Association of Self-reflection With Cognition and Brain Health in Cognitively Unimpaired Older Adults

Mental health and psychological processes associated with cognitive aging and dementia

PURPOSE OF REVIEW

This review focuses on the role of psychological factors in cognitive aging and dementia, an area that has received less attention compared to other modifiable factors (e.g. sleep, physical activity, and so on) or reduction of disease risk.

RECENT FINDINGS

A range of mental health and psychological aspects, including clinical symptoms, stable personality traits, and more specific constructs or processes (e.g. repetitive negative thinking, purpose in life), are associated with cognitive aging and dementia risk. Psychological factors can either serve as protective or risk elements, influencing brain health through general mechanisms, including stress regulation and impact on several biological systems, as well as modulate brain resistance and cognitive resilience to Alzheimer's disease and age-related brain changes. Protective psychological traits are linked to healthier lifestyle habits, while risk factors are associated with negative behaviors, and may impact cognitive function across the lifespan, suggesting benefits for psychological education from early life.

SUMMARY

The review emphasizes the need for greater focus on optimizing psychological well being, particularly in at-risk populations, and suggests that interventions should be tailored to individuals' values and life purposes. Additionally, further research is needed to explore the neurobiological mechanisms through which psychologically focused interventions may influence cognitive decline and dementia.

Circulating Stress Hormones, Brain Health, and Cognition in Healthy Older Adults: Cross-Sectional Findings and Sex Differences in Age-Well

Background

Increased stress is a proposed risk factor for Alzheimer's disease (AD). We examined cross-sectional associations between circulating stress biomarkers and multimodal measures of brain health and cognition susceptible to AD in older adults and sex-specific subgroups.

Methods

Baseline data from 132 cognitively unimpaired participants without depression (age, mean ± SD = 74.0 ± 4.0 years, women: n = 80) in the Age-Well trial (NCT02977819) were included. Stress hormone levels were measured in overnight fasting blood serum (cortisol, dehydroepiandrosterone sulfate) and blood plasma (epinephrine, norepinephrine) samples. AD-sensitive measures of brain health, including glucose metabolism (n = 89), cerebral perfusion, gray matter volume, amyloid deposition in a priori regions of interest, and cognitive markers were evaluated. Models were adjusted for age, sex, education, trait anxiety, and depressive symptoms.

Results

Higher epinephrine levels were associated (false discovery rate-corrected p < .05) with lower glucose metabolism in the anterior cingulate cortex (β = -0.26, p = .008), posterior cingulate cortex (β = -0.32, p = .006), and precuneus (β = -0.27, p = .021) and lower perfusion in the posterior cingulate cortex (β = -0.23, p = .013). Interactions between stress hormones and sex showed (false discovery rate-corrected p < .05) that in women only, higher epinephrine was associated with larger anterior cingulate cortex volume (interaction: β = 0.32, p = .016), whereas in men only, higher cortisol was associated with lower episodic memory performance (interaction: β = 0.98, p = .012).

Conclusions

The current study demonstrates the involvement of circulating stress hormones, particularly epinephrine and cortisol, in greater resilience or vulnerability of brain health and cognitive indicators of susceptibility to AD in older adults. The identification of sex-specific patterns in these associations may inform the development of more effective and tailored interventions.

Research progress on brain network imaging biomarkers of subjective cognitive decline

Purpose

Subjective cognitive decline (SCD) is an early manifestation of the Alzheimer's disease (AD) continuum, and accurately diagnosing SCD to differentiate it from neurotypical aging in older adults is a common challenge for researchers.

Methods

This review examines and summarizes relevant studies regarding the neuroimaging of the AD continuum, and comprehensively summarizes and outlines the SCD clinical features characterizing along with the corresponding neuroimaging changes involving structural, functional, and metabolic networks.

Results

The clinical characteristics of SCD include a subjective decline in self-perceived cognitive function, and there are significant imaging changes, such as reductions in gray matter volume in certain brain regions, abnormalities in the integrity of white matter tracts and diffusion metrics, alterations in functional connectivity between different sub-networks or within networks, as well as abnormalities in brain metabolic networks and cerebral blood flow perfusion.

Conclusion

The 147 referenced studies in this paper indicate that exploring the structural, functional, and metabolic network changes in the brain related to SCD through neuroimaging aims to enhance the goals and mission of brain science development programs: "Understanding the Brain," "Protecting the Brain," and "Creating the Brain," thereby strengthening researchers' investigation into the mechanisms of brain function. Early diagnosis of SCD, along with prompt intervention, can reduce the incidence of AD spectrum while improving patients' quality of life, even integrating numerous scientific research achievements into unified and established standards and applying them in clinical practice by doctors, thus all encouraging researchers to further investigate SCD issues in older adults.

Decoding meditation mechanisms underlying brain preservation and psycho-affective health in older expert meditators and older meditation-naive participants

Meditation is a mental training approach that can improve mental health and well-being in aging. Yet the underlying mechanisms remain unknown. The Medit-Ageing model stipulates that three mechanisms - attentional, constructive, and deconstructive - upregulate positive psycho-affective factors and downregulate negative ones. To test this hypothesis, we measured brain structural MRI and perfusion, negative and positive psycho-affective composite scores, and meditation mechanisms in 27 older expert meditators and 135 meditation-naive older controls. We identified brain and psycho-affective differences and performed mediation analyses to assess whether and which meditation mechanisms mediate their links.Meditators showed significantly higher volume in fronto-parietal areas and perfusion in temporo-occipito-parietal areas. They also had higher positive and lower negative psycho-affective scores. Attentional and constructive mechanisms both mediated the links between brain differences and the positive psycho-affective score whereas the deconstructive mechanism mediated the links between brain differences and the negative psycho-affective score.Our results corroborate the Medit-Ageing model, indicating that, in aging, meditation leads to brain changes that decrease negative psycho-affective factors and increase positive ones through relatively specific mechanisms. Shedding light on the neurobiological and psycho-affective mechanisms of meditation in aging, these findings provide insights to refine future interventions.

The Impact of Rhythmic Physical Activity on Mental Health and Quality of Life in Older Adults with and without Cognitive Impairment: A Systematic Review and Meta-Analysis

(1) Background: Nowadays, it is essential to implement new non-pharmacological strategies, such as rhythmic physical activity, to improve mental health and quality of life in both individuals experiencing normal brain aging and those with cognitive impairment. Therefore, the objective of this study is to identify the effects of rhythmic physical activity interventions on mental health and quality of life in older adults, with or without mild cognitive impairment; (2) Methods: We conducted a systematic review with a meta-analysis, searching the Pubmed, Scopus, Web of Science, and Cochrane Plus databases using specific keywords. We selected studies that included rhythmic physical activity as the primary intervention for patients aged 65 and above, with or without cognitive impairment. We assessed the methodological quality of the articles using the PEDro scale; (3) Results: Out of 961 identified studies, we included 11 in this review, all of which employed rhythmic physical activity as an intervention. The selected studies consistently measured depression, anxiety, and quality of life; (4) Conclusions: This review demonstrates that rhythmic physical activity can effectively improve depression, anxiety, and quality of life in older adults, whether or not they have mild cognitive impairment. However, it is worth noting that while we have identified beneficial outcomes, the evidence supporting the use of rhythmic physical activity in enhancing depression, anxiety, and quality of life in older adults with or without mild cognitive impairment remains somewhat limited.

The Impact of Dance Movement Interventions on Psychological Health in Older Adults without Dementia: A Systematic Review and Meta-Analysis

BACKGROUND

Lifestyle-based multimodal interventions that integrate physical, sensory, cognitive and social enrichment are suggested to promote healthy mental aging and resilience against aging and Alzheimer's disease (AD).

OBJECTIVES

This meta-analysis examined the efficacy of dance movement interventions (DMI) as an integrated mind-body activity on outcomes of psychological health in older adults.

METHODS

Pre-registration was carried out with PROSPERO (CRD42021265112). PubMed, Web of Science and PsycINFO were searched for randomized controlled trials (RCT) evaluating the effects of DMI (>4 weeks' duration) compared to comparators on measures of psychological health (primary outcome) and cognitive function (additional outcome) among older adults without dementia (aged ≥55). Data of 14 primary RCT (n = 983, n-DMI = 494, n-control = 489) were synthesized using a random effects meta-analysis with robust variance estimation.

RESULTS

DMI had a small positive effect on overall psychological health (g = 0.30; 95% confidence interval [CI]: 0.06, 0.53; p = 0.02, I²= 65.04) compared to control conditions. Small effects of DMI on positive and negative psychological domains as well as quality of life were not statistically significant. DMI had a medium positive effect on general cognitive function (g = 0.50; 95% CI: 0.12, 0.89, p = 0.02, I²= 79.61) over comparators. None of the primary intervention studies evaluated measures of neuroplasticity.

CONCLUSIONS

We found that DMI was effective in promoting mental health amongst older adults without dementia, suggesting that the multimodal enrichment tool is a potential strategy for health promotion and prevention of AD. High-quality intervention studies are needed to expand evidence on DMI-induced changes in specific psychological domains and identify underlying neurophysiological correlates.