scholarly journals Global processing deficit in Alzheimer’s disease

2010 ◽  
Vol 3 (3) ◽  
pp. 22-26
Author(s):  
María J. Blanca ◽  
Teresa Rodrigo ◽  
Rebecca Bendayan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Visual Information ◽  
Local Level ◽  
Global Processing ◽  
Attention Task ◽  
Visual Elements ◽  
Lower Accuracy ◽  
Divided Attention Task ◽  
Global And Local

Several studies of Alzheimer’s disease (AD) reveal an impaired capacity to integrate visual elements into global pictures, leading to a deficit in global processing of visual information. The aim of this paper was to explore global and local processing in people with AD at non-advanced stage. The Global and Local Attention Test (AGL; from the original Spanish: AGL-Atención global y local) was administered to a group of 100 participants with a mean age of 75.36 years. Fifty of them were AD patients at a mild or moderate stage, while the remainder comprised healthy elders. The AGL provides two scores that indicate speed and accuracy in analyzing global and local figures. Participants had to indicate the figures where the target appeared at either global or local levels in a divided attention task. The results showed lower accuracy in the AD group compared with controls. Also in the AD group, and in line with previous findings, accuracy in detecting the target was much lower at the global level than at the local level, thereby confirming the expected deficit in global processing associated with AD. This deficit did not vary according to sex or age.

Greater Impairment of Ability in the Divided Attention Task Is Seen in Alzheimer’s Disease Patients with Depression than in Those without Depression

2007 ◽  
Vol 23 (4) ◽  
pp. 231-240 ◽  
Author(s):  
Shutaro Nakaaki ◽  
Yoshie Murata ◽  
Junko Sato ◽  
Yoshihiro Shinagawa ◽  
Hiroshi Tatsumi ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Divided Attention ◽  
Attention Task ◽  
Divided Attention Task

scholarly journals A comparison of resting state EEG and structural MRI for classifying Alzheimer’s disease and mild cognitive impairment

2019 ◽  
Author(s):  
FR Farina ◽  
DD Emek-Savaş ◽  
L Rueda-Delgado ◽  
R Boyle ◽  
H Kiiski ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Resting State ◽  
Healthy Aging ◽  
Neurodegenerative Disorder ◽  
Low Cost ◽  
Structural Mri ◽  
Lower Accuracy

AbstractAlzheimer’s disease (AD) is a neurodegenerative disorder characterised by severe cognitive decline and loss of autonomy. AD is the leading cause of dementia. AD is preceded by mild cognitive impairment (MCI). By 2050, 68% of new dementia cases will occur in low- and middle-income countries. In the absence of objective biomarkers, psychological assessments are typically used to diagnose MCI and AD. However, these require specialist training and rely on subjective judgements. The need for low-cost, accessible and objective tools to aid AD and MCI diagnosis is therefore crucial. Electroencephalography (EEG) has potential as one such tool: it is relatively inexpensive (cf. magnetic resonance imaging; MRI) and is portable. In this study, we collected resting state EEG, structural MRI and rich neuropsychological data from older adults (55+ years) with AD, with MCI and from healthy controls (n~60 per group). Our goal was to evaluate the utility of EEG, relative to MRI, for the classification of MCI and AD. We also assessed the performance of combined EEG and behavioural (Mini-Mental State Examination; MMSE) and structural MRI classification models. Resting state EEG classified AD and HC participants with moderate accuracy (AROC=0.76), with lower accuracy when distinguishing MCI from HC participants (AROC=0.67). The addition of EEG data to MMSE scores had no additional value compared to MMSE alone. Structural MRI out-performed EEG (AD vs HC, AD vs MCI: AROCs=1.00; HC vs MCI: AROC=0.73). Resting state EEG does not appear to be a suitable tool for classifying AD. However, EEG classification accuracy was comparable to structural MRI when distinguishing MCI from healthy aging, although neither were sufficiently accurate to have clinical utility. This is the first direct comparison of EEG and MRI as classification tools in AD and MCI participants.

Fiat Lux: The Light Became Therapy. An Overview on the Bright Light Therapy in Alzheimer’s Disease Sleep Disorders

2020 ◽  
Vol 77 (1) ◽  
pp. 113-125 ◽  
Author(s):  
Ilaria Roccaro ◽  
Daniela Smirni
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Sleep Disorders ◽  
Visual Information ◽  
Bright Light ◽  
Light Therapy ◽  
Pharmacological Intervention ◽  
Biological Clocks ◽  
Bright Light Therapy ◽  
Effective Response

Background: A system of photosensitive retinal ganglion cells provides ‘non-visual’ information on the circadian sequences of light to the suprachiasmatic nucleus (SCN), which, as the ‘master clock’, synchronizes the chronobiological mechanisms of all the biological clocks. Damage to SCN structure alters circadian behavioral and hormonal rhythms and interferes with a regular sleep-wake pattern. Several studies have shown that, in aging and in Alzheimer’s disease (AD), circadian rhythms change their synchronization with the environment and behavior loses sync with light. Objective: The current overview aims to examine research studies showing the effect of bright light therapy (BLT) on sleep disorders and sleep-wake patterns in AD. Methods: A literature search was conducted, taking into consideration the relevant studies over the last 20 years. Fifteen studies have been thorough: seven followed an environmental-architectural approach and eight followed a treatment devices approach. Results: Studies agree in considering BLT as a promising non-pharmacological intervention to compensate for circadian rhythm alterations and they support the need for standardized protocols that allow a comparison between multicenter studies. Conclusion: Interestingly, in an attempt to contain the spread of the COVID-19 pandemic, health authorities have forced the population to stay home. Therefore, AD people are not currently able to enjoy exposure to sunlight. It is predictable that they may experience an exacerbation of circadian disturbances and that the BLT can be an effective response to prevent such exacerbation.

Dysfunction of Visual Cortex Contributes to Disturbed Processing of Visual Information in Alzheimer's Disease

1995 ◽  
Vol 82 (1-2) ◽  
pp. 1-9 ◽  
Author(s):  
Ruediger Mielke ◽  
Josef Kessler ◽  
Gereon Fink ◽  
Karl Herholz ◽  
Wolf-Dieter Heiss
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Visual Cortex ◽  
Visual Information ◽  
Processing Of Visual Information

scholarly journals O3-08-05: Global and Local Interactions between Amyloid-B Pathology and Intrinsic Connectivity along the Spectrum of Alzheimer's Disease

2016 ◽  
Vol 12 ◽  
pp. P306-P306
Author(s):  
Lorenzo Pasquini ◽  
Gloria Benson ◽  
Martin Scherr ◽  
Igor Yakushev ◽  
Timo Grimmer ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Local Interactions ◽  
Intrinsic Connectivity ◽  
Global And Local

Segmentation and selection contribute to local processing in hierarchical analysis

2002 ◽  
Vol 55 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Shihui Han ◽  
Glyn W. Humphreys
Keyword(s):  
Attention Task ◽  
Local Responses ◽  
Attentional Control Settings ◽  
Local Element ◽  
Selection Processes ◽  
Hierarchical Stimuli ◽  
Divided Attention Task ◽  
Local Interference ◽  
Global And Local

The present study examined the role of segmentation and selection processes when we respond to local elements in hierarchical stimuli. The ease of segmentation and selection of an individual local element from hierarchical patterns was manipulated by making one local element substantially distinct from the others in colour. Experiment 1 showed that, when attention was spread across the global and local levels in a divided attention task, the introduction of the local red element speeded responses to local targets but slowed responses when targets appeared at the global level. Experiment 2 used a selective attention task in which subjects responded only to the local or the global shapes across a block of trials. Under these circumstances, the local red element reduced global-to-local interference in addition to speeding local responses. The results suggest that the efficiency with which local elements are segmented and selected affects responses to local aspects of hierarchical patterns; furthermore, the effect of local pop-out on global processing is contingent on top-down attentional control settings.

A developmental change in selective attention and global form perception

2004 ◽  
Vol 28 (4) ◽  
pp. 358-364 ◽  
Author(s):  
Mafalda Porporino ◽  
Grace Iarocci ◽  
David I. Shore ◽  
Jacob A. Burack
Keyword(s):  
Selective Attention ◽  
Developmental Change ◽  
Developmental Trajectories ◽  
Local Level ◽  
Early Adulthood ◽  
Form Perception ◽  
Global Processing ◽  
Older Children ◽  
Local And Global Processing ◽  
Global And Local

The primary purpose of the present study was to examine the processing of local and global perception in relation to selective attention during development from childhood to early adulthood. Filtering was the specific component of selective attention that was examined. The influence of varying distractor congruency and compatibility on relative local-global processing was also examined. Distractor congruency and compatibility did not differentially affect local and global processing. With the presence of neutral distractors, however, 6- and 8-year-old participants demonstrated a greater increase in RTs for global targets relative to local targets whereas older children and adults showed the same pattern of RTs for both local and global targets. The results are suggestive of separate developmental trajectories for global and local level processes, with global processing undergoing developmental change at least until 8 years of age.

scholarly journals Differentiation of Alzheimer’s disease based on local and global parameters in personalized Virtual Brain models

2018 ◽  
Author(s):  
J Zimmermann ◽  
A Perry ◽  
M Breakspear ◽  
M Schirner ◽  
P Sachdev ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Individual Differences ◽  
Healthy Aging ◽  
Local Level ◽  
Functional Brain Imaging ◽  
Global Network ◽  
Model Parameters ◽  
Global Dynamics ◽  
Local And Global Dynamics

AbstractAlzheimer’s disease (AD) is marked by cognitive dysfunction emerging from neuropathological processes impacting brain function. AD affects brain dynamics at the local level, such as changes in the balance of inhibitory and excitatory neuronal populations, as well as long-range changes to the global network. Individual differences in these changes as they relate to behaviour are poorly understood. Here, we use a multi-scale neurophysiological model, “The Virtual Brain (TVB)”, based on empirical multi-modal neuroimaging data, to study how local and global dynamics correlate with individual differences in cognition. In particular, we modeled individual resting-state functional activity of 124 individuals across the behavioral spectrum from healthy aging, to amnesic Mild Cognitive Impairment (MCI), to AD. The model parameters required to accurately simulate empirical functional brain imaging data correlated significantly with cognition, and exceeded the predictive capacity of empirical connectomes.

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