The Memory Deficits in Alzheimer-Type Dementia: A Review

Morris, Robin G.; Kopelman, Michael D.

doi:10.1080/14640748608401615

Cited by 195 publications

(112 citation statements)

References 73 publications

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“…Although it was an initial finding that performance on BrownPeterson paradigms was sensitive to the degree of processing demands required (Morris, 1986;Morris and Kopelman, 1986), there is evidence that impaired dual task performance in AD reflects a specific deficit in dividing attention in AD, rather than the result of a more general processing speed deficit (Baddeley et al, 2001) or effect of task difficulty (Baddeley et al, 1991;Logie et al, 2004).…”

Section: Ces Function In Admentioning

confidence: 99%

Working memory in early Alzheimer's disease: a neuropsychological review

Huntley

Howard

2009

Int J Geriat Psychiatry

163

107

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Background: Reports of the extent of working memory (WM) impairment in early Alzheimer's disease (AD) have been inconsistent. Using the model of WM proposed by Baddeley, neuropsychological evidence for the impairment of WM in early AD is evaluated. Method: Literature searches were performed using Medline, PsycINFO and Embase databases. Individual papers were then examined for additional references not revealed by computerised searches. Results: Phonological loop function is intact at the preclinical and early stages of AD, becoming more impaired as the disease progresses. In mild AD, there is impairment on tasks assessing visuospatial sketchpad (VSS) function; however, these tasks also require executive processing by the central executive system (CES). There is evidence that the CES is impaired in mild AD and may be affected in the earlier preclinical stage of the disease. Episodic buffer function may be impaired but further research is required. Conclusions: Future research into central executive functioning at the earliest stages of the disease, combined with further longitudinal studies, needs to be carried out. Tasks to assess the proposed functions of the episodic buffer and specific tests of the VSS suitable for AD subjects need to be developed and validated. Learning more about these processes and how they are affected in AD is important in understanding and managing the cognitive deficits seen in the early stages of AD.

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Section: Ces Function In Admentioning

confidence: 99%

Working memory in early Alzheimer's disease: a neuropsychological review

Huntley

Howard

2009

Int J Geriat Psychiatry

163

107

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“…Loewenstein and Rubert (1992) have argued that there is an underlying global impairment in memory functioning as well as a general decline in overall cognition. Likewise, Morris and Kopelman (1986) hypothesized that AD-related deficits were the result of deteriorating memory ability and a general deficit in informationprocessing.If one (or two) common factors are responsible for AD-related cognitive decline, one would expect that an individual's performance on one cognitive test would be highly correlated with performance on all other cognitive variables. However, research has indicated that there is great diversity in the clinical manifestation of AD such that patients often present with deficits in some cognitive domains, but not all.…”

mentioning

confidence: 99%

Exploring the structure of a neuropsychological battery across healthy elders and those with questionable dementia and Alzheimer's disease.

2008

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An exploratory factor analysis (EFA) and a series of confirmatory factor analyses were conducted on 17 variables designed to assess different cognitive abilities in a sample of healthy older adults. In the EFA, four factors emerged corresponding to language, memory, processing speed, and fluid ability constructs. The results of the confirmatory factor analyses suggested that a five-factor model with an additional Attention factor improved the fit. The invariance of the five-factor model was examined across three groups-a group of cognitively-healthy older adults, a group of patients diagnosed with questionable dementia (QD), and a group of patients diagnosed with probable Alzheimer's Disease (AD). Results of the invariance analysis suggest that the model may have configural invariance across the three groups, but not metric invariance. Specifically, preliminary analyses suggest that the memory construct may represent something different in the QD and AD group as compared to the healthy elderly group, consistent with the underlying pathology in early AD. KeywordsAlzheimer's disease; questionable dementia; cognition; structural equation modeling; invariance Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by impairments in cognitive abilities and activities of daily living. Although normal aging is associated with age-related declines across a variety of cognitive abilities (e.g. Salthouse, in press), AD-related declines in functioning are different because the declines interfere with daily life. Questionable dementia (QD) is a categorization designed to characterize individuals who demonstrate mild cognitive impairment beyond what is expected by age and education but whose cognitive and/or functional impairment is not sufficient for the diagnosis of dementia.There is overwhelming evidence that there are changes in performance in tests of cognitive functioning across groups of older adults categorized as being either healthy, diagnosed with QD, or diagnosed with probable AD. Specifically, patients with QD and AD perform worse on memory and other tests designed to measure cognitive functions such as attention, language, and executive function than do cognitively-healthy older adults. Although it is clear that there are quantitative differences in the cognitive tests (i.e. demented patients perform worse), it is unclear whether there are consistent qualitative differences across these three diagnostic Correspondence to Yaakov Stern, 630 W 168 th St, New York, NY 10032, tel 212-342-1350, fax 212-342-1838 NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript groups. Qualitative differences refer to differences in relations among variables and differences in what the variables may be measuring. In this paper we used two techniques to address this question: invariance analyses, and comparison of the structure through separate exploratory factor analysis (EFA). Examining whether the structure of variables is the same (invariant) across groups is important beca...

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“…The most prominent early cognitive symptom in AD is a disruption in the ability to acquire new declarative memories (Morris and Kopelman, 1986). Declarative memory has been studied in animals to a large extent using tests of object recognition memory; indeed, it has been suggested that object recognition tasks provide a relatively pure assessment of declarative memory function (Manns et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Paradoxical Facilitation of Object Recognition Memory after Infusion of Scopolamine into Perirhinal Cortex: Implications for Cholinergic System Function

Winters¹,

Saksida²,

Bussey³

2006

J. Neurosci.

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The cholinergic system has long been implicated in learning and memory, yet its specific function remains unclear. In the present study, we investigated the role of cortical acetylcholine in a rodent model of declarative memory by infusing the cholinergic muscarinic receptor antagonist scopolamine into the rat perirhinal cortex during different stages (encoding, storage/consolidation, and retrieval) of the spontaneous object recognition task. Presample infusions of scopolamine significantly impaired object recognition compared with performance of the same group of rats on saline trials; this result is consistent with previous reports supporting a role for perirhinal acetylcholine in object information acquisition. Scopolamine infusions directly before the retrieval stage had no discernible effect on object recognition. However, postsample infusions of scopolamine with sample-to-infusion delays of up to 20 h significantly facilitated performance relative to postsample saline infusion trials. Additional analysis suggested that the infusion episode could cause retroactive or proactive interference with the sample object trace and that scopolamine blocked the acquisition of this interfering information, thereby facilitating recognition memory. This is, to our knowledge, the first example of improved recognition memory after administration of scopolamine. The overall pattern of results is inconsistent with a direct role for cortical acetylcholine in declarative memory consolidation or retrieval. Rather, the cholinergic input to the perirhinal cortex may facilitate acquisition by enhancing the cortical processing of incoming stimulus information.

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The Memory Deficits in Alzheimer-Type Dementia: A Review

Cited by 195 publications

References 73 publications

Working memory in early Alzheimer's disease: a neuropsychological review

Working memory in early Alzheimer's disease: a neuropsychological review

Exploring the structure of a neuropsychological battery across healthy elders and those with questionable dementia and Alzheimer's disease.

Paradoxical Facilitation of Object Recognition Memory after Infusion of Scopolamine into Perirhinal Cortex: Implications for Cholinergic System Function

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