Memory dissociation in Alzheimer's disease.
Item
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Title
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Memory dissociation in Alzheimer's disease.
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Identifier
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AAI9218217
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identifier
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9218217
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Creator
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Apter, Seth Hilton.
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Contributor
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Adviser: Wilma A. Winnick
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Date
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1992
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Clinical | Psychology, Experimental
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Abstract
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The present set of experiments examined the role of cognitive processing demand on dissociations between procedural and declarative memory systems in Alzheimer's disease (AD) and in normal aging. In Experiment 1, 25 AD patients and 25 age- and education-matched healthy adults were presented with a list of words to process and were subsequently administered one of two possible memory tasks: word-fragment completion or free recall. Word-fragment completion is an implicit test of memory which requires a large degree of effortful processing for successful completion. Free recall is an explicit test of memory matched to word-fragment completion in terms of relative cognitive demand. In Experiment 2, subsequent to an identical study phase, 19 AD patients and 22 age- and education-matched healthy adults were administered either a perceptual threshold measurement or a recognition test. Perceptual threshold measurement is an implicit memory task which requires automatic processing. Recognition is an explicit memory test matched to perceptual threshold measurement with regard to degree of cognitive demand. In both experiments, the implicit memory tests reflect the operation of the procedural memory system while the explicit memory tests reflect operation of the declarative memory system. Results indicate that while performance of the AD patients on both explicit tasks of memory was extremely impaired relative to the controls, a more variable pattern emerged on the implicit tests of memory. AD patients performed significantly worse relative to the controls on the effortful processing word-fragment completion task. In contrast, although AD patients had overall slower threshold durations, these subjects actually exhibited a greater degree of priming than the controls on the perceptual threshold measurement test, an automatic processing task. Performance on the implicit memory tasks was therefore dependent upon the degree of cognitive capacity demanded by each task. These findings indicate that AD patients do appear to exhibit a dissociation among systems of memory but that this dissociation appears to be mediated by cognitive processing capacity and demand. Results are discussed with respect to memory systems in general and memory functioning in AD in particular.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
