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1.
Forty-six preclinical Alzheimer's disease (AD) participants and 188 nondemented control persons from the Kungsholmen Project (L. B?ckman et al., 2004) were compared on prospective memory (ProM) and retrospective memory (RetM) tasks 3 years before dementia diagnosis. The preclinical AD participants showed deficits in both ProM and RetM. Most interestingly, logistic regression analyses revealed that ProM made an independent contribution to the prediction of AD over and above that of RetM. This finding suggests that ProM and RetM tap partly different cognitive operations. Furthermore, within the ProM task, both the retrospective and prospective components were similarly impaired in preclinical AD. Within RetM, the preclinical AD participants were impaired on indices of encoding, storage (forgetting), and retrieval of information. Hence, the findings indicate a rather global episodic memory impairment in preclinical AD that cuts across type of memory assessed (ProM and RetM) as well as across different components of both the ProM and RetM tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

2.
Intact executive functioning is believed to be required for performance on tasks requiring cognitive estimations. This study used a revised version of a cognitive estimations test (CET) to investigate whether patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI) were impaired on the CET compared with normal elderly controls (NECs). Neuropsychological tests were administered to determine the relationship between CET performance and other cognitive domains. AD patients displayed impaired CET performance when compared with NECs but MCI patients did not. Negative correlations between tests of working memory (WM) and semantic memory and the CET were found in NECs and AD patients, indicating that these cognitive domains were important for CET performance. Regression analysis suggests that AD patients were unable to maintain semantic information in WM to perform the task. The authors conclude that AD patients display deficits in working memory, semantic memory, and executive function, which are required for adequate CET performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
Previous research suggests that patients with Alzheimer's disease exhibit cognitive impairment in the years preceding a clinical diagnosis. Memory impairments are particularly pronounced, but the relative degree to which other cognitive functions are impaired and the speed with which they decline during the preclinical years remains unclear. The authors report a detailed neuropsychological evaluation of 11 patients over the course of 3 years up to and including the 1st year of nonnormal diagnosis. The results suggest that performance falls off rapidly in all areas of cognitive functioning but that abilities thought to be subserved by the medial and lateral temporal lobes (episodic and semantic memory, respectively) appear to be substantially more impaired than those abilities thought to be subserved by the frontal lobes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

4.
Episodic long-term, short-term, and implicit memory were investigated in 79 elderly subjects who fulfilled criteria for the amnestic form of mild cognitive impairment (a-MCI; i.e., by having an idiopathic amnestic disorder with absence of impairment in cognitive areas other than memory and without confounding medical or psychiatric conditions) and who developed Alzheimer's disease (AD) after 2 years as well as in 111 subjects affected by a-MCI who did not develop dementia. Results document a memory profile in a-MCI subjects characterized by preserved short-term and implicit memory and extensive impairment of episodic long-term memory. In virtually all episodic memory indexes examined (learning, forgetting, recognition abilities), a-MCI subjects who converted to AD were more severely impaired than were subjects who did not become demented. This memory profile, which closely resembles that exhibited by amnestic patients with bilateral mesial-temporal lobe lesions, confirms a precocious phase in preclinical AD characterized by selective involvement of mesial-temporal areas and worsening of the memory impairment as atrophic changes progress in hippocampal structures. In this context of pervasive episodic memory impairment, tests assessing the free recall of verbal material following a delay interval demonstrated the greater sensitivity to memory deficits of a-MCI subjects who developed AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

5.
Two experiments examined different forms of gist and detail memory in people with Alzheimer's disease (AD) and those with amnestic mild cognitive impairment (MCI). In Experiment 1, 14 AD, 14 MCI, and 22 control participants were assessed with the Deese-Roediger-McDermott paradigm. Results indicated that false recognition of nonstudied critical lures (gist memory) was diminished in the AD compared with the MCI and control groups; the two latter cohorts performed similarly. In Experiment 2, 14 AD, 20 MCI, and 26 control participants were tested on a text memory task. Results revealed that recall of both macropropositions (gist information) and micropropositions (detail information) decreased significantly in AD and in MCI as compared with control participants. This experiment also revealed that the impairment was comparable between gist and detail memory. In summary, the results were consistent across experiments in the AD but not in the MCI participants. The discrepancy in MCI participants might be explained by differences in the degree of sensitivity of the experimental procedures and/or by the differences in the cognitive processes these procedures assessed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

6.
Accurate time estimation abilities are assumed to play an important role in efficient performance of many daily activities. The authors investigated the role of episodic memory impairment in temporal perception using a prospective verbal time estimation paradigm. Verbal time estimations were made for filled intervals both within (i.e., 30 s) intervals. The verbal time estimates of both older adult groups, however, deviated more significantly from true time when compared with younger adult controls. In Experiment 2, 17 individuals with Alzheimer's disease (AD) demonstrated greater error and variability in their time estimates, but no disproportionate differences emerged between short- and long-duration estimates when compared with age-matched controls. The findings did not support a noteworthy role for episodic memory impairment in temporal perception but rather elucidated a significant effect of normal aging, as well as a detrimental effect of AD on temporal perception. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

7.
Awareness of deficit was examined in 24 patients with Alzheimer's disease (AD) and their spouses (for a total of 48 participants) using performance prediction-postdiction and questionnaire discrepancy (QD) paradigms. Participants estimated their own memory performances as well the performances of spouses and of a fictional, memory-disordered patient observed on videotape. Patients overpredicted self-performances, but the extent of overestimation decreased for postdictions. Patients and caregivers accurately estimated caregiver performances but overestimated performances of the fictional patient. QD data revealed that patients underestimated their difficulties performing daily functioning tasks as compared with caregiver reports. Awareness of deficit is a complex ability, involving dissociable cognitive processes. AD patients may display intact immediate awareness of memory dysfunction but fail to incorporate incidents of memory failure into generalized self-belief systems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

8.
The goal of the present study was to assess 3 attentional control processes--divided attention, manipulation capacities, and inhibition--in persons with mild cognitive impairment (MCI) and with mild Alzheimer's disease (AD). Manipulation capacities were tested by comparing immediate serial recall with alphabetical-order recall of words. Divided attention was tested with the Brown-Peterson procedure, in which participants divide their attention between simple addition tasks and consonant trigrams over delays. Inhibition was tested with the Hayling procedure, in which participants complete sentences with words irrelevant to their context. Persons with AD showed severe impairment on the 3 attentional control components. Persons with MCI exhibited impaired performance on the Brown-Peterson procedure but normal performance on the other 2 tasks. With AD and MCI participants, there was a negative correlation between general cognitive deficits and impairment on attentional control tasks, indicating that attentional control deficits increase in the MCI/AD continuum. When separating MCI with and without significant subsequent decline, those with subsequent decline showed impaired performance on both the Brown-Peterson procedure and manipulation task. These data suggest that control of attention tasks can track AD at a preclinical stage and that impairment increases gradually during the preclinical phase of AD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

9.
Objective: This study examines working memory (WM) in mild cognitive impairment (MCI) and Alzheimer's disease (AD). Method: Performances on sentence span and operation span were measured in individuals meeting criteria for MCI (n = 20) and AD (n = 16) as well as in healthy older adults (n = 20). In addition, the effect of retention interval was assessed by manipulating the length of first and last items of trials (long-short vs. short-long), as forgetting might contribute to impaired performance in AD and MCI. Results: Results show a group effect (p  相似文献   

10.
This study examined whether the cognitive profile of subjects with mild cognitive impairment (MCI) with vascular disease differs from that of MCI subjects with no vascular disease. Consecutive MCI subjects with vascular disease (n=60) and matched MCI subjects with no vascular disease (n=60) were included in the study and were compared with healthy control subjects (n=60). The neuropsychological assessment comprised tests of speed and attention, episodic memory, visuospatial function, language, and executive function. Control subjects performed significantly better than did both MCI groups on the neuropsychological battery. MCI subjects with no vascular disease performed better overall than did MCI subjects with vascular disease, most clearly on tests of speed and attention, visuospatial function, and executive function. MCI subjects with and without vascular disease exhibited differences, both in terms of overall performance and of cognitive profiles. These differences can be largely explained by deficits in speed and attention and in executive function of the MCI subjects with vascular disease. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

11.
Recognition can be guided by familiarity, a restricted form of retrieval devoid of contextual recall, or by recollection, which occurs when retrieval is sufficient to support the full experience of remembering an episode. Recollection and familiarity were disentangled by testing recognition memory using silhouette object drawings, high target-foil resemblance, and both yes-no and forced-choice procedures. Theoretically, forced-choice recognition could be mediated by familiarity alone. Alzheimer's disease and its preclinical stage, mild cognitive impairment (MCI), were associated with memory impairments that were greater on the yes-no test. Remarkably, forced-choice recognition was unequivocally normal in patients with MCI compared with age-matched controls. Neuropathology in hippocampus and entorhinal cortex, known to be present in MCI, presumably disrupted recollection while leaving familiarity-based recognition intact. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

12.
This study explored the relationship between episodic memory and anosognosia (a lack of deficit awareness) among patients with mild Alzheimer's disease (AD). Participants studied words and pictures for subsequent memory tests. Healthy older adults made fewer false recognition errors when trying to remember pictures compared with words, suggesting that the perceptual distinctiveness of picture memories enhanced retrieval monitoring (the distinctiveness heuristic). In contrast, although participants with AD could discriminate between studied and nonstudied items, they had difficulty recollecting the specific presentation formats (words or pictures), and they had limited use of the distinctiveness heuristic. Critically, the demands of the memory test modulated the relationship between memory accuracy and anosognosia. Greater anosognosia was associated with impaired memory accuracy when participants with AD tried to remember words but not when they tried to remember pictures. These data further delineate the retrieval monitoring difficulties among individuals with AD and suggest that anosognosia measures are most likely to correlate with memory tests that require the effortful retrieval of nondistinctive information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

13.
This study investigated the relationship between premorbid and current cognitive function with respect to the clinical features of patients with various types of neurodegeneration in the form of Alzheimer's disease (AD), mild cognitive impairment (MCI), and subjective cognitive impairment (SCI), as compared with a healthy control group (C). Clinical features (MMSE, cognitive and depressive symptoms), genetics (apolipoprotein E; APOE) and measures of neurodegeneration (Aβ42, t-tau, and p-tau) were examined, as well as present cognitive function. Various methods of assessing premorbid cognitive function were compared, including a Swedish NART-analogous test (Irregularly Spelled Words; ISW), a Swedish lexical decision test (SLDT), a Hold test (Information in WAIS-R), Best current performance test, and combined demographic characteristics. Results showed that cognitive decline (premorbid minus current cognitive function) based on SLDT and ISW was a significant predictor for MMSE and Aβ42, whereas corresponding associations for present cognitive function and decline measures based on other methods were less powerful. Results also showed that specific verbal abilities (e.g., SLDT and ISW) were insensitive to AD and that these abilities indicated premorbid cognitive function in retrospect. In conclusion, cognitive decline from premorbid status reflects the disease processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

14.
In this meta-analysis, the authors evaluated recent suggestions that older adults' episodic memory impairments are partially due to a reduced ability to encode and retrieve associated/bound units of information. Results of 90 studies of episodic memory for both item and associative information in 3,197 young and 3,192 older adults provided support for the age-related associative/binding deficit suggestion, indicating a larger effect of age on memory for associative information than for item information. Moderators assessed included the type of associations, encoding instructions, materials, and test format. Results indicated an age-related associative deficit in memory for source, context, temporal order, spatial location, and item pairings, in both verbal and nonverbal material. An age-related associative deficit was quite pronounced under intentional learning instructions but was not clearly evident under incidental learning instructions. Finally, test format was also found to moderate the associative deficit, with older adults showing an associative/binding deficit when item memory was evaluated via recognition tests but not when item memory was evaluated via recall tests, in which case the age-related deficits were similar for item and associative information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

15.
Mild cognitive impairment (MCI) is associated with increased risk of developing Alzheimer's disease (AD), but up to 40% of cases do not develop AD. Examining a case's specific memory profile may help distinguish which MCI cases will progress to AD: An encoding profile is suggestive of incipient AD, whereas a retrieval profile suggests an alternative etiology. Paired associate learning (PAL) tasks are sensitive for preclinical and early detection of AD, but existing tasks do not enable memory profiling. We developed a novel PAL task enabling the differentiation of memory profiles in 19 people with AD, 17 people with amnestic MCI, and 33 normal elderly controls. Unexpectedly, the AD group demonstrated a retrieval profile for PAL using yes-no recognition, although an encoding profile was evident for forced-choice recognition and for the California Verbal Learning Test--Second Edition (Delis, Kramer, Kaplan, & Ober, 2000). There was considerable heterogeneity within the AD and MCI groups as well as intraindividual discordance for memory profiles. The findings challenge the clinical application of memory profiling in the differential diagnosis of AD, and, by extension, question its potential application in the assessment of MCI. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
Using semantic dementia (SD) as a reference point, the authors assessed semantic memory in four other neurodegenerative disorders: progressive nonfluent aphasia (PNFA), frontal variant frontotemporal dementia (fvFTD), Alzheimer's disease (AD), and posterior cortical atrophy (PCA). Individuals with SD were more impaired than other groups on semantic measures and showed a characteristic pattern across tasks: category fluency (CF) worse than letter fluency (LF), naming worse than comprehension, and visual and verbal comprehension equally affected, suggesting disruption to an amodal semantic system. Individuals with AD demonstrated a similar pattern to a milder degree. Although PNFA, fvFTD, and PCA groups had abnormal scores (relative to controls) on most semantic measures, their differing patterns across measures indicate that the apparent semantic impairment in these conditions is largely secondary to other factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

17.
Attempts to identify cognitive markers of a preclinical phase of Alzheimer's disease (AD) have yielded inconsistent findings. The problem may stem in part from methodologies that are insensitive to potential subgroups within the at-risk, preclinical AD population (PCAD). The present study investigated the utility of asymmetric cognitive profiles in identifying individuals at risk for AD. Twenty elderly adults who were later diagnosed with AD (PCAD) and 20 matched control participants were compared on measures of cognitive asymmetry derived from difference scores on tests of verbal and visuospatial ability. Although both groups performed similarly on the individual tests, comparisons using difference scores revealed significantly larger discrepancies between naming and visuoconstruction skills in the PCAD group. Ile PCAD group also had a higher frequency of asymmetric cognitive profiles relative to a normative group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

18.
Alzheimer's disease (AD) and Parkinson's disease (PD) impair working memory (WM). It is unclear, however, whether the deficits seen early in the course of these diseases are similar. To address this issue, the authors compared the performance of 22 patients with mild AD, 20 patients with early PD and without dementia, and 112 control participants on tests of inhibition, short-term memory, and 2 commonly administered tests of WM. The results suggest that although mild AD and early PD both impair WM, the deficits may be related to the interruption of different processes that contribute to WM performance. Early PD disrupted inhibitory processes, whereas mild AD did not. The WM deficits seen in patients with AD may be secondary to deficits in other cognitive capacities, including semantic memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

19.
Though many cognitive abilities exhibit marked decline over the adult years, individual differences in rates of change have been observed. In the current study, biometrical latent growth models were used to examine sources of variability for ability level (intercept) and change (linear and quadratic effects) for verbal, fluid, memory, and perceptual speed abilities in the Swedish Adoption/Twin Study of Aging. Genetic influences were more important for ability level at age 65 and quadratic change than for linear slope at age 65. Expected variance components indicated decreasing genetic and increasing nonshared environmental variation over age. Exceptions included one verbal and two memory measures that showed increasing genetic and nonshared environmental variance. The present findings provide support for theories of the increasing influence of the environment with age on cognitive abilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

20.
Older adults are assumed to have poor destination memory—knowing to whom they tell particular information—and anecdotes about them repeating stories to the same people are cited as informal evidence for this claim. Experiment 1 assessed young and older adults' destination memory by having participants tell facts (e.g., “A dime has 118 ridges around its edge”) to pictures of famous people (e.g., Oprah Winfrey). Surprise recognition memory tests, which also assessed confidence, revealed that older adults, compared to young adults, were disproportionately impaired on destination memory relative to spared memory for the individual components (i.e., facts, faces) of the episode. Older adults also were more confident that they had not told a fact to a particular person when they actually had (i.e., a miss); this presumably causes them to repeat information more often than young adults. When the direction of information transfer was reversed in Experiment 2, such that the famous people shared information with the participants (i.e., a source memory experiment), age-related memory differences disappeared. In contrast to the destination memory experiment, older adults in the source memory experiment were more confident than young adults that someone had shared a fact with them when a different person actually had shared the fact (i.e., a false alarm). Overall, accuracy and confidence jointly influence age-related changes to destination memory, a fundamental component of successful communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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