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What Is Dementia?
Dementia Defined
If you had mentioned ādementiaā to Mrs. Dell, she would not have known exactly what you were talking about. She had heard of Alzheimerās disease but didnāt realize that Alzheimerās is a type of dementia.
Dementia is a condition in which the brain gradually loses its ability to think and remember clearly. It involves a decline in memory or other thinking skillsāsuch as judgment, orientation, comprehension, and languageāthat affects a personās ability to carry out everyday activities. Whenever nerve cells in the brain are significantly damaged, the result is eventually dementia.
Dementia begins with damage to a number of nerve cells followed by initial symptoms beginning to show. As more nerve cells are damaged and eventually die, more symptoms occur, and the individual starts having more difficulty with memory and the ability to think clearly. Their behavior also begins to change. No one notices these symptoms at first, but as more brain cells die, the symptoms become more noticeable. Eventually, oneās ability to carry out daily activities becomes so impaired that someone else has to assist them in their everyday routines. This is the point at which a person is given the diagnosis of dementia. Perhaps the person first loses the ability to drive to the store. Then they are unable to perform basic functions such as dressing themselves or walking or eating without assistance. Eventually, they become bedridden and require care around the clock. Dementia is fatal, but the sad part of dementia is that life is gone long before death arrives. An article published in the medical journal Annals of Internal Medicine explains the definition of dementia best. Dementia is characterized by a change in memory, plus judgment, orientation, comprehension, or language, that is severe enough to interfere with daily life. We will cover the three stages of Alzheimerās shortly and you will see that the term dementia corresponds with the beginning of the third stage of Alzheimerās. When a personās memory or reasoning or thought or understanding or awareness gets to the point of interfering with their daily life, from that point on, the process will be called Alzheimerās dementia.
One other word you will see frequently mentioned in these medical reports is the word cognition. That word is used in the evaluation of mental testing of Alzheimerās that relates to the participantās memory, awareness of what is going on around them, comprehension and understanding of instructions, or their reasoning in making good decisions. The tests that are given to evaluate whether the Alzheimerās is progressing or not is a measure of cognition. As your cognition worsens, so does the degree of Alzheimerās progress.
Alzheimerās Dementia
I have had people ask if a particular person had Alzheimerās or dementia. One individual told me that both his grandfather and father lost their memory and ended up bedridden and dependent on others. He said his grandfather had dementia and his father had Alzheimerās. They were different diseases in his thinking. If you say someone has Alzheimerās, most people have a picture in mind of what is going on with that individual. They have known people with Alzheimerās, have seen such people in movies, or have read books about such people. But if you were to tell the same people that someone has dementia, the picture that comes to mind is not nearly as clear. Most people are not sure what dementia is, and many think dementia and Alzheimerās are different disease processes. The fact is that Alzheimerās is a form of dementia. We will cover the three stages of Alzheimerās later, and you will see that dementia corresponds with the third stage of Alzheimerās.
Alzheimerās dementia is the most common form of dementia. Alzheimerās dementia is a complex entity. From a medical standpoint, we do not yet know what the initial step in the process is or what exactly causes Alzheimerās dementia to get worse. We do know there are two basic markers within the brains of Alzheimerās patients. These two protein products are called beta-amyloid and tau. In earlier years, to make the diagnosis, one had to perform an autopsy on someone with dementia symptoms in order to see the beta-amyloid plaques and the tau tangles imbedded in certain parts of the brain. In more recent years, brain-imaging devices have been developed that can detect the buildup of these products while a person is still alive. This process has been found to begin more than twenty years prior to any symptoms.
We also know there is more to Alzheimerās than genes. A report in the medical journal Experimental Gerontology stated that Alzheimerās is a chronic degeneration process in which less than 5 percent of all cases are solely due to genetics. If you had asked Mrs. Dell, she would have said Alzheimerās is caused by a personās genes. She would have been partially right, because a gene that is passed on in families can affect a person early on, usually between the ages of thirty and sixty. This type of Alzheimerās is called familial Alzheimerās disease. Very few people who develop Alzheimerās have this early-onset type. It accounts for less than 5 percent of overall cases.
What is more common is called sporadic Alzheimerās disease, and this usually occurs later in life, after the age of sixty. A gene called APOe4 makes a person more vulnerable to this type of Alzheimerās disease. About 20 percent of Americans have this gene, but not everyone with it will end up with Alzheimerās, and some people without the gene develop Alzheimerās. The gene doesnāt cause the disease, but it can increase the risk.
The bottom line is this: you canāt change your inheritance, but you can make lifestyle changes to lower your risk of developing such a dreaded disease.
It wasnāt well known back in the day when Mrs. Dell was living a ānormalā life, but now the Alzheimerās Association says that about half of all people over the age of eighty-five have Alzheimerās. If Mrs. Dell had known, perhaps she would have taken steps at a younger age to help prevent it or at least postpone the symptoms. She did not realize there were things she could do to slow or stop the progression even after she began showing symptoms.
Vascular Dementia
The second most common form of dementia is caused by disease in the arteries leading to the brain and within the brain. This is called vascular dementia. The symptoms of Alzheimerās dementia and vascular dementia are practically indistinguishable, but pathological findings within the brain tissues reveal which type of problem is causing the symptoms of dementia.
If you were to do autopsy studies on the brains of people who have such symptoms, you would find certain specific abnormalities in the brain. If you were to look under a microscope at a thin slice of a particular area of the brain of someone who had the symptoms of forgetfulness or problems with their thinking process, you may see some unusual-looking protein plaques surrounding an area of brain cells that had died. If you looked closer inside those cells and saw a special type of protein called tau and saw these strands of tau protein were all tangled up, you would have the combination of findings for the diagnosis of Alzheimerās dementia.
As we already discussed, the brains of people with Alzheimerās dementia contain beta-amyloid plaques and tau tangles. The brains of those with vascular dementia contain very few of these plaques or tangles but do contain medium-sized or smaller arteries that became diseased and closed off from an inflammatory response with bleeding or became plugged due to plaque buildup within their walls. The autopsies of such brains would reveal large areas of brain damage as a result of a stroke. In such cases, the patients most likely experienced a stroke that was obvious to themselves and everyone else. It may have affected speech or some type of motor movement. This may have been followed sooner or later by the dementia symptoms we have been discussing. This form of vascular dementia is a result of disease of the larger arteries to the brain.
There is another form of vascular dementia that is different from the kind that reveals large strokes at autopsy. In this second form, autopsies of brain tissue reveal blockages in extremely small micro-arteries, and only a very small area of brain tissue is affected. Such areas are also the result of a stroke, but the blockage was so small and the area of brain tissue affected so petite that no symptoms of a stroke occurred. The patient didnāt even know they had a light stroke. Such a stroke is called a silent stroke, and a multitude of such events can lead to vascular dementia.
This type of stroke was highlighted in an eye-opening study done by the National Alzheimerās Coordinating Center and published in the medical journal Neurology. In an autopsy study of brains, researchers found that 79.6 percent of individuals showing evidence of a stroke upon examination of the brain did not have a history of a stroke during their lifetimes. They did not have any symptoms.
If a small stroke is a little bit larger, the patient may witness a tinge of a problem that lasts only a short time, and then they completely recover. Such a stroke is called a transient ischemic attack or TIA. The symptoms are very transient, or brief, and then they disappear and the person is back to normal.
If I were back in medical school taking notes on a lecture on vascular dementia, I would write a short summary statement like this: a significant part of preventing dementia is the health of my arteriesāfrom my largest artery to my smallest.
The Connection between Alzheimerās Dementia, Vascular Dementia, and Mixed Dementia
If you were to go to your doctor with memory problems or with difficulty making decisions or because you werenāt able to figure out how to do something you used to do well, they would not be able to tell you definitively whether you had Alzheimerās or problems in your brain caused by disease of the arteries. If you presented with memory symptoms, would the cause be solely beta-amyloid plaques, solely problems with the arteries, or a combination of the two?
The answer to that question is that the majority of Alzheimerās cases have a mixed cause. Examinations of brain structure reveal a mixture of the Alzheimerās beta-amyloid plaques and problems with the arteries of the brain.
An article published in Biomechanical Pharmacology concerned Alzheimerās dementia and vascular dementia. The report stated that Alzheimerās is a mixed disease and that the idea that these entities are completely separate has vanished.
You might think it would be simple to figure out if dementia were caused either by those beta-amyloid plaques and tau tangles that make the diagnosis of Alzheimerās dementia or by the disease of the arteries that make the diagnosis of vascular dementia. But it is not that simple.
An article in the medical journal Lancet reported that the majority of dementia in the aging population is a mixture of plaques and tangles with arterial involvement. Researchers pointed out that if they examined the brains of individuals over the age of eighty who had been diagnosed with Alzheimerās, they would likely not find only plaques or only blocked arteries as the sole cause. This combination of beta-amyloid plaques and arterial disease is called mixed dementia. A Statement for Healthcare Professionals from the American Heart Association/American Stroke Association states that a mixed cause, including the arterial component and the Alzheimerās component, is the most common explanation for cognitive impairment in aging. This study showed that the effects of arterial disease on the brain were found in 84 percent of Alzheimerās patients.
Another statement from the medical literature concerning the intertwining of Alzheimerās dementia and vascular dementia is found in the medical journal Archives of Neurology. It stated, āAlthough Alzheimerās dementia and vascular dementia have traditionally been viewed as distinct disorders, it is now generally agreed that the two rarely occur in isolation.ā The article pointed out that what is a risk factor for one is a risk factor for the other. With there being no medication that can prevent or cure Alzheimerās, modifying your lifestyle to alleviate the risk factors remains the cornerstone for the prevention of Alzheimerās.
Several studies have found that in patients with a combination of Alzheimerās disease and arterial disease, fewer of the hallmark beta-amyloid plaques are necessary to cause dementia symptoms if there is associated arterial disease. A key reminder is that the greater the decrease in the flow of blood in the brain, the greater the decline in cognitive function. We know steps that can be taken to prevent the arterial part of the problem. The health of your arteries is a key playe...