Dietary interventions and cognition of Alzheimer’s disease patients: a systematic review of randomized controlled trial

ABSTRACT. It is estimated that by 2030 there will be 82 million people in the world with dementia. Objective: To evaluate the effect of dietary interventions on the cognitive performance of individuals with Alzheimer’s disease (AD). Methods: A systematic review of randomized controlled trials (RCT) was conducted in the Scopus, PubMed, and Cochrane databases. Thirty-two RCT were included. Results: Omega-3 fatty acid showed positive effects at different doses. Fortasyn Connect seemed to be effective in the early stages of the disease. Probiotic, Ginseng, Inositol and specialized nutritional formulas seemed to have a positive effect on cognition. Most of the primary studies presented poor methodological quality, included patients with mild AD, small samples, and did not obtain significative results for all the cognitive outcomes. Conclusions: The effect of most dietary interventions on cognition in AD patients remains inconclusive, however, several nutrients, isolated or not, show potential to improve cognitive function in AD, especially in its early stages.

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Virtual Reality-Based Cognitive Stimulation on People with Mild to Moderate Dementia due to Alzheimer’s Disease: A Pilot Randomized Controlled Trial

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18105290 ◽

2021 ◽

Vol 18 (10) ◽

pp. 5290

Author(s):

Jorge Oliveira ◽

Pedro Gamito ◽

Teresa Souto ◽

Rita Conde ◽

Maria Ferreira ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Randomized Controlled Trial ◽

Virtual Reality ◽

Cognitive Function ◽

Controlled Trial ◽

Cognitive Stimulation ◽

Randomized Controlled ◽

Moderate Dementia ◽

Pilot Randomized Controlled Trial

The use of ecologically oriented approaches with virtual reality (VR) depicting instrumental activities of daily living (IADL) is a promising approach for interventions on acquired brain injuries. However, the results of such an approach on dementia caused by Alzheimer’s disease (AD) are still lacking. This research reports on a pilot randomized controlled trial that aimed to explore the effect of a cognitive stimulation reproducing several IADL in VR on people with mild-to-moderate dementia caused by AD. Patients were recruited from residential care homes of Santa Casa da Misericórdia da Amadora (SCMA), which is a relevant nonprofit social and healthcare provider in Portugal. This intervention lasted two months, with a total of 10 sessions (two sessions/week). A neuropsychological assessment was carried out at the baseline and follow-up using established neuropsychological instruments for assessing memory, attention, and executive functions. The sample consisted of 17 patients of both genders randomly assigned to the experimental and control groups. The preliminary results suggested an improvement in overall cognitive function in the experimental group, with an effect size corresponding to a large effect in global cognition, which suggests that this approach is effective for neurocognitive stimulation in older adults with dementia, contributing to maintaining cognitive function in AD.

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Cognitive Effects of Aerobic Exercise in Alzheimer’s Disease: A Pilot Randomized Controlled Trial

Journal of Alzheimer s Disease ◽

10.3233/jad-201100 ◽

2021 ◽

pp. 1-12

Author(s):

Fang Yu ◽

David M. Vock ◽

Lin Zhang ◽

Dereck Salisbury ◽

Nathaniel W. Nelson ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Older Adults ◽

Alzheimer's Disease ◽

Randomized Controlled Trial ◽

Aerobic Exercise ◽

Controlled Trial ◽

Moderate Intensity ◽

Cognitive Effects ◽

Data Set ◽

Randomized Controlled

Background: Aerobic exercise has shown inconsistent cognitive effects in older adults with Alzheimer’s disease (AD) dementia. Objective: To examine the immediate and longitudinal effects of 6-month cycling on cognition in older adults with AD dementia. Methods: This randomized controlled trial randomized 96 participants (64 to cycling and 32 to stretching for six months) and followed them for another six months. The intervention was supervised, moderate-intensity cycling for 20–50 minutes, 3 times a week for six months. The control was light-intensity stretching. Cognition was assessed at baseline, 3, 6, 9, and 12 months using the AD Assessment Scale-Cognition (ADAS-Cog). Discrete cognitive domains were measured using the AD Uniform Data Set battery. Results: The participants were 77.4±6.8 years old with 15.6±2.9 years of education, and 55%were male. The 6-month change in ADAS-Cog was 1.0±4.6 (cycling) and 0.1±4.1 (stretching), which were both significantly less than the natural 3.2±6.3-point increase observed naturally with disease progression. The 12-month change was 2.4±5.2 (cycling) and 2.2±5.7 (control). ADAS-Cog did not differ between groups at 6 (p = 0.386) and 12 months (p = 0.856). There were no differences in the 12-month rate of change in ADAS-Cog (0.192 versus 0.197, p = 0.967), memory (–0.012 versus –0.019, p = 0.373), executive function (–0.020 versus –0.012, p = 0.383), attention (–0.035 versus –0.033, p = 0.908), or language (–0.028 versus –0.026, p = 0.756). Conclusion: Exercise may reduce decline in global cognition in older adults with mild-to-moderate AD dementia. Aerobic exercise did not show superior cognitive effects to stretching in our pilot trial, possibly due to the lack of power.

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Comparison of effects of different dietary interventions on cognitive function in Alzheimer’s disease: protocol for systematic review and network meta-analysis

BMJ Open ◽

10.1136/bmjopen-2020-042997 ◽

2021 ◽

Vol 11 (1) ◽

pp. e042997

Author(s):

Lili Chen ◽

Xinhua Xu ◽

Huizhen Cao ◽

Hong Li

Keyword(s):

Systematic Review ◽

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Function ◽

Risk Of Bias ◽

Evaluation Framework ◽

Controlled Trials ◽

Cochrane Central Register ◽

Dietary Interventions ◽

Meta Analyses

IntroductionAlzheimer’s disease (AD) is the most common neurodegenerative disease and is characterised by cognitive impairment. Non-pharmacological treatments such as diet therapy have been widely investigated in studies on AD. Given the synergistic effects of nutrients present in foods, considering overall dietary composition rather than focusing on a single nutrient may be more useful for evaluating the relationship between diet and AD cognition. The present study aimed to assess the efficacy of different dietary interventions (eg, ketogenic and Mediterranean diets) on cognitive function in patients with AD in a systematic review and pairwise and network meta-analyses of randomised controlled trials or clinical trials.Methods and analysisTwo reviewers will independently conduct searches of PubMed, Cochrane Central Register of Controlled Trials, Embase, CINAHL, PsycINFO and China National Knowledge Infrastructure databases. Data will be extracted from selected studies and risk of bias will be assessed using the revised Cochrane risk-of-bias tool, and evidence quality will be assessed according to the Grading of Recommendations, Assessment, Development and Evaluation framework. The primary outcome of interest is cognitive function in patients with AD; secondary outcomes include biochemical biomarkers of AD and oxidative stress and/or inﬂammatory biomarkers in cerebrospinal fluid or plasma. For each outcome, random-effects pairwise and network meta-analyses will be carried out to determine the pooled relative effect of each intervention relative to every other intervention.Ethics and disseminationAs this study is based solely on published literature, no ethics approval is required. The research will be published in a peer-reviewed journal.

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