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Arquivos de Neuro-psiquiatria Apr 2021Anosognosia, i.e. lack of awareness of one's own symptoms, is a very common finding in patients with dementia and is related to neuropsychiatric symptoms and worse...
BACKGROUND
Anosognosia, i.e. lack of awareness of one's own symptoms, is a very common finding in patients with dementia and is related to neuropsychiatric symptoms and worse prognosis. Although dementia with Lewy bodies (DLB) is the second most common form of degenerative dementia, literature on anosognosia in this disease is scarce.
OBJECTIVES
This paper aimed to review the current evidence on anosognosia in patients with DLB, including its prevalence in comparison with other neurological conditions, its severity and anatomical correlations.
METHODS
Database searches were performed in PubMed, Web of Knowledge and PsycINFO for articles assessing anosognosia in DLB. A total of 243 studies were retrieved, but only six were included in the review.
RESULTS
Potential risk of selection, comparison or outcome biases were detected in relation to all the studies selected. Most of the studies used self-report memory questionnaires to assess cognitive complaints and compared their results to scores from informant-based instruments or to participants' cognitive performance in neuropsychological tasks. Subjects with DLB had worse awareness regarding memory than healthy older controls, but the results concerning differences in anosognosia between DLB and Alzheimer's disease (AD) patients were inconsistent across studies. Presence of AD pathology and neuroimaging biomarkers appeared to increase the prevalence of anosognosia in individuals with DLB.
CONCLUSION
Anosognosia is a common manifestation of DLB, but it is not clear how its prevalence and severity compare with AD. Co-existence of AD pathology seems to play a role in memory deficit awareness in DLB.
Topics: Agnosia; Alzheimer Disease; Biomarkers; Humans; Lewy Body Disease; Neuroimaging; Neuropsychological Tests
PubMed: 34133514
DOI: 10.1590/0004-282X-ANP-2020-0247 -
Scientific Reports Dec 2022Insight impairment contributes significantly to morbidity in psychiatric disorders. The neurologic concept of anosognosia, reflecting deficits in metacognitive awareness...
Insight impairment contributes significantly to morbidity in psychiatric disorders. The neurologic concept of anosognosia, reflecting deficits in metacognitive awareness of illness, is increasingly understood as relevant to psychopathology, but has been little explored in psychiatric disorders other than schizophrenia. We explored anosognosia as an aspect of insight impairment in n = 71 individuals with DSM-5 hoarding disorder. We used a standardized clutter severity measure to assess whether individuals with hoarding disorder underreport home clutter levels relative to independent examiners. We then explored whether underreporting, as a proxy for anosognosia, is predicted by clinical or neurocognitive behavioral measures. We found that individuals with hoarding disorder underreport their clutter, and that underreporting is predicted by objective severity of clutter. In an n = 53 subset of participants, we found that underreporting is predicted by altered performance on tests of cognitive control and inhibition, specifically Go/No-Go and Stroop tests. The relation of underreporting to objective clutter, the cardinal symptom of hoarding disorder, suggests that anosognosia may reflect core pathophysiology of the disorder. The neurocognitive predictors of clutter underreporting suggest that anosognosia in hoarding disorder shares a neural basis with metacognitive awareness deficits in other neuropsychiatric disorders and that executive anosognosia may be a transdiagnostic manifestation of psychopathology.
Topics: Humans; Hoarding Disorder; Agnosia; Diagnostic and Statistical Manual of Mental Disorders; Metacognition
PubMed: 36526652
DOI: 10.1038/s41598-022-25532-4 -
International Journal of Molecular... Apr 2021Deficits in olfaction and taste are among the most frequent non-motor manifestations in Parkinson's disease (PD) that start very early and frequently precede the PD... (Review)
Review
Deficits in olfaction and taste are among the most frequent non-motor manifestations in Parkinson's disease (PD) that start very early and frequently precede the PD motor symptoms. The limited data available suggest that the basis of the olfactory and gustatory dysfunction related to PD are likely multifactorial and may include the same determinants responsible for other non-motor symptoms of PD. This review describes the most relevant molecular and genetic factors involved in the PD-related smell and taste impairments, and their associations with the microbiota, which also may represent risk factors associated with the disease.
Topics: Agnosia; Biomarkers; Disease Susceptibility; Genetic Predisposition to Disease; Genetic Variation; Humans; Microbiota; Models, Biological; Olfactory Perception; Parkinson Disease; Taste Perception
PubMed: 33924222
DOI: 10.3390/ijms22084286 -
Neuropsychology Review Jun 2019Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been...
Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been used to assess the neural correlates of anosognosia in mild cognitive impairment (MCI) and Alzheimer's disease (AD). A systematic review of this literature was performed, following the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement, on PubMed, EMBASE, and PsycINFO databases. Twenty-five articles met all inclusion criteria. Specifically, four brain connectivity and 21 brain perfusion, metabolism, and activation articles. Anosognosia is associated in MCI with frontal lobe and cortical midline regional dysfunction (reduced perfusion and activation), and with reduced parietotemporal metabolism. Reduced within and between network connectivity is observed in the default mode network regions of AD patients with anosognosia compared to AD patients without anosognosia and controls. During initial stages of cognitive decline in anosognosia, reduced indirect neural activity (i.e. perfusion, metabolism, and activation) is associated with the cortical midline regions, followed by the parietotemporal structures in later stages and culminating in frontotemporal dysfunction. Although the current evidence suggests differences in activation between AD or MCI patients with anosognosia and healthy controls, more evidence is needed exploring the differences between MCI and AD patients with and without anosognosia using resting state and task related paradigms.
Topics: Agnosia; Alzheimer Disease; Brain; Cognitive Dysfunction; Humans; Magnetic Resonance Imaging; Neural Pathways; Positron-Emission Tomography; Tomography, Emission-Computed, Single-Photon
PubMed: 31161466
DOI: 10.1007/s11065-019-09410-x -
Brain : a Journal of Neurology Mar 2016Following right-hemisphere damage, a specific disorder of motor awareness can occur called anosognosia for hemiplegia, i.e. the denial of motor deficits contralateral to...
Following right-hemisphere damage, a specific disorder of motor awareness can occur called anosognosia for hemiplegia, i.e. the denial of motor deficits contralateral to a brain lesion. The study of anosognosia can offer unique insights into the neurocognitive basis of awareness. Typically, however, awareness is assessed as a first person judgement and the ability of patients to think about their bodies in more 'objective' (third person) terms is not directly assessed. This may be important as right-hemisphere spatial abilities may underlie our ability to take third person perspectives. This possibility was assessed for the first time in the present study. We investigated third person perspective taking using both visuospatial and verbal tasks in right-hemisphere stroke patients with anosognosia (n = 15) and without anosognosia (n = 15), as well as neurologically healthy control subjects (n = 15). The anosognosic group performed worse than both control groups when having to perform the tasks from a third versus a first person perspective. Individual analysis further revealed a classical dissociation between most anosognosic patients and control subjects in mental (but not visuospatial) third person perspective taking abilities. Finally, the severity of unawareness in anosognosia patients was correlated to greater impairments in such third person, mental perspective taking abilities (but not visuospatial perspective taking). In voxel-based lesion mapping we also identified the lesion sites linked with such deficits, including some brain areas previously associated with inhibition, perspective taking and mentalizing, such as the inferior and middle frontal gyri, as well as the supramarginal and superior temporal gyri. These results suggest that neurocognitive deficits in mental perspective taking may contribute to anosognosia and provide novel insights regarding the relation between self-awareness and social cognition.
Topics: Adult; Aged; Aged, 80 and over; Agnosia; Cognition; Female; Hemiplegia; Humans; Interpersonal Relations; Male; Middle Aged; Perceptual Disorders; Photic Stimulation; Psychomotor Performance; Space Perception; Theory of Mind
PubMed: 26811254
DOI: 10.1093/brain/awv390 -
Proceedings of the National Academy of... Feb 1998Studies of patients with focal brain damage suggest that topographical representation is subserved by dissociable neural subcomponents. This article offers a condensed... (Review)
Review
Studies of patients with focal brain damage suggest that topographical representation is subserved by dissociable neural subcomponents. This article offers a condensed review of the literature of "topographical disorientation" and describes several functional MRI studies designed to test hypotheses generated by that review. Three hypotheses are considered: (i) The parahippocampal cortex is critically involved in the acquisition of exocentric spatial information in humans; (ii) separable, posterior, dorsal, and ventral cortical regions subserve the perception and long term representation of position and identity, respectively, of landmarks; and (iii) there is a distinct area of the ventral occipitotemporal cortex that responds maximally to building stimuli and may play a role in the perception of salient landmarks. We conclude with a discussion of the inferential limitations of neuroimaging and lesion studies. It is proposed that combining these two approaches allows for inferences regarding the computational involvement of a neuroanatomical substrate in a given cognitive process although neither method can strictly support this conclusion alone.
Topics: Agnosia; Animals; Brain; Brain Mapping; Head Injuries, Closed; Humans; Magnetic Resonance Imaging; Maze Learning; Models, Neurological; Space Perception; Temporal Lobe
PubMed: 9448249
DOI: 10.1073/pnas.95.3.839 -
Wiley Interdisciplinary Reviews.... 2016Developmental prosopagnosia (DP) is a neurodevelopmental condition characterized by severe face identity recognition problems that results from a failure to develop the... (Review)
Review
Developmental prosopagnosia (DP) is a neurodevelopmental condition characterized by severe face identity recognition problems that results from a failure to develop the mechanisms necessary for adequate face processing (Duchaine BC, Nakayama K. Developmental prosopagnosia: a window to content-specific face processing. Curr Opin Neurobiol 2006, 16:166-173.). It occurs in children and adults with normal visual acuity, and without intellectual impairments or known brain injuries. Given the importance of face recognition in daily life, and the detrimental effects of impaired face recognition, DP is an important area of study. Yet conventions for classifying individuals as DP for research purposes are poorly defined. In this focus paper, we discuss: (1) criteria for an operational definition of DP; 2) tests of face recognition and conventions for classifying individuals as DP; and 3) important considerations regarding common associations and dissociations, and cognitive heterogeneity in DP. We also highlight issues unique to studying DP in children, a relatively new endeavor that is proving to be an important complement to the work with adults. Ultimately, we hope to identify challenges researchers face when studying DP, and offer guidelines for others to consider when embarking on their own research pursuits on the topic. For further resources related to this article, please visit the WIREs website.
Topics: Adult; Age Factors; Child; Female; Humans; Male; Neuropsychological Tests; Prosopagnosia; Research Design
PubMed: 26681428
DOI: 10.1002/wcs.1374 -
Neurobiology of Aging Oct 2020Awareness of one's own cognitive processes (metacognition) or of one's own illness or deficits (anosognosia) can be impaired in people with Alzheimer's disease (AD). The...
Awareness of one's own cognitive processes (metacognition) or of one's own illness or deficits (anosognosia) can be impaired in people with Alzheimer's disease (AD). The neural correlates of anosognosia within AD remain inconclusive. Understanding anosognosia is of importance because of its impact on carer burden and increased institutionalization. A systematic review of structural and functional neuroimaging studies was conducted to identify specific brain regions associated with anosognosia within AD. Thirty-two studies were included in the systematic review. Reduced gray matter density, cerebral blood flow, and hypometabolism in 8 key regions were significantly associated with increased anosognosia scores in people with AD. The most frequently associated regions were the inferior frontal gyrus, anterior cingulate cortex, and medial temporal lobe. Other key regions include the superior frontal gyrus, medial frontal gyrus, orbitofrontal cortex, posterior cingulate cortex, and the insula. Identifying brain regions associated with anosognosia can aid understanding and identification of anosognosia in people with AD and potentially facilitate improvements in care.
Topics: Agnosia; Alzheimer Disease; Female; Humans; Male; Metacognition; Neuroimaging
PubMed: 32679396
DOI: 10.1016/j.neurobiolaging.2020.06.011 -
Journal of Neurology, Neurosurgery, and... Apr 1986Visual agnosia is impaired visual recognition not explained by defective visual acuity, visual fields, attention, or general mental ability. Two nonapraxic patients with...
Visual agnosia is impaired visual recognition not explained by defective visual acuity, visual fields, attention, or general mental ability. Two nonapraxic patients with lesions in the left occipital lobe could imitate pantomimes they could not recognise. Although both patients had a hemianopia, sparing of gesture imitation shows that no visual defect accounts for their inability to recognise pantomimes. Both patients were amnestic and alexic but had no general impairment of cognitive ability to account for a pantomime-recognition disorder. These patients seem to have agnosia for pantomime. From the computed tomograms from these patients, we propose that inferior visual association cortex is critical for gesture comprehension, whereas superior portions of these structures are critical for imitating or performing pantomime to an object presented visually.
Topics: Aged; Agnosia; Brain Mapping; Cerebral Hemorrhage; Gestures; Humans; Kinesics; Male; Occipital Lobe; Tomography, X-Ray Computed; Visual Cortex; Visual Perception
PubMed: 3701356
DOI: 10.1136/jnnp.49.4.451 -
Journal of Neurology, Neurosurgery, and... Feb 2002From a series of glimpses, we perceive a seamless and richly detailed visual world. Cerebral damage, however, can destroy this illusion. In the case of Bálint's... (Review)
Review
OBJECTIVES
From a series of glimpses, we perceive a seamless and richly detailed visual world. Cerebral damage, however, can destroy this illusion. In the case of Bálint's syndrome, the visual world is perceived erratically, as a series of single objects. The goal of this review is to explore a range of psychological and anatomical explanations for this striking visual disorder and to propose new directions for interpreting the findings in Bálint's syndrome and related cerebral disorders of visual processing.
METHODS
Bálint's syndrome is reviewed in the light of current concepts and methodologies of vision research.
RESULTS
The syndrome affects visual perception (causing simultanagnosia/visual disorientation) and visual control of eye and hand movement (causing ocular apraxia and optic ataxia). Although it has been generally construed as a biparietal syndrome causing an inability to see more than one object at a time, other lesions and mechanisms are also possible. Key syndrome components are dissociable and comprise a range of disturbances that overlap the hemineglect syndrome. Inouye's observations in similar cases, beginning in 1900, antedated Bálint's initial report. Because Bálint's syndrome is not common and is difficult to assess with standard clinical tools, the literature is dominated by case reports and confounded by case selection bias, non-uniform application of operational definitions, inadequate study of basic vision, poor lesion localisation, and failure to distinguish between deficits in the acute and chronic phases of recovery.
CONCLUSIONS
Studies of Bálint's syndrome have provided unique evidence on neural substrates for attention, perception, and visuomotor control. Future studies should address possible underlying psychoanatomical mechanisms at "bottom up" and "top down" levels, and should specifically consider visual working memory and attention (including object based attention) as well as systems for identification of object structure and depth from binocular stereopsis, kinetic depth, motion parallax, eye movement signals, and other cues.
Topics: Agnosia; Attention; Brain Mapping; Cerebrovascular Disorders; Dominance, Cerebral; Humans; Occipital Lobe; Perceptual Disorders; Psychomotor Disorders; Visual Cortex; Visual Perception
PubMed: 11796765
DOI: 10.1136/jnnp.72.2.162