S lost the ability to tell the time some years ago. Then she developed an obsession with clocks and watches. She would want to buy every clock and watch she saw. She had an idea that she would be able to relearn how to tell the time. I had to call a halt eventually when we had about four - fortunately cheap - watches and a similar number of clocks. We had some heated exchanges as she could not remember how many clocks and watches we already owned. Often those she wanted to buy would not even have been suitable if she had still been able to tell the time - they had Roman numerals, or no numerals at all.
Now she still has some concept of whereabouts we are in the day but, for instance, the times when she wants to go to bed can vary between 8 and some time after midnight. Her getting up times are similarly varied. Often these things do not matter too much, though when I'm feeling tired myself and cannot get her to come to bed it's rather frustrating - there's absolutely no way I can go to bed without her.
In public discussion of the condition the focus on memory loss - the most obvious symptom - often leads to these other symptoms being overlooked. Everyone knows that eventually you 'lose your marbles' but possibly not everyone appreciates the gradually disabling effects of the difficulties that arise when the brain just cannot accurately interpret the information it gets from the eyes, for instance.