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How Different Types of Dementia Affect the Brain

Restituto Miranda Sr. occasionally reminisced about driving a taxicab, working in an office supplies store and riding his motorcycle.

But there was one problem: To the best of his family’s knowledge, Miranda — who had worked as a meat cutter with the American Meat Packing Corp. in Chicago — never had done any of these things, says his son Resti Miranda Jr.

Seeing how happy he seemed telling the stories, family members didn’t correct the elder Miranda, diagnosed in 2014 with vascular dementia after experiencing a second stroke. Dementia can affect a person’s brain in such a way that individuals may remember only fragments of something that occurred years earlier, or they may make up stories.

The elder Miranda passed away in January 2020 at the age of 82. It was hard, Miranda Jr. says, to see his once-healthy, strong father fight through complications from two strokes and vascular dementia.

All dementias involve changes in the brain, but symptoms vary. Alzheimer’s disease comprises 60% to 80% of dementia cases. Here are some other types:

Vascular dementia

Vascular dementia, which can occur after stroke or heart disease, is one of several types of dementia, says Terrianne Reynolds, director of healthcare initiatives at the Alzheimer’s Association, Illinois Chapter.

This type of dementia can result from brain damage due to impaired blood flow and other conditions that damage blood vessels and reduce circulation, such as atherosclerosis, heart disease and stroke.

Vascular dementia is marked by a decline in thinking skills caused by conditions that block or reduce blood flow to the brain, depriving brain cells of vital oxygen and nutrients. “These changes can sometimes occur suddenly following strokes that block major brain blood vessels,” Reynolds says.

Symptoms include memory loss, confusion, language problems, difficulty paying attention and visual orientation problems. These symptoms may develop gradually or become apparent after a stroke or major surgery such as heart bypass.

While tests can determine that you have dementia, there’s not a specific test that confirms vascular dementia, according to the Mayo Clinic. Your symptoms, medical history, and history of stroke or cardiovascular issues can point to vascular dementia.

Lewy body dementia

Lewy body dementia is an umbrella term for two related clinical diagnoses: dementia with Lewy bodies and Parkinson’s disease dementia. The most common symptoms are changes in cognition, movement, sleep and behavior. Lewy body dementia typically begins at age 50 or older, although sometimes younger people develop it.

In the early stages of Lewy body dementia, symptoms can be mild, according to the National Institute on Aging (NIA). But as the disease advances, people with Lewy body dementia need more help — and eventually often depend entirely on others — because of the decline in their thinking and movement abilities.

Some Lewy body dementia symptoms may respond to treatment for a period of time, but there’s not yet a cure. However, the NIA reports that research is improving scientists’ understanding of this condition. That knowledge may one day lead to earlier diagnoses, improved care and new treatments.

Frontotemporal dementia

Frontotemporal dementia is a group of disorders caused by progressive cell degeneration in the brain’s frontal lobes (the areas behind the forehead) or its temporal lobes (the regions behind the ears).

The most common dementia for those under 60, frontotemporal dementia is misunderstood and frequently misdiagnosed as Alzheimer’s disease, Parkinson’s disease, depression or a mental health disorder, according to the Association for Frontotemporal Degeneration. It takes an average of 3.6 years to receive an accurate diagnosis, the association says.

Mixed dementia

When symptoms of more than one type of dementia occur simultaneously, it’s called mixed dementia. The likelihood of having mixed dementia increases with age and is highest in people age 85 and older.



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