Cognitive decline

About: Cognitive decline is a research topic. Over the lifetime, 29308 publications have been published within this topic receiving 1174689 citations.

Preventing Alzheimer's disease and cognitive decline.

Abstract: Objectives To assess whether previous research on purported risk or protective factors for Alzheimer's disease (AD) and cognitive decline is of sufficient strength to warrant specific recommendations for behavioral, lifestyle, or pharmaceutical interventions/modifications targeted to these endpoints. Data sources MEDLINE and the Cochrane Database of Systematic Reviews. Additional studies were identified from reference lists and technical experts. Review methods A group of experts in the field developed the list of factors to be evaluated in preparation for an upcoming National Institutes of Health (NIH) Office of Medical Applications of Research (OMAR) State-of-the-Science Conference addressing the prevention of AD and cognitive decline. We grouped the factors into the following categories: nutritional factors, medical conditions and prescription and non-prescription medications, social/economic/behavioral factors, toxic environmental factors, and genetics. Outcomes of interest were the development of AD or cognitive decline. Both observational and intervention studies were evaluated. Studies were evaluated for eligibility and quality, and data were abstracted on study design, demographics, intervention or predictor factor, and cognitive outcomes. Results A total of 25 systematic reviews and 250 primary research studies were included. Only a few factors showed a consistent association with AD or cognitive decline across multiple studies, including both observational studies and randomized controlled trials (when available). Such factors associated with increased risk of AD and cognitive decline were: diabetes, epsilon 4 allele of the apolipoprotein E gene (APOE e4), smoking, and depression. Factors showing a fairly consistent association with decreased risk of AD and cognitive decline were: cognitive engagement and physical activities. A consistent association does not imply that findings were robust, as the data were often limited, and the quality of evidence was typically low. In addition, the modification of risk for reported associations was typically small to moderate for AD, and small for cognitive decline. Some of the factors that did not show an association with AD or cognitive decline in this review may still play an influential role in late-life cognition, but there was not sufficient evidence to draw this conclusion. Many of the factors evaluated are not amenable to randomization, so rigorous observational studies are required to assess their effect on AD and cognitive decline. Conclusions The current research on the list of putative risk or protective factors is largely inadequate to confidently assess their association with AD or cognitive decline. Further research that addresses the limitations of existing studies is needed prior to be able to make recommendations on interventions.

Fish consumption, long-chain omega-3 fatty acids and risk of cognitive decline or Alzheimer disease: a complex association

Abstract: Long-chain omega-3 fatty acids could have neuroprotective properties against dementia, which is becoming a major global public health issue. We conducted a systematic review of the literature to establish the association between eating fish (a source of long-chain omega-3 fatty acids) or taking long-chain omega-3 fatty acid supplements and the risk of cognitive decline or Alzheimer disease (AD). We identified eleven observational studies and four clinical trials. All three observational studies that used cognitive decline as an outcome reported significant benefits, whereas only four of eight observational studies that used incidence of AD or dementia as an outcome reported positive findings. None of four small clinical trials provided convincing evidence for the use of this approach in the prevention or treatment of any form of dementia. In summary, the existing data favor a role for long-chain omega-3 fatty acids in slowing cognitive decline in elderly individuals without dementia, but not for the prevention or treatment of dementia (including AD). This apparent dichotomy might reflect differences in study designs with regard to participants, dosages, the ratio of long-chain omega-3 to omega-6 fatty acids, or the choice of outcome measurements. Large clinical trials of extended duration should help to provide definitive answers.

Multifunctional activities of green tea catechins in neuroprotection. Modulation of cell survival genes, iron-dependent oxidative stress and PKC signaling pathway.

Abstract: Many lines of evidence suggest that oxidative stress resulting in reactive oxygen species (ROS) generation and infl ammation play a pivotal role in the age-associated cognitive decline and neuronal loss in neurodegenerative diseases including Alzheimer’s (AD), Parkinson’s (PD) and Huntington’s diseases. One cardinal chemical pathology observed in these disorders is the accumulation of iron at sites where the neurons die. The buildup of an iron gradient in conjunction with ROS (superoxide, hydroxyl radical and nitric oxide) are thought to constitute a major trigger in neuronal toxicity and demise in all these diseases. Thus, promising future treatment of neurodegenerative diseases and aging depends on availability of effective brain permeable, iron-chelatable/radical scavenger neuroprotective drugs that would prevent the progression of neurodegeneration. Tea fl avonoids (catechins) have been reported to possess potent ironchelating, radical-scavenging and anti-infl ammatory ac

The NIH Cognitive and Emotional Health Project

Abstract: Background The Cognitive and Emotional Health Project (CEHP) seeks to identify the demographic, social, and biological determinants of cognitive and emotional health in the older adult. As part of the CEHP, a critical evaluation study committee was formed to assess the state of epidemiological research on demographic, social, and biological determinants of cognitive and emotional health. Methods Criteria for inclusion in the survey were large cohort studies, longitudinal in design, participants predominantly 65 years or older, with measurements of both cognition and emotion, and information on a wide variety of demographic, psychosocial, and biological factors. North American and European studies, which met these criteria, were selected for the review. Outcome measures included cognition, cognitive decline, and cognitive function. For emotion, symptoms included depression and anxiety, positive and negative affect, subjective well being, mastery, and resilience. Results Ninety-six papers were identified that addressed cognitive and emotional outcomes. A large variety of risk factors were consistently identified with cognitive outcomes, particularly those previously associated with increased risk of cardiovascular disease. There was considerable overlap between risk factors for cognitive and emotional outcomes. Conclusion This review identifies a large number of lifestyle and health behaviors that alter the risk for maintenance of cognitive and emotional health. Large longitudinal cohort studies are a unique source to explore factors associated with cognitive and emotional health. Secondary analyses of these studies should be encouraged as should the development of standardized questionnaires to measure cognitive and emotional health. Future research in this field should study cognitive and emotional health simultaneously.

Neuropathology of dementia in Parkinson's disease: a prospective, community-based study.

Abstract: Twenty-two patients with Parkinson's disease drawn from a community-based study were followed prospectively until their deaths. Even though 18 patients had dementia, none fulfilled Braak and Braak or The National Institute on Aging and Ronald and Nancy Reagan Institute of the Alzheimer's Association, whereas all patients had limbic or neocortical Lewy body disease. The Lewy body score and Braak and Braak stage were significantly associated with the rate of cognitive decline, but only the Lewy body score was associated with the rate of cognitive decline in the univariate analyses. This study strongly suggests that Lewy body disease is the main substrate driving the progression of cognitive impairment in Parkinson's disease.