That Neuroscience Guy - The Neuroscience of Dementia

Episode Date: March 10, 2025

According to the WHO, more than 55 million people worldwide have dementia, with nearly 10 million new cases every year. In today's episode of That Neuroscience Guy, we discuss the neuroscience behind different types of dementia.

Hi, my name is Olav Krogolson and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. So today I'm going to talk to you about dementia. I'm going to do it for a couple of reasons. The number one is that we've had requests for more information on dementia and specific types of dementia. So don't forget, if you have an idea for a podcast episode, email us, thatneuroscienceguy

at gmail.com, or you can hit us on threads or x at thatneurosciguy, or also on Instagram now, thatneuroscience guy. Send us your ideas because we want to know what you want to know about the neuroscience of daily life. To make sure I'm very clear here, dementia is like a broad label for a bunch of different types of dementia. I'm going to talk about the 10 most common types of dementia today and of those 10 types Alzheimer's disease is the most common form of dementia now people tend to use Alzheimer's disease and dementia Interchangeably, but it's important to remember is lesson number one of this podcast that Alzheimer's disease is just a type of dementia All right. It's not the only form of dementia.

Now, basically all types of dementia affect the brain, and specifically they impact memory. So people with dementia typically have problems with memory. They can impact language, so the ability to speak or understand what's being said, and they typically impact decision-making. All right, so all the forms of dementia target those three things,

memory, language, and decision-making. However, there's some other specific things that get targeted depending on the type of dementia, and I'm gonna take you through them. Now, like I said, Alzheimer's disease is the most common form of dementia. Statistics say it's between about 60 to 80% of all dementia cases. With Alzheimer's disease there are some early signs that are out there. Typically forgetting is a common one.

People forget names, they forget recent events, you know, they forget these things that are out there that they're supposed to know. They tend to not look after themselves. People with Alzheimer's disease do a really bad job of checking in on themselves and making sure that they're, you know, they're washing themselves, you know, putting on clean clothes. You typically see mood and personality changes. People with Alzheimer's disease, sometimes they can be a bit silly and giggly. Sometimes they can be very quick to anger. And then disorientation. People with Alzheimer's disease in the early stages,

generally, you know, they get, they're not sure where they are. They can lose, they just sort of, they're, they get confused fairly easily. Now, basically what causes Alzheimer's disease? Well, it's, it's death of brain cells. Um, the two most common ones that are debated are amyloid plaques and tau proteins. I'm not going to go into too much detail on those cause I did talk about them in a previous podcast, but essentially you can think of brain tissue dying and when it dies, it leaves behind junk. All right. Garbage, if you will. podcast, but essentially you can think of brain tissue dying and when it dies,

it leaves behind junk. All right. Garbage, if you will. And that garbage when it accumulates causes more brain issues. Now what are the risk factors for Alzheimer's disease? You know, I'm going to say at the outset with most forms of dementia, there's one or two where it's fairly obvious, but with a lot of them we're still learning a lot about it, but typically increasing age is a risk factor. As we get older, we can some people, a subset of people

transition to what's called mild cognitive impairment. And then from mild cognitive impairment, they transition. Some people, not everyone, transition into Alzheimer's disease or another form of dementia. Family history is something there is research that shows that family history and therefore genetics play a role in whether you'll get Alzheimer's disease or not. Now don't panic if there are people with Alzheimer's disease in your family. It doesn't mean that you're going to get it. Now we've talked about Alzheimer's disease before so I'm going

to move on. Another very common form of dementia is vascular dementia. It's the second most common form. And basically what causes this form of dementia, if you haven't guessed, is blood flow. And in this case, a lack of blood flow to specific parts of the brain. Now typically as you age, the risk factors that you get, high blood pressure for instance and things like that, they are risk factors for vascular dementia. So increasing age, if you've had strokes before, heart attacks, high cholesterol, anything

that impacts the vascular system. And typically it's most commonly seen after a stroke. Now remember it's a form of dementia, alright? So you do get confusion, you do get memory issues, you get language issues, but it's being caused for a different reason. What's interesting with vascular dementia is it can onset very suddenly, alright? If someone has a severe enough stroke, they can literally have dementia, you know, almost instantaneously, whereas with Alzheimer's disease, the progression is quite slower. Now with that being said, with vascular dementia, it can progress slowly as well. There's something called a TIA,

which is basically a mini-stroke, and if people have a series of mini-strokes, then vascular dementia might occur incrementally. So it can come very suddenly, but it can come incrementally. People with vascular dementia sometimes also have problems with vision because of pressure on the eyes and also hallucinations depending on what's going on in the brain specifically. Now another form of dementia that's out there is called Lewy body dementia. Now, specifically, what is a Lewy body? Basically, it's a protein deposit.

It's garbage. Again, it's the brain breaking down and it leaves behind just accumulations of protein in the nerve cells. And basically what happens is those protein deposits that are there, the Lewy bodies, they interrupt neural communication, all right? They disrupt neural communication, and as a result, what happens is you get dementia-like symptoms. So you get all of the common ones, all right?

Memory issues, language issues, decision-making issues, but people with Lewy body dementia might also experience visual hallucinations, trouble falling asleep at night. Sometimes they fall asleep during the day so they can't sleep at night, but then they fall asleep very unexpectedly during the day. And fainting can be a thing. So that is Lewy body dementia. The exact causes of Lewy body dementia are being debated still, but there are some risk factors, which is being a male,

problems with body posture. If you have problems walking as you get older and there's no obvious reason for it, problems just moving in general, sometimes you get like something where you get numbness on the left side or the right side of the body. And typically if they try to treat it, if you don't respond to medication, because there are forms of dementia where medication does help, it could be a sign of Lewy body dementia. Some of these things, as you can imagine, it's pretty hard to figure out if you've got these proteins

in real time for Alzheimer's disease with instance, to detect those tau proteins of those amyloid plaques, it has to be done post-mortem. Now, very similar to Lewy body dementia is Parkinson's disease dementia. So a lot of people think of Parkinson's disease as a movement disorder, which it is But it also comes with cognitive issues and people with Parkinson's disease eventually develop dementia not all it's about 70 to 75%

But with Parkinson's disease dementia you get the exact same sort of symptoms, if you will. Memory loss, language issues, problems making decisions, like I've said a few times. Irritability is there, paranoia, some more mental issues typically seem to be there. And what's interesting with Parkinson's disease dementia is it's definitely tied to motor disorders or movement disorders, because that's of course what you see with Parkinson's disease. Doctors actually have a fairly hard time separating

Parkinson's disease dementia from Lewy body dementia and basically the way doctors assess it and make the decision is if the motor symptoms come before the cognitive symptoms then they're going to say it's Parkinson's disease dementia but if the cognitive symptoms come before the cognitive symptoms, then they're gonna say it's Parkinson's disease dementia. But if the cognitive symptoms come before the motor symptoms, then they're gonna diagnose Lewy body dementia. Now, like I said, there's a couple of other types of dementia out there. There's frontotemporal dementia.

Basically, frontotemporal dementia is interesting because it basically just affects the prefrontal cortex and that leads to control of language and behavior and the issues there. But there are other problems as well, loss of motivation, compulsive behavior and things like this. Basically frontal temporal dementia, the causes are still a little bit unknown, but they believe it's tied to genetic mutations. All right, so you've got genes in your body that have mutated, and that is typically what's observed in people with frontal temporal dementia.

And just so you know, sometimes people call frontal temporal dementia PICS disease. Another form of dementia is mixed dementia. It is exactly what it sounds like. It's basically the diagnosis you get if you have multiple forms of dementia. So people might have Alzheimer's disease and Lewy body dementia, somewhat sadly, and then you'd be diagnosed with mixed dementia. Basically if you take the group of people with dementia, it's estimated that around 20% of people with dementia have more than one form of dementia.

Another thing that leads to dementia is called normal pressure hydrocephalus. Basically it's just excess fluid in the brain, specifically in the brain's ventricles, that causes pressure on the brain and the spinal cord. Because of that, that impacts brain function. One of the ways they diagnose normal pressure hydrocephalus is basically ruling out other things. It's what we call a diagnosis of omission. You treat or you test for other things and if they don't show up then you go after and you assume that it might be normal pressure

hydrocephalus. What causes it? It's the buildup of fluid. What causes the buildup of fluid? Typically it's some form of damage to the brain that's going to trigger that. Now, things that cause it typically is, like I said, brain injury. So brain tumors, brain surgeries that have gone poorly, infections, bleeding, and an acute injury, a car accident, for instance. Another form of dementia, I've got a few more to go, is Creutzfeldt-Jakob disease or Creutzfeldt-Jackob disease depending on how you

want to pronounce it. It's one of the rarest forms of dementia. It's an estimated one in one million people worldwide each year. What's sad about Creutzfeldt-Jakob disease is it progresses very rapidly from the time of diagnosis, typically less than a year. You get all of the same symptoms, again, memory issues, language issues, decision-making issues, agitation, depression are there and problems with the muscle. Typically you see either twitching muscles or stiff muscles with Kurzweil Jakob disease. And what causes it, of course, something called, well, it's down to proteins again.

In this case, they're called prions specifically, and it basically has to do with the fact that the proteins aren't normal. Typically, they're physically not the same as other proteins. And these prions when they build up calls Kurzweil-Jacob disease. The last couple I will cover, the one I'll cover next is called Huntington's disease. It's a genetic condition.

Basically it's a premature breakdown of brain cells. People are still not exactly sure what triggers Huntington's disease, but basically it's like your brain decides to, you lose about 25,000 neurons a day. This process in people with Huntington's disease is expedited, and this massive breakdown of brain cells, the death of brain cells,

leads to dementia-like symptoms, all right? So again, the trifecta is memory, language, and decision making. But mood swings are very common and because the brain is actually dying more quickly, you get all sorts of other issues, motor problems, and the rest of it. The last one I'll cover is called Wernicke-Korsakov Syndrome. It does lead to dementia. Basically, Wernicke-Korsakov Syndrome, the most common cause of it is actually alcohol abuse. So people that drink too much can actually give themselves

a form of dementia. You get the same sort of problems, okay? Problems with memory, problems with language, problems processing information. What's interesting about Wernicke-Korsakoff syndrome is you can reverse the dementia by stopping drinking. Now that's if you catch it early enough. So if you're listening and you happen to be a heavy drinker,

you could literally be giving yourself a form of dementia, but if you stop, all right, then you can reverse that. So the cause is human. The other two principal causes are malnutrition. So people that are extremely malnourished can get Wernicke-Korsakoff syndrome, and also chronic infections. Some chronic infections lead to Wernicke-Korsakoff syndrome. So there you go. Those are the top 10 sort of types of dementia that are out there.

You know, the common theme are these language issues, all right, problems with memory and problems with decision-making. I've mentioned some that target the motor system, some that target the emotional system. some that target the emotional system. But again, the one thing I want you to remember is dementia is a blanket term for all of these age-related or non-age-related in some cases,

related to these brain issues where you've got problems with language, memory, and decision-making. Alzheimer's just being a subset, common one, but not the only kind of dementia. In terms of treatments for dementia, I thought I'd end with this. With the exception of Wernicke-Korsakoff syndrome, there's no cure for dementia. Really, the hope is to make quality of life as good as possible and to engage in activities that prolong the cognitive process before breakdown.

So, you know, all the things that we talked about, good brain health, these are things that you would want to do to try to offset the progression of dementia or hopefully not even experience dementia. All right, that's a lot on dementia and 10 different types of dementia. Hopefully you got something out of that. Don't forget patreon You can support us. There's a link to it on our website that neuroscience guy calm There's our Etsy store where you can buy t-shirts and some other merch. We do have some stuff coming soon Of course, like I've said multiple times. We've got Instagram that neuroscience guy. We've got

We've got Instagram, That Neuroscience Guy. We've got threads and X, That Neuroscience Guy. And you can email us, thatneuroscienceguy at gmail.com. In case you've got ideas, we really want to know what you want to know about the neuroscience of daily life. And this episode, like I said, was triggered by you, the listeners. And of course, thank you so much for listening. If you haven't subscribed yet, please do. It really helps.

My name is Olav Kirgelsen and I'm that neuroscience guy. I'll see you soon for another full episode of the podcast.