Mechanisms of Spatial Impairment in Alzheimer's Disease Subgroups: Differential Breakdown of Directed Attention to Global-Local Stimuli

Global-local stimuli (e.g., a large 1 composed of small 2 s) were presented to subgroups of patients with Alzheimer's disease (AD) and to normal controls in a directed-attention reaction-time experiment. Pronounced dissociations in performance were found among the AD subgroups. Those patients w...

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Bibliographic Details
Published in:Neuropsychology 1993-04, Vol.7 (2), p.172-181
Main Authors: Massman, Paul J, Delis, Dean C, Filoteo, J. Vincent, Butters, Nelson, Salmon, David P, Demadura, Theresa L
Format: Article
Language:English
Subjects:
Alzheimer's Disease
Attention
Cognitive Processes
Human
Spatial Ability
Verbal Ability
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Summary:Global-local stimuli (e.g., a large 1 composed of small 2 s) were presented to subgroups of patients with Alzheimer's disease (AD) and to normal controls in a directed-attention reaction-time experiment. Pronounced dissociations in performance were found among the AD subgroups. Those patients who displayed greater impairment in verbal than in spatial skills on traditional clinical tests had particular difficulty processing local (detail) forms, whereas patients who had greater spatial than verbal impairment exhibited striking deficits in processing global (configural) forms. Results indicate that the AD patients were impaired primarily in inhibiting responses associated with their strong area when attending to forms in their weak area, although they did evince mild impairment in the perceptual processing of forms in their weak area as well. Thus, it appears that the AD patients' global-local processing deficits interacted with deficient inhibitory mechanisms to produce their patterns of deficits on the directed attention task.
ISSN:0894-4105
1931-1559
DOI:10.1037/0894-4105.7.2.172