Introduction:
Last month our speaker Ann Reisenberg talked with us about the various medications currently in use with Alzheimer’s treatment. She talked about how some of the drugs went to work on the neurotransmitters to either increase the amount of neurotransmitter, acetylcholine that is released or to increase the receptivity of the neurotransmitter in the process of the brain transferring information through the neurons, or brain cells. And that the newer drugs are targeting the plaques and tangles characteristic of Alzheimer’s disease.
As a way to review that information and begin to move into tonight’s topic, we have a brief video clip we’d like to show you. This excerpt is from the video entitled “Understanding Alzheimer’s Disease, volume 1”, which is available for you to borrow without charge from the Alzheimer’s Association.
Since Alzheimer’s early discoveries, scientists have studied the pathology that occurs in the inner and outer layers of the brain and is also found in brain tissue and nerve cells. There are three characteristics that suggest brain changes. First and most important are neurofibrillary tangles, an accumulation of abnormal fibers concentrated in the cytoplasm of a cell. Under the electron microscope, these fibers appear as a tangle of filaments.
The second change related to Alzheimer’s disease is a change within the brain cells themselves. When brain tissue is observed through an electron microscope, one can see a granulovascular degeneration within the cell. The cell becomes filled with vacuoles that have fluid and granular material, or plaque, made of a chemical called beta-amyloid protein. These plaques look like loose bundles of long, thin fibers that gather in sticky clumps, and serve to interfere with the release and reception of the neurotransmitter, acetylcholine. Acetylcholine, or ACH for short, is produced by the enzyme choline acetyltransferase, or CAT for short. If the CAT levels in the brain drop to as much as 90 percent, the level of ACH in the hippocampus and the cerebral cortex is badly reduced; the brain does not have enough ACH for memory formation.
The third characteristic of Alzheimer’s disease is the loss of brain tissue in the outer cortex. If you look at the autopsied brain of a person with Alzheimer’s disease and the brain of a person without Alzheimer’s disease, you will see that the brain tissue of the person with Alzheimer’s disease has withered and is considerably smaller. This relates back to the tangles and plaques. As the tangles and plaques accumulate, not only cause the neurotransmitters to have more difficulty in relaying messages to the brain cells, they also cause some of the brain cells to die or to fragment. This causes loss of brain tissue. The constant loss of brain cells is so accelerated in the person with Alzheimer’s disease that the brain shrinks and appears to be a very aged brain. At the same time, the ventricles (or inner spaces) of the brain increase in size and the outer layer of cells becomes less dense and thinner.
Alzheimer’s disease attacks the inside of the brain first. The hypothalamus and the hippocampus. The tangles occur most densely in an area of the brain known as the hippocampus. Recent or short term memory is associated with this area, which is also part of a system called the limbic system, otherwise known as the seat of the emotions. The hippocampus is located under the base of the temporal lobe, and is a seahorse shaped section of matter. The onset of Alzheimer’s disease is insidious, meaning that its effects appear gradually. At first there is no decrease in function and no sign of cognitive decline. Then as the tangles increase, the person starts to complain of forgetting where he or she has put things. The person may also have a bit less energy, drive, and initiative and be slower to react and to learn new things.
The hypothalamus is the part of the brain that controls our internal thermostat, our appetite, and our sleep regulator. So we may see the person with Alzheimer’s disease getting chilled or overheated easily. They may also become frequently hungry and feel the need to snack a lot. They may not remember that they have already eaten, or they may not remember they have NOT eaten and tell you they aren’t hungry. And the person will experience a lot of sleep disturbances, waking up in the night and having difficulty getting back to sleep.
The one of the functions of the right temporal lobe is to serve in time orientation. As the disease begins to affect the right temporal lobe, the person may get lost in time, and frequently ask what day or time it is. One of the functions of the left temporal lobe is language, so as the disease affects the left temporal lobe they may also have some early language problems such as “lost words”, or it’s on the tip of my tongue, so they may describe things rather than name them.
The second area of the brain to be affected is the parietal lobe of the brain. This is the area of the brain that serves to put pieces of information together. It is the part of the brain that allows us to drive a familiar route and get from a starting point to a planned destination. It is also the part of the brain that allows us to follow complex directions. As the Alzheimer’s disease progress to this part of the brain, the person with Alzheimer’s disease will start getting lost or not recognizing how to get to a particular destination that they have always known how to get to. The person will also have difficulty following multistep directions. This is the point where often times families realize there is a problem and seek help if they haven’t already.
The third area of the brain to be affected is the occipital lobe of the brain. This is the area of the brain where vision is processed. A person with Alzheimer’s disease may not be able to recognize what they see. Initially the concept of 3 dimensions is affected, and that will show up as a problem seeing steps or changes in elevation when one walks. Or differentiating the toilet from the floor and wall in a pastel bathroom with white fixtures. As the disease progresses, the person’s peripheral vision is affected as well, leaving them with a sense of only central vision. They can see only what is directly in front of them. At this point, if someone comes up from their side, the person with Alzheimer’s disease may be startled, because they didn’t see or notice them coming.
The 4th area of the brain to be affected is the Frontal lobe of the brain. This area of the brain serves in the executive position. It is the boss. It is the part of the brain that makes you behave socially, it helps you reason and make decisions based on judgment. When this area of the brain in affected, the person with Alzheimer’s disease may exhibit socially inappropriate behavior or make socially inappropriate comments. They may exhibit poor judgment and leave the stove on, or go outside without a coat in cold weather. They may stop caring about their appearance, and want to wear the same outfit all the time. They lose their ability to make choices. If you ask them what they would like for breakfast, they may respond “I’ll have what you are having” because they can’t make choices, they can’t process that much information.
The 5th area or last area of the brain to be affected is the Motor area of the Parietal lobe. This is the part of the brain that helps us move around, walk, feed ourselves, dress ourselves, talk and swallow. As this area of the brain is affected, the person with Alzheimer’s disease begins to have trouble with walking. They begin to shuffle their feet because they have trouble picking up their feet. They walk stooped over from the waist. They develop troubles feeding themselves. You may have to put the food on the fork or spoon, put the utensil in their hand and raise their hand to their mouth. Sometimes once you get them started, they can go from there. But as the disease progresses, you will need to remind them to chew and to swallow. It is in this stage that the person with Alzheimer’s disease will lose weight, and this weight loss is irreversible. It is also in this stage that the person is very susceptible to pneumonia, particularly aspiration pneumonia, because of their swallowing difficulties.
Even though a lot of the brain is affected by Alzheimer’s disease as it progresses, one area that seems to not be affected is the sensory section of the parietal lobe of the brain. This is the area of the brain that interprets the sense of hearing, taste, smell and touch. It is also the part that interprets facial expressions and tone of voice. To the very end, a person with Alzheimer’s disease will be able to sense that he or she is treated with love and respect, they will be able to hear and see and taste, and feel touch.
If you notice, there is a very predictable sequence in how the brain is affected by Alzheimer’s disease. It is the reverse order that we gain skills and information as a baby, a child and a young adult.
This predictable pattern of skills loss is what has allowed physicians to develop a rating scale for the various stages of Alzheimer’s disease. We have a handout of those stages, that may help you understand what is going on with your loved one.
The information we have reviewed tonight will be one of the building blocks that we will use in our future education sessions, to help you learn how to cope with your loved one’s disease and provide helpful tips that may make your life and your loved ones’ life easier and safer.
