Pathological markers associated with normal aging and dementia in the elderly

Area of Science:

• Neurology
• Gerontology
• Pathology

Background:

• Alzheimer's disease (AD) is a leading cause of dementia, but its prevalence and pathology in the very elderly are not fully understood.
• Dementia in older adults can result from various pathologies, including AD, Lewy body disease, and vascular factors.

Purpose of the Study:

• To investigate the association of pathological markers of Alzheimer's disease (AD), diffuse Lewy body disease, and vascular dementia with cognitive function in non-demented and demented elderly individuals.
• To explore the changing landscape of dementia pathology in the tenth decade of life.

Main Methods:

• Prospective study of 55 subjects (20 non-demented, 35 demented), median age 88 years, over 4.0 +/- 2.1 years.
• Assessment of pathological markers including senile plaques, cortical Lewy bodies, hippocampal sclerosis, leukoencephalopathy, and multiple lacunae.
• Correlation of pathological findings with cognitive status.

Main Results:

• Very old demented subjects frequently had non-neuritic senile plaques, but over half lacked significant AD pathology.
• Five demented subjects presented with cortical Lewy bodies.
• Vascular dementia markers (hippocampal sclerosis, leukoencephalopathy, multiple lacunae) were significantly associated with dementia, present in 40% of demented subjects.

Conclusions:

• Alzheimer's disease pathology may be less prevalent in the very elderly than previously thought.
• Vascular dementia appears to be an increasingly significant contributor to cognitive decline in individuals aged 90 and older.
• Identifying vascular dementia markers is crucial for understanding dementia in advanced age.