What does the word dementia mean? Dementia is defined as an acquired syndrome of deterioration in cognitive abilities that impairs performance of daily living activities. From latin the meaning of dementia means to be out of one's mind. So family and friends, when you say that my "_______ has dementia." You are saying that your loved one has declined in their mental capabilities and cannot perform simple everyday tasks. Dementia is basically a very large umbrella term and includes so many diseases that involve the mind that I am only going to focus on one and name a few others you may have heard of. Dementia is a syndrome, not a diagnosed disease. A syndrome is more of a description of a group of signs and symptoms. A disease is a diagnosed impairment of health or a condition of abnormal functioning. They sound similar, but are not. The most famous disease that falls under the syndrome dementia is Alzheimer's Disease. It is pronounced, "Alls-Hi-Mers" not Altimers or old-timers. Haha. Just to make that clear. Saying words right I swear is half the battle of medical school. Other diseases that fall under the dementia umbrella are Huntingtons Disease, Lewy-Body Dementia, Creutzfeldt-Jakob Disease, Cortical Base Degeneration, Vascular Dementia, and numerous others.
So all dementia type diseases are based off of the parts of the brain they affect and the chemical signal malfunction that causes the disease. The human brain uses chemical signals, called neurotransmitters, to communicate information along nerves. These neurotransmitters are designed to control movement, make memories, modify behavior, control mood, and numerous other functions. Many chemicals have multiple functions. It not very cut and dry what each signal does and does not do. Neurologists have been piecing together the function of these chemicals in our brain and are making drugs that mimic these chemical signals or create higher amounts of neurotransmitters in our bodies. What you need to understand is that we really only know what these neurotransmitters do because when a person has a deficit in these neurotransmitters they do not function "normally."
If I haven't bored you guys yet just hang on. I am getting to the stuff that you can learn to teach your friends so you can humiliate them and make them look stupid in public when they act like they know what they are talking about, but they don't. Haha. Just playing, be nice! I am going to focus on Alzheimer's disease because I feel it is more important to know what that is so you don't confuse it with other terminology. I will organize the main points I feel are important into bullets. I like to organize and see my information placed in bullets when I study as it keeps my thoughts organized. Disclaimer: What I say is not perfect nor is 100% accurate. Most things are just too complicated to explain in a blog post. So I dumbed it down and generalized a few things. Don't go looking things up and being like, "well Glen actually...." I will seriously hunt you down and possibly slap you. JK. After these points I will put up a few pictures that will help you visualize what I may be talking about.
- Alzheimer's Disease
- Where does it affect the brain?
- Medial Temporal Lobe
- The medial temporal lobe, the medial portion of your temporal lobe, is located close to the middle of your brain. The temporal lobes are on the side parts of your brain. So if you slap your hand on the side of your head you are hitting your temporal lobe. In order to reach the medial temporal lobe you would have to take a pencil and put it in your nose and shove it at an angle of about 45 degrees vertical to hit your medial temporal lobe. Don't do that!!!! Sorry to be graphic.
- What does the Medial Temporal Lobe do?
- The Medial Temporal Lobe is in charge of memory storage, formation, and recall. Specifically the medial temporal lobe contains a structure called the hippocampus. This little structure is what forms memories. It is a loop of neurons/nerves that send signals around in a little circle that repeats itself over and over again. While the hippocampus runs in circles, your brain makes decisions on what part of the repeating loop it wants send up to your the rest of your brain to remember. So when you are trying to memorize something, for example the word, "Acetocholine" your hippocampus basically runs around in circles telling your brain that this word is important to remember. The more you say and see the word "Acetocholine" the more times the word runs in this little hippocampus circle and your brains recognizes it as being more and more important and will make it a memory. I hope that makes sense.
- How is the Medial Temporal Lobe damaged in Alzheimer's Disease?
- So when a person begins to have Alzheimer's Disease the hippocampus is damaged and the person cannot form new memories. The damage is caused by a buildup of misfolded molecules called proteins. These proteins are not just any type of protein you drink from a smoothie, but are proteins which are normally found in a healthy brain that have become corrupted and now harm your brain. Most of your brain is made a little healthy proteins. Proteins can be described as little microscopic chains of chemicals that are linked together. The proteins that cause Alzheimer's Disease are chains that have been broken or bent so they don't link together to form normal brain stuff. They end up forming tangles and knots, called Amyloid Plaques and Neurofibrillary Tangles, that disrupt the chemical signals from reaching their proper destination (see picture below). So in the case of the hippocampus, these proteins would break up the memory loop needed to form new memories. The person with Alzheimer's would then be unable to form memories for simple things, like recent events and instructions. Then as the disease progresses more of the storage system of the brain, which is located around medial temporal lobe, becomes damaged and the older memories are forgotten. I hope this makes sense.
- Interesting fact: Emotional memory, which is the ability for a person to recognize and express emotion, is the last type of memory to be affected by Alzheimer's Disease. So people with Alzheimer's are able to understand and express emotion until the very end stages of the disease. If you are around a person with Alzheimer's disease that individual will notice and respond to when you are getting frustrated, angry, sad, or happy even if they can barely talk, walk, or act "normal". Alzheimer's patients respond very well to stimuli that evoke emotion. For example, bringing a baby to an Alzheimer's patient can stimulate feelings of joy in that patient's brain, and you can see in the patients face that they remember that babies make them happy even though they might not even know how to say the word "baby" or even know who that baby is. Pretty cool!
- How is it diagnosed? It's complicated!
- The picture above show a brain scan of 3 people. The colors reflect the action happening in the parts of the brain. Red is highly active and blue is less active. The middle of the brain is more like relay center rather than a hard working factory like the rest of the brain so it appears blue. The middle portion is probably the most important part of the brain and just because it is blue doesn't mean it isn't working less hard. If you look at the blue part on the scan on the far left that is the two halves of of the medial temporal lobes. That is wear memory is formed and relayed to the rest of the brain. So as Alzheimer's progresses that part of the brain shuts down and becomes that black hole on the far right and that person loses all those memories and their brain fails to make sense of pretty much everything.
- Brain scans can be used to diagnose Alzheimer's, but the scans only take a snapshot of what is happening in the brain at that moment. So in order to really diagnose Alzheimer's with brain scans a person would need to go get brain scans often to show the disease progression. This is extremely expensive and most insurances won't cover this because imaging the disease will not really change the outcomes of the disease. Insurance feels if we can't cure it then why do we need to keep imaging it. In real life, if doctor's suspect Alzheimer's then usually it is just a wait and see what happens type of thing.
- Alzheimer's can only be officially diagnosed in two ways. The first way is by basically ruling out all the other possible forms of dementia through expensive imaging and then doing strict mental tests that often upset the patient before an official diagnosis can be made. The second and more accurate, quicker way of diagnosing Alzheimer's is through autopsy. Yes, only after you die can we say, "Yep you had Alzheimer's." That doesn't do much good, so most people opt not to have their family member get their brain removed after they die and just say what is done is done.
- How can we treat Alzheimer's Disease? It depends, and its complicated!
- Here are the top two FDA approved drugs that are "proven", I use that term loosely, to help with Alzheimer's and what they do:
- Donepezil/Aricept: well we don't know exactly how it helps Alzheimers, but I will explain what we think it does. The main chemical signal used in the hippocampus, the memory loop thingy, is called Acetocholine. The name is not important, just know that Acetocholine is what makes the hippocampus memory loop thingy go round and round. People with Alzheimer's don't have enough Acetocholine in the hippocampus because it is getting destroyed by overactive proteins called enzymes. Donepezil goes in and shuts off the enzymes that break down Acetocholine and therefore let the hippocampus run in circles to form memories. Wow I hope you guys can make sense of this!!! After a while though the damage from Alzheimer's gets bad enough to where it doesn't matter how much Acetocholine you have, the loop is broken so the drugs won't help.
- Rivastigmine: is basically a manufactured form of Acetocholine that gets transported from your gut, into your blood, and then to your brain to keep your Acetocholine levels high.
I hope this was educational and interesting. Send me questions if you have any. If you guys are curious about other diseases and medical things let me know and I will try to find answers. I have a ton of resources not many people have and I know google is great, but it often times isn't the best resources for current issues. I hope to check in every month and write about a few topics I have been curious about. I think next I want to talk about what to do when babies are sick and how to tell if it is serious or not. I think many people would enjoy that.
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