Alzheimer's Disease Neuroimaging Initiative. Brain substrates of learning and retention in mild cognitive impairment diagnosis and progression to Alzheimer's disease

Department of Psychiatry, University of California, San Diego, 8950 Villa La Jolla Drive Suite C101, La Jolla, CA 92037, USA.
Neuropsychologia (Impact Factor: 3.3). 04/2010; 48(5):1237-47. DOI: 10.1016/j.neuropsychologia.2009.12.024
Source: PubMed


Understanding the underlying qualitative features of memory deficits in mild cognitive impairment (MCI) can provide critical information for early detection of Alzheimer's disease (AD). This study sought to investigate the utility of both learning and retention measures in (a) the diagnosis of MCI, (b) predicting progression to AD, and (c) examining their underlying brain morphometric correlates. A total of 607 participants were assigned to three MCI groups (high learning-low retention; low learning-high retention; low learning-low retention) and one control group (high learning-high retention) based on scores above or below a 1.5 SD cutoff on learning and retention indices of the Rey Auditory Verbal Learning Test. Our results demonstrated that MCI individuals with predominantly a learning deficit showed a widespread pattern of gray matter loss at baseline, whereas individuals with a retention deficit showed more focal gray matter loss. Moreover, either learning or retention measures provided good predictive value for longitudinal clinical outcome over two years, although impaired learning had modestly better predictive power than impaired retention. As expected, impairments in both measures provided the best predictive power. Thus, the conventional practice of relying solely on the use of delayed recall or retention measures in studies of amnestic MCI misses an important subset of older adults at risk of developing AD. Overall, our results highlight the importance of including learning measures in addition to retention measures when making a diagnosis of MCI and for predicting clinical outcome.

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    • "The delayed recall allows a retention index to be obtained. It has been suggested that an index of rapid forgetting can be a predictor of progression to dementia among elderly subjects[27,28], especially if used jointly with learning measures[29], representing a promising tool to use in the clinical practice[30]. In terms of the performance of each subject, the MBT may be affected by sociodemographic factors, as the majority of neuropsychological tests. "
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    ABSTRACT: Background: The Memory Binding Test (MBT) is a novel test based on the learning of two lists of words, developed to detect early memory impairment suggestive of Alzheimer's disease (AD). Objective: To present and provide reference data of the Spanish MBT in a midlife population of mainly first-degree descendants of AD patients. Methods: 472 cognitively unimpaired subjects, aged 45 to 65 and participants of the ALFA STUDY, were included. Raw scores were transformed to scaled scores on which multivariate regression analysis was applied adjusting by age, gender, and education level. A standard linear regression was employed to derive the scaled score adjusted. Sociodemographic corrections were applied and an adjustment table was constructed. Results: Performance was heterogeneously influenced by sociodemographic factors. Age negatively influenced free recall. Education tends to have an influence in the results showing lower performance with lower education level. Women tend to outperform men in the learning of the first list and total recall. Only a few variables were unaffected by sociodemographic factors such as those related to semantic proactive interference (SPI) and to the retention of learned material. Our results point out that some vulnerability to SPI is expectable in cognitively healthy subjects. Close to 100% of the learned material was maintained across the delay interval. Conclusion: This study contributes with reference data for the MBT providing the necessary adjustments for sociodemographic characteristics. Our data may prove to be useful for detecting asymptomatic at-risk candidates for secondary prevention studies of AD.
    No preview · Article · Sep 2015 · Journal of Alzheimer's disease: JAD
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    • "Ces auteurs font donc une distinction importante entre l'encodage, qui reflè terait uniquement des mé canismes a ` court-terme, et le stockage [27] ou la consolidation [29], qui correspondrait a ` des processus opé rant sur le long terme. Par opposition, d'autres auteurs se ré fè rent a ` l'encodage pour dé signer le processus continu de transformation de l'information en une repré sentation stocké e a ` long terme, ce qui ne respecte pas la distinction proposé e plus haut [26]. D'autres utilisent les termes « apprentissage » ou « acquisition » pour dé signer les mêmes processus [30]. "
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    ABSTRACT: Memory impairment, especially verbal episodic memory (VEM), represents a common ground for cognitive complaint in patients with multiple sclerosis (MS). Beyond the difficulty caused in daily life, these deficits may impact on occupational activities. Neuropsychological assessment of these patients has to include VEM tests, to describe the level of dysfunction of the different processes contributing to VEM and, if required, to guide adapted cognitive rehabilitation. The objective of the present paper is to propose a critique review of the literature on VEM abilities in MS. This review will present the conceptual references and the psychometric characteristics of the main VEM tests applied in MS (isolated tests or included within more general batteries developed specifically for MS). In a second phase, we propose an inventory of work on MS presented as a function of the cognitive processes involved. This approach provides an approach to the limitations of each conception and possible terminological ambiguities. Contributions to knowledge of MS memory impairments will be clarified, as well as the impact of the disease characteristics (MS forms, disease duration, EDSS).
    Full-text · Article · May 2015 · Revue Neurologique
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    • "Episodic memory tests with multiple learning-test trials are more sensitive than those with single learning–test trial for the diagnosis of MCI [4-9]. A multi-trial learning test involves complex memory processes, such as memory span, learning rate, and the ability to acquire and consolidate information, which may take different impaired patterns in AD and in aMCI patients [10-12]. Thus, some important information might have been overlooked in the usual summary statistics by only relying on the comparison of total memory performance, and thus the memory impairment in multi-trial learning tests of aMCI patients needs be investigated in more detail. "
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    ABSTRACT: It has been established that the overall performance of associative memory was disproportionately impaired in contrast to item memory in aMCI (Amnestic mild cognitive impairment) patients, but little is known about the specific aspects of the memory process that show differences between aMCI and healthy controls. By comparing an item-item associative learning test with an individual item learning test, the present study investigated whether the rate of learning was slower in associative memory than in item memory in aMCI. Furthermore, we examined whether deficits in intertrial acquisition and consolidation contributed to the potential disproportionate impairments in the learning rate of associative memory for aMCI patients. In addition, we further explored whether the aMCI-discriminative power of the associative memory test increases more than that of the item memory test when the number of learning-test trials increases. A group of 40 aMCI patients and 40 matched control participants were administered a standardized item memory test (Auditory Verbal Learning Test, AVLT) and a standardized associative memory test (Paired Associative Learning Test, PALT), as well as other neuropsychological tests and clinical assessments. The results indicated that the learning rate deficits in aMCI patients were more obvious for associative memory than for item memory and that the deficits resulted from impairments in both intertrial acquisition and consolidation. In addition, the receiver operating characteristic curve and logistical regression analysis revealed that the discriminative power of the associative memory test for aMCI was larger than that of the item memory test, especially with more than one learning-test trials. Due to more deficits in learning rate of associative memory than that of item memory, the discriminative power for aMCI tended to be larger in associative memory than in item memory when the number of learning-test trials increased. It is suggested that associative memory tests with multiple trials may be particularly useful for early detection of aMCI.
    Full-text · Article · Jul 2013 · Behavioral and Brain Functions
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