Task Complexity and Signal Detection Analyses of Lexical Decision Performance in Alzheimer's Disease

The aim of this study is to analyze dual-task effects on free and adaptive gait in Alzheimer's disease (AD) patients. Nineteen elders with AD participated in the study. A veteran neuropsychiatrist established the degree of AD in the sample. To determine dual-task effects on free and adaptive gait, patients performed five trials for each experimental condition: free and adaptive gait with and without a dual-task (regressive countdown). Spatial and temporal parameters were collected through an optoelectronic tridimensional system. The central stride was analyzed in free gait, and the steps immediately before (approaching phase) and during the obstacle crossing were analyzed in adaptive gait. Results indicated that AD patients walked more slowly during adaptive gait and free gait, using conservative strategies when confronted either with an obstacle or a secondary task. Furthermore, patients sought for stability to perform the tasks, particularly for adaptive gait with dual task, who used anticipatory and online adjustments to perform the task. Therefore, the increase of task complexity enhances cognitive load and risk of falls for AD patients.

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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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