This reason that this question is so hard to answer is that for each person who
has Alzheimer's, there is a different reaction or symptoms. Not all Alzheimer's progresses at the same rate. Effect people the same way. Or limit people the same or cause the same problems in each AD sufferer. As everyone's life experiences are different. And, as everyone's brain is different. You can see why you may ask this question to a hundred people and get 100 different answers that are for the general part,,,similar, yet none the same. Now I know that this is a rather vague answer. But, then again your question was again a little vague also.
I think that what you are asking is that, do AD patients remember long ago and do they remember it with more clarity than the present? The answer is yes and no. They remember long ago, yes. Do they remember it clearer, well "no", not really. See, it's not so much that they are remembering events like you and I would remember a baseball game we attended 40 years ago. It's more like they are watching the baseball game on TV and wonder why you don't see Babe Ruth also? "Well, there he is, right there you idiot, don't tell me you can't see him?" My mom didn't remember what her girlhood house looked like. But, she did want to go "home" to her "mom and dad" 'cause she was tired of playing at my house and her mom would worry because she had never stayed away from home this long before.
No, people are not actually remembering the past so much as they are caught in a time loop and they are LIVING in the past, in the here and now. The past is the present to them. You may ask me who the president is, I'd say George W....ask my mom and it could be Hoover or FDR. That's just the way it is. It's paticularly horrid if someone has been abused in childhood or their early years. This is especially horriable for them to relive that horror, everyday as if it is happening again, right now. It's not that today is hard to remember. I found that in most cases with digression that today, indeed, has not happened yet! And, no matter the degree of digression, if it's 1940, 1960 or yesterday,,,,,the brain is not connecting properly so facts will become less clear, not more clear as time and brain damage progresses. Not only do they digress back into time, but time and events become muddy and confused in a tangle of short circuts and electron miss-fireings, that short out in a tangled and confused mess. My mom used to love to go danceing. And in the present, right now, she was bed-ridden and 82. One evening as I tucked her in for the night she said, "CAll the boys will you, and tell them that we can't meet them tonight? I am just exhausted and just don't feel like danceing." I told her that I was also tired and didn't feel like danceing tonight either, and that I'm sure that the "boys" will understand and we can always make it another night. She was grateful for that. And she went right to sleep.
The human brain is a marvelous thing. It's just so sad and heartbreaking when it turns against you. And even harder still when it takes the one's that you love away from you, (inch by inch, cell by cell). And, especially when THEY don't even know it. It truely is a "LIVING DEATH".
I am sorry, but I can't be of much help. Everyone, you see, is different. I went to a Alzheimer's seminar last Spring. They said to think of Alzheimer's as a window blind. With the blind up all the way, it's today,,,,,today in space and in time. As the AD progresses, the blind slowly lowers. And, as it lowers it becomes just that much farther back in time for the Alzheimer's patient. You could also say that as the blind lowers, that there is just that much less life ahead also for that person, as we ALL have only a finite time on this earth. With the blind down half way the person will be in a mid-life time line. They may find that the home that they are living in now doesn't look like the one in 1950, or in 1962. They may want to know where someone is that died many years ago, and they may not even recognise people in their lives who are less than 20--30 or 40 years old, (because of course, they havent been born yet). Also, none of us look like we do 20-30--40 or 50 years ago, even if we are still alive. So, we may be mistaken for an older relative. (My girlfriend is mistaken as her mothers sister, because her mother has digressed to a state before her children were born ,and her sister died young. So, once a week her mother visits with her "sister" for a few hours. What harm is there in that? Once my friend found out, how and why her mom's brain worked, she no longer felt slighted by her mom's not recognising her. And was just glad to bring a smile to her mom's face every week, as she posed as her own dead aunt and happily chats away with her mom).
Alzheimer's is a crazy diesase. My only suggestion is to not curse what it has taken away, just be ever so greatful for what is still left.
Hope this helps,
Gizmo