Dementia comes in many forms; Alzheimer's is just one

Here's what to know about the other main types and how they affect the brain

- Dana G. Smith

Alzheimer's disease is the most commonly diagnosed form of dementia, but it's far from the only one. In fact, most people who have dementia (including Alzheimer's) show signs of several different types of neurodegenerative disease in their brains.

That can include the amyloid plaques and tau tangles that are hallmarks of Alzheimer's; damage to the brain's blood vessels, which is indicative of vascular dementia; and clumps of assorted other toxic proteins that cause Lewy body dementia, frontotemporal dementia and LATE. "If you look at the old people with dementia, what do they have? Well, they have a little bit of everything," said Dr Costantino Iadecola, a professor of neurology at Weill Cornell Medicine.

A person's diagnosis largely depends on their main symptoms and what neurologists can see in their brain. While there aren't treatments yet to stop or reverse the progression of any form of dementia, experts say that getting an accurate diagnosis is important to help manage symptoms and know what to expect as the disease progresses.

Here's an explainer on the other primary types, including how they affect the brain and their symptoms:

Vascular dementia

Vascular dementia is the second most common kind of dementia. It can arise after a stroke, either one large one or several smaller ones, but more typically stems from long-term wear and tear on the brain's smaller blood vessels. Damage often occurs to the brain's white matter the insulated nerve fibres that carry signals from one neuron to the next. Those fibres are the last stop for the smaller blood vessels, so if blood flow is occluded, it's the white matter that suffers first.

When blood flow to the brain is disrupted, the brain cells are deprived of oxygen and nutrients, said Silvia Fossati, a professor of neural sciences at Temple University's Lewis Katz School of Medicine.