The Experts below are selected from a list of 2478 Experts worldwide ranked by ideXlab platform

Sebastian J. Crutch - One of the best experts on this subject based on the ideXlab platform.

  • Impairments of auditory scene analysis in Posterior Cortical Atrophy.
    Brain : a journal of neurology, 2020
    Co-Authors: Chris J.d. Hardy, Johanna C. Goll, Sebastian J. Crutch, Keir Yong, Jason D Warren
    Abstract:

    Although Posterior Cortical Atrophy is often regarded as the canonical 'visual dementia', auditory symptoms may also be salient in this disorder. Patients often report particular difficulty hearing in busy environments; however, the core cognitive process-parsing of the auditory environment ('auditory scene analysis')-has been poorly characterized. In this cross-sectional study, we used customized perceptual tasks to assess two generic cognitive operations underpinning auditory scene analysis-sound source segregation and sound event grouping-in a cohort of 21 patients with Posterior Cortical Atrophy, referenced to 15 healthy age-matched individuals and 21 patients with typical Alzheimer's disease. After adjusting for peripheral hearing function and performance on control tasks assessing perceptual and executive response demands, patients with Posterior Cortical Atrophy performed significantly worse on both auditory scene analysis tasks relative to healthy controls and patients with typical Alzheimer's disease (all P < 0.05). Our findings provide further evidence of central auditory dysfunction in Posterior Cortical Atrophy, with implications for our pathophysiological understanding of Alzheimer syndromes as well as clinical diagnosis and management.

  • Posterior Cortical Atrophy.
    Continuum (Minneapolis Minn.), 2019
    Co-Authors: Jonathan M. Schott, Sebastian J. Crutch
    Abstract:

    ABSTRACTPURPOSE OF REVIEWThis article presents an overview of the clinical syndrome of Posterior Cortical Atrophy (PCA), including its pathologic underpinnings, clinical presentation, investigation findings, diagnostic criteria, and management.RECENT FINDINGSPCA is usually an atypical form of Alzhei

  • Can patients without early, prominent visual deficits still be diagnosed of Posterior Cortical Atrophy?
    Journal of the neurological sciences, 2016
    Co-Authors: Aida Suarez-gonzalez, Sebastian J. Crutch, F. Roldán Lora, Emilio Franco-macías, Eulogio Gil-néciga
    Abstract:

    Background Early and progressive disabling visual impairment is a core feature for the diagnosis of Posterior Cortical Atrophy (PCA). However, some individuals that fulfil criteria over time might initially present with an onset of prominent Posterior dysfunction other than visuoperceptual.

  • Abnormalities of fixation, saccade and pursuit in Posterior Cortical Atrophy
    Brain, 2015
    Co-Authors: Timothy J. Shakespeare, Keir Yong, Ross W. Paterson, Jonathan M. Schott, Diego Kaski, Catherine F. Slattery, Natalie S. Ryan, Sebastian J. Crutch
    Abstract:

    The clinico-neuroradiological syndrome Posterior Cortical Atrophy is the cardinal 'visual dementia' and most common atypical Alzheimer's disease phenotype, offering insights into mechanisms underlying clinical heterogeneity, pathological propagation and basic visual phenomena (e.g. visual crowding). Given the extensive attention paid to patients' (higher order) perceptual function, it is surprising that there have been no systematic analyses of basic oculomotor function in this population. Here 20 patients with Posterior Cortical Atrophy, 17 patients with typical Alzheimer's disease and 22 healthy controls completed tests of fixation, saccade (including fixation/target gap and overlap conditions) and smooth pursuit eye movements using an infrared pupil-tracking system. Participants underwent detailed neuropsychological and neurological examinations, with a proportion also undertaking brain imaging and analysis of molecular pathology. In contrast to informal clinical evaluations of oculomotor dysfunction frequency (previous studies: 38%, current clinical examination: 33%), detailed eyetracking investigations revealed eye movement abnormalities in 80% of patients with Posterior Cortical Atrophy (compared to 17% typical Alzheimer's disease, 5% controls). The greatest differences between Posterior Cortical Atrophy and typical Alzheimer's disease were seen in saccadic performance. Patients with Posterior Cortical Atrophy made significantly shorter saccades especially for distant targets. They also exhibited a significant exacerbation of the normal gap/overlap effect, consistent with 'sticky fixation'. Time to reach saccadic targets was significantly associated with parietal and occipital Cortical thickness measures. On fixation stability tasks, patients with typical Alzheimer's disease showed more square wave jerks whose frequency was associated with lower cerebellar grey matter volume, while patients with Posterior Cortical Atrophy showed large saccadic intrusions whose frequency correlated significantly with generalized reductions in Cortical thickness. Patients with both Posterior Cortical Atrophy and typical Alzheimer's disease showed lower gain in smooth pursuit compared to controls. The current study establishes that eye movement abnormalities are near-ubiquitous in Posterior Cortical Atrophy, and highlights multiple aspects of saccadic performance which distinguish Posterior Cortical Atrophy from typical Alzheimer's disease. We suggest the Posterior Cortical Atrophy oculomotor profile (e.g. exacerbation of the saccadic gap/overlap effect, preserved saccadic velocity) reflects weak input from degraded occipito-parietal spatial representations of stimulus location into a superior collicular spatial map for eye movement regulation. This may indicate greater impairment of identification of oculomotor targets rather than generation of oculomotor movements. The results highlight the critical role of spatial attention and object identification but also precise stimulus localization in explaining the complex real world perception deficits observed in Posterior Cortical Atrophy and many other patients with dementia-related visual impairment.

  • Posterior Cortical Atrophy: An Atypical Variant of Alzheimer Disease
    The Psychiatric clinics of North America, 2015
    Co-Authors: Aida Suarez-gonzalez, Susie M.d. Henley, Jill Walton, Sebastian J. Crutch
    Abstract:

    Posterior Cortical Atrophy (PCA) is a neurodegenerative syndrome characterized by striking progressive visual impairment and a pattern of Atrophy mainly involving Posterior cortices. PCA is the most frequent atypical presentation of Alzheimer disease. The purpose of this article is to provide a summary of PCA's neuropsychiatric manifestations. Emotional and psychotic symptoms are discussed in the context of signal characteristic features of the PCA syndrome (the early onset, focal loss of visual perception, focal Posterior brain Atrophy) and the underlying cause of the disease. The authors' experience with psychotherapeutic intervention and PCA support groups is shared in detail.

Gordon T. Plant - One of the best experts on this subject based on the ideXlab platform.

  • Visual Dysfunction in Posterior Cortical Atrophy.
    Frontiers in neurology, 2017
    Co-Authors: Mari N. Maia Da Silva, Rebecca S. Millington, Holly Bridge, Merle James-galton, Gordon T. Plant
    Abstract:

    Posterior Cortical Atrophy is a syndromic diagnosis. It is characterised by progressive impairment of higher (Cortical) visual function with imaging evidence of degeneration affecting the occipital, parietal and Posterior temporal lobes bilaterally. Most caseswill prove to have Alzheimer pathology. The aim of this review is to summarise the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognised visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarised, with special attention to its role on the differential diagnosis with related conditions.

Guoping Peng - One of the best experts on this subject based on the ideXlab platform.

  • Neural Mechanisms of Visual Dysfunction in Posterior Cortical Atrophy.
    Frontiers in neurology, 2019
    Co-Authors: Yi Chen, Ping Liu, Yunyun Wang, Guoping Peng
    Abstract:

    Posterior Cortical Atrophy (PCA) is characterized predominantly by visual dysfunction that arises from bilateral impairments in occipital, parietal, and temporal regions of the brain. PCA is clinically identified based primarily on visual symptoms and neuroimaging findings. Region-specific gray and white matter deficits have been discussed in detail, and are associated with clinical manifestations that present with similar patterns of perfusion and metabolic findings. Here, we discuss both structural and functional changes in the ventral and dorsal visual streams along with their underlying relationships. We also discuss the most recent developments in neuroimaging characteristics and summarize correlations between distinct neuroimaging presentations.

Raffaella Migliaccio - One of the best experts on this subject based on the ideXlab platform.

  • Working memory in Posterior Cortical Atrophy.
    Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology, 2019
    Co-Authors: Laura Trotta, Paolo Bartolomeo, Delphine Lamoureux, Raffaella Migliaccio
    Abstract:

    We used an ad hoc created neuropsychological battery to evaluate in details both verbal and visuospatial working memory (WM) in patients with Posterior Cortical Atrophy (PCA, n = 5). PCA is a rare, early-onset neurodegenerative dementia, often due to Alzheimer’s disease (AD) pathology. Clinically, PCA patients present with visual, visuospatial, and visuomotor deficits, and no memory complaints. PCA patients’ patterns of performance were compared with those of 11 typical, amnestic AD patients matched for disease severity, as well as with 17 age-matched healthy controls. Both groups of patients had impaired WM performance compared to controls. However, PCA patients were more impaired than typical AD patients for both verbal and visuospatial WM. Moreover, PCA patients showed a more consistent impairment of visuospatial WM, as compared with verbal WM. Systematic WM evaluation should be part of the standard assessment in PCA. WM deficits affect patients’ quality of life and can be detrimental to rehabilitation programs.

  • Posterior Cortical Atrophy: from vision to emotion.
    Geriatrie et psychologie neuropsychiatrie du vieillissement, 2018
    Co-Authors: Maxime Montembeault, Marie-odile Habert, Aurélie Kas, Lucette Lacomblez, Raffaella Migliaccio
    Abstract:

    In this review of the literature on Posterior Cortical Atrophy (PCA), the history of the disease is first told through the studies of Frank Benson and Oliver Sacks. Then, we detail the possible underlying pathologies, Alzheimer's disease being the most common cause. Clinical, cognitive, and biological features are described, with a specific focus on the neuroimaging. We also describe the emotional aspects of PCA. These aspects are often overlooked, but deserve a particular attention due to their impact on the quality of life and prognostic implications for the patients. A multilevel care strategy for PCA patients is suggested.

  • Neural correlates of cognitive impairment in Posterior Cortical Atrophy
    Brain, 2011
    Co-Authors: Aurélie Kas, Leonardo Cruz Souza, Dalila Samri, Paolo Bartolomeo, Lucette Lacomblez, Michel Kalafat, Raffaella Migliaccio, Michel Thiebaut De Schotten, Laurent D. Cohen, Bruno Dubois
    Abstract:

    With the prospect of disease-modifying drugs that will target the physiopathological process of Alzheimer's disease, it is now crucial to increase the understanding of the atypical focal presentations of Alzheimer's disease, such as Posterior Cortical Atrophy. This study aimed to (i) characterize the brain perfusion profile in Posterior Cortical Atrophy using regions of interest and a voxel-based approach; (ii) study the influence of the disease duration on the clinical and imaging profiles; and (iii) explore the correlations between brain perfusion and cognitive deficits. Thirty-nine patients with Posterior Cortical Atrophy underwent a specific battery of neuropsychological tests, mainly targeting visuospatial functions, and a brain perfusion scintigraphy with 99mTc-ethyl cysteinate dimer. The imaging analysis included a comparison with a group of 24 patients with Alzheimer's disease, matched for age, disease duration and Mini-Mental State Examination, and 24 healthy controls. The single-photon emission computed tomography profile in patients with Posterior Cortical Atrophy was characterized by extensive and severe hypoperfusion in the occipital, parietal, Posterior temporal cortices and in a smaller Cortical area corresponding to the frontal eye fields (Brodmann areas 6/8). Compared with patients with Alzheimer's disease, the group with Posterior Cortical Atrophy showed more severe occipitoparietal hypoperfusion and higher perfusion in the frontal, anterior cingulate and mesiotemporal regions. When considering the disease duration, the functional changes began and remained centred on the Posterior lobes, even in the late stage. Correlation analyses of brain perfusion and neuropsychological scores in Posterior Cortical Atrophy highlighted the prominent role of left inferior parietal damage in acalculia, Gerstmann’s syndrome, left–right indistinction and limb apraxia, whereas damage to the bilateral dorsal occipitoparietal regions appeared to be involved in Balint’s syndrome. Our findings provide new insight into the natural history of functional changes according to disease duration and highlight the role of parietal and occipital cortices in the cognitive syndromes that characterize the Posterior Cortical Atrophy. * Abbreviations : MMSE  :  Mini-Mental State Examination PCA  :  Posterior Cortical Atrophy SPECT  :  single photon emission computed tomography

  • Neural correlates of cognitive impairment in Posterior Cortical Atrophy.
    Brain : a journal of neurology, 2011
    Co-Authors: Aurélie Kas, Leonardo Cruz Souza, Dalila Samri, Paolo Bartolomeo, Lucette Lacomblez, Michel Kalafat, Raffaella Migliaccio, Michel Thiebaut De Schotten, Laurent Cohen, Bruno Dubois
    Abstract:

    With the prospect of disease-modifying drugs that will target the physiopathological process of Alzheimer's disease, it is now crucial to increase the understanding of the atypical focal presentations of Alzheimer's disease, such as Posterior Cortical Atrophy. This study aimed to (i) characterize the brain perfusion profile in Posterior Cortical Atrophy using regions of interest and a voxel-based approach; (ii) study the influence of the disease duration on the clinical and imaging profiles; and (iii) explore the correlations between brain perfusion and cognitive deficits. Thirty-nine patients with Posterior Cortical Atrophy underwent a specific battery of neuropsychological tests, mainly targeting visuospatial functions, and a brain perfusion scintigraphy with 99mTc-ethyl cysteinate dimer. The imaging analysis included a comparison with a group of 24 patients with Alzheimer's disease, matched for age, disease duration and Mini-Mental State Examination, and 24 healthy controls. The single-photon emission computed tomography profile in patients with Posterior Cortical Atrophy was characterized by extensive and severe hypoperfusion in the occipital, parietal, Posterior temporal cortices and in a smaller Cortical area corresponding to the frontal eye fields (Brodmann areas 6/8). Compared with patients with Alzheimer's disease, the group with Posterior Cortical Atrophy showed more severe occipitoparietal hypoperfusion and higher perfusion in the frontal, anterior cingulate and mesiotemporal regions. When considering the disease duration, the functional changes began and remained centred on the Posterior lobes, even in the late stage. Correlation analyses of brain perfusion and neuropsychological scores in Posterior Cortical Atrophy highlighted the prominent role of left inferior parietal damage in acalculia, Gerstmann's syndrome, left-right indistinction and limb apraxia, whereas damage to the bilateral dorsal occipitoparietal regions appeared to be involved in Bálint's syndrome. Our findings provide new insight into the natural history of functional changes according to disease duration and highlight the role of parietal and occipital cortices in the cognitive syndromes that characterize the Posterior Cortical Atrophy.

Mari N. Maia Da Silva - One of the best experts on this subject based on the ideXlab platform.

  • Visual Dysfunction in Posterior Cortical Atrophy.
    Frontiers in neurology, 2017
    Co-Authors: Mari N. Maia Da Silva, Rebecca S. Millington, Holly Bridge, Merle James-galton, Gordon T. Plant
    Abstract:

    Posterior Cortical Atrophy is a syndromic diagnosis. It is characterised by progressive impairment of higher (Cortical) visual function with imaging evidence of degeneration affecting the occipital, parietal and Posterior temporal lobes bilaterally. Most caseswill prove to have Alzheimer pathology. The aim of this review is to summarise the development of the concept of this disorder since it was first introduced. A critical discussion of the evolving diagnostic criteria is presented and the differential diagnosis with regard to the underlying pathology is reviewed. Emphasis is given to the visual dysfunction that defines the disorder, and the classical deficits, such as simultanagnosia and visual agnosia, as well as the more recently recognised visual field defects, are reviewed, along with the evidence on their neural correlates. The latest developments on the imaging of PCA are summarised, with special attention to its role on the differential diagnosis with related conditions.