Naming and Knowing in Dementia of Alzheimer's Type

University Neurology Unit, University of Cambridge, Cambridge, United Kingdom.
Brain and Language (Impact Factor: 3.31). 09/1996; 54(2):302-25. DOI: 10.1006/brln.1996.0077
Source: PubMed

ABSTRACT We studied the relationship between naming and the integrity of physical and associative knowledge in a group of patients with dementia of the Alzheimer type (DAT) and matched normal controls. All subjects named 48 line drawings and later generated verbal definitions in response to the names of a subset of the 48 items, which included a minimum of six definitions for correctly named objects and six definitions for items that the subject failed to name. A comprehensive scoring system was designed for the definitions, including physical and associative features of a general and a specific type, a superordinate label, the core concept, and various categories of errors. The definitions generated by the DAT patients, even those in the minimal group, contained significantly less correct information than those of normal subjects, and definitions corresponding to unnamed items were more impoverished than those for named items. Particularly striking was the loss of core concept for unnamed items. There was also a disproportionate reduction in physical information on unnamed compared to named items. We conclude that quantitative assessment of verbal definitions is a sensitive index of semantic memory breakdown. Our findings offer some support for the hypothesis that successful naming depends upon integrity of the subset of semantic knowledge comprising physical features.

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Available from: Karalyn Patterson, Aug 27, 2015
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    • "Pour Hodges et al. (1991), la production fréquente d'hyperonymes et de cohyponymes s'expliquerait par la dégradation des informations sémantiques spécifiques tandis que les circonlocutions montreraient que les connaissances sémantiques disponibles ne sont pas suffissantes pour permettre la production de la cible. Dans cette hypothèse, les troubles de la dénomination seraient associés à des troubles sémantiques et des troubles de la compréhension lexicale (Martin & Fedio, 1983 ; Hodges et al., 1996). De nombreux auteurs parlent ainsi de troubles lexico-sémantiques, considérés comme caractéristiques de la maladie d'Alzheimer (Huff et al., 1988, Cardebat et al. 1995 ; Joannette et al., 2006). "
    01/2012; 1(2261-2424):1659-1672. DOI:10.1051/shsconf/20120100211
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    • "Two possible causes have been identified ; on the one hand, AD has been characterised as a 'storage' disorder in which representations are lost from semantic memory. Proponents of this view report a pattern of gradual decline of knowledge in AD, leading to a consistent impairment of the same concepts across different tasks [8] [9] [10] [11] [12] [13]. Alternatively, others have shown that the level of semantic impairment in this condition is not stable but varies in line with changing task demands. "
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    ABSTRACT: Despite a vast literature examining semantic impairment in Alzheimer's disease (AD), consensus regarding the nature of the deficit remains elusive. We re-considered this issue in the context of a framework that assumes semantic cognition can break down in two ways: (1) core semantic representations can degrade or (2) cognitive control mechanisms can become impaired. We hypothesised and confirmed that the nature of semantic impairment in AD changes with disease severity. Patients at mild or severe stages of the disorder exhibited impairment across various semantic tasks but the nature of those deficits differed qualitatively for the two groups. Commensurate with early dysfunction of the cognitive control, temporoparietal-frontal-cingulate network, characteristics of deregulated semantic cognition were exhibited by the mild AD cases. In contrast, the severe AD group reproduced features of additional degradation of core semantic representations. These results suggest that spread of pathology into lateral anterior temporal lobes in later stage AD produces degradation of semantic representations, exacerbating the already deregulated system. Moreover, the dual nature of severe patients' impairment was highlighted by disproportionately poor performance on tasks placing high demand on both conceptual knowledge and control processes--e.g., category fluency.
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    • "to 60 ( total correct TAS scores ) . Semantic category fluency task : This simple task involves specifying as many words as possible belonging to a given category such as ' animals ' , during a period of 1 min . The dependent variable Author ' s personal copy is the number of relevant non - repeated words uttered by the subject . Various authors ( Hodges et al . , 1996 ) consider this to be one of the most reliable tasks for discriminating between the initial phases of cognitive impairment . WM evaluation task ( Yuill et al . , 1989 ) : This task measures the extent of WM through the presentation of cards consisting of three numbers . The subject is required to read the numbers of each card aloud and "
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    Archives of gerontology and geriatrics 12/2010; 53(3):292-7. DOI:10.1016/j.archger.2010.11.030 · 1.53 Impact Factor
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