Answer by Jae Starr, 15-plus years working with Alzheimer's and related dementias:
This is an excellent question, and one I've considered often in the last decade-plus of working with such folks.
First, it depends upon the stage of dementia: mild, moderate, or severe.
In mild dementia, it seems to be like being a functional alcoholic's day, as far as cognition goes. You're able to do what you need to do, but some little things get missed, such as your T-shirt is on backward, but you don't notice, or you can't find the sugar bowl, so you start taking apart cupboards and end up going without coffee and the kitchen is a mess. Later, you swear you did not do that. You have no memory of doing it, and the more another person argues that you did indeed make that mess, the angrier you get. You did not. He or she is lying.
The whole day goes like this—close to normal, but not quite. Routines are easy, but anything new is more difficult. And, if asked about someone or thing from earlier in the day, you may or may not remember the event. By the end of the day, you're tired of thinking, but your brain keeps throwing up odd thoughts and ideas—things like, "I can't find the car keys. Someone must have stolen them! I need the car keys." You may wander, rummage, pull things out of drawers for a couple hours, at the end of which you may be unable to tell anyone what it was you were searching for. Even more telling, you may not have driven a car for the past five years.
During moderate dementia, each day is more moment to moment, and routine is your friend. Anything that is routine is easier for you to experience. Breakfast, lunch, dinner—that's how your day is scheduled. But something out of the ordinary, like a doctor's appointment, can throw you. You may balk at going, at getting dressed and getting in the car and going. There's so much mental stimulation involved in such a nonroutine event that you prefer to stick to what you know: breakfast, lunch, dinner, and maybe sitting in the sun, watching the world go by.
Activities like taking a shower can become difficult for you. If you think about it, a shower is an event that is very high in stimulation of all sorts. The bathroom is very separate from your normal living space—usually hard-edged and cold-seeming. Then you must take all your clothing off—that's just a lot of stimulation itself, and the memories loosely associated with nakedness are also fraught with stimulation. The shower makes noise, the temperature difference is apparent, there's soap and shampoo and the scrunchie thing, water in your eyes, your ears, the space is confined, and by this time someone is usually in there with you, "helping," which is just weird, no matter how much you understand and accept that you need help. It's one diagnostic sign of moderate dementia: You may start to not like to be washed and clean—shower or bath.
I remember a gentleman in the facility I worked at in Washington state. He was new and hadn't been showered at the hospital, so on his first full day, the aides gave him a shower. He spent the rest of the afternoon in tears because, "They threw me in the corner and pelted me with rocks like a piece of trash!" That's what he felt like. Another woman would walk up and down the corridors but stay far away from windows, saying "There's Indians out there! They're going to attack!" It took a long time to figure this one out. She would pace and pace and could not sit still, always talking about Native Americans shooting arrows at us. Finally a nurse asked her if she had been hit by an arrow. Yes, she said. Where'd they get you? Right here, and she clutched her low back: Arrggghhhh! It hurt so much! Going through her medical history a bit closer, we discovered she had been in a car accident years before and suffered a low back injury. She'd been telling us for weeks what was happening to her, but not in a way that made sense to us. To her, it made perfect sense: It felt like an arrow in her back. And who used arrows? American Indians.
You are losing words, but it doesn't matter much since those around you ignore that loss and fill in the blanks. Sometimes you cannot understand what someone else said, like he is speaking a foreign language, and this can make you automatically refuse whatever is being spoken about—that, too, makes a certain amount of sense. Someone babbling to you in a foreign language and making "Come with me" motions is someone to view with suspicion, don't you think? Moderate dementia is usually the longest part of the disease, which is why I'm spending so much time on it.
The slow slide into severe dementia is sometimes difficult to spot as far as an actual line of demarcation, but one sign is sleeping more and more often. Even during formerly pleasurable activities, such as familiar and enjoyed music, the damage to your brain is so profound that the stimulation is not enough to keep you awake. You sleep, perchance to dream, but we don't know. We know that damage to the areas that are usually lit up like a Christmas tree during dreaming is profound, but since we don't really understand sleep or dreaming, it seems rather cruel to take someone who doesn't do well in new situations into a sleep lab and wire his brain for sound and color, stick him in a tube, and say, "Don't move." So we don't know. But that is one of the things I've always wondered about; it seems to me by the time you are in severe dementia, the difference between awake and dreaming is invisible.
Speech is limited. You may have a full thought in your head, but only one or two words come out, if any. Caregivers learn to listen for the first two or so words and try to discern what the thought is from there, because that's usually all we get. Eyesight is odd; you don't know what it is you are seeing. My current furthest-along-in-Alzheimer's resident recently did not recognize a puppy. She saw it, she gazed at it, I placed her hand on it, but she looked at her hand and not the puppy, and there was absolutely no engagement between her and the stimulation provided. She no longer hears music, which is a shame, because she loved music her whole life long. We still play it for her, and we still put on her favorite musicals, but there's no engagement anymore. She does not hear or see any of it other than perhaps a fleeting spark of memory, now gone.
In severe dementia, everything is moment to moment. Routine means nothing anymore, because there is no past or future, only now.
And then you start your last slide into end-stage dementia; you sleep 23½ hours out of 24, and when you are awake, you may as well be dreaming. You do not meet anyone's eyes. You do not react in any manner to much beyond very painful stimulation. You are almost gone. We try to feed you, but you don't seem to know what to do with the food in your mouth, and you may choke, which could result in aspiration pneumonia—never a good thing. Your urine output drops, peristalsis decreases, and your body temperature may rise. And as your organs start to shut down, you sleep, and sleep, and sleep, and slip away, very peacefully. You're gone.
That's what Alzheimer's-type dementia is like.
More questions on Quora: