scholarly journals Altered central and peripheral glutathione in Alzheimer disease and mild cognitive impairment: A meta‐analysis

2021 ◽  
Vol 17 (S5) ◽  
Author(s):  
Jinghan Jenny Chen ◽  
Mathura Thiyagarajah ◽  
Jianmeng Song ◽  
Qi Zhen Chen ◽  
Nathan Herrmann ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Alzheimer Disease ◽  
Meta Analysis

scholarly journals Altered central and blood glutathione in Alzheimer Disease and Mild Cognitive Impairment: a meta-analysis

2021 ◽  
Author(s):  
Jinghan J Chen ◽  
Mathura Thiyagarajah ◽  
Jianmeng Song ◽  
Clara Chen ◽  
Nathan Herrmann ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Alzheimer Disease ◽  
Publication Bias ◽  
Subgroup Analysis ◽  
Meta Analysis ◽  
Random Effects Models ◽  
Mean Differences ◽  
Meta Analyses

Abstract Background: Increasing evidence implicates oxidative stress (OS) in Alzheimer Disease (AD) and Mild Cognitive Impairment (MCI). Depletion of the brain antioxidant glutathione (GSH) may be important in OS-mediated neurodegeneration, though studies of post-mortem brain GSH changes in AD have been inconclusive. Recent in vivo measurements of brain and blood GSH may shed light on GSH changes earlier in the disease.Aim: To quantitatively review in vivo GSH in AD and MCI compared to healthy controls (HC) using meta-analyses. Method: Studies with in vivo brain or blood GSH levels in MCI or AD with a HC group were identified using Medline, PsychInfo, and Embase (1947-June 2020). Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated for outcomes using random effects models. Outcome measures included brain GSH (Meshcher-Garwood Point Resolved Spectroscopy (MEGA-PRESS) versus non-MEGA-PRESS), and blood GSH (intracellular versus extracellular) in AD and MCI. The Q statistic and Egger’s test were used to assess heterogeneity and risk of publication bias, respectively. Results: For brain GSH, 4 AD (AD=135, HC=223) and 4 MCI (MCI=213, HC=211) studies were included. For blood GSH, 26 AD (AD=1203, HC=1135) and 7 MCI (MCI=434, HC=408) studies were included. Brain GSH overall did not differ in AD or MCI compared to HC; however, the subgroup of studies using MEGA-PRESS reported lower brain GSH in AD (SMD [95%CI] -1.45 [-1.83, -1.06], p<0.001) and MCI (-1.15 [-1.71, -0.59], z=4.0, p<0.001). AD had lower intracellular and extracellular blood GSH overall (-1.10 [-1.58, -0.62], z=4.46, p<0.001). In a subgroup analysis, intracellular GSH was lower in MCI (-0.66 [-1.11, -0.21], p=0.025). Heterogeneity was observed throughout (I2 >85%) and not fully accounted by subgroup analysis. Egger’s test indicated risk of publication bias.Conclusion: Blood intracellular GSH decrease is seen in MCI, while both intra- and extracellular decreases were seen in AD. Brain GSH is decreased in AD and MCI in subgroup analysis. Potential bias and heterogeneity suggest the need for measurement standardization and additional studies to explore sources of heterogeneity.

scholarly journals The Prevalence of Mild Cognitive Impairment among Chinese People: A Meta-Analysis

2021 ◽  
Vol 55 (2) ◽  
pp. 79-91
Author(s):  
Yan Deng ◽  
Siqi Zhao ◽  
Guangwen Cheng ◽  
Jiajia Yang ◽  
Benchao Li ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Diagnostic Criteria ◽  
Meta Analysis ◽  
Random Effect ◽  
Random Effect Model ◽  
Internal Validity ◽  
Screening Tools ◽  
Chinese Elderly ◽  
Pooled Prevalence

<b><i>Background:</i></b> Mild cognitive impairment (MCI) induced the majority number of dementia patients. The prevalence of MCI in China varied across studies with different screening tools and diagnostic criteria. <b><i>Objective:</i></b> A systematic review and meta-analysis was conducted to estimate the pooled MCI prevalence among the population aged 55 years and older in China. <b><i>Methods:</i></b> PubMed, EMBASE, CNKI, Wanfang, CQVIP, and CBMdisc were searched for studies on prevalence of MCI among Chinese elderly between January 1, 1980, and February 10, 2020. The quality assessment was conducted via external validity, internal validity, and informativity, the pooled prevalence was calculated through the random-effect model, and the homogeneity was evaluated by Cochran’s <i>Q</i> test and <i>I</i><sup>2</sup>. <b><i>Results:</i></b> Fifty-three studies with 123,766 subjects were included. The pooled prevalence of MCI among Chinese elderly was 15.4% (95% CI: 13.5–17.4%). Subgroup analyses indicated that the prevalence calculated with different screening tools was 20.2% (95% CI: 15.1–25.9%) for Montreal Cognitive Assessment (MoCA) and 13.0% (95% CI: 10.7–15.5%) for Mini-Mental State Examination (MMSE). According to different diagnostic criteria, the prevalence was 14.8% (95% CI: 12.2–17.6%) for Petersen criteria, 15.0% (95% CI: 12.7–17.5%) for DSM-IV, and 21.2% (95% CI: 17.5–25.2%) for Chinese Expert Consensus on Cognitive Impairment (CECCI). Besides, women, older adults, illiterate people, rural residents, and those who lived with unhealthy lifestyles and morbidity showed higher prevalence. <b><i>Conclusions:</i></b> The prevalence of MCI in China was 15.4%, which varied by demographics, lifestyles, morbidity, screening tools, and diagnostic criteria. In further studies, screening tools and diagnosis criteria should be considered when estimating MCI prevalence.

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

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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