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

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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Procedural Learning in Individuals with Amnestic Mild Cognitive Impairment and Alzheimer’s Dementia: a Systematic Review and Meta-analysis

Neuropsychology Review ◽

10.1007/s11065-020-09449-1 ◽

2020 ◽

Author(s):

Liselotte De Wit ◽

Michael Marsiske ◽

Deirdre O’Shea ◽

Roy P.C. Kessels ◽

Andrea M. Kurasz ◽

...

Keyword(s):

Systematic Review ◽

Older Adults ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Meta Analysis ◽

Amnestic Mild Cognitive Impairment ◽

Procedural Learning ◽

Learning Performance ◽

Healthy Older Adults ◽

Standard Mean Difference

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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Exploring Cognitively Loaded Physical Activity Compared With Control to Improve Global Cognitive Function in Older Community-Dwelling Adults With Mild Cognitive Impairment: Systematic Review With Meta-Analysis

American Journal of Lifestyle Medicine ◽

10.1177/1559827619876887 ◽

2019 ◽

pp. 155982761987688

Author(s):

Kristina Zawaly ◽

Richard Fortier ◽

Stephen Buetow ◽

Lynette Tippett ◽

Ngaire Kerse

Keyword(s):

Physical Activity ◽

Systematic Review ◽

Older Adults ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Meta Analysis ◽

Community Dwelling ◽

Controlled Trials ◽

Global Cognitive Function ◽

Global Cognition

Objective. A systematic review with a meta-analysis explored effects of cognitively loaded physical activity interventions on global cognition in community-dwelling older adults (≥65 years of age) experiencing mild cognitive impairment (MCI), compared to any control. Methods. A literature search was conducted in 4 databases (MEDLINE [OvidSP], PubMed, CINAHL, and the Cochrane Central Register of Controlled Trials [Wiley]) from inception until January 30, 2018. The meta-analysis was conducted with Review Manager 5.3. Results. Six randomized controlled trials (RCTs) with 547 participants were identified. The interventions ranged from 4 to 52 weeks. Baseline and initial follow-up assessments were used. The primary pooled analysis of all RCTs demonstrated a nonsignificant trivial effect (standardized mean difference [SMD] 0.07, 95% confidence interval [CI] −0.44 to 0.58) favoring the intervention. In pooled subanalysis of 4 RCTs (n = 405) using the same global cognition measure (Mini-Mental State Examination) and duration of intervention >12 weeks, the intervention group achieved a small but significant improvement for global cognition (SMD 0.45, 95% CI 0.14 to 0.75). Conclusion. When all the RCTs were pooled, the effect of cognitively loaded physical activity intervention on global cognitive function in older adults with MCI remained unclear. The subgroup analysis provides translation evidence for future RCT study designs.

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