How dementia can affect memory

Incomplete storage

Most types of dementia start with a new kind of memory being stored.
This has the feelings about what has just happened, but without the facts to explain them.
The first such gap is just a brief moment without its facts.
These gaps happen more and more often.
In advanced dementia, a person’s most recent memories may contain mostly feelings,
with hardly any new facts being stored.

Retrieval - only what's there

People with dementia have not lost their minds;
their supply of new information is just getting patchier.
They need to find facts to fit their feelings, as we all do.
But fewer and fewer new facts are being stored,
so their recent memory has the most gaps.
If the newest facts are missing, the person can’t use them to make sense of what’s going on now.
The most reliable memories, with their facts intact, were stored before the onset of dementia.

If people try to use such old facts to explain their present feelings, they may appear to be living in the past.
But if we correct them, we will just show up their mistakes and make them feel even worse.