Meta-analysis of Controlled Oral Word Association Test (COWAT) FAS performance in amnestic mild cognitive impairment and cognitively unimpaired older adults

Abstract The notion that procedural learning and memory is spared in Alzheimer’s disease (AD) has important implications for interventions aiming to build on intact cognitive functions. However, despite these clinical implications, there are mixed findings in the literature about whether or not procedural learning remains intact. This meta-analysis examines the standard mean difference of all published studies regarding procedural learning in AD dementia or amnestic Mild Cognitive Impairment (aMCI) compared to cognitively healthy older adults. Additionally, we conducted statistical equivalence analyses. Our systematic review showed that only a limited number of studies (k = 17) have compared procedural learning between individuals with aMCI or AD dementia and healthy controls. Our meta-analysis, which synthesized these studies, demonstrated that while procedural learning performance was not statistically equivalent between individuals with aMCI or AD dementia, and healthy older adults, the difference was clinically and statistically trivial. Although larger studies are needed, the present findings suggest that procedural learning does appear to remain spared in aMCI and AD dementia.

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Recruitment of a multi‐site randomized controlled trial of aerobic exercise for older adults with amnestic mild cognitive impairment: The EXERT trial

Alzheimer s & Dementia ◽

10.1002/alz.12401 ◽

2021 ◽

Author(s):

Aladdin H. Shadyab ◽

Andrea Z. LaCroix ◽

Howard H. Feldman ◽

Christopher H. Dyck ◽

Ozioma C. Okonkwo ◽

...

Keyword(s):

Older Adults ◽

Randomized Controlled Trial ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Aerobic Exercise ◽

Controlled Trial ◽

Amnestic Mild Cognitive Impairment ◽

Randomized Controlled

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Repetition Priming in Individuals with Amnestic Mild Cognitive Impairment and Alzheimer’s Dementia: a Systematic Review and Meta-Analysis

Neuropsychology Review ◽

10.1007/s11065-021-09504-5 ◽

2021 ◽

Author(s):

Liselotte De Wit ◽

Vitoria Piai ◽

Pilar Thangwaritorn ◽

Brynn Johnson ◽

Deirdre O’Shea ◽

...

Keyword(s):

Systematic Review ◽

Older Adults ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Repetition Priming ◽

Meta Analysis ◽

Healthy Older Adults ◽

Amnestic Mci ◽

Standard Mean Difference ◽

Priming Paradigm

AbstractThe literature on repetition priming in Alzheimer’s disease (AD) is inconsistent, with some findings supporting spared priming while others do not. Several factors may explain these inconsistencies, including AD severity (e.g., dementia vs. Mild Cognitive Impairment; MCI) and priming paradigm-related characteristics. This systematic review and meta-analysis provides a quantitative summary of repetition priming in AD. We examined the between-group standard mean difference comparing repetition priming in AD dementia or amnestic MCI (aMCI; presumably due to AD) to controls. Thirty-two studies were selected, including 590 individuals with AD dementia, 267 individuals with amnestic MCI, and 703 controls. Our results indicated that both individuals with aMCI and AD dementia perform worse on repetition priming tasks than cognitively older adults. Paradigm-related moderators suggested that the effect size between studies comparing the combined aMCI or AD dementia group to cognitively healthy older adults was the highest for paradigms that required participants to produce, rather than identify, primes during the test phase. Our results further suggested that priming in AD is impaired for both conceptual and perceptual priming tasks. Lastly, while our results suggested that priming in AD is impaired for priming tasks that require deep processing, we were unable to draw firm conclusions about whether priming is less impaired in aMCI or AD dementia for paradigms that require shallow processing.

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Neurocognitive Plasticity Is Associated with Cardiorespiratory Fitness Following Physical Exercise in Older Adults with Amnestic Mild Cognitive Impairment

Journal of Alzheimer s Disease ◽

10.3233/jad-201429 ◽

2021 ◽

pp. 1-22

Author(s):

Galit Yogev-Seligmann ◽

Tamir Eisenstein ◽

Elissa Ash ◽

Nir Giladi ◽

Haggai Sharon ◽

...

Keyword(s):

Older Adults ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Aerobic Exercise ◽

Cardiorespiratory Fitness ◽

Neuropsychological Tests ◽

Aerobic Training ◽

Amnestic Mild Cognitive Impairment ◽

Control Group ◽

Memory Encoding

Background: Aerobic training has been shown to promote structural and functional neurocognitive plasticity in cognitively intact older adults. However, little is known about the neuroplastic potential of aerobic exercise in individuals at risk of Alzheimer’s disease (AD) and dementia. Objective: We aimed to explore the effect of aerobic exercise intervention and cardiorespiratory fitness improvement on brain and cognitive functions in older adults with amnestic mild cognitive impairment (aMCI). Methods: 27 participants with aMCI were randomized to either aerobic training (n = 13) or balance and toning (BAT) control group (n = 14) for a 16-week intervention. Pre- and post-assessments included functional MRI experiments of brain activation during associative memory encoding and neural synchronization during complex information processing, cognitive evaluation using neuropsychological tests, and cardiorespiratory fitness assessment. Results: The aerobic group demonstrated increased frontal activity during memory encoding and increased neural synchronization in higher-order cognitive regions such as the frontal cortex and temporo-parietal junction (TPJ) following the intervention. In contrast, the BAT control group demonstrated decreased brain activity during memory encoding, primarily in occipital, temporal, and parietal areas. Increases in cardiorespiratory fitness were associated with increases in brain activation in both the left inferior frontal and precentral gyri. Furthermore, changes in cardiorespiratory fitness were also correlated with changes in performance on several neuropsychological tests. Conclusion: Aerobic exercise training may result in functional plasticity of high-order cognitive areas, especially, frontal regions, among older adults at risk of AD and dementia. Furthermore, cardiorespiratory fitness may be an important mediating factor of the observed changes in neurocognitive functions.

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