When the person with a cognitive disability talks more than a few sentences, their identity begins to be obsolete right after the onset of a cognitive disability. They honestly believe that they can still do things just like they used to do them, and will swear to it in court.
Underlying the stories and activities is a person who still thinks that they are the same as they used to be. Their worldview is so odd that it is reminiscent of a science fiction movie with time travel into the past. Their view of the world and of themselves got trapped in the past, before the onset of their cognitive disability. The strange and confusing observation is that their overall worldview is partially right and partially wrong. Understanding their stagnant identity removes some of the confusion.