How does the brain work in dementia?

Uncategorized Mar 16, 2022

Over the past few weeks we have talked a lot about the brain, particularly the different lobes of the brain and how each lobe is related to symptoms seen in dementia. Today I want to take some time to talk about some other facts about the brain and touch on a few conditions that it is possible your LOWD may also have experienced. 


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Let’s start with a more general overview of the brain. 


A healthy human brain weighs about 3 pounds, is about the same size as two clenched fists put together, and contains about 85 billion cells or neurons. With normal aging and learning, brain cells die and new connections in the brain are formed. This is the underlying process of how we learn. 


In dementia, we know that there is damage or disease in some area of the brain, reducing the number of brain cells in that area. Further in conditions that cause dementia, we see the normal dying, and in some cases, accelerated dying of brain cells BUT we do not see the same level of formation of new connections in the brain. For example, in individuals with Alzheimer’s disease, this can be seen on brain scans in that the overall size of the brain appears smaller than a typical brain. Additionally, brains of people with Alzheimer’s disease typically weigh 8-10% LESS than the average brain. This means if a typical brain is 3lbs, the typical Alzeiheimer’s disease brain weighs 2.7 pounds. 


Some other important facts about the brain to know:

The brain is actually very soft. Whenever a brain is shown on TV, in a movie, or even if you have ever seen a video of a real brain being dissected, which has gone through a preservation process, it is always shown as generally firm but somewhat squishy, kind of like a stress or rubber ball. In reality the brain is more like jello.

So, Careblazer, why do I tell you this? To emphasize that the brain is easily damaged by both outside and inside forces. There has also been a lot of information more recently coming out about brain injuries or traumatic brain injury. It is much easier to see how these could happen when you understand how the brain is set up. The symptoms that can result from a brain injury vary widely depending on what area of the brain was injured and how severely it was injured. While a single traumatic brain injury does not cause dementia, something like a head injury can contribute to dementia. There is also research that repeated head injuries, resulting in repeated brain damage can lead to something called Chronic Traumatic Encephalopathy which has been associated with dementia. 

So…the brain needs protection!!! In order to protect this soft, easily injured organ, we have developed a pretty sophisticated method of protection: it floats inside of a hard protector: your skull.

Surrounding your brain and spinal cord, filling all the gaps, and made and stored in specially designed holding areas or ventricles in your brain is something called cerebral spinal fluid. This is a clear liquid that helps to keep your brain floating, cushions it if there is injury, and actually helps to kind of clean up anything that doesn’t need to stay in your brain. While cerebrospinal fluid is important to protect your brain, there is also a chance of it not draining properly or it building up faster than it can drain leading to something called hydrocephalus, sometimes also called “water on the brain.” This is one of the few causes of dementia that, if found and treated, can have some very positive management of symptoms and, in some cases, the dementia is even reversible. When there is too much water but it is not causing increased pressure in the brain it is called normal pressure hydrocephalus.  The symptoms are the 3 Ws: wet, wacky, and wobbly meaning bladder control issues, dementia, and changes in walking. Hydrocephalus that causes changes in brain pressure can have a more lasting impact and often needs to be addressed more immediately.   

So the brain is also filled with blood vessels that bring nutrition to all areas of the brain. When someone has a stroke that means that something with these blood vessels has happened. There are ischemic strokes which means there is a blockage in the vessel. We can take the example of a water pipe, there can be full blockages or partial blockages. Either way if there is a blockage there is not enough blood, or in our example of a pipe water, getting by. This means that the areas of the brain that normally get nutrition from that vessel are no longer getting what they need and start to die. The second type of stroke is hemorrhagic. This can be compared to a leak in the pipe or in some cases a busted pipe. This means that blood is not getting to where it needs to AND is being deposited in areas of the brain where it should not be- leading to extra pressure AND certain areas of the brain not getting the nutrition it needs.

Transient ischemic attacks are a form of ischemic stroke but the blockages are eventually pushed through. Essentially a blockage happens and then the blood eventually pushes the blockage aside restoring blood flow. It is important to understand that these blood vessels can be damaged by a number of medical conditions such as diabetes, high cholesterol, and high blood pressure. This can lead to vascular dementia. Because blood vessels are all over the brain, the symptoms seen in vascular dementia are often related to speed of thinking, attention, and problem-solving. 


Careblazers the brain is a very complex organ. So, I’m going to end here for today. If you don’t remember much of this, that is ok- you can come back to this whenever you think you might need it. I will keep adding bits of information about the brain and how it can impact your LOWD’s thinking in future videos.


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