Dementia- Causes

Transcript

“So the causes of dementia are not completely understood. With Alzheimer’s disease, we know that as the disease progresses, there’s further accumulation of toxic proteins. One of these proteins is amyloid and it forms these plaques that you can visualize in the brain under a microscope. Another protein named Tau will form abnormal aggregates of these proteins. We don’t quite understand if these proteins are the direct cause of the progression of dementia, but we know that they accumulate throughout the course of dementia. What we’re trying to further understand is what triggers the formation of these proteins. So in some rare cases, it is related to a genetic mutation. So there are familial forms of Alzheimer’s disease, but those are much less common. Most cases of Alzheimer’s disease are not hereditary. We do suspect that there are some environmental factors, potentially involved in Alzheimer’s disease. Toxins in the environment, smoking. Other factors that do seem to increase the risk of Alzheimer’s disease include blood pressure, diabetes, and obesity.

We know that many people with Alzheimer’s disease also have vascular changes in the brain, which would involve stroke-like changes due to hardening of the arteries. In the case of vascular dementia, typically the causes are either multiple acute strokes with symptoms eventually causing cognitive decline, or in many cases, we will just see what look like stroke-like changes in the brain. And essentially what we’re seeing are silent strokes, little areas of stroke changes in the brain that accumulate over time and can lead to progressive cognitive dysfunction. In other dementias, such as Lewy body disease, there again are formations of toxic proteins. In the case of Lewy body disease, these are called Lewy bodies. Specifically named after a physician who discovered these. And their formation of aggregates of [?], a different protein. But you can also see amyloid and Tau in the patients of people with Lewy body disease.

Again, we don’t fully understand what triggers this process, but we are gaining understanding in knowing the steps along the way, where these proteins are forming these abnormal aggregates or clumps of toxic protein. In the case of frontal temporal dementia, again, there are toxic proteins, most notably, pick bodies. Again, we don’t know what exactly triggers the formation of these, but over time they can accumulate in particular areas of the brain. The other process that occurs in all dementia types, unfortunately, is the degeneration and death of neurons and the support cells in the brain. Again, what causes that degeneration is not exactly understood,, but it is associated with the accumulation of these proteins and may be related to other factors such as high blood pressure and diabetes.”