When an 86-year-old man is admitted to your rehabilitation f…

When an 86-year-old man is admitted to your rehabilitation facility on Tuesday morning with deconditioning following a prolonged hospitalization, he is awake, alert, and oriented to person, place, and time. While you are rounding on Wednesday morning you notice that he is slightly difficult to arouse and falls asleep several times during your exam. When you ask him what the date is he tells you his birthdate. When you ask for the current year he tells you it is 1989, and he cannot tell you the name of the city. Later in the morning he is more awake and is again oriented to the correct time and place.  Which of the following factors lead you to think he may be experiencing delirium?