Other Irreversible Dementias Affecting the Older Population: Examples & Summary

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  • 0:01 Definition
  • 1:18 Multi-Infarct Dementia
  • 3:18 Parkinson's Disease
  • 4:54 AIDS Dementia
  • 5:50 Lesson Summary
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Lesson Transcript
Instructor: Devin Kowalczyk

Devin has taught psychology and has a master's degree in clinical forensic psychology. He is working on his PhD.

In this lesson, we will explore which dementias are permanent and why they are not curable by modern medicine. We will also look at possible treatments to help mitigate the effects of dementia.


Imagine a building made up out of spider web and cheese. This building would be extremely unstable and incredibly wobbly. Your brain, in turn, is mostly water and fat with some protein thrown in there. It is frightening how fragile the brain is.

With this in mind, we can see why certain brain traumas are so catastrophic. If you threw warm cheese at the wall really hard, then it's going to go everywhere. The brain is a living organ, so there are blood vessels and a million other things going on with it.

Many things that can go wrong lead to dementia, which is a decline of cognitive abilities, memory, verbal abilities, and executive functioning. Let's look at some of the bigger causes of permanent dementias, and find out if there are ways they can be treated. Not cured, mind you, but treated.

Please note many of the following types of dementias kill brain cells. Brain cells are unique in many ways. One of the unfortunate ways is that they don't grow back. Once they are gone, they are gone. This makes any damage or cell death that occurs permanent.

Multi-Infarct Dementia

Let's take a look at one type of permanent dementia. Multi-infarct dementia, sometimes shortened to MID, is a series of small blood clots in the brain which interrupts blood supply. Don't do this, but imagine holding your breath for several minutes. Some of your brain cells will begin to die off. If you hold your breath for longer, more brain cells would die off. This is effectively what is happening: a small clot has blocked off part of the brain and is starving it of oxygen and nutrients.

MID is the second most common cause of dementia in people 65 and older; the first being Alzheimer's, which will be discussed in other lessons. MID often affects men more than women, likely due to a combination of diet and general poorer health. Diabetes, smoking, high blood pressure, hardening of the arteries, and other strokes are all risk factors that increase the likelihood of MID.

These small strokes, each on their own, can go unnoticed. The area that was damaged can be compensated for in some ways. However, over time, these mini-strokes can add up, leading to larger and larger areas of dead tissue in the brain. That's kind of gross to think about, isn't it? The brain tissue is dead after a stroke, and it's just sitting there in your skull. Some early symptoms that indicate that a larger MID is imminent include:

  • Difficulty performing tasks that used to come easily
  • Frequently becoming lost in familiar areas
  • Language problems
  • Mood disturbances
  • Personality changes

Unfortunately, there is no real treatment for this type of dementia. Once the brain tissue has died, it is dead. However, an ounce of prevention is worth a pound of cure. Avoiding fatty foods, exercise, avoiding smoking, and avoiding alcoholic drinks can all decrease the chances of having MID.

Parkinson's Disease

Another brain disease has two components. The first is a buildup of Lewey bodies, which are accumulations of alpha-synuclein, a protein which forms small structures. There is also the decay of the nigrostriatal tract, which is a set of axons involved with the refining of motor movements. This disease can be a genetic anomaly, known as Parkinson's disease, which is death or destruction of the nigrostriatal tract and crowding of the Lewey bodies. It also can be caused by trauma. This is really bad for boxers, whose very job it is to take a beating to the head.

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