The “hidden” semantic category dissociation in mild-moderate Alzheimer's disease patients

The contribution of perceptual and semantic processing deficits to naming-test performance by Alzheimer's Disease subjects was examined. Groups of 34 Alzheimer subjects and 25 elderly controls completed tests of naming standard line drawings and naming perceptually degraded figures, and a test of verbal fluency for a specific semantic category. Alzheimer subjects were impaired on all measures and, when their naming-test errors were analyzed, they showed higher proportions of perceptual errors and failures to respond. Further, considerable variability in the proportions of different types of error was found both among subjects and among test items. These findings indicate that poor naming-test performance cannot necessarily be attributed to a specific deficit in semantic processing. Also, the discrepancies between previous reports of the naming deficits in Alzheimer's Disease may reflect differences in task difficulty and item selection that were apparent in this study.

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Disparate letter and semantic category fluency deficits in autopsy-confirmed frontotemporal dementia and Alzheimer's disease.

Neuropsychology ◽

10.1037/0894-4105.21.1.20 ◽

2007 ◽

Vol 21 (1) ◽

pp. 20-30 ◽

Cited By ~ 90

Author(s):

Katya Rascovsky ◽

David P. Salmon ◽

Lawrence A. Hansen ◽

Leon J. Thal ◽

Douglas Galasko

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Frontotemporal Dementia ◽

Semantic Category ◽

Category Fluency

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Differential decline in word generation from phonemic and semantic categories during the course of Alzheimer's disease: Implications for the integrity of semantic memory

Journal of the International Neuropsychological Society ◽

10.1017/s1355617799577126 ◽

1999 ◽

Vol 5 (7) ◽

pp. 692-703 ◽

Cited By ~ 65

Author(s):

DAVID P. SALMON ◽

WILLIAM C. HEINDEL ◽

KELLY L. LANGE

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Semantic Memory ◽

Fruits And Vegetables ◽

Semantic Category ◽

Word Generation ◽

Semantic Categories ◽

Rate Of Decline ◽

Normal Controls ◽

Phonemic Category

The ability to generate words from phonemic (i.e., words beginning with ‘F,’ ‘A,’ and ‘S’) and semantic (i.e., animals, fruits, and vegetables) categories was assessed longitudinally in patients with Alzheimer's disease (AD; N = 59) and normal controls (NC; N = 59). Patients with AD performed worse than NC participants on both tasks at each of 4 annual evaluations and exhibited greater impairment relative to controls on the semantic-category task than on the phonemic-category task. In addition, the performance of the patients with AD declined over time on both tasks, but the rate of decline was faster on the semantic-category than on the phonemic-category task. Examination of individual responses across the annual evaluations revealed that patients with AD were more consistent than NC participants in failing to generate previously produced semantic-category, but not phonemic-category, items in all years following the 1st year in which the item was not produced. These results are consistent with the notion that patients with AD suffer a gradual deterioration of the organization and content of semantic memory as the disease progresses. (JINS, 1999, 5, 692–703.)

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Cognitive control constrains memory attributions

Behavioral and Brain Sciences ◽

10.1017/s0140525x19001869 ◽

2019 ◽

Vol 42 ◽

Author(s):

Colleen M. Kelley ◽

Larry L. Jacoby

Keyword(s):

Alzheimer’S Disease ◽

Older Adults ◽

Alzheimer's Disease ◽

Traumatic Brain Injury ◽

Brain Injury ◽

Cognitive Control

Abstract Cognitive control constrains retrieval processing and so restricts what comes to mind as input to the attribution system. We review evidence that older adults, patients with Alzheimer's disease, and people with traumatic brain injury exert less cognitive control during retrieval, and so are susceptible to memory misattributions in the form of dramatic levels of false remembering.

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Review for "Expression profiling of precuneus layer III cathepsin D‐immunopositive pyramidal neurons in mild cognitive impairment and Alzheimer's disease: Evidence for neuronal signaling vulnerability"

10.1002/cne.24929/v2/review1 ◽

2020 ◽

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Expression Profiling ◽

Cathepsin D ◽

Pyramidal Neurons ◽

Neuronal Signaling

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Formation of paired helical filaments in Alzheimer's disease

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111628 ◽

1984 ◽

Vol 42 ◽

pp. 302-303

Author(s):

J. Metuzals ◽

D. F. Clapin ◽

V. Montpetit

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Frontal Lobe ◽

Giant Axon ◽

Paired Helical Filaments ◽

Normal Brain ◽

Protein Assemblies ◽

Electron Microscopic ◽

Helical Symmetry ◽

Structural Levels

Information on the conformation of paired helical filaments (PHF) and the neurofilamentous (NF) network is essential for an understanding of the mechanisms involved in the formation of the primary lesions of Alzheimer's disease (AD): tangles and plaques. The structural and chemical relationships between the NF and the PHF have to be clarified in order to discover the etiological factors of this disease. We are investigating by stereo electron microscopic and biochemical techniques frontal lobe biopsies from patients with AD and squid giant axon preparations. The helical nature of the lesion in AD is related to pathological alterations of basic properties of the nervous system due to the helical symmetry that exists at all hierarchic structural levels in the normal brain. Because of this helical symmetry of NF protein assemblies and PHF, the employment of structure reconstruction techniques to determine the conformation, particularly the handedness of these structures, is most promising. Figs. 1-3 are frontal lobe biopsies.

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Computer-aided methods for 3-D visualization of serial sections and thick biological specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100129930 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1060-1061

Author(s):

Mark Ellisman ◽

Maryann Martone ◽

Gabriel Soto ◽

Eleizer Masliah ◽

David Hessler ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Three Dimensional ◽

Neuritic Plaque ◽

Dimensional Structure ◽

Data Sets ◽

Molecular Physiology ◽

Research Activities ◽

Computer Aided ◽

Dimensional Reconstruction

Structurally-oriented biologists examine cells, tissues, organelles and macromolecules in order to gain insight into cellular and molecular physiology by relating structure to function. The understanding of these structures can be greatly enhanced by the use of techniques for the visualization and quantitative analysis of three-dimensional structure. Three projects from current research activities will be presented in order to illustrate both the present capabilities of computer aided techniques as well as their limitations and future possibilities.The first project concerns the three-dimensional reconstruction of the neuritic plaques found in the brains of patients with Alzheimer's disease. We have developed a software package “Synu” for investigation of 3D data sets which has been used in conjunction with laser confocal light microscopy to study the structure of the neuritic plaque. Tissue sections of autopsy samples from patients with Alzheimer's disease were double-labeled for tau, a cytoskeletal marker for abnormal neurites, and synaptophysin, a marker of presynaptic terminals.

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