Cognitive decline

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

Nucleus basalis of Meynert revisited: anatomy, history and differential involvement in Alzheimer's and Parkinson's disease

Abstract: It has been well established that neuronal loss within the cholinergic nucleus basalis of Meynert (nbM) correlates with cognitive decline in dementing disorders such as Alzheimer’s disease (AD). Friedrich Lewy first observed his eponymous inclusion bodies in the nbM of postmortem brain tissue from patients with Parkinson’s disease (PD) and cell loss in this area can be at least as extensive as that seen in AD. There has been confusion with regard to the terminology and exact localisation of the nbM within the human basal forebrain for decades due to the diffuse and broad structure of this “nucleus”. Also, while topographical projections from the nbM have been mapped out in subhuman primates, no direct clinicopathological correlations between subregional nbM and cortical pathology and specific cognitive profile decline have been performed in human tissue. Here, we review the evolution of the term nbM and the importance of standardised nbM sampling for neuropathological studies. Extensive review of the literature suggests that there is a caudorostral pattern of neuronal loss within the nbM in AD brains. However, the findings in PD are less clear due to the limited number of studies performed. Given the differing neuropsychiatric and cognitive deficits in Lewy body-associated dementias (PD dementia and dementia with Lewy bodies) as compared to AD, we hypothesise that a different pattern of neuronal loss will be found in the nbM of Lewy body disease brains. Understanding the functional significance of the subregions of the nbM could prove important in elucidating the pathogenesis of dementia in PD.

Homocysteine, white matter hyperintensities, and cognition in healthy elderly people.

Abstract: Hyperhomocysteinemia is associated with an increased risk of vascular disease, and recent results suggest that it also could increase the risk of dementia. We examined the relationship between homocysteine and cognitive decline in 1,241 subjects aged 61 to 73 years, followed up over 4 years. Plasma homocysteine levels were determined in all participants as well as cardiovascular risk factors, apolipoprotein E genotype, plasma levels of folate, and vitamin B12. Cognitive performances were assessed repeatedly by using Mini-Mental State Examination, Trail Making Test, Digit Symbol Substitution Test, and Finger Tapping Test. At 2-year follow-up, 841 subjects underwent cerebral magnetic resonance imaging, and white matter hyperintensities were rated visually. Analyses were adjusted for all cardiovascular risk factors. Cross-sectional analyses showed that higher concentrations of homocysteine were significantly related to poorer performances at all neuropsychological tests. Longitudinal analyses confirmed this finding. The odds of cognitive decline was 2.8-fold (p < 0.05) higher in subjects with homocysteine levels above 15 micromol/L compared with those with homocysteine levels below 10 micromol/L. In participants who underwent magnetic resonance imaging, the relationship between homocysteine and cognition was unchanged after taking into account white matter hyperintensities suggesting that white matter hyperintensities do not mediate the association between homocysteine and cognition.

Tooth loss and periodontal disease predict poor cognitive function in older men

Abstract: OBJECTIVES: To determine whether rates of tooth loss, periodontal disease progression, and caries incidence predict cognitive decline in men. DESIGN: Prospective study. SETTING: Community-dwelling men enrolled in the Veterans Affairs Dental Longitudinal Study. PARTICIPANTS: Five hundred ninety-seven dentate men aged 28 to 70 at study baseline who have been followed up to 32 years. MEASUREMENTS: Oral examinations were conducted approximately every 3 years. Periodontal disease measures included probing pocket depth and radiographic alveolar bone height. Participants underwent cognitive testing beginning in 1993. Low cognitive status was defined as less than 25 points or less than 90% of the age- and education-specific median on the Mini-Mental State Examination (MMSE) and less than 10 points on a spatial copying task. RESULTS: Each tooth lost per decade since the baseline dental examination increased the risks of low MMSE score (hazard ratio (HR)=1.09, 95% confidence interval (CI)=1.01–1.18) and low spatial copying score (HR=1.12, CI=1.05–1.18). Risks were greater per additional tooth with progression of alveolar bone loss (spatial copying: HR=1.03, CI=1.01–1.06), probing pocket depth (MMSE: HR=1.04, CI=1.01–1.09; spatial copying: HR=1.04, CI=1.01–1.06), and caries (spatial copying: HR=1.05, CI=1.01–1.08). Risks were consistently higher in men who were older than 45.5 at baseline than in younger men. CONCLUSION: Risk of cognitive decline in older men increases as more teeth are lost. Periodontal disease and caries, major reasons for tooth loss, are also related to cognitive decline.