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Stages of dementia and Alzheimer's disease

Visit us (http://www.khanacademy.org/science/healthcare-and-medicine) for health and medicine content or (http://www.khanacademy.org/test-prep/mcat) for MCAT related content. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video. Created by Tanner Marshall.

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Video transcript

- [Voiceover] So, Alzheimer's disease, vascular dementia, Lewy body dementia, and every other type of dementia causes damage to your brain cells, right, which, in turn, causes some difficulties with various things your brain controls, like memory, language, reasoning, and judgement. But a lot of the time, these signs and symptoms can present themselves slightly differently. Since Alzheimer's disease accounts for the majority of dementia cases and the other forms can often overlap anyways, the main focus here will be on the symptoms and progression of Alzheimer's disease. Dementia in Alzheimer's disease typically develop over the course of years, but the speed at which it develops can vary pretty dramatically, from four years in some patients, eight in others, and even as high as 20 years in some cases. We're going to go through some of the general stages of progressing Alzheimer's disease, but considering that it's such a gradual disease, it's actually really tough to classify this progression. And it's important to remember that there are no clear-cut or well-defined stages, and many of these stages that we'll go through can even overlap. But, with that said, there are a few models that are used for the progression of Alzheimer's disease, and we're going to sort of combine the definitions from a more broad three-stage model and also the more specific seven-stage Reisberg Scale. So, from the three-stage model, we have the very early to mild stages of Alzheimer's, lasting about two to seven years. And then, if we look at the Reisberg Scale, stage one is simply no impairment. So, your memory and cognitive abilities appear normal, especially to everyone else. If there are any impairments, they might only be slightly apparent to the patient themselves. Stage two, however, is a very mild cognitive decline. So, maybe they have some trouble remembering recent events or information, but it could be more subtle things like forgetting a word or misplacing things. And, again, at this stage, these lapses and changes in thinking aren't usually detected by friends, family, or even medical personnel, especially considering half of all people over 65 begin noticing problems with concentration and word recall just as a normal consequence of aging. Stage three is signs of early confusion and mild cognitive impairment. At this point, subtle difficulties can start to impact their daily life. The patient might consciously or even subconsciously try to hide these issues. They might have trouble retrieving words, remembering what was just said or read, and planning and organizing, which can all start to affect life at home or at work. It could still be difficult, though, to diagnose Alzheimer's at this very early stage. Now, stage four is considered mild Alzheimer's disease. This stage lasts about two years. And during these two years, things like financials and math start to become very challenging. And the ability to remember recent events and what was just learned becomes increasingly difficult. The patient might have trouble carrying out tasks, especially if there are specific sequences, like cooking or driving. But the patients are still usually able to recognize their family and friends, although a diagnosis at this stage is usually accurate. Stage five is considered early dementia to moderate Alzheimer's disease. In this stage, cognitive decline starts to become more drastic, and the patient requires assistance. They'll probably have trouble remembering things like address or phone number and can be disoriented very easily regarding the time or place. Decision and judgement skills can also be affected, like choosing the appropriate clothes for the day or season. And so, the patient may need increased supervision. This stage can last an average of about 1.5 years. Stage six is considered moderately severe Alzheimer's disease, and in this stage, there's a significant lack of awareness of present events, and this inability to remember the past and carry on a conversation, and they'll likely need help with basic daily tasks like getting dressed, eating, and going to the bathroom. The patient will likely be unable to recall names of family members but will likely know that they're familiar. This stage lasts about 2.5 years. In the final stage or stage seven, speech becomes severely limited, and we see a serious decline in basic abilities. Even movement abilities begin to be affected as the disease has started to spread to those areas of the brain, so eating, walking, sitting, or even standing up all start to fade. And patients will likely need extensive assistance eating and drinking, as they can lose the ability to discern when they're thirsty or hungry. And so they need total assistance around the clock for all functions of daily life and care. And at this stage, due to these inabilities, they become much more susceptible to secondary complications, diseases and infections, especially pneumonia and falls. And this final stage can last from one to two and a half years. But, again, it's very important to stress the flexibility in this timeline, in these stages. Not all patients with Alzheimer's will experience this exact progression, and some may deviate significantly from the expected duration with each stage and the disease itself.