The document discusses brain changes that occur with normal aging and how they differ from conditions like dementia and Alzheimer's disease. As people age, the brain shrinks and there are increases in issues like strokes, white matter lesions, and dementia. Alzheimer's accounts for 60% of dementia cases and involves plaques, tangles, and neurodegeneration in brain areas controlling thought, memory, and language. It progresses from mild memory loss to inability to communicate. While memory issues are common with aging, dementia and Alzheimer's are not normal parts of aging and involve greater cognitive decline beyond memory.