Spatial navigation in older adults with mild cognitive impairment and dementia: A systematic review and meta-analysis.

In this systematic review and meta-analysis, we compared the spatial navigation performance of older adults with mild cognitive impairment (MCI), Alzheimer's Disease (AD), and other dementias, using healthy older adults as controls. In addition, we evaluated the possible influence of the environment type (virtual and real), protocol (object- or environment-based), and the navigation mode (active and passive navigation) on spatial navigation task performance. In total, 1372 articles were identified and 24 studies were included in the meta-analysis. We found a large effect size on the spatial navigation performance of patients with cognitive decline (standardized mean difference (SMD) = 0.87, confidence interval (CI95%) = 0.62-1.09, p < 0.001), especially amnestic MCI (SMD = 1.10, CI95% = 0.71-1.49, p < 0.001) and patients with AD (SMD = 1.60, CI95% = 1.25-1.95, p < 0.001). However, the tasks did not identify mixed and vascular dementia (SMD = 0.92, CI95% = -0.33-2.18, p = 0.15 and SMD = 0.65, CI95% = -0.67-1.97, p = 0.33, respectively). Spatial navigation ability assessed using the Floor Maze Test showed the largest effect size in differentiating healthy older adults and patients with cognitive decline (SMD = 1.98,CI95% = 1.00-2.97, p < 0.001). In addition, tasks that require walking showed the greatest differences between the two groups. These results suggest that spatial navigation impairment is important, but disease-specific behavioral biomarker of the dementia pathology process that can be identified even in the early stages.

The Link between Exercise and Homocysteine in the Alzheimer's Disease: A Bioinformatic Network Model.

Elevated peripheral expression of homocysteine (Hcy) is associated with an increased risk of coronary heart disease and stroke, diabetes, and cancer. It is also associated with cognitive impairment as it has been reported that high levels of Hcy cause cognitive dysfunction and memory deficit. Among several etiological factors that contribute to the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD), Hcy seems to directly contribute to the generation of neurotoxicity factors. This study aims to hypothesize the molecular mechanism by which exercise can reduce the risk of neurological complications promoted by hyperhomocysteinemia (HHcy), and discuss how exercise could reduce the risk of developing AD by using bioinformatics network models. According to the genes network, there are connections between proteins and amino acids associated with Hcy, exercise, and AD. Studies have evidenced that exercise may be one of several processes by which acid nitric availability can be maximized in the human body, which is particularly important in reducing cell loss and tau pathology and, thereby, leading to a reduced risk of complications associated with HHcy and AD.

Malnutrition Is Associated With Impaired Functional Status in Older People Receiving Home Care Nursing Service.

Objective: This study aimed to explore the magnitude and significance of associations among nutritional status, functional status, comorbidities, age, and gender in older adults receiving assistance from the in-home nursing care service. Method: In this cross-sectional study, 210 home-dwelling persons 65 years or older who received in-home nursing care service were evaluated. Demographic variables, nutritional status, comorbidities, and the dependency levels of activities of daily living were analyzed. To assess the correlation among the factors that influence nutritional status, a theoretical model was developed and adjusted using the path analysis model. Results: The primary finding is that functional status is directly associated with nutritional status (ß = 0.32; p < 0.001) and severity of comorbidities is indirectly associated with nutritional status (ß = -0.07; p < 0.017). Conclusion: The elicited outcomes in this study reinforce the concept that nutritional status is linked with functional status in older adults receiving in-home care nursing service.

Does hyperglycemia downregulate glucose transporters in the brain?

Diabetes is a metabolic condition associated with hyperglycemia manifested by the elevation of blood glucose levels occurring when the pancreas decreases or stops the production of insulin, in case of insulin resistance or both. The current literature supports that insulin resistance may be responsible for the memory decline associated with diabetes. Glucose transporters (GLUTs) are a family of proteins involved in glucose transport across biological membranes. GLUT-1 and GLUT-3 are involved in glucose delivery to the brain. Evidence suggests that both transporters are downregulated in chronic peripheral hyperglycemia. Here we show the mechanisms of glucose transport and its influence on cognitive function, including a hypothesis of how peripheral hyperglycemia related genes network interactions may lead to glucose transporters downregulation and its possible consequences.