The Experts below are selected from a list of 21 Experts worldwide ranked by ideXlab platform

Andrew Kertesz - One of the best experts on this subject based on the ideXlab platform.

  • the cognitive profile of posterior cortical atrophy
    Neurology, 2006
    Co-Authors: Paul Mcmonagle, Fiona Deering, Yaniv Berliner, Andrew Kertesz
    Abstract:

    Background: Posterior cortical atrophy (PCA) is a progressive dementia characterized by prominent disorders of higher visual processing, affecting both dorsal and ventral streams to cause Balint’s syndrome, alexia, and visual Agnosia. Objective: To define the cognitive profile of PCA and compare to the typical, primary amnestic dementia of the Alzheimer’s type (DAT). Methods: The authors used standard cognitive tests and a novel battery designed to reflect dysfunction in both ventral (Object, Face & Color Agnosia Screen [OFCAS]) and dorsal (complex pictures and compound stimuli) visual streams. The authors identified 19 patients with PCA and compared their performance to a matched group of patients with DAT and normal controls. Results: Patients with PCA were younger with marked impairment in visuospatial tasks, reading, and writing but relative preservation of memory compared to DAT using standard tests. Dorsal stream signs were most prevalent among the patients with PCA with no pure ventral stream syndromes found. All novel tests distinguished reliably between subjects with complex picture descriptions and processing of compound stimuli showing the most significant differences compared to DAT. Conclusions: PCA is predominantly a dorsal stream syndrome, distinct from typical DAT, which involves occipitotemporal regions over time.

Daniel N Bub - One of the best experts on this subject based on the ideXlab platform.

  • analysis of errors in Color Agnosia a single case study
    Neurocase, 1999
    Co-Authors: Todd S Woodward, Mike J Dixon, Kathy T Mullen, Karin M Christensen, Daniel N Bub
    Abstract:

    Abstract The performance of an adult with Color Agnosia (JT) was investigated. Although perceptual Color tests clearly demonstrated no difficulty in Color discrimination, multidimensional scaling analysis (MDS) revealed that naming errors were constrained to confusions of adjacent points in the three-dimensional visual semantic Color space. This pattern of confuslons replicated across other tasks drawing on knowledge of Color concepts. The findings are interpreted as a partial disruption in mapping perceptual representations of Color to prototype nodes in visual semantic Color space. We propose that this methodology, already proven useful for investigation of category-specific visual object Agnosia, will allow more detailed cross-case cornparlsons of Color recognition disorders.

Maryse Lassonde - One of the best experts on this subject based on the ideXlab platform.

  • childhood visual Agnosia a seven year follow up
    Neurocase, 1997
    Co-Authors: Alessandra Schiavetto, Jean-claude Décarie, Janine Flessas, Guy Geoffroy, Maryse Lassonde
    Abstract:

    Abstract We describe the case of a child who developed an associative visual Agnosia and document her neuropsychological and neuroimaging progression over the past 7 years. AR contracted a viral encephalitis at age 9 that destroyed the right temporal lobe and a portion of the left inferotemporal region. A triad of symptoms was observed: associative visual Agnosia, prosopAgnosia and Color Agnosia. With time, AR has shown limited behavioral improvement. Neuroimaging showed that, apart from the initial ‘normal’ findings, the neuroanatomical correlates remained stable over time. Strikingly, a clear dissociation between object and spatial representations is present in this patient, which is the basis for her apparent recovery of function. Indeed, she uses spatial as well as local cues to compensate for her recognition deficits. AR's inability to recognize objects is interpreted as a deficit in the inferior temporal ventral pathway specialized for object perception, whereas the posterior parietal dorsal pathway...

Paul Mcmonagle - One of the best experts on this subject based on the ideXlab platform.

  • the cognitive profile of posterior cortical atrophy
    Neurology, 2006
    Co-Authors: Paul Mcmonagle, Fiona Deering, Yaniv Berliner, Andrew Kertesz
    Abstract:

    Background: Posterior cortical atrophy (PCA) is a progressive dementia characterized by prominent disorders of higher visual processing, affecting both dorsal and ventral streams to cause Balint’s syndrome, alexia, and visual Agnosia. Objective: To define the cognitive profile of PCA and compare to the typical, primary amnestic dementia of the Alzheimer’s type (DAT). Methods: The authors used standard cognitive tests and a novel battery designed to reflect dysfunction in both ventral (Object, Face & Color Agnosia Screen [OFCAS]) and dorsal (complex pictures and compound stimuli) visual streams. The authors identified 19 patients with PCA and compared their performance to a matched group of patients with DAT and normal controls. Results: Patients with PCA were younger with marked impairment in visuospatial tasks, reading, and writing but relative preservation of memory compared to DAT using standard tests. Dorsal stream signs were most prevalent among the patients with PCA with no pure ventral stream syndromes found. All novel tests distinguished reliably between subjects with complex picture descriptions and processing of compound stimuli showing the most significant differences compared to DAT. Conclusions: PCA is predominantly a dorsal stream syndrome, distinct from typical DAT, which involves occipitotemporal regions over time.

Todd S Woodward - One of the best experts on this subject based on the ideXlab platform.

  • analysis of errors in Color Agnosia a single case study
    Neurocase, 1999
    Co-Authors: Todd S Woodward, Mike J Dixon, Kathy T Mullen, Karin M Christensen, Daniel N Bub
    Abstract:

    Abstract The performance of an adult with Color Agnosia (JT) was investigated. Although perceptual Color tests clearly demonstrated no difficulty in Color discrimination, multidimensional scaling analysis (MDS) revealed that naming errors were constrained to confusions of adjacent points in the three-dimensional visual semantic Color space. This pattern of confuslons replicated across other tasks drawing on knowledge of Color concepts. The findings are interpreted as a partial disruption in mapping perceptual representations of Color to prototype nodes in visual semantic Color space. We propose that this methodology, already proven useful for investigation of category-specific visual object Agnosia, will allow more detailed cross-case cornparlsons of Color recognition disorders.