Alzheimer's Unraveled

To fully understand what dementia is, we need to start with a basic foundation. The term dementia, in and of itself, is not really a disease. It is a term that describes symptoms of cognitive decline. For example, if a person has deficits in their short-term memory and one other areas of cognitive function, such as their ability to use language, they may be said to have "dementia". Again you are describing the symptoms, but not really identifying the underlying cause. For instance some people labeled with dementia actually have a true progressive condition, like Alzheimer's disease, while others have underlying medical conditions that can be addressed, like a vitamin B12 deficiency, infection, etc. Even something as simple as poor sleep patterns or urinary tract infections can make older adults seem like they have dementia. The key to effective treatment is to find the true underlying cause of a person's "dementia". Another way to think about it is to imagine you suddenly experience back pain so you go to your doctor. He examines you, notes that your back hurts and diagnoses you with "back pain". That doesn't really tell you anything does it? You want to know if you have slipped a disc, pulled a muscle, pinched a nerve, etc. In the same fashion, if you have a deficit in your memory and other cognitive functions, visit your doctor and get labeled with "dementia", that doesn't really give you a lot of information does it? You want to know, is it Alzheimer's disease, is it a vitamin deficiency, is it a brain tumor....what is happening to me?! Our job as family members and advocates is to push our doctors and medical support teams to find the root cause of the issue. Only then can we actually hope to fix the issue or at least prepare for its progression accordingly. The problem is most of us aren't neurologists or specialists, so how can we feel comfortable advocating for our loved ones? The doctors are the experts right? Not necessarily. Don't get me wrong, physicians are a great resource and we should consult them at every phase of our loved one's care, but as consumers we must realize that very few medical programs in the United States require specific training in the area of geriatric medicine. In most cases the typical physician takes one elective course dedicated solely to geriatric medicine during training and receives little continuing education in this field following graduation. To this point, we must always involve multiple professionals in our loved ones care and we ourselves need to be as educated as possible. I hope the Dementia Connections blog can be another tool you use to gather the information you need to make educated decisions about your loved one's care. Let's get started by talking about the root cause of Alzheimer's disease and how it progresses. Alzheimer's disease is still by far the largest cause of true dementia accounting for up to 70%+ of reported cases depending on what research you cite. Since Alzheimer's is still the biggest bully on the block, we'll unravel it first to serve as a good foundation for understanding other forms of dementia in the future. To understand what goes wrong in the brain of someone who is diagnosised with Alzheimer's disease, we must first understand how a "normal" brain typically works. Don't worry, this isn't a neurology classroom. Let's keep it basic:) The basic building blocks of the brain are called neurons. That's just the fancy terms for the cells that make up the brain. Neurons work by sending chemical signals back and forth. These chemicals, called neurotransmitters, send messages throughout the brain. Some neurotransmitters, like Dopamine, deal with movement, others, like Serotonin, deal with mood and yet others, like Acetylcholine, deal with cognition. As long as these cells are healthy, working well and sending signals back and forth, the brain works normally. In Alzheimer's, however, this communication between cells in interrupted. When cells are damaged and can't communicate with other cells around them, they actually start to die off. In Alzheimer's disease, the interruption of communication between cells occurs due to the build of a common protein in the brain called Beta Amyloid. In most people, Beta Amyloid works within the cells in the brain, breaks away from the cells and is then removed from the brain during the normal process of cerebrospinal fluid washing over the brain and removing waste and by products. Don't freak out, it's happening to you right now!:) The problem is, if you have Alzheimer's disease, when these Beta Amyloid structures break away from cell they aren't shaped correctly and actually become sticky and toxic. There are some genetic factors and cell damage brought on by life style choices, diet, exposure to environmental stimuli, etc. that play a role in why this may happen, but that's a whole other post. For now, just picture these sticky toxic structures floating around in the brain and when the cerebrospinal fluid comes to wash them away.....you guessed it, nothing happens. Over time they build up and form what most people refer to as "plaque". As this plaque builds up it begins to interrupt the cells ability to communicate with each other. Imagine trying to pass a note to someone in class, but a wall of plaque is in the way and no messages can get through. The other person will never receive your message and therefore can't respond or act on it. Same thing with the cells. At first they have trouble receiving the message timely and eventually they stop getting it altogether. You can see an artistic rendering of this plaque build up around cells below. This image can be found at www.alz.org under the brain tour section.

While the "plaque" is building up around the cells another process starts taking place inside them to further complicate matters. Another protein, called Tau, which helps give the cells their shape, starts to break down causing the cell to tangle on itself. Thus you have "plaques" and "tangles" in the brain that interrupt the neurons' ability to communicate with each other. When this happens, neurons litterally start to die off. That's right, an individual with Alzheimer's disease is actually losing brain cells. By the end of the process an individual's brain upon autopsy can lose up to 1/3 of it's original mass. Please see the image below.

If you understand this basic premise, that cells are dying and therefore they can no longer do their jobs, then the next logical step is to see where the cells are dying in the brain and learn what their jobs actually were. Think about it. If the cells in your leg were dying, you would anticipate having difficulty doing things like standing and walking because you know what your legs do and how they work. We can take that same idea and apply it to the brain. We know through autopsy and specialized imaging of the brain that the first cells that start to die off in individuals with Alzheimer's disease are found in the Hippocampus. Don't worry if you've never heard of that term, just focus on what its job is. The Hippocampus is a tiny structure in the brain that helps encode new information. I.E. it is the gate keepr to your short-term memory. Picture him as the bouncer standing at the door of a venue you want to get into. If you come up and seem important, he lets you in and directs you where to go. If you and a group of 100 other people swarm the door all at the same time, he will let the important people in and everyone else has to stay outside. So if you apply this to memory, the Hippocampus takes in new information and, if it is important, it sends it off to other places in the cortex (the outer brain, the outside layer you think of when you invision a brain) to be stored. Too much information flooding in at one time, it captures as much of the important stuff as possible and the rest is never encoded, i.e. forgotten. Think about it. Do you remember every word of every conversation you have ever had. Every word of every book? Ofcourse not. Our brains prioritize, take in what they can and keep on moving. So now that we know what the Hippocampus does for a living, think of the repercussions if the cells that formed the Hippocampus started to die off. At first it wouldn't be an issue as we have so many redundant or extra cells in the brain as a safety measure against injury, but over time the function of the Hippocampus would be impacted. What would that look like in real life? Remember, understand the brain and you understand behavior. If the structure that controls access to new information/short-term memory stops working properly, then you begin to notice someone having difficulty with their short-term memory. Make sense? Think about it. What were the first symptoms you noticed in your loved one or yourself. Your memory started to change. See why? Now if Alzheimer's stopped there then people would only have trouble with their memory, but unfortunately the process we reviewed above continues to march throughout the brain. From the Hippocampus, it marches into the frontal lobe (front of the brain) and the temporal lobe (side of the brain) causing cells to die in these areas too. Without going into too much detail, the frontal lobe controls executive function. Think of things like attention, abstract thought, complex problem solving, calculations, etc. The temporal lobe controls our ability to understand language, produce the words we are thinking of and even has a role in our orientation to time and place. See the pieces of the puzzle coming together? Use the image below from the Alzheimer's Association Brain Tour (www.alz.org) to visual the process of cell death advancing throughout the brain, think about what those areas control, then think about your loved one's progression. Did they first have memory problems that got progessively worse, then you noticed they had trouble doing more executive functions, like balancing a check book or not acting impulsively, then you noticed they seemed to be having trouble following general conversation and made mistakes or switched words when they spoke. Then came disorientation to time and place. Do you see how the behaviors that we see overlap perfectly with what is happening in the brain?

In the image above you can see the progressive cell death represented by the areas of blue in the brains. It starts centrally in the Hippocampus and steadily marches out as we have previously described. You can see it is a slow, systematic patten that actually makes the general characteristics of Alzheimer's disease, as horrible as they are, fairly predictable. You can see as the blue areas leave the side of the brain (temporal lobe) they move into the back of the brain (occipital lobe) that controls processing of visual information. Because of this, even if your loved one has no issues with their actual eyes, they will begin having difficulty visually making sense of the world around them. One of the first hallmarks is the development of tunnel vision, which we will explore in future posts. From there it marches through the upper cortex impacting the motor strip, first robbing individuals of their fine motor skills (like manipulating small objects) and then impacting gross motor skills (like the ability to walk), and the parietal lobe. The parietal lobe deals with our ability to process and understand sensory information from the environment. Thus someone losing cells in this area will have increasing issues with balance, may not tolerate uncomfortable clothing items, loud noises, bright lights, etc. You can see that if Alzheimer's disease is allowed to progress, it eventually impacts every area of the brain. This is why we see the later stages of Alzheimer's disease impacting even basic functions like the ability to swallow or turn in bed. As devastating as the effects of Alzheimer's disease are, their predictable nature allow us to compensate for deficits, maximize remaining abilities and make individualized adjustments to our loved one's schedule and care to maximize functional ability and quality of life. Now that we have addressed the basic underpinnings of Alzheimer's disease we can take a more detailed look at the various stages we described above and offer real world strategies to maximize independence at each phase. Please look for my next post as we explore the Global Deterioration Scale, a quick tool that helps us see where our loved ones are in the disease process, and discuss ways to STAY CONNECTED!