Journal of Alzheimer's disease : JAD
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Comparative Study
Episodic memory decline predicts cortical amyloid status in community-dwelling older adults.
Intra-individual decline in memory and cognition is characteristic of prodromal Alzheimer's disease (AD) and may allow detection of very early AD pathology. Episodic memory task scores on a brief computerized cognitive battery (CogState) were prospectively evaluated at baseline, and 3-, 6-, 9-, 12-, and 24-months post-baseline. Linear mixed models were conducted to compute age-adjusted slopes. ⋯ One of the memory decliners and none of the non-decliners fulfilled criteria for mild cognitive impairment, but the groups did not differ with respect to subjective memory impairment, neuropsychological evidence of episodic memory impairment, or MRI imaging abnormalities. Intra-individual decline in episodic memory can be detected using a brief computerized cognitive performance test optimized to detect change in community-dwelling non-demented older persons and appears predictive of the presence of cerebral amyloid in about half of these persons. This approach may help detect early prodromal AD pathology in wider-scale community screening programs.
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Longitudinal changes of cerebrospinal fluid (CSF) biomarkers in Alzheimer's disease (AD) have been studied, but there are few consistent conclusions and even less is known about their variation during the different stages of the disease. We hypothesized that changes in CSF biomarker values would correlate with the progression of the cognitive decline in AD. One hundred and thirty-one memory clinic patients [56 AD, 57 mild cognitive impairment (MCI), 10 other neurological disorders, eight unimpaired subjects] underwent a clinical follow-up with repeated Mini-Mental Status Examination (MMSE) tests and two lumbar punctures with a median interval of 3 years. ⋯ Concentrations of hyperphosphorylated tau decline in the late stages of the AD process. The decrease of p-tau-181 appears to correlate with cognitive functioning and probably reflects neuronal loss. More longitudinal studies of CSF biomarker dynamics are needed, especially in patients during the preclinical stage of the disease.
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To evaluate the mortality, thirteen years after the baseline wave (1994), of participants suffering dementia in the Neurological Disorders in Central Spain (NEDICES) Cohort Study, we conducted a population-based cohort study in the elderly (65 years and more) with 5,278 screened participants at baseline. Mortality has been evaluated by means of the National Death Registry of Spain at 1-5-2007, 13 years after enrolment. Cox's proportional hazards regression models were used to evaluate the hazard of death according to dementia severity and type, adjusting for potential covariates (gender, age, level of education, and co-morbidity). ⋯ Dementia intensity increases the mortality risk at ten years in the NEDICES Study as in other cohort studies. Age, gender, and co-morbidity are associated with higher mortality in dementia patients. Almost one third of deaths in persons over 85 years-old could be attributable to dementia.
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A brain atrophy and lesion index (BALI) based on high-field magnetic resonance imaging (MRI) has recently been validated to evaluate structural changes in the aging brain. The present study investigated the two-year progression of brain structural deficits in people with Alzheimer's disease (AD) and mild cognitive impairment (MCI), and in healthy control older adults (HC) using the BALI rating. ⋯ The BALI rating quantified the progression of brain deficits over two years, which is associated with cognitive decline. BALI ratings may be used to help summarize AD-associated structural variations.
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Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Prion disease, Huntington's disease, and amyotrophic lateral sclerosis are increasingly being realized to have common cellular and molecular mechanisms including protein aggregation and inclusion body formation in selected brain regions. The aggregates usually consist of insoluble fibrillar aggregates containing misfolded protein with β-sheet conformation. The most probable explanation is that inclusions and the aggregates symbolize an end stage of a molecular cascade of several events, and that earlier event in the cascade may be more directly tied up to pathogenesis than the inclusions themselves. ⋯ Compelling evidence suggests the role of misfolded proteins in the form of oligomers might lead to synaptic dysfunction, neuronal apoptosis and brain damage. However, the mechanism by which oligomers trigger neurodegeneration still remains mysterious. The aim of this article is to review the literature around the molecular mechanism and role of oligomers in neurodegeneration and leading approaches toward rational therapeutics.