Distinct mechanisms of impairment in cognitive ageing and Alzheimer's disease.

@article{Mapstone2008DistinctMO,
  title={Distinct mechanisms of impairment in cognitive ageing and Alzheimer's disease.},
  author={Mark Mapstone and Kathryn C. Dickerson and Charles Duffy},
  journal={Brain : a journal of neurology},
  year={2008},
  volume={131 Pt 6},
  pages={
          1618-29
        }
}
Similar manifestations of functional decline in ageing and Alzheimer's disease obscure differences in the underlying cognitive mechanisms of impairment. We sought to examine the contributions of top-down attentional and bottom-up perceptual factors to visual self-movement processing in ageing and Alzheimer's disease. We administered a novel heading discrimination task requiring subjects to determine direction of simulated self-movement from left or right offset optic flow fields of several… 

Figures and Tables from this paper

Perception and Cognition in Aging and Alzheimer's Disease: Visual Psychophysics and Neurophysiology
TLDR
This dissertation includes research on visual motion evoked potentials in the study of visuospatial orientation, the utility of this neurophysiological approach in gaining insight into brain aging, and its potential utility for the objective assessment of AD.
Approaching objects cause confusion in patients with Alzheimer's disease regarding their direction of self-movement.
TLDR
It is concluded that perceptual factors limit safe, autonomous navigation in early Alzheimer's disease, in particular the presence of independently moving objects in naturalistic environments limits the capacity of patients with Alzheimer’s disease to judge their heading of self-movement.
Visual search in mild cognitive impairment: a longitudinal study.
TLDR
Results from the longitudinal aspect of this study illustrate how heterogeneity in the performance of brain operations other than memory in aMCI may help to inform the likelihood of their developing dementia, as those patients who were diagnosed with dementia within 2.5 years of baseline measurement showed significantly poorer visual search performance compared to those who did not.
Visual evoked potentials to pattern, motion and cognitive stimuli in Alzheimer’s disease
TLDR
There were significantly smaller N2 peak amplitudes of motion-onset VEPs in patients with AD, which suggests a dysfunction of the motion-processing system or the dorsal cortical stream, and the individual AD diagnostics based on ERPs seems to be limited by rather high inter-individual variability of the ERP latencies.
Inclusion of Neuropsychological Scores in Atrophy Models Improves Diagnostic Classification of Alzheimer's Disease and Mild Cognitive Impairment
TLDR
A feature selection technique using backward stepwise linear regression together with linear discriminant analysis is designed to classify cognitive normal (CN) subjects, early MCI (EMCI), lateMCI (LMCI), and AD subjects in an exhaustive two-group classification process, showing a dominance of the neuropsychological parameters like MMSE and RAVLT.
Visuo-cognitive skill deficits in Alzheimer's disease and Lewy body disease: A comparative analysis
TLDR
An exhaustive internet search of all relevant medical databases was carried out using a series of key-word applications, including The Cochrane Library, MEDLINE, PSYCHINFO, EMBASE, CINAHL, AMED, SportDiscus, Science Citation Index, Index to Theses, ZETOC, PEDro and occupational therapy (OT) seeker and OT search.
Differentiation of mild cognitive impairment using an entorhinal cortex-based test of VR navigation
TLDR
Evidence that navigation tasks may aid early diagnosis of Alzheimer's disease is provided, and the basis of this in animal cellular and behavioural studies provides the opportunity to answer the unmet need for translatable outcome measures for comparing treatment effect across preclinical and clinical trial phases of future anti-Alzheimer’s drugs.
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 56 REFERENCES
Visual mechanisms of spatial disorientation in Alzheimer's disease.
TLDR
The greater prevalence of global pattern deficits suggests that it might precede local motion processing impairments, possibly relating to the sequence of early hippocampal and later posterior cortical damage that is typical of AD.
Neurophysiological and perceptual correlates of navigational impairment in Alzheimer's disease.
TLDR
It is concluded that navigational impairment in Alzheimer's disease is linked to a disorder of extrastriate visual cortical motion processing reflected in specific perceptual and neurophysiological measures.
Cognitive and behavioral heterogeneity in Alzheimer’s disease: seeking the neurobiological basis
  • J. Cummings
  • Psychology, Biology
    Neurobiology of Aging
  • 2000
Spatial- and object-based attentional deficits in Alzheimer's disease. Relationship to HMPAO-SPECT measures of parietal perfusion.
TLDR
Results provide evidence for the specialized roles of the right and left parietal regions in the spatial and object components of attentional shifting respectively, and suggest that the cognitive profile associated with Alzheimer's disease includes both spatial- and object-based attentional impairments.
Dynamic allocation of attention in aging and Alzheimer disease: uncoupling of the eye and mind.
TLDR
To determine if subjects who have AD and cognitively intact older subjects shift their gaze more often than young subjects while viewing a dynamic stimulus that emphasizes global attention, experimental study of eye fixation patterns in response to a simulated driving scene with stationary and moving distractors.
A visuospatial variant of mild cognitive impairment
TLDR
Impaired visual motion processing may accompany memory deficits in MCI or AD, or may occur alone in otherwise intact ON subjects, suggesting that visuospatial impairment may develop as an independent sign of neurodegenerative disease, possibly preceding the clinical onset of AD.
Directed and divided attention in Alzheimer's disease: impairment in shifting of attention to global and local stimuli.
TLDR
It is demonstrated that Alzheimer's disease patients are impaired in disengaging and shifting attention across levels of perceptual organization within the same stimulus.
Evidence for cortical “disconnection” as a mechanism of age-related cognitive decline
TLDR
Findings provide direct evidence that white matter tract disruption occurs in normal aging and would be consistent with the cortical disconnection hypothesis of age-related cognitive decline and provide a plausible structural basis for selective loss of executive functions.
An Anatomic Substrate for Visual Disconnection in Alzheimer's Disease a
TLDR
Data suggest that in some cases of AD, the particular psychologic and neurologic symptomatology may be caused by the selective loss of specific corticocortical systems, as reflected by a differential distribution of the neuropathologic markers of the disease.
Neurophysiologic analyses of low- and high-level visual processing in Alzheimer disease
TLDR
It is concluded that visual evoked potentials (EPs) are abnormal in all patients with Alzheimer disease (AD), and those with small pattern and motion onset EPs may have greater AD pathology in visual cortex, whereas those with larger pattern onset Eps may have larger AD pathologyIn higher centers.
...
1
2
3
4
5
...