Have just been reading online about extremely slow progression of this disease. Wondering if anyone else knows about this.

My parents have apparently the slowest progression imaginable. Looked it up just now and this is apparently really rare but it does happen.

First symptoms were in their early 60's.

Anger/forgetfulness combined. Arguing with me about what they were forgetting, etc.

Took until their 80's to noticeably progress.

Now they are in their 90's and the progression is increasing.

They were not diagnosed with any​thing when it first started and are still only diagnosed with "mild cognitive impairment" now but have many symptoms that are basically classic Alzheimer's symptoms such as claiming I am lying and a liar and calling either or both of them a liar, etc.

They are still aware of their surroundings and know what is going on and have so far opted out of any additional testing. There can be no additional diagnosis without it.

Both parents have always been intelligent and have a high level of education.

This cannot slow the actual progression of the disease, most likely, but can increase their ability to mask it.

This is very likely what has been going on.

Online information suggests these same conclusions so far.