Final answer:
The two most common causes of dementia in older adults are Alzheimer's disease, which involves the buildup of amyloid plaques and neurofibrillary tangles, and vascular dementia, which is caused by reduced blood flow to the brain. Alzheimer's is the most prevalent, especially among the aging population.
Step-by-step explanation:
The two most common causes of dementia in older adults are Alzheimer's disease and vascular dementia. Alzheimer's disease is a neurodegenerative condition that was first detailed by Alois Alzheimer in 1911. This disease is characterized by the presence of amyloid plaques and neurofibrillary tangles in the brain, as well as a general reduction in brain volume, particularly severe loss of neurons in the hippocampus, all of which contribute to the dementia symptoms. Vascular dementia, on the other hand, is caused by reduced blood flow to the brain, typically due to a stroke or series of strokes, which results in brain damage. Both of these conditions lead to impairments in cognitive functions such as memory, reasoning, and judgment.
As of 2012, it was estimated that 5.4 million Americans were living with Alzheimer's disease, with projections suggesting that there could be as many as 13 million Alzheimer's patients in the United States by 2050, largely due to the aging baby-boomer generation. Costs for their care were estimated at $200 billion. It is also worth noting that dementia can result from various causes, including Parkinson's disease and Huntington's disease, among others, which also affect the nervous system and can lead to a decline in mental function.