and involuntary movement. This study combines a cross-sectional and longitudinal design. The completed data sample will include a minimum of 60 acute and 100 sub-acute stroke patients. When possible, patients are followed up to the chronic stage. Complementary evaluations are administered to assess patients’ sensorimotor and cognitive functions as well as UL activity, and brain lesions will be analysed.DiscussionThis study will provide a better understanding of BPs alterations following stroke: their rate and evolution, as well as their associations with sensorimotor deficit, cognitive profile and UL activity, brain lesions and recovery. Ultimately, the results could support the personalization of rehabilitation strategy according to patients’ UL perception to maximize their recovery.Study registrationThe protocol for this study has been pre-registered on the Open Science Framework on July the 7th, 2021: https://osf.io/p6v7f.

Is Anosognosia for Left-Sided Hemiplegia Due to a Specific Self-Awareness Defect or to a Poorly Conscious Working Mode Typical of the Right Hemisphere?

This review aimed to evaluate whether the association between 'anosognosia for hemiplegia' and lesions of the right hemisphere points to a special self-awareness role of the right side of the brain, or could instead be due to a working mode typical of the right hemisphere. This latter viewpoint is consistent with a recently proposed model of human brain asymmetries that assumes that language lateralization in the left hemisphere might have increased the left hemisphere's level of consciousness and intentionality in comparison with the right hemisphere's less conscious and more automatic functioning. To assess these alternatives, I tried to ascertain whether anosognosia is greater for left-sided hemiplegia than for other disorders provoked by right brain lesions, or whether unawareness prevails in tasks more clearly related to the disruption of the right hemisphere's more automatic (and less conscious) functioning. Data consistent with the first alternative would support the existence of a specific link between anosognosia for hemiplegia and self-awareness, whereas data supporting the second option would confirm the model linking anosognosia to a poorly conscious working mode typical of the right hemisphere. Analysis results showed that the incidence of anosognosia of the highly automatic syndrome of unilateral neglect was greater than that concerning the unawareness of left hemiplegia, suggesting that anosognosia for left-sided hemiplegia might be due to the poorly conscious working mode typical of the right hemisphere.

Illusory hand movements in the absence of asomatognosia, spatial neglect and anosognosia for hemiplegia

Illusory hand movements in the absence of asomatognosia, spatial neglect and anosognosia for hemiplegia

Visual and Motor Anosognosia: shared Modality-specific Damage and convergent Disconnections in Temporo-parietal Cortex (P4-12.001)

<h3>Objective:</h3> To assess if different forms of anosognosia share different or common neural mechanisms. <h3>Background:</h3> Anosognosia, the unawareness of a neurological deficit, is a syndrome whose neural correlates are still unclear. Most theories posit that awareness deficits are encapsulated in modality-specific systems. To date, studies of anosognosia have focused on the locus of damage. However, focal lesions cause network effects far beyond the local damage. <h3>Design/Methods:</h3> We characterize and compare lesions and related structural (SDC) and functional disconnection (FDC) in a group of post-stroke Anton syndrome patients (AS) with those suffering anosognosia for hemiplegia (AHP). Sixteen AS lesions were retrieved from the literature and drawn on a standard brain template. Sixteen hemianopic visual controls (VC) were selected and their unilateral lesions were duplicated in the other hemisphere to generate synthetic bilateral lesions. The two groups were compared in terms of lesions, SDC and FDC computed using a connectome derived from a large sample of healthy controls. The resulting disconnection maps were then compared using the same approach to a group of AHP patients (n=28) and hemiplegic controls without anosognosia (HC=35). <h3>Results:</h3> Lesions in AS were cortical involving both primary and extra-striate visual cortex. In contrast, VC lesions clustered in the occipital white matter and/or the primary visual cortex. AS exhibited greater SDC of temporo-parietal and insular regions. The distribution of SDC matched the FDC of dorsal frontoparietal regions. The comparison between AS vs. AHP showed the extensive involvement of modality-specific regions (i.e., visual vs motor), but also convergent SDC of right temporo-parietal white matter and bilateral FDC of dorsal frontoparietal regions involved in attention and multi-sensory integration. <h3>Conclusions:</h3> AS depends on bilateral striate and extra-striate occipital damage, and disconnection of ventral and dorsal frontoparietal regions involved in attention control. Visual and motor anosognosia share the unique combination of modality-specific and supra-modal mechanisms over temporo-parietal cortices. <b>Disclosure:</b> Dr. Monai has nothing to disclose. Miss Palacino has nothing to disclose. Dr. Bisio has nothing to disclose. Dr. Pini has nothing to disclose. Alessandro Salvalaggio has nothing to disclose. Dr. Corbetta has nothing to disclose.

Anosognosia for Hemiplegia and Falls After Stroke: A Prospective Correlational Study.

Anosognosia for Hemiplegia and Falls After Stroke: A Prospective Correlational Study.

Anosognosia for Hemiplegia and Falls After Stroke: A Prospective Correlational Study.

The aim of this study was to explore the association between the presence and severity of anosognosia for hemiplegia (AHP) and falls in stroke survivors. A prospective, correlational research design was utilized. Primary instrumentation included demographic information and the Visual-Analogue Test for Anosognosia for motor impairment (VATA-m). Correlational and regression analyses were performed between a priori variables. There was no statistically significant relationship found between AHP and falls. An incidental finding included that clinicians erroneously charted that their patients were aware of their physical limitations 100% of the time, which indicates that there is discord between clinicians and patients regarding physical limitations. Though no statistically significant relationship was found between AHP and falls, the incidental finding of dissonance between the patient and the clinician has important clinical implications. The relationship between AHP and stroke rehabilitation outcomes is still not understood, and incorporating part of the VATA-m into patient assessment could improve clinician understanding of patient awareness.

Motor awareness: a model based on neurological syndromes.

Motor awareness is a complex, multifaceted construct involving the awareness of both (i) one's motor state while executing a movement or remaining still and (ii) one's motor abilities. The analysis of neurological syndromes associated with motor disorders suggests the existence of various different components which are, however, integrated into a model of motor awareness. These components are: (i) motor intention, namely, a conscious desire to perform an action; (ii) motor monitoring and error recognition, that is, the capacity to check the execution of the action and identify motor errors; and (iii) a general awareness of one's own motor abilities and deficits, that is, the capacity to recognize the general state of one's motor abilities about the performance of specific actions and the potential consequences of motor impairment. Neuroanatomical correlates involving the parietal and insular cortices, the medial and lateral frontal regions, and subcortical structures (basal ganglia and limbic system) support this multi-component model. Specific damage (or disconnections) to these structures results in a number of different disorders in motor awareness, such as anosognosia for hemiplegia and apraxia, and a number of symptoms which are specific to motor intention disorders (e.g., the Anarchic Hand Syndrome and Tourette's Syndrome) or motor monitoring (e.g., Parkinson's and Huntington's diseases). All of these clinical conditions are discussed in the light of a motor awareness model.

Disconnections in personal neglect

Personal neglect is a disorder in the perception and representation of the body that causes the patients to behave as if the contralesional side of their body does not exist. This clinical condition has not been adequately investigated in the past as it has been considered a symptom of unilateral spatial neglect, which has mainly been studied with reference to extrapersonal space. Only a few studies with small samples have investigated the neuroanatomical correlates of personal neglect, and these have mainly focused on discrete cortical lesions and modular accounts, as well as being based on the hypothesis that this disorder is associated with somatosensory and spatial deficits. In the present study, we tested the novel hypothesis that personal neglect may be associated not only with discrete cortical and subcortical lesions, but also with disconnections of white matter tracts. We performed an advanced lesion analyses in a large sample of 104 right hemisphere damaged patients, 72 of whom were suffering from personal neglect. Results from the analyses of the grey and white matter were controlled for co-occurrent clinical variables such as extrapersonal neglect, anosognosia for hemiplegia and motor deficits, along with other lesion-related variables such as lesion size and the interval from the lesion onset to neuroimaging recordings. Our results reveal that personal neglect is associated with lesions in a medial network which involves the temporal cortex (Heschl’s gyrus), the ventro-lateral nuclei of the thalamus and the fornix. This suggests that personal neglect involves a convergence between sensorimotor processes, spatial representation and the processing of self-referred information (episodic memory).

Awareness is in the eye of the observer: Preserved third-person awareness of deficit in anosognosia for hemiplegia

In recent decades, the research traditions of (first-person) embodied cognition and of (third-person) social cognition have approached the study of self-awareness with relative independence. However, neurological disorders of self-awareness offer a unifying perspective to empirically investigate the contribution of embodiment and social cognition to self-awareness. This study focused on a neuropsychological disorder of bodily self-awareness following right-hemisphere damage, namely anosognosia for hemiplegia (AHP). A previous neuropsychological study has shown AHP patients, relative to neurological controls, to have a specific deficit in third-person perspective taking and allocentric stance (the other unrelated to the self) in higher order mentalizing tasks. However, no study has tested if verbal awareness of motor deficits is influenced by perspective-taking and centrism and identified the related anatomical correlates. Accordingly, two novel experiments were conducted with right-hemisphere stroke patients with (n = 17) and without AHP (n = 17) that targeted either their own (egocentric, experiment 1) or another stooge patients (allocentric, experiment 2) motor abilities from a first-or-third person perspective. In both experiments, neurological controls showed no significant difference in perspective-taking, suggesting that social cognition is not a necessary consequence of right-hemisphere damage. More specifically, experiment 1 found AHP patients more aware of their own motor paralysis (egocentric stance) when asked from a third compared to a first-person perspective, using both group level and individual level analysis. In experiment 2, AHP patients were less accurate than controls in making allocentric judgements about the stooge patient, but with only a trend towards significance and with no difference between perspectives. As predicted, deficits in egocentric and allocentric third-person perspective taking were associated with lesions in the middle frontal gyrus, superior temporal and supramarginal gyri, and white matter disconnections were more prominent with deficits in allocentricity. Behavioural and neuroimaging results demonstrate the intersecting relationship between bodily self-awareness and self-and-other-directed metacognition or mentalisation.

Updating beliefs beyond the here-and-now: the counter-factual self in anosognosia for hemiplegia.

The syndrome of anosognosia for hemiplegia, or the lack of awareness for one’s paralysis following right hemisphere stroke, can provide unique insights into the neurocognitive mechanisms of self-awareness. Yet it remains unclear whether anosognosia for hemiplegia is a modality-specific deficit of sensorimotor monitoring, or whether domain-general processes of attention and belief-updating converge to cause anosognosia for hemiplegia. Using a Bayesian learning framework, we formalized and empirically investigated the hypothesis that failures to update anosognosic beliefs can be explained by abnormalities in the relative uncertainty (i.e. precision) ascribed to prior beliefs versus sensory information in different contexts. We designed a new motor belief-updating task that manipulated both the temporal (prospective and retrospective) and spatial (hemispace most affected by inattention and hemispace less affected by inattention) conditions in which beliefs had to be updated, and we validated its sensitivity to anosognosia for hemiplegia in 26 patients with right hemisphere stroke. We then computed and empirically tested two different Bayesian predictors of prospective beliefs using two proxies for precision in anosognosia for hemiplegia patients: (i) standardized, neuropsychological measures of objective attention abilities, i.e. visuospatial neglect scores and (ii) subjective uncertainty reports, i.e. confidence ratings. Our results suggest that while neglect does not affect local, sensorimotor error monitoring, it does seem to affect the degree to which observed errors are used to update more general, prospective beliefs about counterfactual motor abilities in anosognosia for hemiplegia. Difficulties in such ‘counterfactual’ belief-updating were associated with disruptions in tracts of the ventral attentional network (i.e. superior longitudinal fasciculus connecting the temporo-parietal junction and ventral frontal cortex) and associated lesions to the insula, inferior parietal cortex and superior temporal regions. These results suggest that self-awareness extends beyond local, retrospective monitoring, requiring also salience-based, convergence of beliefs about the self that go beyond the ‘here-and-now’ of sensorimotor experience.

The Motor Unawareness Assessment (MUNA): A new tool for the assessment of Anosognosia for hemiplegia

ABSTRACT Introduction: Anosognosia for hemiplegia (AHP) is a condition in which patients with paralysis are unaware of their motor deficits. Research into AHP is important for improving its treatment and providing insight into the neurocognitive mechanism of motor awareness. Unfortunately, most studies use assessments with widely recognized limitations. The study aims at developing a psychometrically validated assessment of AHP. Method: We developed a 40-item Motor Unawareness Assessment (MUNA) and administered it to 131 right-hemisphere stroke patients. Principal Component Analysis (PCA) was used to identify the underlying factor structure. Receiver Operating Characteristics (ROC) analysis was used to determine diagnostic cutoffs, and Area Under the Curve (AUC) analysis used to assess these cutoffs. Relationships with demographic, clinical and neuropsychological variables were explored. Results: Five factors were identified: explicit motor awareness, implicit motor awareness, impaired sense of ownership, agency and illusory movement, and emotional reactions. Established cutoffs had excellent sensitivity and specificity. Clinical, neuropsychological and demographic variables did not predict overall MUNA score but were related to specific subcomponents. Conclusion: The MUNA can differentiate various facets of AHP and provides a detailed profile of (un)awareness. The MUNA can therefore provide robust assessment for research purposes and assist clinicians when developing targeted rehabilitation.

Multiple Network Disconnection in Anosognosia for Hemiplegia.

Anosognosia for hemiplegia (AHP) is a complex syndrome whose neural correlates are still under investigation. One hypothesis, mainly based on lesion mapping studies, is that AHP reflects a breakdown of neural systems of the right hemisphere involved in motor function. However, more recent theories have suggested that AHP may represent a disorder of cognitive systems involved in belief updating, self-referential or body processing. Two recent studies, using a method to estimate the degree of white matter disconnection from lesions, have indeed shown that patients with AHP suffer from damage of several long-range white matter pathways in association cortex. Here, we use a similar indirect disconnection approach to study a group of patients with motor deficits without anosognosia (hemiparesis or hemiplegia, HP, n = 35), or motor deficits with AHP (n = 28). The HP lesions came from a database of stroke patients, while cases of AHP were selected from the published literature. Lesions were traced into an atlas from illustrations of the publications using a standard method. There was no region in the brain that was more damaged in AHP than HP. In terms of structural connectivity, AHP patients had a similar pattern of disconnection of motor pathways to HP patients. However, AHP patients also showed significant disconnection of the right temporo-parietal junction, right insula, right lateral and medial prefrontal cortex. These associative cortical regions were connected through several white matter tracts, including superior longitudinal fasciculus III, arcuate, fronto-insular, frontal inferior longitudinal, and frontal aslant. These tracts connected regions of different cognitive networks: default, ventral attention, and cingulo-opercular. These results were not controlled for clinical variables as concomitant symptoms and other disorders of body representation were not always available for co-variate analysis. In conclusion, we confirm recent studies of disconnection demonstrating that AHP is not limited to dysfunction of motor systems, but involves a much wider set of large-scale cortical networks.

Understanding Anosognosia for Hemiplegia After Stroke.

Understanding Anosognosia for Hemiplegia After Stroke.

Hippocampal diaschisis contributes to anosognosia for hemiplegia: Evidence from lesion network-symptom-mapping

Anosognosia for hemiplegia (AHP) is known to be associated with lesions to the motor system combined with varying lesions to the right insula, premotor cortex, parietal lobe or hippocampus. Due to this widespread cortical lesion distribution, AHP can be understood best as a network disorder. We used lesion maps and behavioral data (n ​= ​49) from two previous studies on AHP and performed a lesion network-symptom-mapping (LNSM) analysis. This new approach permits the identification of relationships between behavior and regions connected to the lesion site based on normative functional connectome data. In a first step, using ordinary voxel-based lesion-symptom mapping, we found an association of AHP with lesions in the right posterior insula. This is in accordance with previous studies. Applying LNSM, we were able to additionally identify a region in the right posterior hippocampus where AHP was associated with significantly higher normative lesion connectivity. Notably, this region was spared by infarction in all patients. We therefore argue that remote neuronal dysfunction caused by disrupted functional connections between the lesion site and the hippocampus (i.e. diaschisis) contributed to the phenotype of AHP. An indirect affection of the hippocampus may lead to memory deficits which, in turn, impair the stable encoding of updated beliefs on the bodily state thus contributing to the multifactorial phenomenon of AHP.

The Phenomenology of Acute Anosognosia for Hemiplegia.

After attempting to move a plegic limb, patients with anosognosia for hemiplegia (AHP) may claim that limb movement occurred, even though the limb remained motionless. The authors investigated the characteristics, natural history, and anatomical basis of AHP phenomenology. Twenty-nine right-hemisphere stroke patients with acute anosognosia for hemiplegia (AHP) were prospectively assessed for the presence and characteristics of movement claims and observable behavior during movement attempts. AHP was transient, with the condition resolving in 68% of patients by 1 week. Patients made movement claims during 31% of unilateral movement attempts and 50% of bilateral movement attempts. Movement claims were idiosyncratic, lacked internal consistency within individual patients, and even dissociated from explicit denial, as several patients made movement claims after they began to explicitly acknowledge hemiplegia. Observable behavior during movement attempts revealed allochiria (moving the right arm instead of the left) in 31% of patients, signs of implicit knowledge of weakness in 24%, and intact intention in 34%. Lesion analysis revealed that allochiria was associated with inferior right parietal lobe damage. These results highlight that heterogeneity, phenomenological complexity, and transience are hallmarks of AHP. This advances clinical AHP assessment by showing that assessment of performance, rather than just verbal response, uncovers multiple dimensions of AHP. Allochiria emerges as an anatomically distinct subcomponent of the disorder. These findings also have theoretical implications, because they do not lend support to unitary pathogenic models proposing that illusions of movement or impaired intention form the basis of AHP. Most patients rapidly improve, which should invigorate the search for typical compensatory mechanisms underlying spontaneous recovery.

Anosognosia for hemiplegia as a tripartite disconnection syndrome.

The syndrome of Anosognosia for Hemiplegia (AHP) can provide unique insights into the neurocognitive processes of motor awareness. Yet, prior studies have only explored predominately discreet lesions. Using advanced structural neuroimaging methods in 174 patients with a right-hemisphere stroke, we were able to identify three neural systems that contribute to AHP, when disconnected or directly damaged: the (i) premotor loop (ii) limbic system, and (iii) ventral attentional network. Our results suggest that human motor awareness is contingent on the joint contribution of these three systems.

Anosognosia in degenerative brain diseases: The role of the right hemisphere and of its dominance for emotions

Earlier studies, which suggested that anosognosia of hemiplegia might be related to right hemisphere (RH) lesions did not control for the influence of confounding variables, such as aphasia, in patients with left-hemisphere lesions and unilateral neglect in those with RH lesions. These confounding variables are absent in patients with degenerative brain disease, where a prevalence of right-sided lesions is often associated with emotional and behavioural disturbances. This review, which can be considered a ‘qualitative synthesis’, aimed, therefore, to determine whether the unawareness phenomena observed in degenerative brain diseases are linked to the RH dominance for emotions. Results of the review confirmed that the neural correlates of anosognosia are often right lateralised in patients with degenerative brain diseases and that emotional disturbances are associated with right frontal lesions and anosognosia in the behavioural variant, i.e., frontotemporal dementia (bvFTD). However, they also showed that anosognosia is a heterogeneous phenomenon and that the role of right frontal lesions is much greater when the loss of insight concerns emotion-linked aspects of personality or behaviour than when it concerns particular aspects of cognition or memory.

Over- and underestimation of motor ability after a stroke: Implications for anosognosia

We administered a discrepancy-based measure of anosognosia for hemiplegia (AHP) to a group of 42 right-brain-damaged (RBD) and left-brain-damaged (LBD) stroke patients with varying levels of functional motor ability. In addition to the expected (anosognosic) pattern of overestimation of motor function in some RBD patients, we found an equal and opposite underestimation in some others, both RBD and LBD. We also found that around a quarter of self-estimation error could be predicted directly from actual ability, such that patients with poorer motor function tended to overestimate, and vice versa. This pattern suggests that some misestimation is attributable simply to statistical regression. However, even after adjusting for this regression effect, levels of overestimation were significantly greater in RBD patients, while LBD patients were more likely to underestimate their motor ability.

Understanding Anosognosia for Hemiplegia After Stroke.

Anosognosia for hemiplegia (AHP) after stroke is a complex cognitive behavioral disorder that removes awareness of one-sided paralysis (hemiplegia). As a result, stroke survivors afflicted with AHP may be more likely to have unrealistic expectations for stroke rehabilitation, display unsafe behaviors and experience falls, and ultimately suffer the physical and psychological consequences of frequent falling. The purpose of this article is to describe AHP by discussing anosognosia within the context of contemporary theoretical understandings, examining current imaging evidence of the disorder, and summarizing emerging interventions designed to reinstate self-awareness in anosognosic patients. Systematic review with a focus on defining and describing AHP based on human experimental studies was conducted within a 10-year period. Eleven studies were identified. The content and foci of the 11 studies fell into one of three categories: theory testing, imaging evidence, and interventions for individuals with AHP.

Motor versus body awareness: Voxel-based lesion analysis in anosognosia for hemiplegia and somatoparaphrenia following right hemisphere stroke

Anosognosia for hemiplegia (AHP) is informative about the neurocognitive basis of motor awareness. However, it is frequently associated with concomitant symptoms, such as hemispatial neglect and disturbances in the sense of body ownership (DSO). Although double dissociations between these symptoms have been reported, there is ongoing debate about whether they are manifestations of independent abnormalities, or a single neurocognitive deficit. We aimed to investigate the specificity of lesions associated with AHP by surpassing four, existing methodological limitations: (a) recruit a relatively large sample of patients (total N = 70) in a multi-centre study; (b) identify lesions associated with AHP in grey and white matter using voxel-based methods; (c) take into account the duration of AHP and concomitant neglect symptoms; and (d) compare lesions against a control hemiplegic group, patients suffering from AHP and DSO, and a few, rare patients with selective DSO. Results indicated that acute AHP is associated with a wide network, mainly including: (1) the Rolandic operculum, (2) the insula and (3) the superior temporal gyri. Subcortically, damage mainly involved the basal ganglia and white matter, mostly the superior corona radiate, arcuate fasciculus and the part of the ventral, superior longitudinal fasciculus. Persistent symptoms were linked with wider damage involving fronto-temporal cortex and long white matter tracts. A shift in the latero-medial direction (mainly involving the basal ganglia and surrounding white matter) emerged when DSO was taken accounted for. These results suggest that while bodily awareness is processed by areas widely distributed across the brain, intact subcortical structures and white matter tracts may be necessary to support basic feelings of owning and controlling contralateral body parts. An accurate and ‘up-to-date’ awareness of our motor abilities, however, may rely also on intact processing in cortical areas which presumably allow higher-order inferences about the current state of the body.